CA1077833A - Secondary recovery process utilizing water saturated with gas - Google Patents

Secondary recovery process utilizing water saturated with gas

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Publication number
CA1077833A
CA1077833A CA282,959A CA282959A CA1077833A CA 1077833 A CA1077833 A CA 1077833A CA 282959 A CA282959 A CA 282959A CA 1077833 A CA1077833 A CA 1077833A
Authority
CA
Canada
Prior art keywords
gas
integer
water
fluid
group
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA282,959A
Other languages
French (fr)
Inventor
Joseph C. Allen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Texaco Development Corp
Original Assignee
Texaco Development Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Texaco Development Corp filed Critical Texaco Development Corp
Priority to CA282,959A priority Critical patent/CA1077833A/en
Application granted granted Critical
Publication of CA1077833A publication Critical patent/CA1077833A/en
Expired legal-status Critical Current

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Abstract

SECONDARY RECOVERY PROCESS UTILIZING WATER
SATURATED WITH GAS
(D#70,212 -F) ABSTRACT OF THE DISCLOSURE
Hydrocarbons are recovered from subterranean formations by injecting into a hydrocarbon bearing formation via an injection well a fluid comprising water saturated with a gas such as natural gas, carbon dioxide, etc., forcing the said fluid through the formation and recovering hydro-carbons through a production well.

-I-

Description

';'8~;3 ., :: BACKGROUND OF TE~E IMVENTION
- FIELD OF THE INVENTION
.
This invention relates to a secondary recovery process for recovering hydrocarbons from a subterranean -~ hydrocarbon-bearing formation penetrated by an injection well and a production well wherein a ~luid such as water saturated with a gas is utilized to displace hydrocarbons ; .
'7' in the ~ormation toward a production well.

PRIOR ART
:, The production of petroleum products is usually -; .
accomplished by drilling into a hydrocarbon-bearing for-mation and utilizing one of the well-known recovery methods ~; for the recovery of the hydrocarbons. However, it is ~: recognized that these primary recovery techniques may recover only a minor portion of the petroleum products present in ~ the formation particularly when applied to reservoirs of -~ viscous crudes~ Even the use of improved recovery practices involving heating, miscible flooding, water flooding and ~` steam processing may still leave up to 70-80 percent of the ~, . .
~,J~: original hydrocarbons in place.

Thus, many large reserves of petroleum fluids rom which only small recoveries have been realized by .....
~ ~ present commercial recovery methods, are yet to reach a ::
` potential recovery approaching their estimated oil-in-place.

Water flooding is one of the more widely practiced secondary recovery methods. A successful water flood may result in recovery of 30-50 percent of the original hydrocarbons left in place. However, generally the application of water flooding to many crudes results in : much lower recoveries.
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The newer development in recovery methods for heavy crudes is ~he use of steam injection which has been applied in several modifications, including the "push-pull"
technique and through-put methods, and has resulted in significant recoveries in some areas. Crude recovery of this process is enhanced through the beneficial effects of the drastic viscosity reduction that accompanies an increase in ternperature. This reduction in viscosity facilitates the production of hydrocarbons since it improves their mobility, i.e., it increases their ability to flow.
However, ~he application o~ these secondary recovery techniques to depleted ormations may have major quantities of oil-in-place, since the crude is tightly bound to the sand particles of the fo~nation, that is, the sorptive capacity of the sand for the crude is great. In addition, interfacial tension between the immiscible phases resul~s in entrapping crude in the pores, thereby reducing recovery. Another disadvantage is the tendency of the aqueous drive fluid to finger, since its viscosity is considerably less than that of the crude, thereby reducing the efficiency of the processes. Another disadvantage is the tendency of the aqueous drive fluid to remove additional gas by diffusion from the in-place oil thus further reducing the already lowered formation oil volurne and increasing the viscosity of the oil.
This is a de~inite need in the art for a water flooding process in which the aqueous fluid forced through the formation does not remove gas ~rorn the in-place oil.
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SUMMARY OF THE INVENTION
Th~s invention relates to a process for recovering hydrocarbons from a subterranean hydrocarbon-bearing forma-tion penetxated by an injection well and a production well which comprises:
a) injecting into the formation via an injection well a driving fluid comprising water saturated at the injection pressure with a gas selected fxom the group con-sisting of natural gas, air, carbon dioxide, flue gas, ammonia and mixtures thereof.-b) forcing the said fluid through the formationand c) recovering hydrocarbons through the production well.

DETAI~ED DESCRIPTION OF THE INVENTION
Prior to practicing the process of this invention it is someti~es desirable to open up a communication path through the formation by a hydraulic fracturing operation.
Hydraulic fracturing is a well-known technique or establish-ing a communication path between an injection well and a production well. Fracturing is usually accomplished by forcing a liquid such as water, oil or any other suitable hydrocarbon fraction into the formation at pressures of from about 300 to about 3000 psig which are sufficient to rupture the formation and to open up channels therein. By use of this method it is possible to position the racture at any desired vertical location with respect to the bottom of the oil-filled zone. It is not essential that the fracture planes be horizontally oriented, although it is of course pre~erable that they be. After the fracture has been established, and without diminishing the ~racture pressure, a propping agent may be injected into the ~racture in order to prevent healing of ~he fracture which would destroy its usefulness for fluid flow communication purposes.
Gravel, metal shot, glass beads, sand, etc, and mixtures thereof are generally employed as propping agents. Which sand is utilized as the propping agent particles have a Tyler mesh size of from about 8 to about 40 are preferred (i.e., from about 0.016 to about 0.093 inches).
In the next step of the process of this invention the driving fluid is prepared by saturating water with gas such as natural gas, air, carbon dioxide, flue gas, ammonia and mixtures thereof at pressure of about 100 to about 6000 psi and at a temperature of about 40 to about 150F.
Generally the injection pressure will vary from about 300 to about 3000 psig. The temperature of the gas-saturated water injected into the formation via the injection well can likewise be varied over a wide-range and generally will be from about 40 to about 150F and preferably from about 70 to about 100F.
If desired, the driving 1uid, that is the gas-saturated water employed may comprise alkaline gas-saturated water or an alkaline, gas-saturated, water composition con-taining a minor amount of a solubilizing agent. The advantageous results achieved with the aqueous alkaline medium used in the pracess of this invention are believed to be derived from the wettability improving characteristics of the alkaline agent and when the solubilizing agenk is employed it is believed that the advantageous results are --4~

' 1~77~33 derived from the solubilizing action on the crude oil ~nd especially on the asphaltene fractions. The solubilizing agent is believed to be effective in releasing the crude from the pore surface or sand surfaces as the case may be so that the surface can be exposed to the alkaline agent.
Useful alkaline agents include compounds selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, and a basic salts of the alkaline metal or alkaline earth metals which are capable of hydrolyzing in an aqueous medium to a given alkaline solution. The concentration of the alkaline agent employed is generally from about 0.001 to 0.5 molar. Also, alkaline materials such as sodium hypochlorite are highly effective as alkaline agents. Examples of these es~ecially useful alkaline agents include sodium hydroxide, potassium hydroxide, lithium hydroxide, ammoni~m hydroxide, sodium hypochlori~te, sodium carbonate, and potassium carbonate.
A wide variety of solubilizng agents are useful in the process of this invention including water-soluble oxyalkylated, nitrogen-containing aromatic compounds where preferably the initiator, i.e., the aromatic com~ound, contains not more than 12 carbon atoms and the number of oxyalkyl units is about 5 to about 60. One especially use-ful group o~ the water-soluble, oxyalkylated, nitrogen-containing aromatic compounds are those having the formula:

R (OR')aOH, wherein R is selected from the group consisting of:

~N ~ ~ S ~ ~

1~77833 whexein R' is alkylene of from 2 to 5 inclusive carbon atoms and a is an integer of from about S to about 50 and prefer-ably from about 5 to about 20. These novel water-soluble, oxyalkylated products can be conveniently prepared by a number of processes well-known in the art and one method ~or their preparation is more completely described in U.S.
Patent 3,731,741 which is incorporated herein by reference in its entirety.
Another group of solubilizing agents which are highly useful in the process of this invention include block-type oxyalkylated compounds of the formula:

R(OC3H6)b (OC2H4)cO

A block-type oxyalkylated compound wherein R is selected from the group consisting of: :

a) o:~N~3 ~3so 2 ~,~,.....
~, .

`` ~077f~33 c~ b~,~

b is from about 3 to about 20, c is from about 10 to about 50 and wherein the sum of b plus c is not more than about 60.
Typical water-soluble, oxyalkylated nitrogen-containing solubilizing agents include ethoxylated-8- hydroxy quinolines of the general formula:
~ ' ''`.
H~CI~o O~J, wherein a is, for example, 5, 8, 11 or 25. Propoxylated 8-quinoline sulfonic acid compounds of the formula:

~ ~.
SOz--~0C3 I`/G);~ ~IJ

where a is for example 5, 12, or 14~are also highly useful solubilizing agents.
Another group of water-soluble, oxyalkylated, nitrogen-containing solubilizing agents which are highly useful in the process of this invention include compounds of the formula:

C~(O~

~ f.
~C1177833 wherein R~is alkylene of from 2 to 5 carbon atoms and d is an integer of from about 5 to about SO. ~11 of the water-soluble, oxyalkylated, nitrogen-containing solubil-zing compounds set out above can be prepared in the same manner as described in U.S. Patent 3,731,741. Typical compounds of this group include:

-C-(OC~2c~2)12o8 (a)~

~---C-(OCH2C82)z308 (b) and O CH3 .
~ -C- (O-Cd-ClI2 ) 801i ( cl .

A wide variety of surfactants such as linear alkylaryl sulfonates, alkyl poly-ethoxylated sulfates, etc.
may also be included as a part of the driving fluid composition.
This invention i5 best understoody by reference to the followîng example which is offered only as an ~

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~ 1~77833 illustrative embodiment of this inv~ntion and is nok intend-ed to be limitative.
E X A M P L E
In a field in which ~he primary production has already been exhausted, an injection well is completed in the hydrocarbon bearing formation and perforations are formed between the interval of 8910-8930 feet. A production well is drilled approximately 405 feet distance from the injection well, and perforations are similarly made in the same hydrocarbon bearing formation at 8915-8935 feet.
The hydrocarbon bearing formation in both the injection well and the production well is hydraulically fractured using conventional techniques, and a gravel-sand mixture is injected into the fracture to hold it open and prevent healing of the ~racture.
In the next step water saturated with natural gas at a temperature 60F and 5000 psig made alkaline with sodium hypochlorite and containing 0.002 weight percent of a solubilizing agent of the formula:

~--c--(oc~ c~ OH

is injected into the formation at this same pressure and at a rate of one barrel per minute. Injection of the driving fluid is continued at the rate of one barrel per minute and the production o~ oil via the production well gradually increases. Injection is continued and at the end o~ 60 days the rate of production is substantially greater than with water injection alone.

Claims (14)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation penetrated by an injecting well and a production well which comprises:
a) injecting into the formation via an injection well a fluid comprising water saturated at the injection pressure with a gas selected from the groups consisting of natural gas, carbon dioxide, ammonia, flue gas, and mixtures thereof, b) forcing the said fluid through the formation, and c) recovering hydrocarbons through the production well.
2. The process of Claim 1 wherein the said gas-saturated water contains a surfactant.
3. The process of Claim 1 wherein the gas employed to saturate the water is natural gas.
4. The process of Claim 1 wherein an alkaline agent selected from the group consisting of sodium hydroxide and sodium hypochlorite is included with the said fluid.
5. The process of Claim 4 wherein the water saturated with gas is made alkaline through the addition of sodium hydroxide.
6. The process of Claim 4 wherein in step (a) the water saturated with gas is made alkaline by the addi-tion of sodium hypochlorite.
7. The method of Claim 1 wherein in step (a) the water-saturated with gas is heated to formation temperature prior to injection.
8. The process of Claim 1 wherein a solubilizing agent is added to the water saturated with gas.
9. The process of Claim 8 wherein the said solubilizing agent is a compound of the formula:

R(OR')aoH

wherein R is selected from the group consisting of:

, and , ~nd J

R' is alkylene of from 2 to 5 carbon atoms and a is from about 5 to about 50.
10. The process of Claim 9 wherein the said solubilizing agent is a compound of the formula:

, wherein R' is alkylene of from 2 to 5 carbon atoms and d is an integer of from about 5 to about 50.
11. The process of Claim 9 wherein the said solubilizing agent is a compound of the formula:

R(OC3H6)b(OC2H4)cOH

wherein R is selected from the group consisting:

, and b is an integer of from about 3 to about 20, c is an integer of from about 10 to about 50 and the sum of b plus c is not more than 60.
12. A fluid comprising water-saturated with a gas selected from the group consisting of natural gas, carbon dioxide, ammonia, flue gas and mixtures thereof con-taining a minor amount of a solubilizing agent selected from the group consisting of compounds of the formula:
A) R(OR')aOH
wherein R is selected from the group consisting of:

, and R' is alkylene of from 2 to 5 carbon atoms and a is an integer of from about 5 to about 50, B) R(OC3H6)b(OC2H4)c wherein R has the same meaning as previously described, b is an integer of from about 3 to about 20, c is an integer of from about 10 to about 50 and wherein the sum of b plus c is not more than about 60, and c) wherein R' has the same meaning as previously described and d is an integer of from about 5 to about 50.
13. The fluid of Claim 12 wherein the said solubilizing agent is a compound of the formula:

, wherein R' is alkylene of from 2 to 5 carbon atoms and d is an integer of from about 5 to about 50.
14. The fluid of Claim 12 wherein the said solubilizing agent is a compound of the formula:
R (OC3H6)b(OC2H4)cOH
wherein R is selected from the group consiting of:

, and , b is an integer of from about 3 to about 20, c is an integer of from about 10 to about 50 and wherein the sum of b plus c is more than about 60.
CA282,959A 1977-07-18 1977-07-18 Secondary recovery process utilizing water saturated with gas Expired CA1077833A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA282,959A CA1077833A (en) 1977-07-18 1977-07-18 Secondary recovery process utilizing water saturated with gas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA282,959A CA1077833A (en) 1977-07-18 1977-07-18 Secondary recovery process utilizing water saturated with gas

Publications (1)

Publication Number Publication Date
CA1077833A true CA1077833A (en) 1980-05-20

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10012064B2 (en) 2015-04-09 2018-07-03 Highlands Natural Resources, Plc Gas diverter for well and reservoir stimulation
US10344204B2 (en) 2015-04-09 2019-07-09 Diversion Technologies, LLC Gas diverter for well and reservoir stimulation
US10982520B2 (en) 2016-04-27 2021-04-20 Highland Natural Resources, PLC Gas diverter for well and reservoir stimulation

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10012064B2 (en) 2015-04-09 2018-07-03 Highlands Natural Resources, Plc Gas diverter for well and reservoir stimulation
US10344204B2 (en) 2015-04-09 2019-07-09 Diversion Technologies, LLC Gas diverter for well and reservoir stimulation
US10385258B2 (en) 2015-04-09 2019-08-20 Highlands Natural Resources, Plc Gas diverter for well and reservoir stimulation
US10385257B2 (en) 2015-04-09 2019-08-20 Highands Natural Resources, PLC Gas diverter for well and reservoir stimulation
US10982520B2 (en) 2016-04-27 2021-04-20 Highland Natural Resources, PLC Gas diverter for well and reservoir stimulation

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