US3385360A - Steam flood process for producing oil - Google Patents

Steam flood process for producing oil Download PDF

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Publication number
US3385360A
US3385360A US523882A US52388266A US3385360A US 3385360 A US3385360 A US 3385360A US 523882 A US523882 A US 523882A US 52388266 A US52388266 A US 52388266A US 3385360 A US3385360 A US 3385360A
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steam
injection
oil
rate
well
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US523882A
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Robert V Smith
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Phillips Petroleum Co
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Phillips Petroleum Co
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • E21B43/20—Displacing by water
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
    • E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection

Definitions

  • This invention relates to a process for producing oil from an oil stratum by steam flood or drive.
  • Oil is being produced from oil strata by steam flooding, which comprises injecting steam thru one or more injection wells and driving the steam thru the oil stratum toward one or more production wells so as to displace oil into a production well(s).
  • Huff and puff steam operation is also in use. This procedure involves injecting steam into an oil stratum thru an input-output well with offset wells shut in or otherwise not open to flow thereinto, so as to build up additional reservoir pressure, and thereafter terminating steam injection and opening the injection well to flow so that the heated oil (now less viscous) flows into the injection well.
  • the huff and puff operation there is no drive of steam from one well to another but rather production from an annular or generally circular section of the stratum around a single Well.
  • This invention is concerned with a steam flooding process which conserves steam by making more effective use of a minimum amount of injected steam.
  • an object of the invention to provide an improved steam flooding process for the production of oil from an oil stratum. Another object is to provide a direct drive steam process which makes more effective use of steam and the latent heat therein in a direct drive steam process. A further object is to provide a steam flooding process which produces oil more economically than processes heretofore known.
  • the invention involves injecting steam thru an injection well into an oil stratum at normal rates for a substantial period of time, so as to form a steam bubble adjacent or surrounding the injection well, and thereafter substantially reducing the rate of steam injection to no more than that of the initial injection period for another substantial period, the production well(s) being open to flow during these periods.
  • the normal steam injection rate during the initial injection period is in the range of 5,000 to 50,000 pounds of steam per hour and usually this rate will be in the range of 10,000 to 45,000 pounds per hour. Even higher steam injection rates are possible, depending upon the size of the input well, the permeability and thickness of the stratum, the character 3,385,300 Patented May 28, 1968 of the in-place oil, etc.
  • the initial steam injection is continued until the injected steam is in the range of 0.05 to 0.6 pore volumes of the sweep pattern and, preferably, in the range of 0.1 to 0.25 pore volumes.
  • the initial injection period is at least several weeks and up to six months or more, depending upon the character of the stratum, the oil, and. the well pattern or spacing being utilized.
  • the initial injection period will usually be in the range of two to six months.
  • the steam injection rate is cut back substantially and, preferably, to not more than 7 the initial injection rate. It is preferred to reduce the steam injection rate to no more than that of the normal steam injection rate, during the reduced injection rate period. A substantial advantage is obtained even when the injection rate is cut substantially to zero. In other words, the injection of steam may be cut off entirely for a substantial period between normal injection phases of the process.
  • the period of lower steam injection rates or no steam injection at all ranges from X; to several times the initial or normal steam injection rate periods. Thus, in an operation utilizing normal injection rates for a period of six months, the period of reduced or zero injection steam rate is in the range of three weeks to eighteen months or longer.
  • the cycling of steam in accordance with the invention is continued at least up to steam breakthru in the production well(s) and may be continued until oil is no longer produced. It is feasible to inject a slug of gas or a slug of gas followed by a slug of water as driving agents after sufiicient steam has been injected, intermittently, to provide sufficient steam bubble and heat to sweep the well pattern, thus further conserving steam and heat.
  • the successive periods of normal steam injection may be substantially equal or they may be varied either up or down in length, it being not essential to maintain either the periods or normal injection or of reduced injection the same in any given field operation.
  • Steam injection temperatures will range from 350 to 750 F.
  • the steam may be either a low-grade steam or a super-heated steam.
  • a decrease in pressure in the steam body in an underground reservoir causes a realignment in the fluids with the colder oil and water that have been displaced by the steam moving into the zone of higher temperature previously occupied by the steam.
  • the reservoir rock serves as a heat exchange agent between the steam and the fluids in the reservoir.
  • the cold fluids move into the hot steam zone under the influence of pressure and gravity drainage.
  • Another beneflt from the cyclic steam flood is the generation of steam within the underground reservoir from the natural and induced water contained in the high temperature steam zone.
  • the decrease in pressure on shut-in or reduced injection rate part of the cycle causes the water a in the liquid state to boil and release large volumes of steam.
  • the generation of steam from the natural and induced water in the reservoir causes the oil to be released from around the grains of the reservoir rock, and further assists in the realignment of the fluids in the reservoir.
  • the invention is a straight steam drive from injector well to producer well and is independent of how thick the reservoir is, how much is open in the injection well, and whether the steam is injected into the top, middle, or bottom of the stratum being produced. Normally, steam is injected over the entire exposed cross section of the stratum open to the injection well.
  • the invention is based upon the fact that the nature of steam permits it to move thru the oil-bearing rock or sand too fast for sufiicient utilization of all of the heat therein so that by terminating injection or reducing injection rates at spaced intervals, each volume of steam thus injected is permitted to contact the rock or sand for a longer time interval.
  • the invention is being applied in the North Burbank Unit steam injection project in Osage County, Okla., in addition to Smackover Field. Operation in the Smackover Field resulted in additional ultimate recovery of 7,500 barrels of oil for each cycle.
  • a process for producing oil from an oil stratum by steam drive from an injection well to an offset production well penetrating said stratum comprising the steps of:
  • step (2) 3. The process of claim 1 wherein the rate of steam injection in step (2) is about /2 that in step ('1).

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Description

United States Patent Oflice 3,385,360 STEAM FLOOD PROCESS FOR PRODUCING OIL Robert V. Smith, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Filed Feb. 1, 1966, Ser. No. 523,882 3 Claims. (Cl. 166-11) ABSTRACT OF THE DISCLOSURE Oil is produced from an oil stratum by a direct steam drive using normal steam injection rates in the range of 5,000 to 50,000 pounds per hour for an extended period of at least several weeks and preferably several months followed by a period of injecting steam at a substantially reduced rate amounting to no more than three fifths of the previous injection rate, and alternating these steps of full injection rate and reduced injection rate while recovering oil from an offset production well.
This invention relates to a process for producing oil from an oil stratum by steam flood or drive.
Oil is being produced from oil strata by steam flooding, which comprises injecting steam thru one or more injection wells and driving the steam thru the oil stratum toward one or more production wells so as to displace oil into a production well(s). Huff and puff steam operation is also in use. This procedure involves injecting steam into an oil stratum thru an input-output well with offset wells shut in or otherwise not open to flow thereinto, so as to build up additional reservoir pressure, and thereafter terminating steam injection and opening the injection well to flow so that the heated oil (now less viscous) flows into the injection well. In the huff and puff operation there is no drive of steam from one well to another but rather production from an annular or generally circular section of the stratum around a single Well. In direct drive steam flooding, steam is continuously injected thru the injection well(s) at least until breakthru in the production well(s) occurs. Thus, the steam requirements are considerable in this type of operation. To illustrate, in one field of operation the injection rate of steam is 44,000 pounds per hour.
This invention is concerned with a steam flooding process which conserves steam by making more effective use of a minimum amount of injected steam.
Accordingly, it is an object of the invention to provide an improved steam flooding process for the production of oil from an oil stratum. Another object is to provide a direct drive steam process which makes more effective use of steam and the latent heat therein in a direct drive steam process. A further object is to provide a steam flooding process which produces oil more economically than processes heretofore known. Other objects of the invention will become apparent to one skilled in the art upon consideration of the accompanying disclosure.
The invention involves injecting steam thru an injection well into an oil stratum at normal rates for a substantial period of time, so as to form a steam bubble adjacent or surrounding the injection well, and thereafter substantially reducing the rate of steam injection to no more than that of the initial injection period for another substantial period, the production well(s) being open to flow during these periods. The normal steam injection rate during the initial injection period is in the range of 5,000 to 50,000 pounds of steam per hour and usually this rate will be in the range of 10,000 to 45,000 pounds per hour. Even higher steam injection rates are possible, depending upon the size of the input well, the permeability and thickness of the stratum, the character 3,385,300 Patented May 28, 1968 of the in-place oil, etc. The initial steam injection is continued until the injected steam is in the range of 0.05 to 0.6 pore volumes of the sweep pattern and, preferably, in the range of 0.1 to 0.25 pore volumes. The initial injection period is at least several weeks and up to six months or more, depending upon the character of the stratum, the oil, and. the well pattern or spacing being utilized. The initial injection period will usually be in the range of two to six months.
After the initial steam injection period, the steam injection rate is cut back substantially and, preferably, to not more than 7 the initial injection rate. It is preferred to reduce the steam injection rate to no more than that of the normal steam injection rate, during the reduced injection rate period. A substantial advantage is obtained even when the injection rate is cut substantially to zero. In other words, the injection of steam may be cut off entirely for a substantial period between normal injection phases of the process. The period of lower steam injection rates or no steam injection at all ranges from X; to several times the initial or normal steam injection rate periods. Thus, in an operation utilizing normal injection rates for a period of six months, the period of reduced or zero injection steam rate is in the range of three weeks to eighteen months or longer.
The cycling of steam in accordance with the invention (a period of normal injection rate followed by a period of reduced injection rate) is continued at least up to steam breakthru in the production well(s) and may be continued until oil is no longer produced. It is feasible to inject a slug of gas or a slug of gas followed by a slug of water as driving agents after sufiicient steam has been injected, intermittently, to provide sufficient steam bubble and heat to sweep the well pattern, thus further conserving steam and heat.
The successive periods of normal steam injection may be substantially equal or they may be varied either up or down in length, it being not essential to maintain either the periods or normal injection or of reduced injection the same in any given field operation.
Steam injection temperatures will range from 350 to 750 F. Thus, the steam may be either a low-grade steam or a super-heated steam.
In a recent field operation in Nacatoch Sand reservoir of the Smackover Field in Ouachita County, Arkansas, it became necessary to reduce the rate of steam injection for several days to approximately the normal rate. Upon resumption of normal operations (injection of steam at a rate of 44,000 pounds per hour), a substantial increase in the rate of oil production was noticed. Under the reduced rate of steam injection, the pressure and temperature in the steam body in the reservoir decreased and, after resumption of normal operation, the pressure and temperature began to return to the values previously observed.
A decrease in pressure in the steam body in an underground reservoir causes a realignment in the fluids with the colder oil and water that have been displaced by the steam moving into the zone of higher temperature previously occupied by the steam. The reservoir rock serves as a heat exchange agent between the steam and the fluids in the reservoir. Thus, the heat exchange between the steam and oil in the reservoir becomes more efi'icient, which accomplishes the purpose of the steam flood at less expense. The cold fluids move into the hot steam zone under the influence of pressure and gravity drainage. Another beneflt from the cyclic steam flood is the generation of steam within the underground reservoir from the natural and induced water contained in the high temperature steam zone. The decrease in pressure on shut-in or reduced injection rate part of the cycle causes the water a in the liquid state to boil and release large volumes of steam. The generation of steam from the natural and induced water in the reservoir causes the oil to be released from around the grains of the reservoir rock, and further assists in the realignment of the fluids in the reservoir.
The invention is a straight steam drive from injector well to producer well and is independent of how thick the reservoir is, how much is open in the injection well, and whether the steam is injected into the top, middle, or bottom of the stratum being produced. Normally, steam is injected over the entire exposed cross section of the stratum open to the injection well. The invention is based upon the fact that the nature of steam permits it to move thru the oil-bearing rock or sand too fast for sufiicient utilization of all of the heat therein so that by terminating injection or reducing injection rates at spaced intervals, each volume of steam thus injected is permitted to contact the rock or sand for a longer time interval. This enables heat to be conducted into portions of the reservoir or stratum thru which the steam will not pass and, thus, the reservoir is heated more uniformly than in conventional steam flooding. Termination of injection also results in a pressure drop which causes heated oil to move into the path of the steam and subsequently be displaced. This oil cannot be recovered by continuous injection.
The invention is being applied in the North Burbank Unit steam injection project in Osage County, Okla., in addition to Smackover Field. Operation in the Smackover Field resulted in additional ultimate recovery of 7,500 barrels of oil for each cycle.
Certain modifications of the invention will become apparent to those skilled in the art and the illustrative details disclosed are not to be construed as imposing unnecessary limitations on the invention.
I claim:
1. A process for producing oil from an oil stratum by steam drive from an injection well to an offset production well penetrating said stratum comprising the steps of:
(1) injecting steam into said stratum at normal injection rates in the range of 5,000 to 50,000 pounds per hour thru said injection well for a period of one to six months until 0.05 to 0.6 pore volumes of steam have been injected;
(2) thereafter, injecting steam at a substantial rate no more than /5 of that in step (1) for a period in the range of one half to several times the period of p (3) repeating steps (1) and (2) with said production well open to flow so as to displace oil thereinto; and
(4) producing oil from said production well.
2. The process of claim 1 wherein said steam is injected at a temperature in the range of 350 to 750 F.
3. The process of claim 1 wherein the rate of steam injection in step (2) is about /2 that in step ('1).
References Cited UNITED STATES PATENTS 2,584,606 2/1952 Merriam et al. 1661'1 2,813,583 ll/1957 Marx et al. 166-40X 3,042,114 7/1962 Willman 16640X 3,193,009 7/1965 Wallace et al. 16640X FOREIGN PATENTS 511,768 8/1939 Great Britain.
STEPHEN J. NOVOSAD, Primary Examiner.
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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3948323A (en) * 1975-07-14 1976-04-06 Carmel Energy, Inc. Thermal injection process for recovery of heavy viscous petroleum
US4121661A (en) * 1977-09-28 1978-10-24 Texas Exploration Canada, Ltd. Viscous oil recovery method
US4450911A (en) * 1982-07-20 1984-05-29 Mobil Oil Corporation Viscous oil recovery method
US20090229818A1 (en) * 2006-04-11 2009-09-17 David William Tuk System and Method For Management of Steam Flooding For Oil Wells
US20150198022A1 (en) * 2014-01-13 2015-07-16 Conocophillips Company Oil recovery with fishbone wells and steam
US9488042B2 (en) 2014-04-17 2016-11-08 Saudi Arabian Oil Company Chemically-induced pulsed fracturing method
US9556718B2 (en) 2012-01-17 2017-01-31 Saudi Arabian Oil Company Non-acidic exothermic sandstone stimulation fluids
US9701894B2 (en) 2014-04-17 2017-07-11 Saudi Arabian Oil Company Method for enhanced fracture cleanup using redox treatment
US9738824B2 (en) 2011-11-23 2017-08-22 Saudi Arabian Oil Company Tight gas stimulation by in-situ nitrogen generation
US9803133B2 (en) 2012-05-29 2017-10-31 Saudi Arabian Oil Company Enhanced oil recovery by in-situ steam generation
US10053614B2 (en) 2014-04-17 2018-08-21 Saudi Arabian Oil Company Compositions for enhanced fracture cleanup using redox treatment
US10308862B2 (en) 2014-04-17 2019-06-04 Saudi Arabian Oil Company Compositions and methods for enhanced fracture cleanup using redox treatment
US11414972B2 (en) 2015-11-05 2022-08-16 Saudi Arabian Oil Company Methods and apparatus for spatially-oriented chemically-induced pulsed fracturing in reservoirs
US11739616B1 (en) 2022-06-02 2023-08-29 Saudi Arabian Oil Company Forming perforation tunnels in a subterranean formation

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB511768A (en) * 1937-11-19 1939-08-24 Mark Benson Improvements in or relating to extraction of petroleum
US2584606A (en) * 1948-07-02 1952-02-05 Edmund S Merriam Thermal drive method for recovery of oil
US2813583A (en) * 1954-12-06 1957-11-19 Phillips Petroleum Co Process for recovery of petroleum from sands and shale
US3042114A (en) * 1958-09-29 1962-07-03 Company Jersey Produc Research Process for recovering oil from underground reservoirs
US3193009A (en) * 1963-02-28 1965-07-06 Shell Oil Co Use of low-grade steam containing dissolved salts in an oil production method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB511768A (en) * 1937-11-19 1939-08-24 Mark Benson Improvements in or relating to extraction of petroleum
US2584606A (en) * 1948-07-02 1952-02-05 Edmund S Merriam Thermal drive method for recovery of oil
US2813583A (en) * 1954-12-06 1957-11-19 Phillips Petroleum Co Process for recovery of petroleum from sands and shale
US3042114A (en) * 1958-09-29 1962-07-03 Company Jersey Produc Research Process for recovering oil from underground reservoirs
US3193009A (en) * 1963-02-28 1965-07-06 Shell Oil Co Use of low-grade steam containing dissolved salts in an oil production method

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3948323A (en) * 1975-07-14 1976-04-06 Carmel Energy, Inc. Thermal injection process for recovery of heavy viscous petroleum
US4121661A (en) * 1977-09-28 1978-10-24 Texas Exploration Canada, Ltd. Viscous oil recovery method
US4450911A (en) * 1982-07-20 1984-05-29 Mobil Oil Corporation Viscous oil recovery method
US20090229818A1 (en) * 2006-04-11 2009-09-17 David William Tuk System and Method For Management of Steam Flooding For Oil Wells
US7891427B2 (en) * 2006-04-11 2011-02-22 Chevron U.S.A. Inc. System and method for management of steam flooding for oil wells
US9738824B2 (en) 2011-11-23 2017-08-22 Saudi Arabian Oil Company Tight gas stimulation by in-situ nitrogen generation
US10047277B2 (en) 2012-01-17 2018-08-14 Saudi Arabian Oil Company Non-acidic exothermic sandstone stimulation fluids
US9556718B2 (en) 2012-01-17 2017-01-31 Saudi Arabian Oil Company Non-acidic exothermic sandstone stimulation fluids
US9803133B2 (en) 2012-05-29 2017-10-31 Saudi Arabian Oil Company Enhanced oil recovery by in-situ steam generation
US20150198022A1 (en) * 2014-01-13 2015-07-16 Conocophillips Company Oil recovery with fishbone wells and steam
US10385666B2 (en) * 2014-01-13 2019-08-20 Conocophillips Company Oil recovery with fishbone wells and steam
US9701894B2 (en) 2014-04-17 2017-07-11 Saudi Arabian Oil Company Method for enhanced fracture cleanup using redox treatment
US9963631B2 (en) 2014-04-17 2018-05-08 Saudi Arabian Oil Company Composition for enhanced fracture cleanup using redox treatment
US9488042B2 (en) 2014-04-17 2016-11-08 Saudi Arabian Oil Company Chemically-induced pulsed fracturing method
US10053614B2 (en) 2014-04-17 2018-08-21 Saudi Arabian Oil Company Compositions for enhanced fracture cleanup using redox treatment
US10308862B2 (en) 2014-04-17 2019-06-04 Saudi Arabian Oil Company Compositions and methods for enhanced fracture cleanup using redox treatment
US10442977B2 (en) 2014-04-17 2019-10-15 Saudi Arabian Oil Company Compositions and methods for enhanced fracture cleanup using redox treatment
US10442978B2 (en) 2014-04-17 2019-10-15 Saudi Arabian Oil Company Compositions and methods for enhanced fracture cleanup using redox treatment
US10450499B2 (en) 2014-04-17 2019-10-22 Saudi Arabian Oil Company Compositions and methods for enhanced fracture cleanup using redox treatment
US11414972B2 (en) 2015-11-05 2022-08-16 Saudi Arabian Oil Company Methods and apparatus for spatially-oriented chemically-induced pulsed fracturing in reservoirs
US11739616B1 (en) 2022-06-02 2023-08-29 Saudi Arabian Oil Company Forming perforation tunnels in a subterranean formation

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