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 numberUS3131763 A
Publication typeGrant
Publication dateMay 5, 1964
Filing dateDec 30, 1959
Priority dateDec 30, 1959
Publication numberUS 3131763 A, US 3131763A, US-A-3131763, US3131763 A, US3131763A
InventorsBednarski Valery N, Kunetka Robert E, Towell Billy H, Woodward Charles D
Original AssigneeTexaco Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrical borehole heater
US 3131763 A
Abstract  available in
Images(4)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

May 5, 1954 R. E. KU|-|r-;TK.1=\ ETAL ELECTRICAL BoREHoLE HEATER 4 Sheets-Sheet 1 Filed Deo. 5o, 1959 May 5, 1964 R. E. KUNETKA ETAL ELECTRICAL BoREHoLE HEATER 4 Sheets-Sheet 2 Filed Dec. 30, 1959 N.. .wwwsmwww s QQXWT 1%/ JZ/,d

MF/Tl n@ May 5, 1964 Filed Dec. 30, 1959 R. E. KUNETKA ETAL ELECTRICAL BOREHOLE HEATER 4 SheP'cS-Sheekl 3 May 5, 1964 R. E. KUNETKA ETAL 3,131,763

ELECTRICAL BOREHOLE HEATER 4 Sheets-Sheet 4 Filed Dec. '50, 1959 United States Patent O 3,131,763 ELECTRICAL BBREHLE HEATER Robert E. Kunetha, Houston, Valery N. Bednarsiri, Beilaire, and Billy H. Terrell and Charles D. Woodward,

Houston, Tex., assigner-s to rlexaco lne., New York,

FLY., a corporation of eiaware Filed Dec. 3i), i959, Ser. N 862,876 6 Claims. (Ci. l @-66) This invention relates to the treatment of underground formations and, more particularly, this invention relates to a heater suitable for use in boreholes.

Various techniques have been proposed for the recovery of petroleum from underground formations. One of the techniques involves in situ combustion. In this technique, as practiced in secondary recovery operations, the .petroleum producing .formation in the vicinity of a borehole or injection well is heated to a high temperature, for example 1000c F., and oxidizing gas, such as air, is supplied to the underground formation. The combustion gases produced around the borehole migrate through the formation to an output well or wells leading from n e formation from which a petroleum product is removed.

In accordance with this invention `an improved electrical heater is provided for initiating combustion of the hydrocarbon material in the subsurface formation, which is of a simple, rugged construction capable of withstanding greater thermal shock `due to rapid temperature changes than can prior art electrical borehole heaters, and can operate at higher temperatures for longer periods of time. Heat from the heater is introduced into the borehole at a relatively rapid rate until there exists a high temperature zone around the borehole suiiicient in extent 4to sustain the in situ combustion process.

The heater, in addition to being useful in secondary recovery operations, may also be used for the carbonization of the area around the well as a means of making it preferentially wettable `to oil and thereby to improve permeability. Furthermore, the Iheater may lbe used for the removal of moisture in subsurface formations in the vicinity of the well bore and for any other application where a concentrated high temperature is desired. The heater of the present invention comprises an electrically resistive wire wound in the form of a helix threaded through annular insulators carried by an elongated supporting structure.

`For a better understanding of the invention, reference may be had -to the accompanying drawing in which:

PIG. l is a vertical sectional view through a portion of a borehole traversing subsurface formations showing therein the general arrangement of the apparatus used in accordance with this invention,

FlGS. 2, 2a, 2b, 2c and 2d illustrate in more detail the apparatus shown in FIG. l,

FIG. 3 illustrates the electrical circuitry used in the apparatus of this invention,

FiG. 4 illustrates the heater element supporting frame of the apparatus of the invention,

FG. 5 is a cross-sectional View of the apparatus at 5 5 of FIG. 2b,

FIG. 6 is a cross-sectional view of the apparatus at 6 5 of FG. 2b,

FG. 7 is a cross-sectional lview of the apparatus taken at 7-7 of FIG. 2b, and

FIG. 8 is a cross sectional view of the yapparatus taken at y8 8 of FiG. 2c.

Referring to the drawing wherein like reference numerals refer to similar elements illustrated in the various figures, there is shown in FIG. l a borehole 10 traversing a producing formation l2. The upper portion of the bore- 3,131,763 Patented May 5, 1964 ice hole l0 is lined with a casing lli having La closed casing or braden head i6 yat the upper end thereof.

The well heating system or electrical borehole heater of the present invention which is suitable for use to heat a subsurface formation, such as formation l2, in the Vicinity of a borehole comprises `a heater housing 18 which includes a thin sheath `2% having a 41/2" outside diameter and a suitable length depending upon reservoir thickness, for example, l5 feet, a bottom plug 22 attached to the sheath 20 so as to form a seal therewith and a heater head 24 attached to the upper end of the sheath 2Q, a power cable 26 which is connected to a pair of heater elements 149 and 142 disposed within the sheath 20, temperature signal cable 28 which contains seven copper conductors for transmitting electrical signals indicative of temperature variations from four thermocouples 29, Si), 3l and 33 and a thermistor v.76 to the earths surface through suitable openings in the casing head 16, and a protective cable tubing 32 attached at its lower end to the heater head 24 and at its upper end to a cable cross-over 34 having an intake structure for receiving `the cables 26 and 28 so as to introduce these cables into the protective tubing 32. The cable cross-over 34, protective cable tubing 32, and the heater housing l are supported Iin the borehole by well tubing 35 having a pup-joint 33 at the lower end thereof, which tubing is suspended from the casing head .16. The power cable 25 and the signal cable 2S are supported in the well by a plurality of ties 2.1 made of suitable banding material attached to the well tubing 36 at longitudinally `spaced points. Connected to the upper end `of the Well tubing 36, preferably through a valve 39, is a gauge 4u yfor indicating the pressure in the borehole 1%. A pipe 4-2 having a valve 44 is connected to the upper portion of the casing 1d to introduce an oxidizing gas, for example, air into the borehole. The heater housing l has a heating section 27 located in the lower portion thereof and a heat baille section 23 located in the upper portion thereof. The four therrnocouples 29, 3d, 3l and 33` are disposed in the heater housing 13 Iat longitudinally spaced apart points.

As shown in more detail in FlGS. 2, 2a, 2b, 2c, and 2d, the apparatus or" the present invention includes a hanger head do having a shoulder 47 at the upper portion thereof as shown herein supported on the edge of a lirst pipe 49 disposed between the cable cross-over 34 and the pup-joint 3S of the well tubing 35. A top plug 43 having a circumferential groove therein containing an O-ring 45 is disposed within the lower end of the pupjoint 38 to provide a seal between the interior of the pup-joint 3S and the interior of the rst pipe 49. The pup-joint 33 and the first pipe @-9 are coupled together by a lirst coupler 35. A chain hanger 43 having a loop 51 at the lower end is inserted through an opening or passageway in the hanger head d6 and is supported by a wing nut Sil threaded thereon. The power cable 26, which includes two relatively high potential conductors 17 and 19, is introduced into the cable cross-over 34 through a passage S2 in a cable cross-over head 54. A packing 56 and a packing screw gland 58 surround the cable 26 witln'n the cable cross-over head 54 so as to provide a fluid-tight joint. A set screw 6i) is inserted into the cable cross-over head 54 to restrain the power cable 26 in the passage 52. The signal cable 2S is similarly introduced into the cable cross-over 34 through a passage 62, a packing 64 and packing screw gland 66. The crossover head 54 also has a gas entry port and valve 25 communicating with the passage in which the chain hanger 48 is disposed to introduce an inert gas into the cable cross-over 34 and the protectice cable tubing 32. The valve 2S may be protected by a suitable pipe Y 3 plug 59; An O-ring 68 is disposed in a circumferential groove in the cross-over head 54 so as to form a fluidtight seal between the cross-over head 54 and a cylindrical sheath 7G of the cable cross-over 34. Attached to the loop S1 of the chain hanger 4S is a chair; 72 for supporting the cables 26 arid 2S within the cable protective tubing 32. Suitable ties 74, which are made preferably of stainless steel annealed wire, are used to lash the cables 26 and 28 to the chain 72. A thermistor 76 connected to two of the seven copper conductors of the signal cable 2S is mounted within the cable cross-over dV so as to provide an indication of the temperature therein. A cable cross-over adapter 77 having a circumferential groove containing an O-ring 'i9 couples the cable cross-over 34 to the protective cable tubing 32. Thermocouple wires 73 of the four thermocouples 29, 3i?, 31 and 33, which are preferably made of material known by the trade name Alumel and Chromel, are connected to the remaining five conductors of the signal cable 23 in the cable cross-over 34 at a cold junction terminal 75 in the vicinity of the thermistor 76. The power cable 26 and the thermocouple wires 73 are supported Within the heater head 24% by means of cable clamps '78 i and a cable bracket iii? attached to a vertical support member S1 mounted on a supporting block 84. Disposed within the heater head 24 is the uppermost or first thermocouple 29, as shown in FIG. 2b. An O-ring 33 is contained in a groove disposed around the lower portion of the heater head 24 to provide a seal between the heater head 24 and the supporting block S4. The supporting block 84 has a pair of O-rings 92 to form a seal between the supporting block S4 and the sheath 29 of the heater housing 18. The supporting block 84 also has a gas entry port and valve 86 communicating with a passage 8S which is used to introduce an inert gas into the heater housing 1S. The valve S6 may be protected by a suitable pipe plug Qil. The supporting block 34 further includes a shoulder 85 supported by the upper edge of the sheath 20. The supporting block S4- is firmly held in position within the sheath 2l) by a plurality of set screws 94,k as shown more clearly in FG. 7 of the drawing.

FIG. 2b or" the drawing shows the two power leads 17 and 19 passing through passageways 1116 and 162 in the supporting block S4, a seal being provided between each ofthe power leads 17 and 19 and the supporting block S4 by a packing 1194 and a packing screw gland 166. The wires 73 of the three thermocouples 3G, 31 and 33 disposed in the heating section 27 of the heater are fed through a passageway 168 in the supporting block 84 and a packing 110 and a packing screw gland 112 provide a seal between the thermocouple wires 73 and the supporting block 84.

A heater element support frame 114 is suspended from the supporting block 84 by means of a plurality of frame hangersV 116. The frame hangers 116 are preferably welded to the supporting block 84 and the support frame 114 is secured to the frame hangers 116 by means of a nut and bolt arrangement 118, as shown in FIG. 6 as well as in FIG. 2b of the drawing. The supporting frame 114 comprises an elongated plate 120 and two elongated L-snaped members 122 and 124 welded to opposite faces of the plate 126 to provide a frame having a cruciform transverse cross-section, as shown more clearly in FIG. 4 of the drawing. The frame 114 extends from the supporting block 84 longitudinally through the heat baille section 23 and the heating section 27 of the heater housing 18 to a point spaced a given distance from the top of the bottom plug 22 toallow for differential eXpansion associated with temperature changes in the heater Vhousing 18. The outer edges of the cruciform frame V114 are spaced from the sheath 20 of the heater housing 13 also to allow for dierential expansion due to temperature changes. The outer sheath 20 of the heater housing 18 and the portion of the supporting frame 114 within the heating section 27 of the heater housing 18 are preferably made of Ineonel which includes Ni(77.0). Cu(0.2), Fe(7.0), Mn(0.25), Si(0.25), C(0.08), S(0.0G7), and Cr(l5.0). The portion of the supporting frame 114- within the baille section 23 is preferably made of stainless steel. A plurality of lead-in brackets 126 each having a U-shaped edge opening to deine a saddle for receiving an annular insulator 127, preferably made of a ceramic material such as that known by the trade name Aisimag #222, for restraining one of the two power conductors or leads 17, 19 are mounted on the supporting frame 114, as shown in FIGS. 2b, 2c, 4 and 5. Also mounted on the supporting frame 114 are an upper heat baille 123 and a lower heat baille 13? suitably disposed in the heat Vbaille section 23 to protect the heater head 24 and the cables 26 and 2S at the upper portion of the heater from the high temperatures produced in the heating section 27. The heat bailles 128 and 130 are preferably made of insulator-tiberium ceramic liber paper. The thermocouple wires 73 are held in position against the supporting frame 114 but insulated therefrom by means of a plurality of straps 131. The thermocouple wires `V'73 are insulated throughout their entire length to a point spaced a short distance from their hot junction terminals, a iirst hot junction terminal 30 being located at the upper end, a second hot junction terminal 31 at the mid-point and a third hot junction terminal 33 at the lower end of the heating section 27.

In the heating section 27 of 4the heater the power conductors 17 and 19 are terminated at power lead terminals 132 and 134, respectively, to which 'they may be welded. A plurality of saddles vare formed in each of the four outer edges of the supporting frame 114 in the heating section 27 by removing a cup-shaped or U- shaped portion therefrom, the spacing between the saddles-115 being preferably greater at the mid-portion (not shown) than at the ends of the heating section 27. Annular insulators 127 are also inserted in each of the saddles 115 and held therein by retaining lingers or arfcuate arms 138 made by deforming a portion of the frame 114 embracing the annular insulators 127 at their outer periphery. This structure is consistent for all saddles 115 although only specioally illustrated in FIG. 4 and the upper left hand few saddles of FIG. 2c, for sake of convenience.

The heating section 27 contains two heater elements 140 and 142. Each of these heater elements is wound 'tin the form of a helix having a minor constant or uniform radius forming a `tirst coil which coil is in turn then wound in the form of a helix of major constant or uniform radius through the annular insulators 127 in the saddles 115 of the frame 1'14 to -form a second Icoil extending yfrom one of the two power lead terminals 132, 134 located at the upper end of `the heatfing section 27 to the lower end of the frame 114 and returning -to the upper end of the heating section 27 to the other of the two power lead terminals 132, 134, the pitch of each turn of the second coil being such as to receive in complementary fashion the turns of the other second coil. The ends of lthe two heater eletments 140 and 142 are preferably welded to the power lead terminals 132 and 134 to prov-ide electrical connection to the power'leads 17 and 19. The heater elements in the double helical form -are threaded through the annular insulators 127 so as to be supported by land electrically insulated from the supporting frame 114, as shown in FIGS. 2c, 2d, and 8. Each of the heater elements or wires 140 and 142 Vis preferably 175 long, formed in coils 40.5 feet long known by the trade name of #l2 Iellil` Alloy K wire. The heater elements 149 and 142 are connected in parallel and each is grounded at its electrical cen-V ter to the supporting lframe 114. This circuit arrangemeut provides a heater resistance of l1 ohms and has arid made of what is i a rating of approximately 16 kw. at 440 volts at a rating for the wire of l5 watts per square inch surface area.

The electrical circuit of the heater may be more clearly seen in FIG. 3 of the drawing. A suitable power source, which may be, for example, a 480 volt single phase 60 cycle per second source, is connected to a primary winding 156 of a power transformer 151 which has a secondary winding 152 grounded at its mid-point. The secondary winding 152 is connected across a coil 153 which with first and second variable taps 156 and 15S respectively, form an autotransformer 155 for supplying 4an adjustable voltage between the power conductors 117 and 19 connected to the two heater elements 149 and 142.

A temperature indicating device 160 which may be of any conventional type -is connected to the thermistor 76 ylocated in the cable cross-over 34 and also to each of the therrnocouples 29, 313, 31 and 33. A balancing network 162 which may be, yfor example, any suitable known bridge arrangement is selectively coupled through a three-position switch 164 having `a movable arm m and three stationary contacts zz, b and c, to one of the three thermocouples 39, 31 and 33 located in the heating section 27 oi the heater housing 18. The balancing network 162 is also coupled to a potentiometer 166 which has two iixed terminals 163 and v'176 and an adjustable tap 172. A rst reversible motor 174 is electrically controlled by the balancing network 162 and is mechanically coupled to the adjustable tap 172 of the potentiometer 166. A marker (not shown) of a stripchart recorder 167 is fitted on the tap 172 of the potentiometer v166 so as to produce a graph 176 on a stripchart 178 of the recorder 167 to provide a record of the borehole temperature thereon. The strip-chart 17S is driven at a uniform speed `by the ychart drive motor 182.

A movable Contact 184 is mounted on the tap 172 of potentiometer 166 so as to be electrically insulated therefrom. First and second electrical contacts 186 and 18S lare disposed at fixed spaced apart points so as to be electrically contacted by the movable contact 184 at various time intervals. The lirst electrical contact 186 is connected directly to one terminal of a first 110 volts, 60 cycle per second source 191 and the second electrical contact 13S is connected to the other terminal of the first ll() volt source 191 through a protective resistor 15). A relay 192 has a coil 194 connected between the second electrical contact 188 land the movable contact 184. The relay 192 also has a nst fixed contact 1136 and a cooperating first movable arm 198 normally in an open position yand second and third xed spaced apart contacts 2G13 and 262 and 'a cooperating second movable arm 294 normally contacting the third med Contact 292. The rst movable arm 198 is electrically connected to the movable contact 154 and the iirst ixed contact 196 is yconnected to the first electrical Contact 186. A second ll() volt, 6C cycle per second source 193 has a iirst terminal connected to a first terminal 295 of a second lreversible motor 296. A second terminal of the second 110 volt source 193 is connected through the second movable arm 294 and the lthird iixed .Contact 292 of the relay 152 and through a `first normally closed motor switch 268 to a second terminal 299 of the second reversible motor 2116. A third terminal 21) of the second reversible motor 2116 is connected through a second normally closed motor switch 212 to the Second lfixed contact 261B of the relay 122. A motor switch actuating arm 214 is mounted on the iirst variable tap 156 of the autotransformer 155 to open the fiest and second motor switches 26S and 212 when the desired voltage limits between the variable taps 156 and 158 are reached. The variable taps 156 and 15S of the autotransformer 155 are mechanically coupled to the second reversible motor 2156. The rst motor switch 208 .is disposed -in cooperation with the actuating arm 214 so as to provide a 'lower voltage limit for the heater elements 146 and 142 and the second motor switch 212 is disposed in cooperation with the actuating arm 214 so as to provide an upper voltage limit for the heater elements and 142.

In operation the electrical heater elements 140 and 142 may be assembled within the heater housing 18 at any convenient location but preferably without connecting thereto the power and signal cables 26 and 25 which may be done at the well site. The temperature indicating device 160, the strip-chart recorder 167, the balancing network 162, the relay 192 and the first and second reversible motors 174 and 296 may be installed in a vantype truck for ease of operation and protection from the elements. At the well site the necessary length of the insulation coated power cable 26, for example, a Teflon cable, is connected to the power leads 17 and 19 in the heater head 24. The heater head 24 is then attached to the heater housing sheath 20 and the interior of the heater housing 1S is pressurized through valve 86 located in the support block S4 to approximately 200 p.s.i.g. to protect the housing 18 from high borehole pressure. The power and signal cables 26 and 28 and the chain 72 are taped or tied together and threaded through successive joints of the protective tubing 32 for approximately 200 feet and, preferably, the number of feet necessary to prevent the cable cross-over 34 from being immersed in the borehole liquid. The heater housing 1S and its contents are then placed in the borehole and the protective tubing 32, with the cables enclosed, is made up into a string as the heater housing 18 is lowered into the well. The cable cross-over 34 through which the cables 26 and 28 pass horn inside to the outside thereof is then connected to the upper end of the protective tubing 32 and this section of the string is pressurized through the valve 25 in the cross-over 34 to approximately 200 p.s.i.g. to insure against collapsing of this section during normal operations when the annulus pressure is about 500 p.s.i.g., or higher.

The perforated pup-joint 38 is next placed in the string to allow the well bore to be flushed from the bottom upward with a gas, for example, carbon dioxide, prior to pulling the heater from the borehole following the completion of the in situ combustion operation. Successive joints of well tubing 36 are then made up in the tubing string with the cables 26 and 28 banded or tied to the string by ties 21, preferably, at each joint, until the heating section 27 of the heater housing 13 is lowered to a total depth adjacent to the formation to be treated, as shown in FIG. l of the drawing.

The braden head 16 of the well 10 is installed with the cables 26 and 28 passing therethrough and packed olf pressure tight. The power cable 26 is connected to the autotransformer and the signal cable 23 is connected to the temperature indicating device and two of the conductors of the signal cable 23 also are connected to the balancing network 162 so as to couple the balancing network 162 to one of the three thermocouples 30, 31 and 33 in the heating section 27 through the three-position switch 164.

With the down hole equipment in place, an air compressor (not shown) is operated to force air through the pipe 42 into the annular space between the well casing 14 and the outside of the strings of tubing 32 and 36. The air may be injected into the well through the pipe 42 at a relatively high initial pressure to remove the borehole tiuid and then reduced by a substantial amount. The voltage is then applied to the power cable 26 to supply energy to the heater elements 140 and 142. The system of the present invention has been so designed that, if desired, full load may be applied to the heater elements 146 and 142 at any time without regard to a thermal gradient.

The temperature indicating device 160 continuously and simultaneously indicates the temperature of five longitudinally spaced points in the borehole, at the thermistor 76 which provides indications of the temperature in the cable cross-over 34, at the first thermocouple 29 which provides an indication of the temperature in the heater head 24 and at the thermocouples 3i), 31 and 33 which provide indications of the temperature at the upper, middle and lower portions, respectively, of the heating section 27. The temperature detected by one of the thermocouples 30, 31 or 33 may be recorded in the strip-chart recorder 167 by placing the movable arm m iu contact with one of the stationary contacts a, b or c, respectively, of the three-position switch 164. As shown in FIGURE 3 of the drawing, the movable arm m is in contact With iixed contact b of the three-position switch 164 so that a record will be provided of the temperature detected by the thermocouple 31 located in the middle portion of the heating section 27. Thus, the voltage produced by the thermocouple 31 will be applied to the balancing network 162. The potentiometer 166 has a constant voltage applied to the tWo fixed terminals 168 and 176 to produce a range oi' voltages which may be used to balance the voltage produced by the thermocouple 31. The required voltage to balance-the balancing network 162 is derived from the adjustable tap 172 of the potentiometer 166, the portion of which is adjusted by the first reversible motor 174. When the balancing network 162 is in equilibrium the iirst motor 174 is stationary, but when the voltage produced by the therrnocouple 31 increases, the unbalanced condition will cause the first motor 174 to move the tap 172 in one direction until a balancing voltage is reached, and when the voltage produced by the thermocouple 31 is decreased, the unbalanced condition will cause the first motor 174 to move the tap 172 of the potentiometer 166 in the opposite direction until a balancing voltage is reached, so as to again produce au equilibrium condition in the balancing network 162 at which time the rst reversible motor 174 ceases to .drive the adjustable tap 172. Since the position of the tap 172 of the potentiometer 166 is an indication of the temperature in the middle portion of the heating section 27, a marker mounted on the tap 172 of the potentiometer 166 produces a graph 176 on the strip chart 178 of the recorder 167.

v In order to control the temperature range within which the heater elements 14) and 142 are to operate the first and second electrical contacts 136 and 188 are positioned at spacedV apart points so as to cause an increase in the voltage applied to the conductors 17 and 19 of the power cable 26 when the temperature in the heating section 27 falls to the minimum desired temperature and to cause a decrease in the voltage applied to the conductors 17 and 19 of the power cable 26 when the temperature in the heating section reaches the desired maximum temperature. When the desired maximum temperature is produced in the heating section 27 the movable contact 184 mounted on the tap 172 is in electrical contact with the second electrical contact 183 which shorts out the coil 1% of the relay 192. With the coil 194 shorted the second movable arm 204 contacts the third xed contact 292 of the relay 192 to complete the circuit from the second llO volt source 193 through the lirst normally closed motor switch 26S to the second terminal 209 of the second reversible motor 266. The variable tap 156 which carries the actuatirig arm 214 of the autotransformer 155 is then driven to the right as illustrated in FIGURE 3 of the drawing to decrease the voltage between the first and second variable taps 156 and 158 and thus between conductors 17 and 19 of the power cable 26. The first variable tap 156 will continue to move toward the right until the actuating arm 214 opens the irst motor switch 26S thusl to provide the minimum voltage applied to the conductors 17 and 19 of the power cable 26. The decrease in voltage between the conductors 17 and 19 produces a decrease in the arnount of energy supplied to the heating section 27. This will tend to cause a decrease in the temperature in the heating section 27 and thus Vthe rst reversible motor 174 in response to the output from the balancing network 162 will drive the tap 172 of the potentiometer 166 toward the first electrical Contact 186. When the tap 172 reaches the point on the potentiometer 166 corresponding to the desired minimum temperature the movable Contact 184 will contact the first electrical contact 136 to energize the coil 194 of the relay 192. When the coil 194 is energized the rst movable arm 198 contacts the lirst fixed contact 196 which continues to connect the coil 194 to the first 110 volt source 191 even after the movable contact 184 hasy been disconnected from the first electrical Contact 186. When the coil 194 is energized the second movable arm 204 of the relay 192 is in contact with the second ixed Contact 200 of the relay 192. With the movable arm 204 contacting the second iixed Contact 260, the second ll() volt source 193 is connected through the second normally closed motor switch 212 to the third terminal 210 of the second reversible motor 2%. The variable taps 156 and 158 of the autotransformer 155 will now move toward the left as illustrated in FIGURE 3 of the drawing Lmtil the actuating arm 214 on the variable tap 156 opens the second motor switch 212 thus to provide the maximum voltage applied to the two conductors 17 Vand 19 of the power cable 26. This maximum voltage will be applied continuously to the heating elements and 142 tmtil the desired maximum temperature is reached in the heating section 27 at which time the movable contact 184 will contact the second electrical contact 188, as shown in FIG. 3 of the drawing to short circuit the coil 194 of the relay 192 to again place the second movable arm 2li-- in contact with the third Xed contact 202 of the relay 192 to cause motor 266 to drive the first and second variable taps 156 and 155 or the autotransformer toward the right in the direction which decreases the voltage applied to the conductors 17 and 19 of the power cable 26. This operation is repeated for any desired length of time.

In one well in which an in situ combustion operation was performed with the heater of the present invention, an initial pressure of 680 p.s.i.g. was maintained in the well for about one hour after which time the pressure was decreased to 500 p.s.i.g. at which level it was held constant for five hours. During this period of time, the fluid in the well bore was displaced into the subsurface formations. The air injection rate during this period was about 340,000 cubic feet per day. After about two days of operation, the air injection ratewas reduced and varied between about 160,000 to 200,000 cubic feet per day for the remainder of the in situ combustion operation. The electrical power to the heater was turned on and increased over a period of ten hours to a load of 360 volts and 28.2 amperes, with a recorded temperature of approximately 870 F. After the borehole temperature reached approximately 870 F., the temperature in the well bore increased without an increase of power input to the electrical heater. The power to the heater was then cut off and the temperature continued to increase to about l,350 F. and then gradually decreased over a period of about three hours to approximately 950 F. At this point the power was again turned on and gradually increased to 440 volts and 33.5 amperes where it remained for about l2() hours, i.e. until the in situ combustion operation was completed.

Although in the above-mentioned in situ combustlon operation of one well the heater operated at 950 F. for a period of 120 hours, it has been successfully operated at higher temperatures for longer periods of time and 1s capable of sustained operation at l,500 F.

Accordingly, it can be seen that an improved heater for the recovery of petroleum by thermal methodshas been provided. Furthermore, the invention has provided a heater which is easily positioned in a borehole by the use of standard oil field supplies ordinarily found at a Well site which eliminates the need for expensive armored mul ti-conductor cables.

Obviously, many modifications and variations of the invention as hereinabove set forth may be made Without departing from the spirit and scope thereof and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. An electrical borehole heater comprising in combination an elongated heater housing having a heating section below a heat baille section, an electrically resistive element located in said heating section, a support frame for said element disposed Within said housing, said frame extending longitudinally over the lengaA of both said heating and heat baille sections, said comprising elongated ilat plates disposed transversely along a longitudinal axis to form a cruciform cross-section, a plurality of openings in said frame located in said heating section and near the longitudinal exterior edges of said plates, a plurality of annular insulators for supporting said resistive element and adapted to be inserted in said openings, electric circuit rneans in said housing for supplying electrical energy to said resistive element, and means for suspending said housinJ at a predetermined location in a borehole.

2. An electrical borehole heater as set forth in claim 1 wherein said electrically resistive element is wound in the forni of a first helix of a irst constant radius which first helix is Wound in the form of a second helix of a second constant radius substantially greater than the iirst radius, and the internal diameter of each of said annular insulators is substantially equal to the external diameter of the first helix.

3. An electrical borehole heater as set forth in claim l wherein said sus ending means includes a string of protective tubing connected to the upper portion of said heater housing coaxial therewith, and wherein Said electric circuit means includes a power cable disposed within said protective tubing, said string of protective tubing including means for providing a fluid-tight seal between the interior and exterior thereof.

4. An electrical borehole heater as set forth in claim 3 further including means disposed within said protective tubing for supporting said power cable.

5. An electrical borehole heater as set forth in claim 4 wherein said supporting means includes a chain and a plurality of longitudinally spaced ties attaching said power cable to said chain.

6. An electrical borehole heater as set forth in claim 1 further including temperature responsive means in said heater housing, and means responsive to said temperature responsive means for controlling the flow of electrical energy to said resistive element.

References Cited in the tile of this patent UNITED STATES PATENTS 1,140,982 Huff May 25, 1915 1,841,332 Kranz Jan. 12, 1932 2,771,140 Barclay et al. Nov. 20, 1956 2,792,895 Carpenter May 2l, 1957 2,836,248 Covington May 27, 1958 FOREIGN PATENTS 316,463 Great Britain Aug. 1, 1929 331,436 Great Britain `luly 3, 1930

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1140982 *Apr 6, 1915May 25, 1915Louise Guidry MossOperating oil-wells.
US1841332 *May 9, 1929Jan 12, 1932Grigsby Grunow CompanyResistance device
US2771140 *Aug 28, 1953Nov 20, 1956Socony Mobil Oil Co IncSubsurface igniter
US2792895 *May 3, 1954May 21, 1957Union Oil CoWell heater
US2836248 *Nov 13, 1951May 27, 1958Union Oil CoWell heater
GB316463A * Title not available
GB331436A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4570715 *Apr 6, 1984Feb 18, 1986Shell Oil CompanyFormation-tailored method and apparatus for uniformly heating long subterranean intervals at high temperature
US4585066 *Nov 30, 1984Apr 29, 1986Shell Oil CompanyWell treating process for installing a cable bundle containing strands of changing diameter
US4704514 *Jan 11, 1985Nov 3, 1987Egmond Cor F VanHeating rate variant elongated electrical resistance heater
US4805698 *Nov 17, 1987Feb 21, 1989Hughes Tool CompanyPacker cooling system for a downhole steam generator assembly
US4834174 *Nov 17, 1987May 30, 1989Hughes Tool CompanyCompletion system for downhole steam generator
US4886118 *Feb 17, 1988Dec 12, 1989Shell Oil CompanyConductively heating a subterranean oil shale to create permeability and subsequently produce oil
US5060287 *Dec 4, 1990Oct 22, 1991Shell Oil CompanyHeater utilizing copper-nickel alloy core
US5065818 *Jan 7, 1991Nov 19, 1991Shell Oil CompanySubterranean heaters
US5255742 *Jun 12, 1992Oct 26, 1993Shell Oil CompanyHeat injection process
US5297626 *Jun 12, 1992Mar 29, 1994Shell Oil CompanyOil recovery process
US6269876 *Mar 8, 1999Aug 7, 2001Shell Oil CompanyElectrical heater
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 CompanyIn situ thermal processing of a coal formation to produce nitrogen and/or sulfur containing formation fluids
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 CompanyIn situ thermal processing of a coal formation with a selected vitrinite reflectance
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 CompanyIn situ thermal processing of a hydrocarbon containing formation using a selected production well spacing
US6712137Apr 24, 2001Mar 30, 2004Shell Oil CompanyIn situ thermal processing of a coal formation to pyrolyze a selected percentage of hydrocarbon material
US6715546Apr 24, 2001Apr 6, 2004Shell Oil CompanyIn situ production of synthesis gas from a hydrocarbon containing formation through a heat source wellbore
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 CompanyIn situ thermal processing of a hydrocarbon containing formation to produce nitrogen containing formation fluids
US6715549Apr 24, 2001Apr 6, 2004Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation with a selected atomic oxygen to carbon ratio
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 CompanyIn situ thermal processing of a hydrocarbon containing formation and ammonia production
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 CompanyIn situ thermal processing of a hydrocarbon containing formation to pyrolyze a selected percentage of hydrocarbon material
US6732796Apr 24, 2001May 11, 2004Shell Oil CompanyIn situ production of synthesis gas from a hydrocarbon containing formation, the synthesis gas having a selected H2 to CO 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 CompanyProduction of synthesis gas from a hydrocarbon containing formation
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 CompanyIn situ thermal processing of a hydrocarbon containing formation by controlling a pressure of the formation
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 CompanyIn situ thermal processing of a coal formation using a controlled heating rate
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 CompanyIn situ thermal processing of a hydrocarbon containing formation using a relatively slow heating rate
US6761216Apr 24, 2001Jul 13, 2004Shell Oil CompanyIn situ thermal processing of a coal formation to produce hydrocarbon fluids and synthesis gas
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 CompanyIn situ thermal processing of coal formation with a selected hydrogen content and/or selected H/C ratio
US6866097Apr 24, 2001Mar 15, 2005Shell Oil CompanyIn situ thermal processing of a coal formation to increase a permeability/porosity of the formation
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 CompanyIn situ thermal processing of a hydrocarbon containing formation using pressure and/or temperature control
US6877555Apr 24, 2002Apr 12, 2005Shell Oil CompanyIn situ thermal processing of an oil shale formation while inhibiting coking
US6880633Apr 24, 2002Apr 19, 2005Shell Oil CompanyIn situ thermal processing of an oil shale formation to produce a desired product
US6880635Apr 24, 2001Apr 19, 2005Shell Oil CompanyIn situ production of synthesis gas from a coal formation, the synthesis gas having a selected H2 to CO ratio
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 CompanyIn situ thermal processing of a hydrocarbon containing formation having a selected total organic carbon content
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 thermal processing of an oil shale formation in a reducing environment
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
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 CompanyIn situ thermal processing of an oil shale formation using horizontal heat sources
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 CompanySitu thermal processing of a coal formation using pressure and/or temperature control
US6981548Apr 24, 2002Jan 3, 2006Shell Oil CompanyIn situ thermal recovery from a relatively permeable formation
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 CompanyIn situ thermal processing of an oil shale formation using a pattern of heat sources
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
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
US6994168 *Apr 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
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
US7032660 *Apr 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
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
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
US7077198Oct 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
US7086468Apr 24, 2001Aug 8, 2006Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using heat sources positioned within open wellbores
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
US7114566Oct 24, 2002Oct 3, 2006Shell Oil CompanyIn situ thermal processing of a hydrocarbon containing formation using a natural distributed combustor
US7424915Apr 22, 2005Sep 16, 2008Shell Oil CompanyVacuum pumping of conductor-in-conduit heaters
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
US7681647Mar 23, 2010Shell Oil CompanyMethod of producing drive fluid in situ in tar sands formations
US7683296Mar 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 CompanyHigh strength alloys
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
US7798221Sep 21, 2010Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation
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
US7841425Nov 30, 2010Shell Oil CompanyDrilling subsurface wellbores with cutting structures
US7845411Dec 7, 2010Shell Oil CompanyIn situ heat treatment process utilizing a closed loop heating system
US7849922Dec 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 CompanyIn situ oxidation of subsurface formations
US7866388Jan 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
US7942203May 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
US8011451Sep 6, 2011Shell Oil CompanyRanging methods for developing wellbores in subsurface formations
US8027571Sep 27, 2011Shell Oil CompanyIn situ conversion process systems utilizing wellbores in at least two regions of a formation
US8042610Oct 25, 2011Shell Oil CompanyParallel heater system for subsurface formations
US8070840Apr 21, 2006Dec 6, 2011Shell Oil CompanyTreatment of gas from an in situ conversion process
US8083813Dec 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
US8162059Apr 24, 2012Shell Oil CompanyInduction heaters used to heat subsurface formations
US8162405Apr 24, 2012Shell Oil CompanyUsing tunnels for treating subsurface hydrocarbon containing formations
US8172335May 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
US8196658Jun 12, 2012Shell Oil CompanyIrregular spacing of heat sources for treating hydrocarbon containing formations
US8220539Jul 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
US8224165Jul 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
US8233782Jul 31, 2012Shell Oil CompanyGrouped exposed metal heaters
US8238730Aug 7, 2012Shell Oil CompanyHigh voltage temperature limited heaters
US8240774Aug 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
US8257112Sep 4, 2012Shell Oil CompanyPress-fit coupling joint for joining insulated conductors
US8261832Sep 11, 2012Shell Oil CompanyHeating subsurface formations with fluids
US8267170Sep 18, 2012Shell Oil CompanyOffset barrier wells in subsurface formations
US8267185Sep 18, 2012Shell Oil CompanyCirculated heated transfer fluid systems used to treat a subsurface formation
US8272455Sep 25, 2012Shell Oil CompanyMethods for forming wellbores in heated formations
US8276661Oct 2, 2012Shell Oil CompanyHeating subsurface formations by oxidizing fuel on a fuel carrier
US8281861Oct 9, 2012Shell Oil CompanyCirculated heated transfer fluid heating of subsurface hydrocarbon formations
US8327681Dec 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
US8355623Jan 15, 2013Shell Oil CompanyTemperature limited heaters with high power factors
US8356935Oct 8, 2010Jan 22, 2013Shell Oil CompanyMethods for assessing a temperature in a subsurface formation
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
US8448707May 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
US8485256Apr 8, 2011Jul 16, 2013Shell Oil CompanyVariable thickness insulated conductors
US8485847 *Aug 30, 2012Jul 16, 2013Shell Oil CompanyPress-fit coupling joint for joining insulated conductors
US8502120Apr 8, 2011Aug 6, 2013Shell Oil CompanyInsulating blocks and methods for installation in insulated conductor heaters
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
US8586866Oct 7, 2011Nov 19, 2013Shell Oil CompanyHydroformed splice for insulated conductors
US8586867Oct 7, 2011Nov 19, 2013Shell Oil CompanyEnd termination for three-phase insulated conductors
US8606091Oct 20, 2006Dec 10, 2013Shell Oil CompanySubsurface heaters with low sulfidation rates
US8608249Apr 26, 2010Dec 17, 2013Shell Oil CompanyIn situ thermal processing of an oil shale formation
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
US8732946Oct 7, 2011May 27, 2014Shell Oil CompanyMechanical compaction of insulator for insulated conductor splices
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
US8789586Jul 12, 2013Jul 29, 2014Shell Oil CompanyIn situ recovery from a hydrocarbon containing formation
US8791396Apr 18, 2008Jul 29, 2014Shell Oil CompanyFloating insulated conductors for heating subsurface formations
US8816203Oct 8, 2010Aug 26, 2014Shell Oil CompanyCompacted coupling joint for coupling insulated conductors
US8820406Apr 8, 2011Sep 2, 2014Shell Oil CompanyElectrodes for electrical current flow heating of subsurface formations with conductive material in wellbore
US8833453Apr 8, 2011Sep 16, 2014Shell Oil CompanyElectrodes for electrical current flow heating of subsurface formations with tapered copper thickness
US8851170Apr 9, 2010Oct 7, 2014Shell Oil CompanyHeater assisted fluid treatment of a subsurface formation
US8857051Oct 7, 2011Oct 14, 2014Shell Oil CompanySystem and method for coupling lead-in conductor to insulated conductor
US8857506May 24, 2013Oct 14, 2014Shell Oil CompanyAlternate energy source usage methods for in situ heat treatment processes
US8859942Aug 6, 2013Oct 14, 2014Shell Oil CompanyInsulating blocks and methods for installation in insulated conductor heaters
US8881806Oct 9, 2009Nov 11, 2014Shell Oil CompanySystems and methods for treating a subsurface formation with electrical conductors
US8939207Apr 8, 2011Jan 27, 2015Shell Oil CompanyInsulated conductor heaters with semiconductor layers
US8943686Oct 7, 2011Feb 3, 2015Shell Oil CompanyCompaction of electrical insulation for joining insulated conductors
US8967259Apr 8, 2011Mar 3, 2015Shell Oil CompanyHelical winding of insulated conductor heaters for installation
US9016370Apr 6, 2012Apr 28, 2015Shell Oil CompanyPartial solution mining of hydrocarbon containing layers prior to in situ heat treatment
US9022109Jan 21, 2014May 5, 2015Shell Oil CompanyLeak detection in circulated fluid systems for heating subsurface formations
US9022118Oct 9, 2009May 5, 2015Shell Oil CompanyDouble insulated heaters for treating subsurface formations
US9033042Apr 8, 2011May 19, 2015Shell Oil CompanyForming bitumen barriers in subsurface hydrocarbon formations
US9048653Apr 6, 2012Jun 2, 2015Shell Oil CompanySystems for joining insulated conductors
US9051829Oct 9, 2009Jun 9, 2015Shell Oil CompanyPerforated electrical conductors for treating subsurface formations
US9080409Oct 4, 2012Jul 14, 2015Shell Oil CompanyIntegral splice for insulated conductors
US9080917Oct 4, 2012Jul 14, 2015Shell Oil CompanySystem and methods for using dielectric properties of an insulated conductor in a subsurface formation to assess properties of the insulated conductor
US9127523Apr 8, 2011Sep 8, 2015Shell Oil CompanyBarrier methods for use in subsurface hydrocarbon formations
US9127538Apr 8, 2011Sep 8, 2015Shell Oil CompanyMethodologies for treatment of hydrocarbon formations using staged pyrolyzation
US9129728Oct 9, 2009Sep 8, 2015Shell Oil CompanySystems and methods of forming subsurface wellbores
US9181780Apr 18, 2008Nov 10, 2015Shell Oil CompanyControlling and assessing pressure conditions during treatment of tar sands formations
US9226341Oct 4, 2012Dec 29, 2015Shell Oil CompanyForming insulated conductors using a final reduction step after heat treating
US9309755Oct 4, 2012Apr 12, 2016Shell Oil CompanyThermal expansion accommodation for circulated fluid systems used to heat subsurface formations
US9337550Nov 18, 2013May 10, 2016Shell Oil CompanyEnd termination for three-phase insulated conductors
US20020046883 *Apr 24, 2001Apr 25, 2002Wellington Scott LeeIn situ thermal processing of a coal formation using pressure and/or temperature control
US20030079877 *Apr 24, 2002May 1, 2003Wellington Scott LeeIn situ thermal processing of a relatively impermeable formation in a reducing environment
US20030098149 *Apr 24, 2002May 29, 2003Wellington Scott LeeIn situ thermal recovery from a relatively permeable formation using gas to increase mobility
US20030098605 *Apr 24, 2002May 29, 2003Vinegar Harold J.In situ thermal recovery from a relatively permeable formation
US20030102126 *Apr 24, 2002Jun 5, 2003Sumnu-Dindoruk Meliha DenizIn situ thermal recovery from a relatively permeable formation with controlled production rate
US20030131993 *Apr 24, 2002Jul 17, 2003Etuan ZhangIn situ thermal processing of an oil shale formation with a selected property
US20030131995 *Apr 24, 2002Jul 17, 2003De Rouffignac Eric PierreIn situ thermal processing of a relatively impermeable formation to increase permeability of the formation
US20030131996 *Apr 24, 2002Jul 17, 2003Vinegar Harold J.In situ thermal processing of an oil shale formation having permeable and impermeable sections
US20030136558 *Apr 24, 2002Jul 24, 2003Wellington Scott LeeIn situ thermal processing of an oil shale formation to produce a desired product
US20030136559 *Apr 24, 2002Jul 24, 2003Wellington Scott LeeIn situ thermal processing while controlling pressure in an oil shale formation
US20030141067 *Apr 24, 2002Jul 31, 2003Rouffignac Eric Pierre DeIn situ thermal processing of an oil shale formation to increase permeability of the formation
US20030142964 *Apr 24, 2002Jul 31, 2003Wellington Scott LeeIn situ thermal processing of an oil shale formation using a controlled heating rate
US20030146002 *Apr 24, 2002Aug 7, 2003Vinegar Harold J.Removable heat sources for in situ thermal processing of an oil shale formation
US20030164239 *Apr 24, 2002Sep 4, 2003Wellington Scott LeeIn situ thermal processing of an oil shale formation in a reducing environment
US20030173085 *Oct 24, 2002Sep 18, 2003Vinegar Harold J.Upgrading and mining of coal
US20040144541 *Oct 24, 2003Jul 29, 2004Picha Mark GregoryForming wellbores using acoustic methods
US20040211554 *Apr 24, 2002Oct 28, 2004Vinegar Harold J.Heat sources with conductive material for in situ thermal processing of an oil shale formation
US20040211557 *Apr 24, 2002Oct 28, 2004Cole Anthony ThomasConductor-in-conduit heat sources for in situ thermal processing of an oil shale formation
US20070045265 *Apr 21, 2006Mar 1, 2007Mckinzie Billy J IiLow temperature barriers with heat interceptor wells for in situ processes
US20070095536 *Oct 20, 2006May 3, 2007Vinegar Harold JCogeneration systems and processes for treating hydrocarbon containing formations
US20070127897 *Oct 20, 2006Jun 7, 2007John Randy CSubsurface heaters with low sulfidation rates
US20070131419 *Oct 20, 2006Jun 14, 2007Maria Roes Augustinus WMethods of producing alkylated hydrocarbons from an in situ heat treatment process liquid
US20070131420 *Oct 20, 2006Jun 14, 2007Weijian MoMethods of cracking a crude product to produce additional crude products
US20070221377 *Oct 20, 2006Sep 27, 2007Vinegar Harold JSolution mining systems and methods for treating hydrocarbon containing formations
US20080035346 *Apr 20, 2007Feb 14, 2008Vijay NairMethods of producing transportation fuel
US20080035348 *Apr 20, 2007Feb 14, 2008Vitek John MTemperature limited heaters using phase transformation of ferromagnetic material
US20080035705 *Apr 20, 2007Feb 14, 2008Menotti James LWelding shield for coupling heaters
US20080038144 *Apr 20, 2007Feb 14, 2008Maziasz Phillip JHigh strength alloys
US20080107577 *Oct 20, 2006May 8, 2008Vinegar Harold JVarying heating in dawsonite zones in hydrocarbon containing formations
US20080128134 *Oct 19, 2007Jun 5, 2008Ramesh Raju MudunuriProducing drive fluid in situ in tar sands formations
US20080135244 *Oct 19, 2007Jun 12, 2008David Scott MillerHeating hydrocarbon containing formations in a line drive staged process
US20080135253 *Oct 19, 2007Jun 12, 2008Vinegar Harold JTreating tar sands formations with karsted zones
US20080135254 *Oct 19, 2007Jun 12, 2008Vinegar Harold JIn situ heat treatment process utilizing a closed loop heating system
US20080142216 *Oct 19, 2007Jun 19, 2008Vinegar Harold JTreating tar sands formations with dolomite
US20080142217 *Oct 19, 2007Jun 19, 2008Roelof PietersonUsing geothermal energy to heat a portion of a formation for an in situ heat treatment process
US20080173442 *Apr 20, 2007Jul 24, 2008Vinegar Harold JSulfur barrier for use with in situ processes for treating formations
US20080173444 *Apr 20, 2007Jul 24, 2008Francis Marion StoneAlternate energy source usage for in situ heat treatment processes
US20080173450 *Apr 20, 2007Jul 24, 2008Bernard GoldbergTime sequenced heating of multiple layers in a hydrocarbon containing formation
US20080174115 *Apr 20, 2007Jul 24, 2008Gene Richard LambirthPower systems utilizing the heat of produced formation fluid
US20080217004 *Oct 19, 2007Sep 11, 2008De Rouffignac Eric PierreHeating hydrocarbon containing formations in a checkerboard pattern staged process
US20080217015 *Oct 19, 2007Sep 11, 2008Vinegar Harold JHeating hydrocarbon containing formations in a spiral startup staged sequence
US20080277113 *Oct 19, 2007Nov 13, 2008George Leo StegemeierHeating tar sands formations while controlling pressure
US20090014180 *Oct 19, 2007Jan 15, 2009George Leo StegemeierMoving hydrocarbons through portions of tar sands formations with a fluid
US20090014181 *Oct 19, 2007Jan 15, 2009Vinegar Harold JCreating and maintaining a gas cap in tar sands formations
US20090071652 *Apr 18, 2008Mar 19, 2009Vinegar Harold JIn situ heat treatment from multiple layers of a tar sands formation
US20090078461 *Apr 18, 2008Mar 26, 2009Arthur James MansureDrilling subsurface wellbores with cutting structures
US20090084547 *Apr 18, 2008Apr 2, 2009Walter Farman FarmayanDownhole burner systems and methods for heating subsurface formations
US20090090509 *Apr 18, 2008Apr 9, 2009Vinegar Harold JIn situ recovery from residually heated sections in a hydrocarbon containing formation
US20090095476 *Apr 18, 2008Apr 16, 2009Scott Vinh NguyenMolten salt as a heat transfer fluid for heating a subsurface formation
US20090095477 *Apr 18, 2008Apr 16, 2009Scott Vinh NguyenHeating systems for heating subsurface formations
US20090095479 *Apr 18, 2008Apr 16, 2009John Michael KaranikasProduction from multiple zones of a tar sands formation
US20090126929 *Apr 18, 2008May 21, 2009Vinegar Harold JTreating nahcolite containing formations and saline zones
US20090189617 *Jul 30, 2009David BurnsContinuous subsurface heater temperature measurement
US20090194269 *Oct 13, 2008Aug 6, 2009Vinegar Harold JThree-phase heaters with common overburden sections for heating subsurface formations
US20090194282 *Oct 13, 2008Aug 6, 2009Gary Lee BeerIn situ oxidation of subsurface formations
US20090194329 *Oct 13, 2008Aug 6, 2009Rosalvina Ramona GuimeransMethods for forming wellbores in heated formations
US20090194524 *Oct 13, 2008Aug 6, 2009Dong Sub KimMethods for forming long subsurface heaters
US20090200025 *Oct 13, 2008Aug 13, 2009Jose Luis BravoHigh temperature methods for forming oxidizer fuel
US20090200031 *Oct 13, 2008Aug 13, 2009David Scott MillerIrregular spacing of heat sources for treating hydrocarbon containing formations
US20090200854 *Oct 13, 2008Aug 13, 2009Vinegar Harold JSolution mining and in situ treatment of nahcolite beds
US20090260823 *Oct 22, 2009Robert George Prince-WrightMines and tunnels for use in treating subsurface hydrocarbon containing formations
US20090260824 *Oct 22, 2009David Booth BurnsHydrocarbon production from mines and tunnels used in treating subsurface hydrocarbon containing formations
US20090272533 *Apr 10, 2009Nov 5, 2009David Booth BurnsHeated fluid flow in mines and tunnels used in heating subsurface hydrocarbon containing formations
US20090272535 *Nov 5, 2009David Booth BurnsUsing tunnels for treating subsurface hydrocarbon containing formations
US20090272578 *Nov 5, 2009Macdonald Duncan CharlesDual motor systems and non-rotating sensors for use in developing wellbores in subsurface formations
US20100089586 *Oct 9, 2009Apr 15, 2010John Andrew StaneckiMovable heaters for treating subsurface hydrocarbon containing formations
US20100096137 *Oct 9, 2009Apr 22, 2010Scott Vinh NguyenCirculated heated transfer fluid heating of subsurface hydrocarbon formations
US20100101783 *Oct 9, 2009Apr 29, 2010Vinegar Harold JUsing self-regulating nuclear reactors in treating a subsurface formation
US20100101784 *Oct 9, 2009Apr 29, 2010Vinegar Harold JControlling hydrogen pressure in self-regulating nuclear reactors used to treat a subsurface formation
US20100108310 *Oct 9, 2009May 6, 2010Thomas David FowlerOffset barrier wells in subsurface formations
US20100108379 *Oct 9, 2009May 6, 2010David Alston EdburySystems and methods of forming subsurface wellbores
US20110124223 *May 26, 2011David Jon TilleyPress-fit coupling joint for joining insulated conductors
US20110124228 *Oct 8, 2010May 26, 2011John Matthew ColesCompacted coupling joint for coupling insulated conductors
US20110132661 *Oct 8, 2010Jun 9, 2011Patrick Silas HarmasonParallelogram coupling joint for coupling insulated conductors
US20110134958 *Oct 8, 2010Jun 9, 2011Dhruv AroraMethods for assessing a temperature in a subsurface formation
US20140069896 *Sep 9, 2013Mar 13, 2014Foro Energy, Inc.Light weight high power laser presure control systems and methods of use
USRE35696 *Sep 28, 1995Dec 23, 1997Shell Oil CompanyHeat injection process
WO2001081239A2 *Apr 24, 2001Nov 1, 2001Shell Internationale Research Maatschappij B.V.In situ recovery from a hydrocarbon containing formation
WO2001081239A3 *Apr 24, 2001May 23, 2002Shell Oil CoIn situ recovery from a hydrocarbon containing formation
Classifications
U.S. Classification166/60, 166/64
International ClassificationE21B36/04, E21B36/00
Cooperative ClassificationE21B36/04
European ClassificationE21B36/04