US3485300A - Method and apparatus for defoaming crude oil down hole - Google Patents

Description

Dec. 23, 1969 c. J. ENGLE 3,485,300

METHOD AND APPARATUS FOR DEFOAMING CRUDE OIL DOWN HOLE Filed Dec. 20, 1967 i [GAS s GAS FREE OIL INVENTOR.

C. J. ENGLE ATTORNEYS United States Patent 0 3,485,300 METHOD AND APPARATUS FOR DEFOAMING CRUDE OIL DOWN HOLE Charles J. Engle, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Filed Dec. 20, 1967, Ser. No. 692,223 Int. Cl. E211) 39/00; E211 43/24 US. Cl. 166-265 7 Claims ABSTRACT OF THE DISCLOSURE thereof. This further releases any residual gas. The oil then accumulates above the packer. The production tubing extends into the collected oil and the oil is now dumped efliciently up through said tubing.

This invention relates to defoaming crude oil down hole. In one of its aspects it relates to improving pumpability of oil from a well bottom when the oil accumulating therein is foaming. In another of its aspects, the invention relates to the provision of apparatus for better pumping foamy oil by defoaming the same prior to pumping same from the well.

In one of its concepts the invention provides a method for defoaming oil down hole in an oil well which comprises causing said oil to travel through an upwardly extended heating unit placed down hole in the well just above the oil collecting therein, the unit being adapted to receive the oil through a packer which otherwise bars flow of oil upwardly into the casing. Oil is then caused to overflow through the heating unit and to collect around the same and around a production tubing also extending down into the well. Heating of the oil causes dissolved gases such as carbon dioxide and others to emanate from the top of the heating unit and to pass upwardly through the casing while oil flows downwardly around the heating unit and collects in the bottom of the well above the packer. The production tubing is rendered operative to remove defoamed oil more efficiently from the well. In another of its concepts the invention provides apparatus for defoaming and producing a defoamed oil v wardly extending heating unit in open communication 4 through said packer with the oil below the packer, a production tubing extending down the casing to a point just above said packer and pumping means for pumping oil up through said tubing. In a further concept of the invention there is provided an upwardly extending tubular heater which extends sufficiently above the level of oil which can accumulate above the packer that oil from which substantially all gases have been as it were boiled off in the heating unit will now pass downwardly outside the heating unit as a film for removal of any residual gases still dissolved in the oil and to further defoam the oil.

It has been noted in the field that crude oil produced into production well bores sometimes is quite foamy and cannot be pumped efficiently with the conventional bottom hole pumps. The foaming occurs usually as a result of the release of dissolved gases e.g. CO and others.

3,485,300 Patented Dec. 23, 1969 These gases are ordinarily present especially when in situ combustion has been practiced and the gases are products of combustion. As the pressure on the oil drops from reservoir to bottom hole pressure these gases have a tendency to foam up the oil. In the case of low gravity this is oils .such as Morichal oils as encountered in Venezuela. The foaming is quite extensive and the foam is quite stable.

It is an object of this invention to provide a method for producing foamy oil in a more eflicient manner. It is another object of this invention to provide a method for defoaming oil down hole in a well in which it is being produced. It is a further object of the invention to provide an apparatus for defoaming oil down hole of a well in which it is being produced.

Other aspects, concepts and objects of this invention are apparent from a study of this disclosure, the drawing and the appended claims.

According to the invention, there is provided a method for defoaming and producing foamy crude oil which comprises providing down hole in a well producing such oil heating Zone in which the oil can be heated, passing the foamy oil through said zone, therein heating said oil to a temperature and for a time suflicient to substantially release gases from said oil, then pumping said oil from said well.

In one embodiment of the invention there is provided down hole in the well casing a packer positioned just above the level at which foamy oil enters into the casing. Surmounting an aperture in said packer so oil can flow thereinto is placed a tubing which can be heated. This causes oil as it enters from the formation into the well casing to pass upwardly through the heated tubing. At the top of the heated tubing, owing to increased pressure provided by expansion of the gases the gases are substantially released from the oil. The oil overflows the top end of the heated tubing and falls back in the bottom of the well casing just above the packer and is therefore collected and ready for pumping. The usual production tubing equipped with the usual pump extends downwardly into the now defoamed oil and can be used to pump the defoamed oil to the surface.

Referring now to the drawing, 1 is a well casing, 2 is a packer across the bottom of the well casing but above perforations 3 through which foamy oil enters from formation 4 into the very bottom end of the well casing. 5 is a heated tube sealingly engaging the aperture 6 in packer 2. 7 is a production tubing and 8 is a pump operated by a sucker rod 9. 10 are the pump valves of the usual pump.

In operation the foamy oil entering through perforations 3 passes upwardly through aperture 6 and passes still upwardly into tube 5. The oil ultimately fills tube 5 and overflows at the top as indicated by the arrows and is collected above the packer as shown by the dotted lines. On its way upwardly through the tube the oil temperature is considerably raised say to about 300 degrees Fahrenheit for a time of about 60 seconds. This results in considerable expansion of the gas in the oil which then escapes at the top end of the tubing and passes upwardly through the casing. The now heated oil flows downwardly outside tubing 5. While flowing downwardly this oil can additionally release gas therefrom if any remains therein sufficient to interfere with proper pumping of the same. Collected oil is pumped through valves 10 by means of pump 8 and sucker rod 9 outwardly through production tubing 7.

In the embodiment just described the tubular heater consists of a 10 foot length of 2-inch tubings spirally wound with a Chromalox tubular element obtainable from Edwin L. Wiegand Company of Pittsburgh. The

heater coils are shown jacketed by a metal such as copper to insure even heating. The copper jacket can be in the form of a fluted or finned tube for added surface. Heater energy is supplied from the surface through Reda pump type electrical cables, not shown for sake of siniplicity, and the heater is also equipped with a thermocouple for surface monitoring of heater temperature, also not shown for sake of simplicity.

The foot length and the 2-inch tubing need not b used. If desired, a longer tube, say up to and exceeding feet and a 3-inch tubing can be used for rapid production, if desired.

Thus the heater dimensions and power requirements will depend upon the rate of oil production and oil temperature required for eflicient gas stripping.

Although an electrical heater has been described a "ga fire heater can be used to carry out this invention. At present the electrical means appears to be simpler. Accordingly, the invention has been described with such a means.

The invention as noted is particularly applicable to p'roducing oil from in situ combustion project. As the in situ combustion process progresses and the oil is heated in the reservoir, it will be possible to reduce the heat requirements in the heating zone or stripper. In such event the extended tube through which the oil flows upwardly and down around the outside of which the oil flows downwardly as a film will provide a surface from which any gases in the oil can disengage.

Thus, according to the invention natural and in situ combustion gases flow to the surface in the annulus between the casing and the producing tubing and the oil flows out the top of the tubular heater or its equivalent and into the space above the packer so that a conventional sucker rod pump or the like can lift the oil to the surface. The invention is a specific helpful adjunct to the pumping operation in that the pump is now supplied with ample oil which more readily flows into the areas around the pump since gases, particularly the excess gases have been removed.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, the drawing and the appended claims to the invention the essence of which is that there has been provided a method and a concomitant apparatus for down hole heating of a foamy oil and causing said oil to release its gas so that its gas will not impede the pumping operation, the method providing down hole in the well producing such foamy oil the heating zone in which the oil can be heated passing the foamy oil through said zone and therein heating said oil to a temperature and for a time sufficient to substantially release gases from said oil and then pumping said oil from said well; the apparatus comprising in combination down hole in a well casing and packer a heated tube or equivalent surmounting said packer a distance sufficient to suitably heat the oil to cause gases therein to develop enough pressure to disengage themselves from the oil, which can be quite viscous, the oil then flowing downwardly around said tubing or equivalent, there being also above said packer space for accumulation of oil and there being in said casing a production tubing enclosing a pump means wherewith the pump accumulated oil from above the packer to the ground surface.

I claim:

1. A method for producing a foamy oil from a well which comprises causing a foamy oil which is in said well to pass from within said well directly through a heating zone provided down hole in said well, in said heating zone heating said oil in said well to a temperature and for a time sufficient to substantially release gases from said oil and then pumping said oil from said well.

2. A method according to claim 1 wherein the oil is passed through an upwardly extending heated zone and down around said zone and collected in the well from which it is then pumped to the surface.

3. A method according to claim 2 wherein there is provided a zone in the bottom of the well which impedes flow of oil upwardly in the well, there is provided a concentric heating zone extending a substantial distance upwardly through said well and communicating through said first mentioned zone upwardly through said heating zone and into the portion of the well above said first mentioned zone and pumped therefrom to the surface of the ground.

4. A method according to claim 1 for producing a foamy oil from a well which comprises accumulating said foamy oil in said well, passing said foamy oil upwardly through a heating zone located in said well in open communication with said foamy oil, discharging heated foamy oil from said heating zone into a zone in said well above and maintained separate from said foamy oil in said zone disengaging gas from said heated foamy oil, passing said gas upward and ultimately from said well, accumulating in said zone heated oil from which gas has now been disengaged and pumping the thus treated and accumulated oil from said well.

- 5. An apparatus comprising in combination a well casing extending into a well in the ground, a packer across the bottom of said well casing at a point above which liquid in the ground enters into said casing thus impeding flow of liquid accumulating in said casing upwardly through said casing, and means defining a heating zone in said casing just above said packing in direct open communication through said packing with liquid therebelow, means above said packer in said well for pumping liquid therefrom and from above said packer.

6. An apparatus according to claim 5 wherein the heating zone means is constituted at least in part by an extended tubing or pipe of a length sufiicient to heat foamy liquid passing therethrough to a temperature and for a time sufiicient to cause gases therein to become disengaged, said pipe extending from the packer to a level above the means for pumping to provide an upflow for heating Oll and an overflow downward for heated oil, thereby permitting gases disengaged from the oil during its heating to become separated from said oil and to pass upwardly in the well.

7. An apparatus according to claim 6 wherein the heating tube is provided with fins on at least one surface thereof.

References Cited UNITED STATES PATENTS 1,820,291 8/ 1931 Strandell 1666 X 2,134,610 10/1938 Hogg 166-60 2,3 62,680 11/1944 Troupe 16660 2,980,184 4/1961 Reed 16639 X 3,113,622 12/1963 Carpenter l66-39 STEPHEN I NOVOSAD, Primary Examiner US. Cl. X.R. 16660, 302, 314

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