Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS2642943 A
Publication typeGrant
Publication dateJun 23, 1953
Filing dateMay 20, 1949
Priority dateMay 20, 1949
Publication numberUS 2642943 A, US 2642943A, US-A-2642943, US2642943 A, US2642943A
InventorsRobert L Smith, Kenneth M Watson
Original AssigneeSinclair Oil & Gas Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Oil recovery process
US 2642943 A
Images(9)
Previous page
Next page
Description  (OCR text may contain errors)

Patented June 23, 1953 OIL RECOVERY PROCESS Robert L. Smith, Western Springs, and Kenneth M. Watson, Madison, Wis., assignors, by mesne assignments, to Sinclair Oil and Gas Company, Tulsa, Okla, a corporation of Maine No Drawing. Application May 20, 1949, Serial No. 94,506

3 Claims.

This invention relates to improvements in the production of oil and gas from oil-bearing formations, and more particularly to an improved method for recovering gas and oil from partially depleted oil-bearing formations by thermal means.

It is well known that the recovery of oil from producing fields is in general an incomplete process. The production of oil from subterranean oil-bearing formations requires available energy and its efficient expenditure. Where natural sources of energy such as high formation gas pressure or natural water drive have existed and have been coupled with efficient production methods, recoveries have been said to run in rare instances as high as 70% to 80% of the original oil content. In general, however, it is a matter of common knowledge that recoveries of oil have rarely exceeded 25% to 40% of the original oil content, and that vast quantities of oil remain in the produced fields of this countary and the World, even though some have been produced steadily for 25 to 40 years. For example, the Nowata County field of Oklahoma is a relatively shallow field underlain by a portion of the Bartlesville sand averaging about 30 feet in thickness at a depth approximating 600 to 800 feet. This field has been in production for about 40 years, and yet it is estimated that only 44% to 46% of the original oil content has been recovered, say about 17% by primary methods including vacuum, 17% to 19% by gas and air pressuring, and say by water flooding where this has been applied.

Since the very early days of production of oil from subterranean formations, thermal methods for improving recoveries by lowering viscosity and through distillation and cracking have been proposed. Despite the theoretical soundness of some of these proposals these methods have proved characteristically impractical because of the high heat consumption required to improve recovery, for these methods have depended upon heating the entire underlying oil-bearing stratum to the temperature at which the desired improvement in flow would develop, and often have required combustion of substantial proportions of the recoverable oil to Warrant consideration at all.

In contrast to these methods, we have now discovered a method of recovery embodying the advantages of the old thermal schemes but which is characterized by propagation of a high temperature zone coupled with an approximately coincident internal combustion wave front within the oil-bearing formation. The high temperature zone is expanded in a relatively horizontal direction within the formation in such a manner as to sweep out residual oil by force of a heat transmissive gas flow. The combustion wave front is continuously or intermittently generated within the formation and maintained in an approximately coincident relation to the high temperature zone or heat transfer wave so as to continuously or intermittently revivify the heat content of the expanding hot zone.

Thus we propagate a high temperature zone within the formation by forcing hot combustion gases into the formation from an inlet well under elevated pressure for a period of time sufiicient to heat up the surrounding sand structure and produce gas and/or oil flow from one or more nearby outlet wells. The hot gases preferably derive from bottom-hole burning, that is, from the burning of fuel at high rates of heat release at formation level in the input well. When a high temperature zone surrounding the inlet well for a considerable distance has been established, fuel burning is discontinued, and the movement of the heat zone horizontally out into the formation is continued by cycling cold gases through the inlet well.

We have found that a small percentage of asphaltic or carbonaceous material usually remains in the porous structure following passage of the hot gases. For example, purging of an oil sand having a porosity of about 20% and an oil and connate water content of about 2.25% each with inert hot gases at temperatures ranging up to about 1350 F. leaves about 0.5% residual carbon on the sand. This material constitutes a non-recoverable residue, but we have found that it can be ignited and is burned at elevated temperature, say upwards of 450 F. to 500 F., by flow of air or oxygen-containing gas so as to regenerate or revivify the heat transfer zone in compensation for the dissipation of its heat values resulting during its progress out into the formation.

We have found that this residual carbon represents a valuable fuel for improving thermal recovery if it is burned in such a way as to add its heat values to the heat values put into the formation by burning start-up fuel. For we have found that arelatively high temperature, say above about 700 F., is needed to effect practical improvements in oil recoveries after ordinary methods of secondary recovery as by water drive or gas repressuring have reached a point of diminishing return. Yet the dissipation of heat within the vast underground volume of the formation as the ring of the heat transfer zone is expanded from the input well is large even with closely situated output wells. We have found, however, that we can continuously or intermittently revivify the degenerating heat transfer wave by burning the residual carbon left in the sand in a relatively narrow band or moving combustion wave that approximately coincides with the moving heat transfer wave in point of position and rate of movement. For we have discovered that the rate of movement of the combustion wave relative to that of the heat transfer wave primarily depends upon the oxygen content of the driving gases and the residual carbon content of the sands, and that we can obtain the desired coincidence in rate by limiting the oxygen content to a small proportion. It is important that the relative movement of the peak hot zone and the combustion wave be controlled because otherwise the heat values of each will be independently given up to the structure. Thus if the combustion Wave lags behind the heat transfer wave, the heat generated primarily goes into elevating the temperature of that portion of the formation which has been already swept, and the temperature peak is reduced. If the combustion wave ranges too far ahead of the heat transfer wave, the peak again falls off and finally combustion is lost in the too rich and too cold environment of the outer fringe.

In one method of operating according to our invention, therefore, we include in the cold cycle gas drive up to about 5% to 6% of oxygen. The

heat transfer wave is continuously projected out into the formation so as to sweep out the oil and is continuously revivified by the recuperative capacities of the cycling gases in picking up preheat from the swept out portions of the formation and then igniting and burning the residual carbon in the sands in the approximate zone of peak temperature.

We have also discovered that we can intermittently revivify the heat transfer wave by cycling 1 produced gas from outlet Wells or other gas of low oxygen content to advance the heat zone until heat losses reduce the frontal temperature to a point somewhat above the ignition temperature of the carbonaceous residue in the sands. At this point we revivify the heat front by introducing sufficient air or other oxygen-containing gas with the cycling gases to reinitiate combustion or raise the combustion level of residual carbonaceous matter in the zone of high temperature so as to replenish the heat content of the frontal area. Large bands of unburned carbon may be left behind, if desired, to avoid overheating the structure in this cyclical method of operation. Thus by skipping bands of residue, control is bad on the average per cent residue burned, giving an additional measure of control on the rate of the combustion wave.

Thus, according to our invention, the cold cycling gases entering the inlet well are heated as they move through the zone of previously heated sand, leaving cooler sands behind. Heat is thereby recovered and the heat front is simultaneously advanced, for the regenerated heat is transmitted to the cold sand in front of the previous hot zone. In this manner the high temperature Wave is continuously moved forward, and a heat wave is created within the formation by the heat transmissive flow of the hot gases followed by the heat regenerative flow of the cold cycle gases which give up the regenerated heat to the structure in advance of the moving wave front. Since the non-recoverable carbon residue is left behind the advancing front, it may be burned in a relatively narrow band, forming a combustion wave behind the moving heat wave so that a minimum of recoverable oil is consumed. As the frontal zone progresses in distance from the inlet well, the flow rate may be increased. The flow rate requirement may be reduced by a limited use of water injection.

We have found that good recovery is effected at operating temperatures within the range of approx mately 700 F. to 1000 F. Combustion of the residual matter will occur as low as 450 F. to 500 F. but it is Weak, and even at 600 F., the burning band tends to be too broad in area and slow moving for good revivification. In addition, mild cracking begins at about 700 F., reducing the gravity somewhat. Accordingly, we prefer to maintain a temperature above about 700 F., but under the fusion or sintering temperature of the structure, which is ordinarily somewhat above 2000 F. to 2500 F. Ordinarily, incipient sintering below the fusion temperature does not adversely affect permeability. Oil recovery improves with temperature. For example, the percentage of oil produced from Nowata oil sands of about 20% porosity and 2.25 weight per cent oil content approximates 50% of the oil present at 900 F. under an inert gas flow of about 275 cubic feet, per barrel volume of sand per hour while at 1350 F. the recovery approximates Similarly, the desorption of connate water increases with temperature and rate of flow, although the percentage produced is of a significantly lower order under the conditions described.

We have also found surprisingly enough by physiochemical analysis of typical oil sands that, although most of the material is crystalline quartz, as high as 10% or more is porous, high area adsorptive clay, and that substantially all of the oil and water is associated with this portion. It may be that the primary function of the elevated temperature, 1. e. upwards of about 700 F., in recovering oil from exhausted oil sands is to break an adsorption complex between a relatively adsorptive matrix for the crystalline sand, such as kaolin, and water and oil rather than merely to promote flow by cracking and distillation.

Of course, the before-mentioned methods of operating require the presence of sulficient residual carbonaceous matter in the sands to provide fuel for revivification, which is usually the case (or depend upon building up a sufficiently large body of heated sand in the formation). In those other cases, e. g., fields of good permeability bearing high gravity crudes, we intermittently introduce fuel gas along with the oxygen-containing gas. The mixture does not ignite until it contacts the zone of high temperature, since the sands between the frontal zone and input well are cooled by prior cold cycling. Thus this method of producing lean formations requires the preceding cycling of cold gas to produce a sizable area of cooled sand, otherwise burn-back of the incoming mixture to the well will occur with resulting heating of the entire structure and prohibitive expenditure of heat values as well as excessive pressure drop.

As a result of applying the methods of our invention, a moving region of high oil saturation is set up ahead of the moving heat front by reason of the greater susceptibility to flow induced by the thermal effects of cracking, vaporization, and viscosity reduction assisted by the drag effect of the flowing gas. By cooling and condensation, the ases and oil give up heat to the cooler sands in front of the hot zone so that the progression of the high temperature front is maintained. As the region of oil saturation approaches an outlet well, oil under gas pressure flows or is pumped. from the Well.

Since the strata overlying and underlying oilbearing formations are impervious while the formation is relatively permeable, there are no heat losses by convection. Losses by conduction are usually small because of the low thermal conduc-.

tivities of shale and other materials commonly found as bounding strata. Moreover, some of these heat losses will be returned to the formation and picked up again by the cold gas flow. However, suficient gas drive must be maintained to prevent immobilization of the front, or conduc tion losses may become prohibitive.

It should be observed that the travel of the hot zone radially outward does not in itself ordinarily result in a temperature decrease. Although the vertical area of the zone broadens, the heated mass remains the same. The sharpness and height of the temperature profile then remains the same if the sand is uniformly permeable and if the actual heat losses are exactly compensated for by combustion of deposit. The most important effect in causing lowering of temperature and broadening of the mass of the heated zone is non-uniform permeability. That is, both Waves move rapidly through a highly permeable streak, hence heating it up before the adjacent and less permeable streaks but losing heat to them by con' duction, thus lowering the temperature level and increasing the mass of the heated zone. For this reason it is important to keep both waves as close together as possible.

In practicing our invention the high temperature front is propagated within the formation by burning fuel, conveniently natural gas or crude oil, with air at high temperature either on the surface, or preferably within the hole. The resuiting combustion gases under elevated pressure are forced into the porous oil-bearing stratum for a length of time sufficient to raise the temperature of a large body of sand surrounding the well to a temperature below the fusion temperature of the structure but well above the ignition temperature of the residual carbon. At the same time, the formation is partially rte-pressured with resulting now of cold oil and gas from one or more outlet Wells.

During the fuel burning period, there is normally a large excess of oxygen in the combustion continuous and uniform combustion. However, a jet-type, spark ignited combustion system with a high velocity, turbulent air and gas flow in which a relatively large volume of diluent air gas is introduced progressively into the burning zone provides perhaps the most convenient and reliable bottom-hole system. Recycle gas may be utilized as diluent after the temperature has been built up, and Where gas compressors are employed, the compressor exhaust may be utilized as recycle or diluent gas.

The inlet pressures will vary according to the distance between producing and input Wells, the thickness and permeability of the oil-bearing stratum, and the oil and water content of the formation. Similarly, the quantity of gas introduced will be affected by the desired pressure. temperature of the input gases, and the con ditions and heat capacity of the oil-bearing stratum. The pressure for example .Will ordinarily exceed 60 p. s. i. g., but because of problemsof reservoir control, is maintained at a moderate figure, and, of course, is ultimately limited by the over-burden. To minimize plugging or cementing of the porosity of the formation, after-scrubbers or other filtering devices should be employed on compressors in order to remove iron rust or other troublesome carry over. Similarly, it is desirable to incorporate similar devices in the liquid knock-out system employed for handling recycle gas The gas produced is recovered and after recompression to compensate for pressure drop is recycled. Maintaining superatmospheric pressure on producing Wells markedly reduces power costs for recompression in recycling operations. Depending upon its fuel content, the produced gas may be burned as fuel or utilized as flue gas recycle. Naturally, readily liqueriable or other valuable components may be recovered as by ab sorption prior to utilization as recycle.

Pressure drop is desirably kept low and may be controlled by keeping the volume gas rate low and by operating at a high pressure level. Use of water as the principal heat carrying medium serves to keep the volume rate and pressure drop low except in the heated zone, but may require emulsion breaking to avoid plugging troubles. The rate of oil production ordinarily should be high to minimize the proportion of labor and capital expense, although this consideration con= gases because of the use of dilution air in the burner system, which insures clean combustion and prevents the formation of soot that might clog the structure, and additionally assists in heating up the structure by burning carbonaceous residue and some oil.

The use of a bottom-hole burner is advantageous because it eliminates the need for expensive fiicts with most other considerations except that of heat losses to the bounding strata.

When a high temperature, say about 1500 F. but advantageously in the range of about 1000" F. to 2000 F., has been established over the area surrounding the inlet Well, we discontinue the input of hot combustion gases, but continue gas flow by increasing recycle, or admixture of air with combustion gases produced from outlet wells. The cold gases are heated by moving through the zone of previously heated sand, at the same time cooling the sand in back of the previous hot zone. The heated gas and oil vapors at the same time heat the sands in front of the previous hot zone, thus maintaining a heat transfer Wave. With oxygen-containing gas drive, the combustion wave is established by burning residual carbon under the temperature prevailing in the heat transfer wave, and the combustion. Wave is maintained in the zone of peak temperature by regulating rate through control of oxygen content and the rate of gas flow. For example, We consider a total gas input of about 500,000 standard cubic feet per day per well and an oxygen content of from about 1.33 to about 5.0 per cent particularly desirable. With nonoxygen containing gas drive, the temperature in the peak zone is intermittently raised by introducing cold air into the circulating gas stream as it falls off.

Residual carbonaceous matter in the sands burns in a relatively narrow zone determined by depletion of the oxygen at the front and the combustible at the back. Thus this burning zone also travels forward as a wave, and the combustion raises the temperature of and furnishes additional heat for the moving hot zone. Although the flowing air-gas mixture is preheated by the sand, and the sand is preheated by the combustion products, the problem is usually one of effectively controlling the relative rates of movement so that the heat values of the carbon burning wave are effectively added to the heat values of the heat transfer wave. Where exceptionally high carbon residues occur, however, it may be necessary to provide some means of control to I prevent the temperature from rising too high, The loss of some heat to overlying and underlying strata of course is helpful, but again the principal means of control is varying the ratio of heat carrying medium to oxygen in the stream. Liquid water intermittently slugged into the formation may be utilized to supplement the recirculated flue gases for this purpose. The peak temperatures may also be limited by deliberately varying the rates of travel of the waves, and by reducing the rates of wave travel.

Gas analysis of the produced gas, as by the Great method, for oxygen and carbon dioxide content provides a means for determining the state and progress of the front within the formation. During the combustion cycle oxygen content decreases and combustion products increase, while during the cold gas cycle the reverse is true. It is helpful to observe pressure differentials between inlet and outlet flow, which are affected by the temperature, the permeability, whether fusion is occurring, whether an oil and water block is building up, and the position of the heat transfer point and the revivifying combustion point. Control timing is also assisted by the use of deep-well thermometers or temperature recording devices.

For optimum recovery in an economical process, we consider that the rate of travel of the heat transfer hot wave should be almost coincident with that of the revivifying combustion hot wave, in order to minimize losses to sand and bounding strata. If the rate of travel of the combustion wave is appreciably either faster or slower than that of the heat transfer wave, the whole mass of sand between the front of one and the back of the other will be heated to high temperature with consequent losses to sensible heat that may be prohibitive, or so large a body of sand may be heated that the temperature may be too low. Rate of travel of the heat transfer wave is proportional to the ratio, mass velocity of total gas divided by sand density, and to the ratio, specific heat of gas to specific heat of sand. Rate of travel of the combustion wave is proportional to the mass velocity of oxygen consumed (or oxygen supplied less oxygen out), and is inversely proportional to the carbonaceous residue of the sand (at a given temperature level, reactivity, etc.) which is burned.

In applying our invention to large scale recovery operations, it is advantageous to utilize a logically spaced pattern of input and outlet wells.

In many of the fields which have been extensively gas pressured or water flooded. wells have been drilled in 5-spot or 9-spot patterns which will be suitable for applying our invention to further recovery. It may be necessary, however, to drill a new input well or to pull the old casing and replace it with pressure tight piping. The holes may be tightly cemented with a high temperature resistant cement at the top of the formation where necessary to confine the combustion and recycle gases within the formation stratum. Generally an ultimate 1:1 ratio of input and outlet wells will be found advantageous. In planning recovery patterns, it is particularly advantageous to utilize water dams built up in the structure by water injection through selected surrounding wells in order to segregate the working area and retain high pressure.

One of the major problems in secondary recover through gas pressuring is non-uniformity in the porous structure of the formation both vertically and horizontally, so that channeling occurs and control of oil movement within the formation is made diflicult; Non-uniform permeability creates the further problem with our invention of tending to promote broadening of individual hot zones and lowering of temperature. Core analysis is a helpful guide to methods for overcoming channeling by indicating the desirability of well packing at levels where fissures or excessively permeable strata appear. For this purpose, high temperature resistant cements may be used in place of the usual rubber packing devices of low temperature pressuring. The cement is poured into place and solidified. The casing is perforated as by shooting at the desired input levels. In order to prevent horizontal channeling through a relatively narrow streak of relatively high permeability so as to defeat uniform and economic recovery, higher back pressures on the more productive wells may be maintained to increase the resistance to flow in those directions. In addition, well blocking may be resorted to, as by water injection in or mechanical plugging of peripheral wells or wells of quick producing tendency.

The principles underlying our invention will be illustrated in the following examples, which, however, are intended to be merely illustrative and not limiting with respect to conditions and means utilized. Thus no attempt at recycling was made in the pilot scale testing, but air was utilized as the pressuring medium, and control was exercised through variation in the flow rate.

EXAMPLE I We tested the soundness of our concept of developing both a moving high temperature wave and a combustion wave in oil-bearing sand by means of heat transmissive and heat regenerative drive in a trial in which 40 inches of sand having an oil, content of 10% were packed in a 4- inch steel pipe. The test unit consisted of a 4- foot section of 4-inch steel pipe insulated with magnesia, which was maintained in a vertical position with an oil drain-off located at the bottom. A burner was used to preheat the simulated oil sands and was located at the upper end of the pipe, and an arrangement of thermocouples and an automatic temperature recorder were used to follow the movement of the heat zone through the simulated oil sands.

The pipe was equipped with a 1%; inch 0. D. stainless steel thermowell permitting the insertion of a bundle of eight thermocouples, staggered l inch apart, into the well. This thermowell entered the bottom of the pipe through the bottom oil take-off and extended. upward through the center of the pipe to within 1 /2 inches of the tip of the burner which was positioned 3 inches above the top of the sand bed. A fast-acting temperature indicator having a F. to 1600 F. range was used to record the temperature. In order to determine the flame temperature of the burner, a thermocouple was inserted into the thermowell to measure the flame temperature 1 /2 inches below the burner tip. A portable potentiometer was used to measure this temperature,

The pipe was; charged with enough gravel to make a 5-inch layer in the bottom. A 25-mesh stainless steel screen was placed over the gravel, followed by a layer of glass wool. The oil sand charged to the unit was prepared by mixing thoroughly 30.3 lbs. of builders sand, 3.5 lbs. of Santa Barbara 50% reduced crude and 0.15 lb. of coke ground to 100 mesh and finer. The coke was added to the oil sand mixture to simulate the entrapped oil and carbon in a natural oil sand formation. The amount of coke added was equivalent to 0.5 of 1% based on sand. This entire mixture was packed firmly into the 4-inch pipe by tamping during filling. The total depth or the sand bed was 40.5 inches and the top of the bed was located 3 inches below the tip of the gas burner. A wet test meter was used to measure outlet gases,

To start the test the burner was lighted and adjusted visually to give a hot flame and then inserted into the unit. Prior to inserting the lighted burner, the sand bed was air blown to determine whether or not any oil could be removed by airblowing alone. No oil could be removed by airblowing. After the lighted burner had been placed in position above the sand, the flue gas vent at the top of the pipe was closed thus causing all flue gases from the burner to pass through the sand bed. The burner was then adjusted by the aid of the flame temperature thermocouple to give its maximum temperature. The burner was kept on for 38 minutes, until the upper 3 inches of the sand bed was 1000 F. or over. During this period the pressure drop through the sand bed was 20 p. s. 1. After this 38-minute preperiod, the gas was turned off and air alone was passed into the oil sand bed. The amount of fed to the sand was 53 cubic feet per hour. With this amount of air passing into the sand bed, it was determined through the use of a bundie of eight thermocouples, that a flame front or peak temperature zone was bein maintained. Th re was a definite peak temperature in the bed, but it was noticed that as the wave progressed down through the bed, the peak temperatures kept dropping so that 1% hours after turning off the gas the hottest temperature in the sand bed was 800 F. At this time, it was decided to increase the air rate to 132 cubic feet per hour thereby increasing the pressure drop across the bed to p. s. i. The peak temperature responded immediately to this increase in air rate and lined out at about 1000 F. The remainder of the bed was burned off with this increased air rate. Examination of the temperature data obtained indicated that the flame front or combustion wave traveled through the sand bed at the rate of 15 inches per hour. The pressure drop through the sand at the end of the test was 22 p. s. i.

The oil recovered from the unit was found to weigh 3.6 lbs. compared to 3.5 lbs. charged. The increase in weight was caused by the removal of 10 some water from the sand used to make the oil sand mixture.

The temperature data obtained during the test indicated that the high temperature zone was 10- calized, and it appeared that it was confined to a narrow band less than an inch in width.

Upon dumping the sand from the pipe, it was found that there was no oil-bearing sand left. Most of the sand had been burned clean. The sand that had not been burned clean was cemented together, adhering in a cylindrical crust to the inside of the 4-inch pipe. It was observed that this cylindrical crust was thickest at the point where the peak flame temperature was the lowest. At the point where the temperature peak was only 800 F. the cemented crust was so thick that the burned out core through the center of the pipe was only about 1.5 inches in diameter. However, lower down in the sand bed this crust thinned out due to the increased flame front temperature caused by the increased air rate.

EXAMPLE II Following the completion of the test conducted in the 4-inch pipe, another test was made in a unit which more nearly simulated the conditions which would exist in the field. For this test, a rectangular box made of 16 gauge sheet metal was utilized. The inside dimensions of this box were 31 inches wide by 43 inches long by 24 inches deep. In order to reinforce the box, 2- inch by 2-inch angles were used to stiffen the sides and bottom. In mounting the box, one of its narrow edges was raised 6 inches above the other to give the box an 8 slope. A l -inch pipe was placed in the box at its higher edge in a vertical position. This pipe extended to the bottom of the box and served as the burner pipe, through which the gas flame used to ignite the bed was inserted. The burner pipe was perforated with .-inch holes for 15 inches along its lower end. The burner tip was so positioned that 4 inches of its nozzle was within the cover of the box. A second l -inch pipe was placed near the middle of the lower edge of the cover plate in a vertical position with its lower end touching the bottom of the box. This pipe was perforated with /;-inoh holes along 9 inches of its lower end, and the perforated area was covered with wire mesh to keep sand out of the pipe. To remove the oil which drained into the pipe, a inch pipe extending to the bottom of the larger pipe was used. The upper end of the larger pipe was connected to a valve so that back pressure could be imposed in order to cause the oil to flow up through the /4-inch pipe to a receiver.

The material charged to the box consisted of 1600 lbs. of builders sand mixed thoroughly with i 177 lbs. of oil plus 8 lbs. of finely ground coke.

The'oil was Santa Barbara reduced crude, and constituted 10% by weight, while the coke charge was 1 of 1% based on the sand. The oil sand was tamped firmly while being loaded into the box. After being thoroughly tamped into the box, the depth of the sand mixture was 19 inches. On top' of this sand a -inch layer of fine Olmsted earth was spread and the remainder of the 24-inch depth of the box was filled in with a mixture of half Olmsted earth and half builders sand. The box was slightly overfilled so that when the -inch thick cover plate was put into position, it had to be pulled down by clamps in order to be able to weld 'it'to the box. This procedure was used'in order to compress the sand so as to remove any voids within the box. The

4-in hie e e l ad four nc he metal fins extending across the inner width of the box welded to its under side. These fins were spaced about 8 inches apart and served to prevent lay-passing of the gases through any voids forming above the oil sand mixture. After. the box h s be n e tirel welded, hut. i was. ested with n e- 1- i p e s re nd al leak e W l d. shu

In der to ab e fo l t e cours f; the hi h emperatu zon throu h. h and thr e thermowells were used. One passed horizontally hr ugh the m d le of. h an bed al n the ens axis of the ex- AnQ her passed throu h th m ddle. O the sand. b hor zontal y throu h ts h as The. oth r well. nt ed the box ve i a to the en n pass d hr u h the. middl e the. e Be id s hese. h rmewe ls. there ere. tw me hrou h. h ch. t e. flam t rn.- n iet r an tempera ure he nd near the. u ne R pe eeuld e. ees red- 1. ord r. to. follow the high temperature zone along the long axis of the box a bundle of eight thermocouples spaced 1-inch apart. was used. This. bundle. of thermocouples. could be positioned. anywhere in the Well so asto explore thetemperature through-e. out the length of the bed. In the short horizontal and the vertical. thermowells. therewere bundles of five. thermocouples. spaced" 2v inches a tlocatedconcentrically in the. burner; pipe and entered through the. bottom, of the box; This thermowell extended to within 1. inch of. thetip ofthe burner. The thermowell for measurement of the sand temperature adjacent the burner pipe hada bundle of three thermocouplesspaced 2 inchesapart. This. thermowell paralleled the burner pipe and was located 2 inchesfrom it.

During the first attempt to initiate combustion in the sand bed insufiicient preheat was given to the sand surrounding the burner. tube and thus combustion wasnot started. Theqpreheat time was then extended to nine hours. During the reh at neri d h -ay r .p ess re :drop throu h he-b d Wasabeuta ps. 1- Aft r th pr h at perio d ,;the;air andgas. to theburner-Were cut f. 41 a l l ed.- e. he-bex through the .burner Pine a a sed. hr ugh-a r tome en o h tth e1 7.- a e; deems; ey end: b rn ng pe iod could e. et mine u in he; fir t. p rtionof: t end. urnin riedtbe ir ate as. kep hi h nei e te n edeee a .1:.- s iplie eu e on ross h v en -$1.2.- he yer. ur ns es ea erportionof the test a 5 p s, i. d-ifierentialwas'maine ame eree he. end. ed. he ave a a r. rate fer he 38- our u ning ri as. I a ut ub cre tn .-he r- During the initial. part of the sand burning period the peak temperature of the hot zone was about 1l00 F., butas it advanced away from the burner pipe and its area increased, the peak temperaturesfdropped. It was determined that increase of air flow was necessary to maintain or raise. the frontal temperature, but. unfortunately the. air rate through the bed could notv be appreciably increased "because, the box was made of light gauge steel. Thus the air rate through each unitarea of the hot wave decreasedduring the course of the test. The peak temperature in the bed at thetime the test was stopped was 695 F. V

The flue gases from the box-wereanalyzed by Orsat. The CO2 content at the'start of the sand burning period,was;13;5% and decreased gradually as the frontal temperature decreased;

lhe flame temperature thermowell was When it was noticed that the peak'frontal temperatures were continuously dropping a small amount, 6 cubic feet per hour of propane gas were fed to the sand bed along with the air. This procedure did not have any decided eifect on the frontal temperatures or CO2 content of the outlet gases. It was noticed, however, that this inclusion of propane with the. air fed to the box caused some localized heating of the burned off sand around the inlet pipe.

The total elapsed time for the test including the time required for preheating was 47 hours. During this time 126.5 lbs. of oil were recovered of the 1.77 lbs. placed on the sand, representing a recovery of 71%. The recovered oil contained about 5% water as shown by distillation. The gravity of the oil decreased from its original value of 21.8 API to 207 due to the increase in water content caused by the removal of water from the sandy used in the mixture. The odor of the recovered oil was substantially the same as that of the original oil. A, comparison of distillation, data obtained from the original and the. re.- cover d. oilfollowsz.

5%. 1110 in sample.

Upon completion the cover plate was-removed from the box and its contents were examined. It was found that the dry sand-Olmsted earth mixture placed on top of the oil sand bed had not absorbed any oil, and there was no indication that any-gases had by-passed through this dry mixture. There was no evidence of channeling through the oil sand bed. The sand that had been burned clean represented about 35% of the volume of the oil'sand bed and formed an egg-shaped volume. The large end of the eggshape surrounded the inlet or burner pipe, while the small end of the egg pointedtoward and almost touched the-outlet pipe.

EXAMPLE III Testswere made upon coregsamples from typical areas of the Nowata Field'to determine the effectiveness of purging with air and nitrogen within thetemperature range of, 80 F. to 1350. F. at atmospheric pressure. The sample, 442 grams (320 cc.) was ground to l4-mesh and cemented in a quartz tube. The purge gas was passedthrough the tubeafter preliminary drying and preheating. The eilluent gases were led through a; pair" of ice-water traps and calcium sulfate driers' in parallel. The gaseswere col- 13 450 F. to 500 F., judged by oxygen disappearance. Cracking begins at about 700 F., and the recovered oil had an API gravity of 275 to 29.0 and a U. 0. P. characterization factor 11.? to 11.9

"14 Core analysis of the area selected indicates a porosity of approximately 20% and a permeability of approximately 40 millidarcys. The oil content approximates 300 barrels per acre-foot and g i t i 5 the water content, which is entirely connate original oi l 3 2321551 35 1 030 53; 205031 8% re water approximates the same There is Very littl a r i covery increased. Wlbh temperature-rise rate, but e g S ecovemble P the p q decreased with increasing purge rate. The air For t purposes of muStFatmn' an Input Wen rates, it should be noted, however, were high for 10 typlcal 7'mch plpe 1S firmed and 1s field rates; e. g., about 300 cubic feet per minute, {earned and Shot Wlth mtroglycerme to expand but were as low as practicable in the laboratory. W hole Volume Wlthm t Sand to a to 34001? Total oil recovery did not appear to be affect d diameter cavity. In this area wells have been by the nature of the purge gas, air or nitrogen, fi m l patterns for gas pressuring, S0 at approximately Zhourly space velocity and 5. 1 that old Wells may be utilized. The well spacing "F. per minute temperature-rise rate. The iiow approximates 200 feet between input and outletdata are tabulated below in Table 13, nd gas wells and 330 feet between like wells. For test analyses by the mass spectrometer of th efpurposes all surroundin wells except one which fluent of run 0 are reported in Table 0'. is 230 f distant are pp d o plu ed.

Table B Charge Purge Recovered Materials Wt. Percent 011 Recovery, Temperature Based on origi- T t 1 R r Pressure 011 H 0 oo t t e fifgi sand (442 gm) 3. 3. 1. fi r tg. Rise-Rate (Gm.) Gin (cm?) by pentane ex- Range, 3 R/Mm) (Ave) traction (Ave) 1 CoreA N, .235 .020 4.20 3.00 53 2 CoreA(4l5gm.).. Air 1.133 .103 0 .97 3.37 0 OoreB .320 .027 4.40 3. 88 0.90 52 d .427 .013 4.50 5.10 0.39 53 .425 .025 0 .54 5.01 0 .912 .030 5. 82 0.27 10. 03 09 9.020 .103 1.00 12.30 23. 50 27 .327 .020 4.04 0.32 9.30 .490 .019 3.11 0.93 13.10 54 .597 .025 3.00 0. 03 3.47 52 1 Actual recovery. Some oil was lost (leakage).

Table C Cumulative M01 Percent Time of Tempera- Air Purge ture, F.

(HR) H1 N2 0: 00 CO3 01 O2= C2 C3= C3 C4 C4:

1 No samples taken.

EXAMPLE IV 60 To introduce combustion gas intothe forma As an example of an application in the field, our invention may be illustrated by application to the Delaware-Childers field of Nowata County, Oklahoma. This field is underlain by the Bartlesville sand at a depth averaging from 600 to 800 feet. The oil-bearing sand averages to feet in thickness and is overlain by impervious cap rock. Although the sand is somewhat lenticular it represents a formation of average or better uniformity. This field has been produced by primary methods, including vacuum, for over 40 years and has been subjected to major gas and air-pressuring projects and, to a minor. extent, to water flooding.

tion a high-pressure burner with an elongated combustion chamber is lowered through the well casing to formation level. A suitable burner is disclosed in application Serial No. 97,142 filed June 4, 19 19. The burner comprises an elongated combustion chamber to which fuel gas and primary air are separately introduced through concentric piping by means of a mixing plate at its head. A turbulent tangential motion is imparted to the flame by passage of the fuel gas and air through angularly directed ducts in the mixing plate. The mixture is ignited by a spark plug centrally located in the mixing plate. The burner is constructed of stainless steel or other 1 heat resistant metal, advantageously in two sections, the combustion, and an upper section containing an inner pipe for gas and a high tension cable leading to the spark plug. For a heat release rate approximating 500,000 to 600,000 B. t. u. per hour at 40 to 70 p. s. i. g., the dimensions of the burner advantageously are about 2 in diameter by 24" in length of each pipe section. The inner gas line and outer air pipe are extended to the surface with ordinary piping, and primary air and fuel gas are supplied in approximately theoretical proportions for perfect combustion. Secondary air to dilute the combustion gases and control the flame temperature is admitted through the oil-well casing around the burner tubing and combustion chamber.

The burner is operated at a flame temperature of about 1500 F. in the hole and under an inlet pressure of about 360 p. s. i. g. Fuel is burned at a rate in sufficient quantity for a heat release approximating 500,000 13. t. u. per hour. Suflicient air is provided to control the flame temperature and provide excess oxygen in'the fuel gases to accelerate the temperature rise in the formation through internal combustion. A back pressure of about 300 p. s. i. g. is maintained on the outlet well, and produced gas is recycled to the inlet well after repressuring.

The data on an illustrative example of operation are tabulated below;

Table D Nature of Field:

Depth to top of oil sands .i.

Thickness of oil sands.

Well spacing Average permeability of oil sands, millidarcys- 40 Residual oil after other recovery methods, wt.

percent of oil sands Residual carbonaceous solids, wt. percent of oil sands 0.5 Conditions of operation:

Total gas input, std. cu. ft.lday/well Base pressure level, output gas, ii /in.

Input pressure sufficient to maintain gas rate, ii /in.

approximately 360 02 content of total gas to input well, percent 3.33 5.0 Average production, bbl./day/input well. 3. 2 8. 12

At the start of operations, fuel is burned with air, and later recycle gas is also included to give temperatures of combustion of about 1200 F. to 2000 F., until about 180,000,000 cubic feet per well of total gas have been put in. The burner is extinguished and gas drive is now continued without burning extraneous fuel. Under these conditions with an oxygen content of below approximately 1.33%, the heat transfer wave is in front, and the rate is constant. With above 1.33% oxygen, the combustion wave is in front, travelling at a rate proportional to the oxygen content. oxygen, the fire in front will go out because the temperature is too low to sustain combustion and the oxygen-containin gas will simply be cycled through.

Alternatively, the gas drive may be continued with inert or substantially oxygen-free gases until the temperature of the front falls to a figure affecting recovery efficiency and approaching an effective in situ combustion temperature for the residual carbonaceous matter, say about 700 F. example. Air or other oxygen-containing gas is then added to the cycling cold gases so as to provide a sufficient quantity to ignite and support combustion of the residual carbonaceous material under the high temperature condition existing. The cycling of oxygen-containing gas in the gas flow is continued until a high temperature has been re-established. Again the temperaturemay be followed by the means of heat 16 transfer calculations or by deep well thermometers or thermal recording devices situated within the formation.

The use of heat transfer calculations to predict the temperature of the heat transfer wave front as it is moved out into the formation depends upon taking into account the factors mentioned above in columns '7 and 8, including the total amount of combustible material available for combustion in the high temperature region and takin into account the temperature level of the initial high temperature zone established at the input well, checked by data obtained through analysis of the gas recovered from the output well. During the combustion cycle, the presence of excess oxygen and carbon monoxide in the effluent gases is indicative of the completion of the combustion reaction and the correctness of the ratios of oxygen to fuel. The best indication of the temperature of the heat wave is furnished by the extent of decomposition of hydrocarbon gases occurring during the cycle gas or cold gas drive, the period of intermittent operation, Which can be followed by means of a recording calorimeter employed to determine the calorific value or the B. t. u. content of the produced gas. As a result of passage through the high temperature Wave front, the average molecular weight of the cycling hydrocarbon gases is reduced, with the tendency to form hydrogen increasing at conditions of extreme severity. Comparison of the ratios of light to heavy hydrocarbon followed by changes in calorific content forms a relatively sensitive indication of changes in the peak temperature level, which is not seriously confused by moderate changes in the width of the hot zone,

7 provides an additional means for checking the But with above about 5% to 6% of i methods of analysis and calculation but requires additional drilling into some intermediate portion of the formation before the high temperature wave has reached the test area.

We claim:

1. The method of recovering gas and oil from oil-bearing formations penetrated by at least one input well and at least one adjacent output well which comprises establishing a zone of high temperature at about 700 to 2500 F. within the formation surrounding the input well by means of hot gas iiow, moving the high temperature zone as a wave front by means of cold as flow outwardly from the input well and through the formation in a relatively horizontal direction, revivifying the high temperature wave front by establishing a combustion wave front by introduction of free oxygen in an average amount approximating 1.33 to 6.0% into the formation and controlling the rate of movement of the combustion wave front relative to the rate of movement of the high temperature wave front in a manner obtaining approximate coincidence between the combustion wave front and the high temperature wave front by regulating the velocity of free oxygen introduced to the formation during any period of operation and thus controllin the rate of combustion in the front by which its rate of movement is determined, while recovering gas and oil from the outlet Well.

2. The method of recovering gas and oil from oil-bearing formations penetrated by at least one input well and at least one adjacent output well which comprises establishing a zone of high temr 17 perature at about 700 to 2500 F. within the formation surrounding the input well by means of hot gas flow, moving the high temperature zone as a Wave front by means of cold gas flow outwardly from the input well and through the formation in a relatively horizontal direction, continuously revivifying the high temperature Wave front by burning residual carbonaceous matter left in the formation so as to form a combustion Wave front within the zone of high temperature by including free oxygen in thelcold gas drive in an average amount approximating 1.33 to 6.0% and controlling the rate of movement of the combustion wave front relative to the rate of movelment of the high temperature wave front in velocity of free oxygen introduced to the forma- 1 tion during any period of operation and thus controlling the rate of combustion in the front by which its rate of movement is determined, While recovering gas and oil from the outlet well.

3. The method of recovering gas and oil from oil-bearing formations penetrated by at least one input well and at least one adjacent output well which comprises establishing a zone of high temperature at about 700 to 2500 F. Within the formation surrounding the input well by means of hot gas flow which is substantially free of uncombined oxygen outwardly from the input well 18 and through the formation in a relatively horizontal direction, intermittently revivifying the high temperature wave front by burning residual.

carbonaceous matter left in the formation so as to form a carbonaceous wave front in the zone of high temperature by cyclically introducing a free oxygen containing cold gas flow to the formation, controlling the rate of movement of the combustion wave front relative to the rate of movement oftbe high temperature wave front in a manner obtaining approximate coincidence between the combustion wave front and the high temperature wave front by regulating the mass velocity of free oxygen introduced to the formation during this period of operation and thus controlling the rate of combustion in the front by which its rate of movement is determined and by limiting the amount of free oxygen introduced to theformation to an average amount within the range approximating 1.33 to 6.0% of the total References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,382,471 Frey Aug. 14, 1945 2,390,770 Barton et al Dec. 11, 1945

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2382471 *Mar 3, 1941Aug 14, 1945Phillips Petroleum CoMethod of recovering hydrocarbons
US2390770 *Oct 10, 1942Dec 11, 1945Sun Oil CoMethod of producing petroleum
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2734579 *Jun 28, 1952Feb 14, 1956 Production from bituminous sands
US2761512 *Nov 8, 1954Sep 4, 1956Pure Oil CoCombustion and halosilane reaction treatment of a formation to increase production
US2770305 *Sep 2, 1952Nov 13, 1956Stanolind Oil & Gas CoUnderground combustion operation
US2771951 *Sep 11, 1953Nov 27, 1956California Research CorpMethod of oil recovery by in situ combustion
US2780449 *Dec 26, 1952Feb 5, 1957Sinclair Oil & Gas CoThermal process for in-situ decomposition of oil shale
US2788071 *Mar 5, 1954Apr 9, 1957Sinclair Oil & Gas CompanyOil recovery process
US2790248 *Jul 29, 1954Apr 30, 1957United Gas CorpMeans for regenerating adsorbent beds
US2793697 *Jul 5, 1955May 28, 1957California Research CorpMethod of reestablishing in situ combustion in petroliferous formations
US2796132 *Sep 8, 1954Jun 18, 1957Exxon Research Engineering CoMethod of initiating combustion in an oil reservoir
US2796935 *Jul 13, 1954Jun 25, 1957Pure Oil CoIncreasing production rates of gas and oil wells
US2800183 *Nov 9, 1953Jul 23, 1957Socony Mobil Oil Co IncDetermination of the location of the flame front in a subterranean formation
US2803305 *May 14, 1953Aug 20, 1957Pan American Petroleum CorpOil recovery by underground combustion
US2813583 *Dec 6, 1954Nov 19, 1957Phillips Petroleum CoProcess for recovery of petroleum from sands and shale
US2818117 *Mar 9, 1953Dec 31, 1957Socony Mobil Oil Co IncInitiation of combustion in a subterranean petroleum oil reservoir
US2858891 *Apr 8, 1953Nov 4, 1958Otto KriegbaumPressure maintenance and repressuring in oil and gas fields
US2862557 *Sep 12, 1955Dec 2, 1958Shell DevPetroleum production by underground combustion
US2874777 *Jul 14, 1955Feb 24, 1959Shell DevProducing petroleum by underground combustion
US2877847 *Sep 26, 1955Mar 17, 1959Sinclair Oil & Gas CompanyCombustion in well with steel liner
US2880802 *Mar 28, 1955Apr 7, 1959Phillips Petroleum CoRecovery of hydrocarbons from oil-bearing strata
US2880803 *Jan 16, 1958Apr 7, 1959Phillips Petroleum CoInitiating in situ combustion in a stratum
US2889881 *May 14, 1956Jun 9, 1959Phillips Petroleum CoOil recovery by in situ combustion
US2889882 *Jun 6, 1956Jun 9, 1959Phillips Petroleum CoOil recovery by in situ combustion
US2906340 *Apr 5, 1956Sep 29, 1959Texaco IncMethod of treating a petroleum producing formation
US2911206 *Mar 8, 1957Nov 3, 1959Phillips Petroleum CoIn situ retorting of oil shale
US2924276 *Aug 8, 1955Feb 9, 1960Jersey Prod Res CoSecondary recovery operation
US2946382 *Sep 19, 1956Jul 26, 1960Phillips Petroleum CoProcess for recovering hydrocarbons from underground formations
US2958380 *Jun 17, 1957Nov 1, 1960Gulf Research Development CoIn-situ combustion process for the production of oil
US2958519 *Jun 23, 1958Nov 1, 1960Phillips Petroleum CoIn situ combustion process
US2994374 *Oct 28, 1957Aug 1, 1961 In situ combustion process
US3000441 *Jul 18, 1958Sep 19, 1961Texaco IncIn situ combustion
US3003555 *Sep 18, 1956Oct 10, 1961Jersey Prod Res CoOil production from unconsolidated formations
US3007521 *Oct 28, 1957Nov 7, 1961Phillips Petroleum CoRecovery of oil by in situ combustion
US3024841 *Jul 30, 1958Mar 13, 1962Jersey Prod Res CoMethod of oil recovery by in situ combustion
US3035638 *Jun 11, 1958May 22, 1962Phillips Petroleum CoInitiation of counterflow in situ combustion
US3036632 *Dec 24, 1958May 29, 1962Socony Mobil Oil Co IncRecovery of hydrocarbon materials from earth formations by application of heat
US3042114 *Sep 29, 1958Jul 3, 1962Research Company Jersey ProducProcess for recovering oil from underground reservoirs
US3044543 *Oct 25, 1956Jul 17, 1962Socony Mobil Oil Co IncSubterranean recovery process by combustion
US3044545 *Oct 2, 1958Jul 17, 1962Phillips Petroleum CoIn situ combustion process
US3044546 *May 25, 1959Jul 17, 1962Phillips Petroleum CoProduction of unconsolidated sands by in situ combustion
US3047064 *Mar 12, 1958Jul 31, 1962Jersey Prod Res CoIntermittent in-situ burning
US3050116 *May 26, 1958Aug 21, 1962Phillips Petroleum CoMultiple zone production by in situ combustion
US3054448 *Apr 17, 1958Sep 18, 1962Continental Oil CoCounterflow in situ combustion process
US3055422 *Oct 16, 1958Sep 25, 1962Phillips Petroleum CoIn situ combustion process
US3115928 *Aug 14, 1959Dec 31, 1963Pan American Petroleum CorpHeavy oil recovery
US3130781 *Jun 10, 1959Apr 28, 1964Socony Mobil Oil Co IncRecovery of hydrocarbon material by in-situ combustion
US3150716 *Oct 1, 1959Sep 29, 1964Chemical Construction CorpPressurizing oil fields
US3170515 *Jun 12, 1961Feb 23, 1965Jersey Prod Res CoIn-situ combustion process
US3171479 *Apr 30, 1962Mar 2, 1965Pan American Petroleum CorpMethod of forward in situ combustion utilizing air-water injection mixtures
US3182721 *Nov 2, 1962May 11, 1965Sun Oil CoMethod of petroleum production by forward in situ combustion
US3196945 *Oct 8, 1962Jul 27, 1965Pan American Petroleum CompanyMethod of forward in situ combustion with water injection
US3228468 *Dec 8, 1961Jan 11, 1966Socony Mobil Oil Co IncIn-situ recovery of hydrocarbons from underground formations of oil shale
US3254711 *Aug 29, 1963Jun 7, 1966Phillips Petroleum CoNatural gasoline conservation during in situ combustion
US3387654 *Oct 27, 1966Jun 11, 1968Sinclair Research IncMethod for determining oxygen requirements for in-situ combustion
US3457995 *Jan 3, 1967Jul 29, 1969Phillips Petroleum CoIgniting an underground formation
US3461963 *Nov 15, 1966Aug 19, 1969Continental Oil CoMethod of hydrocarbon recovery by in-situ combustion
US3491833 *Dec 5, 1967Jan 27, 1970Texaco IncStabilizing water-sensitive clays in an underground formation
US3872924 *Sep 25, 1973Mar 25, 1975Phillips Petroleum CoGas cap stimulation for oil recovery
US3964545 *Jun 10, 1974Jun 22, 1976Esorco CorporationProcesses for secondarily recovering oil
US3994343 *Mar 4, 1974Nov 30, 1976Occidental Petroleum CorporationCombustion
US3999606 *Oct 6, 1975Dec 28, 1976Cities Service CompanyOil recovery rate by throttling production wells during combustion drive
US4018280 *Dec 10, 1975Apr 19, 1977Mobil Oil CorporationProcess for in situ retorting of oil shale
US4305463 *Oct 31, 1970Dec 15, 1981Oil Trieval CorporationOil recovery method and apparatus
US4634187 *Nov 21, 1984Jan 6, 1987Isl Ventures, Inc.Encapsulation
US4649997 *Dec 24, 1984Mar 17, 1987Texaco Inc.Carbon dioxide injection with in situ combustion process for heavy oils
US4699213 *May 23, 1986Oct 13, 1987Atlantic Richfield CompanyAlternate injections of water, air and hydrocarbons; separation of combustion zones
US6581684Apr 24, 2001Jun 24, 2003Shell Oil CompanyIn Situ thermal processing of a hydrocarbon containing formation to produce sulfur containing formation fluids
US6588504Apr 24, 2001Jul 8, 2003Shell Oil CompanyConversion of hydrocarbons to produce hydrocarbons, hydrogen, and/or novel product streams from underground coal formations; pyrolysis
US6591906Apr 24, 2001Jul 15, 2003Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with a selected oxygen content
US6591907Apr 24, 2001Jul 15, 2003Shell Oil CompanyPyrolysis
US6607033Apr 24, 2001Aug 19, 2003Shell Oil CompanyIn Situ thermal processing of a coal formation to produce a condensate
US6609570Apr 24, 2001Aug 26, 2003Shell Oil CompanyIn situ thermal processing of a coal formation and ammonia production
US6688387Apr 24, 2001Feb 10, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to produce a hydrocarbon condensate
US6698515Apr 24, 2001Mar 2, 2004Shell Oil CompanyIn situ thermal processing of a coal formation using a relatively slow heating rate
US6702016Apr 24, 2001Mar 9, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with heat sources located at an edge of a formation layer
US6708758Apr 24, 2001Mar 23, 2004Shell Oil CompanyIn situ thermal processing of a coal formation leaving one or more selected unprocessed areas
US6712135Apr 24, 2001Mar 30, 2004Shell Oil CompanyIn situ thermal processing of a coal formation in reducing environment
US6712136Apr 24, 2001Mar 30, 2004Shell Oil CompanyProviding heat to the formation; controlling the heat from the heat source such that an average temperature within at least a majority of the selected section of the formation is less than about 375 degrees c.
US6712137Apr 24, 2001Mar 30, 2004Shell Oil CompanyHeat exchanging to superimpose heat
US6715546Apr 24, 2001Apr 6, 2004Shell Oil CompanyChemical and/or physical properties of hydrocarbon material within a subterranean formation may need to be changed to allow hydrocarbon material to be more easily removed
US6715547Apr 24, 2001Apr 6, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to form a substantially uniform, high permeability formation
US6715548Apr 24, 2001Apr 6, 2004Shell Oil CompanyElectrical heaters may be used to heat the subterranean formation by radiation and/or conduction
US6715549Apr 24, 2001Apr 6, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with a selected atomic oxygen to carbon ratio
US6719047Apr 24, 2001Apr 13, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation in a hydrogen-rich environment
US6722429Apr 24, 2001Apr 20, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation leaving one or more selected unprocessed areas
US6722430Apr 24, 2001Apr 20, 2004Shell Oil CompanyIn situ thermal processing of a coal formation with a selected oxygen content and/or selected O/C ratio
US6722431Apr 24, 2001Apr 20, 2004Shell Oil CompanyIn situ thermal processing of hydrocarbons within a relatively permeable formation
US6725920Apr 24, 2001Apr 27, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to convert a selected amount of total organic carbon into hydrocarbon products
US6725921Apr 24, 2001Apr 27, 2004Shell Oil CompanyIn situ thermal processing of a coal formation by controlling a pressure of the formation
US6725928Apr 24, 2001Apr 27, 2004Shell Oil CompanyIn situ thermal processing of a coal formation using a distributed combustor
US6729395Apr 24, 2001May 4, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with a selected ratio of heat sources to production wells
US6729396Apr 24, 2001May 4, 2004Shell Oil CompanyIn situ thermal processing of a coal formation to produce hydrocarbons having a selected carbon number range
US6729397Apr 24, 2001May 4, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with a selected vitrinite reflectance
US6729401Apr 24, 2001May 4, 2004Shell Oil CompanySynthesis gas may be produced from the formation. synthesis gas may be used as a feed stream in an ammonia synthesis process. ammonia may be used as a feed stream in a urea synthesis process.
US6732794Apr 24, 2001May 11, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to produce a mixture with a selected hydrogen content
US6732795Apr 24, 2001May 11, 2004Shell Oil CompanyProviding heat from one or more heat sources to at least one portion of formation; allowing heat to transfer from the one or more heat sources to a selected section of the formation; controlling the heat; producing a mixture from the formation
US6732796Apr 24, 2001May 11, 2004Shell Oil CompanyHeating section of formation with heat sources to temperature allowing generation of synthesis gas, providing synthesis gas generating fluid to section, removing synthesis gas generated, repeating for second section, blending for desired ratio
US6736215Apr 24, 2001May 18, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation, in situ production of synthesis gas, and carbon dioxide sequestration
US6739393Apr 24, 2001May 25, 2004Shell Oil CompanyIn situ thermal processing of a coal formation and tuning production
US6739394Apr 24, 2001May 25, 2004Shell Oil CompanyProviding heat and a synthesis gas generating fluid to the section to generate synthesis gas
US6742587Apr 24, 2001Jun 1, 2004Shell Oil CompanyIn situ thermal processing of a coal formation to form a substantially uniform, relatively high permeable formation
US6742588Apr 24, 2001Jun 1, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to produce formation fluids having a relatively low olefin content
US6742589Apr 24, 2001Jun 1, 2004Shell Oil CompanyIn situ thermal processing of a coal formation using repeating triangular patterns of heat sources
US6742593Apr 24, 2001Jun 1, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using heat transfer from a heat transfer fluid to heat the formation
US6745831Apr 24, 2001Jun 8, 2004Shell Oil CompanyMixture of hydrocarbons, h2, and/or other formation fluids may be produced from the formation. heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature.
US6745832Apr 24, 2001Jun 8, 2004Shell Oil CompanySitu thermal processing of a hydrocarbon containing formation to control product composition
US6745837Apr 24, 2001Jun 8, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using a controlled heating rate
US6749021Apr 24, 2001Jun 15, 2004Shell Oil CompanyPyrolysis
US6752210Apr 24, 2001Jun 22, 2004Shell Oil CompanyIn situ thermal processing of a coal formation using heat sources positioned within open wellbores
US6758268Apr 24, 2001Jul 6, 2004Shell Oil CompanyHeat exchanging, pyrolysis; monitoring temperature
US6761216Apr 24, 2001Jul 13, 2004Shell Oil CompanyPyrolysis temperature
US6763886Apr 24, 2001Jul 20, 2004Shell Oil CompanyIn situ thermal processing of a coal formation with carbon dioxide sequestration
US6769483Apr 24, 2001Aug 3, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using conductor in conduit heat sources
US6769485Apr 24, 2001Aug 3, 2004Shell Oil CompanyIn situ production of synthesis gas from a coal formation through a heat source wellbore
US6789625Apr 24, 2001Sep 14, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using exposed metal heat sources
US6805195Apr 24, 2001Oct 19, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to produce hydrocarbon fluids and synthesis gas
US6820688Apr 24, 2001Nov 23, 2004Shell Oil CompanyHeat exchanging after pyrolyzation to support synthesis gas generation
US6866097Apr 24, 2001Mar 15, 2005Shell Oil CompanySuperpositioning of heaters for pyrolysis to form mixture of hydrocarbons and hydrogen; controlling pressure; heat exchanging
US6871707Apr 24, 2001Mar 29, 2005Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with carbon dioxide sequestration
US6877554Apr 24, 2001Apr 12, 2005Shell Oil CompanyPyrolysis
US6877555Apr 24, 2002Apr 12, 2005Shell Oil CompanyIn situ thermal processing of an oil shale formation while inhibiting coking
US6880633Apr 24, 2002Apr 19, 2005Shell Oil CompanyIncludes shutting-in an in situ treatment process in an oil shale formation may include terminating heating from heat sources providing heat to a portion of the formation; hydrocarbon vapor may be produced
US6880635Apr 24, 2001Apr 19, 2005Shell Oil CompanyMethods and systems for production of hydrocarbons, hydrogen, and/or other products from underground coal formations
US6889769Apr 24, 2001May 10, 2005Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with a selected moisture content
US6896053Apr 24, 2001May 24, 2005Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using repeating triangular patterns of heat sources
US6902003Apr 24, 2001Jun 7, 2005Shell Oil CompanyAllowing heat to transfer from heaters to a formation selected for heating using a total organic matter weight percentage of > 5% and recirculating hydrogen
US6902004Apr 24, 2001Jun 7, 2005Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using a movable heating element
US6910536Apr 24, 2001Jun 28, 2005Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using a natural distributed combustor
US6913078Apr 24, 2001Jul 5, 2005Shell Oil CompanyIn Situ thermal processing of hydrocarbons within a relatively impermeable formation
US6915850Apr 24, 2002Jul 12, 2005Shell Oil CompanyIn situ thermal processing of an oil shale formation having permeable and impermeable sections
US6918442Apr 24, 2002Jul 19, 2005Shell Oil CompanyIn situ conversion of hydrocarbons to produce hydrocarbons, hydrogen, and/or novel product streams from underground oil shale formations
US6918443Apr 24, 2002Jul 19, 2005Shell Oil CompanyIn situ thermal processing of an oil shale formation to produce hydrocarbons having a selected carbon number range
US6923257Apr 24, 2002Aug 2, 2005Shell Oil CompanyIn situ thermal processing of an oil shale formation to produce a condensate
US6923258Jun 12, 2003Aug 2, 2005Shell Oil CompanyIn situ thermal processsing of a hydrocarbon containing formation to produce a mixture with a selected hydrogen content
US6929067Apr 24, 2002Aug 16, 2005Shell Oil CompanyHeat sources with conductive material for in situ thermal processing of an oil shale formation
US6932155Oct 24, 2002Aug 23, 2005Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation via backproducing through a heater well
US6948562Apr 24, 2002Sep 27, 2005Shell Oil CompanyProduction of a blending agent using an in situ thermal process in a relatively permeable formation
US6948563Apr 24, 2001Sep 27, 2005Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with a selected hydrogen content
US6951247Apr 24, 2002Oct 4, 2005Shell Oil CompanyControl the heat exchanging, pyrolyzing hydrocarbons, enhancing oil recovery
US6953087Apr 24, 2001Oct 11, 2005Shell Oil CompanyThermal processing of a hydrocarbon containing formation to increase a permeability of the formation
US6959761Apr 24, 2001Nov 1, 2005Shell Oil CompanyIn situ thermal processing of a coal formation with a selected ratio of heat sources to production wells
US6964300Apr 24, 2002Nov 15, 2005Shell Oil CompanyIn situ thermal recovery from a relatively permeable formation with backproduction through a heater wellbore
US6966372Apr 24, 2001Nov 22, 2005Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to produce oxygen containing formation fluids
US6966374Apr 24, 2002Nov 22, 2005Shell Oil CompanyIn situ thermal recovery from a relatively permeable formation using gas to increase mobility
US6969123Oct 24, 2002Nov 29, 2005Shell Oil CompanyUpgrading and mining of coal
US6973967Apr 24, 2001Dec 13, 2005Shell Oil Companyhydrocarbons within a coal formation are converted in situ within the formation to yield a mixture of relatively high quality hydrocarbon products, hydrogen, and other products; the coal is heated to to temperatures that allow pyrolysis
US6981548Apr 24, 2002Jan 3, 2006Shell Oil Companyheating and pyrolysis of heavy hydrocarbon sections in subterranean wells to produce light hydrocarbons; reduced viscosity improves movement; fluid removal in liquid and/or vapor phase
US6991031Apr 24, 2001Jan 31, 2006Shell Oil CompanyIn situ thermal processing of a coal formation to convert a selected total organic carbon content into hydrocarbon products
US6991032Apr 24, 2002Jan 31, 2006Shell Oil CompanyHeat sources positioned within the formation in a selected pattern raise a temperature of a portion of the formation to a pyrolysis temperature.
US6991033Apr 24, 2002Jan 31, 2006Shell Oil CompanyIn situ thermal processing while controlling pressure in an oil shale formation
US6991036Apr 24, 2002Jan 31, 2006Shell Oil CompanyThermal processing of a relatively permeable formation
US6991045Oct 24, 2002Jan 31, 2006Shell Oil CompanyForming openings in a hydrocarbon containing formation using magnetic tracking
US6994160Apr 24, 2001Feb 7, 2006Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to produce hydrocarbons having a selected carbon number range
US6994161Apr 24, 2001Feb 7, 2006Kevin Albert MaherIn situ thermal processing of a coal formation with a selected moisture content
US6994168Apr 24, 2001Feb 7, 2006Scott Lee WellingtonIn situ thermal processing of a hydrocarbon containing formation with a selected hydrogen to carbon ratio
US6994169Apr 24, 2002Feb 7, 2006Shell Oil CompanyIn situ thermal processing of an oil shale formation with a selected property
US6997255Apr 24, 2001Feb 14, 2006Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation in a reducing environment
US6997518Apr 24, 2002Feb 14, 2006Shell Oil CompanyIn situ thermal processing and solution mining of an oil shale formation
US7004247Apr 24, 2002Feb 28, 2006Shell Oil CompanyConductor-in-conduit heat sources for in situ thermal processing of an oil shale formation
US7004251Apr 24, 2002Feb 28, 2006Shell Oil CompanyIn situ thermal processing and remediation of an oil shale formation
US7011154Oct 24, 2002Mar 14, 2006Shell Oil CompanyIn situ recovery from a kerogen and liquid hydrocarbon containing formation
US7013972Apr 24, 2002Mar 21, 2006Shell Oil CompanyIn situ thermal processing of an oil shale formation using a natural distributed combustor
US7017661Apr 24, 2001Mar 28, 2006Shell Oil CompanyProduction of synthesis gas from a coal formation
US7032660Apr 24, 2002Apr 25, 2006Shell Oil CompanyIn situ thermal processing and inhibiting migration of fluids into or out of an in situ oil shale formation
US7036583Sep 24, 2001May 2, 2006Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to increase a porosity of the formation
US7040397Apr 24, 2002May 9, 2006Shell Oil CompanyThermal processing of an oil shale formation to increase permeability of the formation
US7040398Apr 24, 2002May 9, 2006Shell Oil CompanyIn situ thermal processing of a relatively permeable formation in a reducing environment
US7040399Apr 24, 2002May 9, 2006Shell Oil CompanyIn situ thermal processing of an oil shale formation using a controlled heating rate
US7040400Apr 24, 2002May 9, 2006Shell Oil CompanyIn situ thermal processing of a relatively impermeable formation using an open wellbore
US7051807Apr 24, 2002May 30, 2006Shell Oil CompanyIn situ thermal recovery from a relatively permeable formation with quality control
US7051808Oct 24, 2002May 30, 2006Shell Oil CompanySeismic monitoring of in situ conversion in a hydrocarbon containing formation
US7051811Apr 24, 2002May 30, 2006Shell Oil CompanyIn situ thermal processing through an open wellbore in an oil shale formation
US7055600Apr 24, 2002Jun 6, 2006Shell Oil CompanyIn situ thermal recovery from a relatively permeable formation with controlled production rate
US7063145Oct 24, 2002Jun 20, 2006Shell Oil CompanyMethods and systems for heating a hydrocarbon containing formation in situ with an opening contacting the earth's surface at two locations
US7066254Oct 24, 2002Jun 27, 2006Shell Oil CompanyIn situ thermal processing of a tar sands formation
US7066257Oct 24, 2002Jun 27, 2006Shell Oil CompanyIn situ recovery from lean and rich zones in a hydrocarbon containing formation
US7073578Oct 24, 2003Jul 11, 2006Shell Oil CompanyStaged and/or patterned heating during in situ thermal processing of a hydrocarbon containing formation
US7077198 *Oct 24, 2002Jul 18, 2006Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation using barriers
US7077199Oct 24, 2002Jul 18, 2006Shell Oil CompanyIn situ thermal processing of an oil reservoir formation
US7086465Oct 24, 2002Aug 8, 2006Shell Oil CompanyIn situ production of a blending agent from a hydrocarbon containing formation
US7086468Apr 24, 2001Aug 8, 2006Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using heat sources positioned within open wellbores
US7090013Oct 24, 2002Aug 15, 2006Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation to produce heated fluids
US7096941Apr 24, 2001Aug 29, 2006Shell Oil CompanyIn situ thermal processing of a coal formation with heat sources located at an edge of a coal layer
US7096942Apr 24, 2002Aug 29, 2006Shell Oil CompanyIn situ thermal processing of a relatively permeable formation while controlling pressure
US7096953Apr 24, 2001Aug 29, 2006Shell Oil CompanyIn situ thermal processing of a coal formation using a movable heating element
US7100994Oct 24, 2002Sep 5, 2006Shell Oil Companyinjecting a heated fluid into the well bore, producing a second fluid from the formation, conducting an in situ conversion process in the selected section.
US7104319Oct 24, 2002Sep 12, 2006Shell Oil CompanyIn situ thermal processing of a heavy oil diatomite formation
US7114566Oct 24, 2002Oct 3, 2006Shell Oil CompanyHeat treatment using natural distributed combustor; oxidation of hydrocarbons to generate heat; pyrolysis
US7121341Oct 24, 2003Oct 17, 2006Shell Oil CompanyConductor-in-conduit temperature limited heaters
US7121342Apr 23, 2004Oct 17, 2006Shell Oil CompanyThermal processes for subsurface formations
US7128153Oct 24, 2002Oct 31, 2006Shell Oil CompanyTreatment of a hydrocarbon containing formation after heating
US7156176Oct 24, 2002Jan 2, 2007Shell Oil CompanyInstallation and use of removable heaters in a hydrocarbon containing formation
US7165615Oct 24, 2002Jan 23, 2007Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation using conductor-in-conduit heat sources with an electrically conductive material in the overburden
US7219734Oct 24, 2003May 22, 2007Shell Oil CompanyInhibiting wellbore deformation during in situ thermal processing of a hydrocarbon containing formation
US7225866Jan 31, 2006Jun 5, 2007Shell Oil CompanyIn situ thermal processing of an oil shale formation using a pattern of heat sources
US7320364Apr 22, 2005Jan 22, 2008Shell Oil CompanyInhibiting reflux in a heated well of an in situ conversion system
US7353872Apr 22, 2005Apr 8, 2008Shell Oil CompanyStart-up of temperature limited heaters using direct current (DC)
US7357180Apr 22, 2005Apr 15, 2008Shell Oil CompanyInhibiting effects of sloughing in wellbores
US7360588Oct 17, 2006Apr 22, 2008Shell Oil CompanyThermal processes for subsurface formations
US7370704Apr 22, 2005May 13, 2008Shell Oil CompanyTriaxial temperature limited heater
US7383877Apr 22, 2005Jun 10, 2008Shell Oil CompanyTemperature limited heaters with thermally conductive fluid used to heat subsurface formations
US7424915Apr 22, 2005Sep 16, 2008Shell Oil CompanyVacuum pumping of conductor-in-conduit heaters
US7431076Apr 22, 2005Oct 7, 2008Shell Oil CompanyTemperature limited heaters using modulated DC power
US7435037Apr 21, 2006Oct 14, 2008Shell Oil CompanyLow temperature barriers with heat interceptor wells for in situ processes
US7461691Jan 23, 2007Dec 9, 2008Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation
US7481274Apr 22, 2005Jan 27, 2009Shell Oil CompanyTemperature limited heaters with relatively constant current
US7490665Apr 22, 2005Feb 17, 2009Shell Oil CompanyVariable frequency temperature limited heaters
US7500528Apr 21, 2006Mar 10, 2009Shell Oil CompanyLow temperature barrier wellbores formed using water flushing
US7510000Apr 22, 2005Mar 31, 2009Shell Oil CompanyReducing viscosity of oil for production from a hydrocarbon containing formation
US7527094Apr 21, 2006May 5, 2009Shell Oil CompanyDouble barrier system for an in situ conversion process
US7533719Apr 20, 2007May 19, 2009Shell Oil CompanyWellhead with non-ferromagnetic materials
US7540324Oct 19, 2007Jun 2, 2009Shell Oil CompanyHeating hydrocarbon containing formations in a checkerboard pattern staged process
US7546873Apr 21, 2006Jun 16, 2009Shell Oil CompanyLow temperature barriers for use with in situ processes
US7549470Oct 20, 2006Jun 23, 2009Shell Oil CompanySolution mining and heating by oxidation for treating hydrocarbon containing formations
US7556095Oct 20, 2006Jul 7, 2009Shell Oil CompanySolution mining dawsonite from hydrocarbon containing formations with a chelating agent
US7556096Oct 20, 2006Jul 7, 2009Shell Oil CompanyVarying heating in dawsonite zones in hydrocarbon containing formations
US7559367Oct 20, 2006Jul 14, 2009Shell Oil CompanyTemperature limited heater with a conduit substantially electrically isolated from the formation
US7559368Oct 20, 2006Jul 14, 2009Shell Oil CompanySolution mining systems and methods for treating hydrocarbon containing formations
US7562706Oct 20, 2006Jul 21, 2009Shell Oil CompanySystems and methods for producing hydrocarbons from tar sands formations
US7562707Oct 19, 2007Jul 21, 2009Shell Oil CompanyHeating hydrocarbon containing formations in a line drive staged process
US7575052Apr 21, 2006Aug 18, 2009Shell Oil CompanyIn situ conversion process utilizing a closed loop heating system
US7575053Apr 21, 2006Aug 18, 2009Shell Oil CompanyLow temperature monitoring system for subsurface barriers
US7581589Oct 20, 2006Sep 1, 2009Shell Oil CompanyMethods of producing alkylated hydrocarbons from an in situ heat treatment process liquid
US7584789Oct 20, 2006Sep 8, 2009Shell Oil CompanyMethods of cracking a crude product to produce additional crude products
US7591310Oct 20, 2006Sep 22, 2009Shell Oil CompanyMethods of hydrotreating a liquid stream to remove clogging compounds
US7597147Apr 20, 2007Oct 6, 2009Shell Oil CompanyTemperature limited heaters using phase transformation of ferromagnetic material
US7604052Apr 20, 2007Oct 20, 2009Shell Oil CompanyCompositions produced using an in situ heat treatment process
US7610962Apr 20, 2007Nov 3, 2009Shell Oil CompanyProviding acidic gas to a subterrean formation, such as oil shale, by heating from an electrical heater and injecting through an oil wellbore; one of the acidic acids includes hydrogen sulfide and is introduced at a pressure below the lithostatic pressure of the formation to produce fluids; efficiency
US7631689Apr 20, 2007Dec 15, 2009Shell Oil CompanySulfur barrier for use with in situ processes for treating formations
US7631690Oct 19, 2007Dec 15, 2009Shell Oil CompanyHeating hydrocarbon containing formations in a spiral startup staged sequence
US7635023Apr 20, 2007Dec 22, 2009Shell Oil CompanyTime sequenced heating of multiple layers in a hydrocarbon containing formation
US7635024Oct 19, 2007Dec 22, 2009Shell Oil CompanyHeating tar sands formations to visbreaking temperatures
US7635025Oct 20, 2006Dec 22, 2009Shell Oil CompanyCogeneration systems and processes for treating hydrocarbon containing formations
US7640980Apr 7, 2008Jan 5, 2010Shell Oil CompanyThermal processes for subsurface formations
US7644765Oct 19, 2007Jan 12, 2010Shell Oil CompanyHeating tar sands formations while controlling pressure
US7673681Oct 19, 2007Mar 9, 2010Shell Oil CompanyTreating tar sands formations with karsted zones
US7673786Apr 20, 2007Mar 9, 2010Shell Oil CompanyWelding shield for coupling heaters
US7677310Oct 19, 2007Mar 16, 2010Shell Oil CompanyCreating and maintaining a gas cap in tar sands formations
US7677314Oct 19, 2007Mar 16, 2010Shell Oil CompanyMethod of condensing vaporized water in situ to treat tar sands formations
US7681647Oct 19, 2007Mar 23, 2010Shell Oil CompanyMethod of producing drive fluid in situ in tar sands formations
US7683296Apr 20, 2007Mar 23, 2010Shell Oil CompanyAdjusting alloy compositions for selected properties in temperature limited heaters
US7703513Oct 19, 2007Apr 27, 2010Shell Oil CompanyWax barrier for use with in situ processes for treating formations
US7717171Oct 19, 2007May 18, 2010Shell Oil CompanyMoving hydrocarbons through portions of tar sands formations with a fluid
US7730945Oct 19, 2007Jun 8, 2010Shell Oil CompanyUsing geothermal energy to heat a portion of a formation for an in situ heat treatment process
US7730946Oct 19, 2007Jun 8, 2010Shell Oil CompanyTreating tar sands formations with dolomite
US7730947Oct 19, 2007Jun 8, 2010Shell Oil CompanyCreating fluid injectivity in tar sands formations
US7735935Jun 1, 2007Jun 15, 2010Shell Oil CompanyIn situ thermal processing of an oil shale formation containing carbonate minerals
US7785427Apr 20, 2007Aug 31, 2010Shell Oil CompanyChromium, nickel, copper; niobium, iron manganese, nitrogen; nanonitrides; system for heating a subterranean formation;
US7793722Apr 20, 2007Sep 14, 2010Shell Oil CompanyNon-ferromagnetic overburden casing
US7798220Apr 18, 2008Sep 21, 2010Shell Oil CompanyIn situ heat treatment of a tar sands formation after drive process treatment
US7798221May 31, 2007Sep 21, 2010Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation
US7831133Apr 21, 2006Nov 9, 2010Shell Oil CompanyInsulated conductor temperature limited heater for subsurface heating coupled in a three-phase WYE configuration
US7831134Apr 21, 2006Nov 9, 2010Shell Oil CompanyGrouped exposed metal heaters
US7832484Apr 18, 2008Nov 16, 2010Shell Oil CompanyMolten salt as a heat transfer fluid for heating a subsurface formation
US7841401Oct 19, 2007Nov 30, 2010Shell Oil CompanyGas injection to inhibit migration during an in situ heat treatment process
US7841408Apr 18, 2008Nov 30, 2010Shell Oil CompanyIn situ heat treatment from multiple layers of a tar sands formation
US7841425Apr 18, 2008Nov 30, 2010Shell Oil CompanyDrilling subsurface wellbores with cutting structures
US7845411Oct 19, 2007Dec 7, 2010Shell Oil CompanyIn situ heat treatment process utilizing a closed loop heating system
US7849922Apr 18, 2008Dec 14, 2010Shell Oil CompanyIn situ recovery from residually heated sections in a hydrocarbon containing formation
US7860377Apr 21, 2006Dec 28, 2010Shell Oil CompanySubsurface connection methods for subsurface heaters
US7866385Apr 20, 2007Jan 11, 2011Shell Oil CompanyPower systems utilizing the heat of produced formation fluid
US7866386Oct 13, 2008Jan 11, 2011Shell Oil Companyproduction of hydrocarbons, hydrogen, and/or other products from various subsurface formations such as hydrocarbon containing formations through use of oxidizing fluids and heat
US7866388Oct 13, 2008Jan 11, 2011Shell Oil CompanyHigh temperature methods for forming oxidizer fuel
US7912358Apr 20, 2007Mar 22, 2011Shell Oil CompanyAlternate energy source usage for in situ heat treatment processes
US7931086Apr 18, 2008Apr 26, 2011Shell Oil CompanyHeating systems for heating subsurface formations
US7942197Apr 21, 2006May 17, 2011Shell Oil CompanyMethods and systems for producing fluid from an in situ conversion process
US7942203Jan 4, 2010May 17, 2011Shell Oil CompanyThermal processes for subsurface formations
US7950453Apr 18, 2008May 31, 2011Shell Oil CompanyDownhole burner systems and methods for heating subsurface formations
US7986869Apr 21, 2006Jul 26, 2011Shell Oil CompanyVarying properties along lengths of temperature limited heaters
US8011451Oct 13, 2008Sep 6, 2011Shell Oil CompanyRanging methods for developing wellbores in subsurface formations
US8027571Apr 21, 2006Sep 27, 2011Shell Oil CompanyIn situ conversion process systems utilizing wellbores in at least two regions of a formation
US8042610Apr 18, 2008Oct 25, 2011Shell Oil CompanyParallel heater system for subsurface formations
US8070840Apr 21, 2006Dec 6, 2011Shell Oil CompanyTreatment of gas from an in situ conversion process
US8083813Apr 20, 2007Dec 27, 2011Shell Oil CompanyMethods of producing transportation fuel
US8113272Oct 13, 2008Feb 14, 2012Shell Oil CompanyThree-phase heaters with common overburden sections for heating subsurface formations
US8146661Oct 13, 2008Apr 3, 2012Shell Oil CompanyCryogenic treatment of gas
US8146669Oct 13, 2008Apr 3, 2012Shell Oil CompanyMulti-step heater deployment in a subsurface formation
US8151880Dec 9, 2010Apr 10, 2012Shell Oil CompanyMethods of making transportation fuel
US8151907Apr 10, 2009Apr 10, 2012Shell Oil CompanyDual motor systems and non-rotating sensors for use in developing wellbores in subsurface formations
US8162059Oct 13, 2008Apr 24, 2012Shell Oil CompanyInduction heaters used to heat subsurface formations
US8162405Apr 10, 2009Apr 24, 2012Shell Oil CompanyUsing tunnels for treating subsurface hydrocarbon containing formations
US8172335Apr 10, 2009May 8, 2012Shell Oil CompanyElectrical current flow between tunnels for use in heating subsurface hydrocarbon containing formations
US8177305Apr 10, 2009May 15, 2012Shell Oil CompanyHeater connections in mines and tunnels for use in treating subsurface hydrocarbon containing formations
US8191630Apr 28, 2010Jun 5, 2012Shell Oil CompanyCreating fluid injectivity in tar sands formations
US8192682Apr 26, 2010Jun 5, 2012Shell Oil CompanyHigh strength alloys
US8196658Oct 13, 2008Jun 12, 2012Shell Oil CompanyIrregular spacing of heat sources for treating hydrocarbon containing formations
US8205674Jul 24, 2007Jun 26, 2012Mountain West Energy Inc.Apparatus, system, and method for in-situ extraction of hydrocarbons
US8220539Oct 9, 2009Jul 17, 2012Shell Oil CompanyControlling hydrogen pressure in self-regulating nuclear reactors used to treat a subsurface formation
US8224163Oct 24, 2003Jul 17, 2012Shell Oil CompanyVariable frequency temperature limited heaters
US8224164Oct 24, 2003Jul 17, 2012Shell Oil CompanyInsulated conductor temperature limited heaters
US8224165Apr 21, 2006Jul 17, 2012Shell Oil CompanyTemperature limited heater utilizing non-ferromagnetic conductor
US8225866Jul 21, 2010Jul 24, 2012Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation
US8230927May 16, 2011Jul 31, 2012Shell Oil CompanyMethods and systems for producing fluid from an in situ conversion process
US8233782Sep 29, 2010Jul 31, 2012Shell Oil CompanyGrouped exposed metal heaters
US8238730Oct 24, 2003Aug 7, 2012Shell Oil CompanyHigh voltage temperature limited heaters
US8240774Oct 13, 2008Aug 14, 2012Shell Oil CompanySolution mining and in situ treatment of nahcolite beds
US8256512Oct 9, 2009Sep 4, 2012Shell Oil CompanyMovable heaters for treating subsurface hydrocarbon containing formations
US8261832Oct 9, 2009Sep 11, 2012Shell Oil CompanyHeating subsurface formations with fluids
US8267170Oct 9, 2009Sep 18, 2012Shell Oil CompanyOffset barrier wells in subsurface formations
US8267185Oct 9, 2009Sep 18, 2012Shell Oil CompanyCirculated heated transfer fluid systems used to treat a subsurface formation
US8272455Oct 13, 2008Sep 25, 2012Shell Oil CompanyMethods for forming wellbores in heated formations
US8276661Oct 13, 2008Oct 2, 2012Shell Oil CompanyHeating subsurface formations by oxidizing fuel on a fuel carrier
US8281861Oct 9, 2009Oct 9, 2012Shell Oil CompanyCirculated heated transfer fluid heating of subsurface hydrocarbon formations
US8327681Apr 18, 2008Dec 11, 2012Shell Oil CompanyWellbore manufacturing processes for in situ heat treatment processes
US8327932Apr 9, 2010Dec 11, 2012Shell Oil CompanyRecovering energy from a subsurface formation
US8353347Oct 9, 2009Jan 15, 2013Shell Oil CompanyDeployment of insulated conductors for treating subsurface formations
US8355623Apr 22, 2005Jan 15, 2013Shell Oil CompanyTemperature limited heaters with high power factors
US8381815Apr 18, 2008Feb 26, 2013Shell Oil CompanyProduction from multiple zones of a tar sands formation
US8434555Apr 9, 2010May 7, 2013Shell Oil CompanyIrregular pattern treatment of a subsurface formation
US8448707Apr 9, 2010May 28, 2013Shell Oil CompanyNon-conducting heater casings
US8459359Apr 18, 2008Jun 11, 2013Shell Oil CompanyTreating nahcolite containing formations and saline zones
US8485252Jul 11, 2012Jul 16, 2013Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation
US8536497Oct 13, 2008Sep 17, 2013Shell Oil CompanyMethods for forming long subsurface heaters
US8555971May 31, 2012Oct 15, 2013Shell Oil CompanyTreating tar sands formations with dolomite
US8562078Nov 25, 2009Oct 22, 2013Shell Oil CompanyHydrocarbon production from mines and tunnels used in treating subsurface hydrocarbon containing formations
US8579031May 17, 2011Nov 12, 2013Shell Oil CompanyThermal processes for subsurface formations
US8606091Oct 20, 2006Dec 10, 2013Shell Oil CompanySubsurface heaters with low sulfidation rates
US8627887Dec 8, 2008Jan 14, 2014Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation
US8631866Apr 8, 2011Jan 21, 2014Shell Oil CompanyLeak detection in circulated fluid systems for heating subsurface formations
US8636323Nov 25, 2009Jan 28, 2014Shell Oil CompanyMines and tunnels for use in treating subsurface hydrocarbon containing formations
US8662175Apr 18, 2008Mar 4, 2014Shell Oil CompanyVarying properties of in situ heat treatment of a tar sands formation based on assessed viscosities
US8701768Apr 8, 2011Apr 22, 2014Shell Oil CompanyMethods for treating hydrocarbon formations
US8701769Apr 8, 2011Apr 22, 2014Shell Oil CompanyMethods for treating hydrocarbon formations based on geology
US8739874Apr 8, 2011Jun 3, 2014Shell Oil CompanyMethods for heating with slots in hydrocarbon formations
US8752904Apr 10, 2009Jun 17, 2014Shell Oil CompanyHeated fluid flow in mines and tunnels used in heating subsurface hydrocarbon containing formations
Classifications
U.S. Classification166/261
International ClassificationE21B43/243
Cooperative ClassificationE21B43/243
European ClassificationE21B43/243