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Publication numberUS20070187093 A1
Publication typeApplication
Application numberUS 11/698,556
Publication dateAug 16, 2007
Filing dateJan 26, 2007
Priority dateFeb 15, 2006
Publication number11698556, 698556, US 2007/0187093 A1, US 2007/187093 A1, US 20070187093 A1, US 20070187093A1, US 2007187093 A1, US 2007187093A1, US-A1-20070187093, US-A1-2007187093, US2007/0187093A1, US2007/187093A1, US20070187093 A1, US20070187093A1, US2007187093 A1, US2007187093A1
InventorsWilliam C. Pfefferle
Original AssigneePfefferle William C
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method for recovery of stranded oil
US 20070187093 A1
The present invention provides a method of recovering stranded oil wherein heated fluid is injected into a reservoir containing stranded oil in a region near the reservoir ceiling. The heated oil drains toward the reservoir floor and is recovered via a production well.
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1. A method of recovering stranded oil comprising:
a) injecting heated fluid into a reservoir containing stranded oil in a region near the reservoir ceiling;
b) allowing heated oil to drain toward the reservoir floor; and
c) recovering drained oil via a production well.
2. The method of claim 1 wherein the heated fluid is produced downhole using a downhole combustor.
3. The method of claim 1 wherein the heated fluid is provided from the surface and passed downhole.
4. The method of claim 1 wherein the heated fluid is injected via a horizontal well.
5. The method of claim 4 wherein the horizontal well comprises a plurality of branches.
6. The method of claim 1 wherein the injected fluid is at a temperature high enough to result in cracking of the stranded oil.
7. The method of claim 6 wherein said temperature is greater than 800F.
8. The method of claim 1 wherein the heated fluid is produced by passage of a fluid through a heated upper layer.
9. The method of claim 8 wherein the fluid to be heated comprises nitrogen.
10. The method of claim 8 wherein the fluid to be heated comprises carbon dioxide.
11. The method of claim 1 wherein the heated fluid is produced downhole by in-situ combustion.
  • [0001]
    This invention relates to a method for the recovery of stranded oil left behind in an oil reservoir after recovery of oil by conventional means.
  • [0002]
    Oil fields typically are abandoned after oil can no longer be produced economically by known secondary or tertiary recovery methods. At this point, the remaining oil in place often represents as much as two-thirds of the amount originally in place. Of the remaining oil, about twenty percent is considered technically recoverable using advanced techniques such as, for example, carbon dioxide flooding. Unfortunately, for stranded oil in most U.S. fields, carbon dioxide is not available. Moreover, there is a need to recover far more stranded oil than can be recovered by known advanced methods such as carbon dioxide flooding. It is therefore an object of the present invention to make possible economic recovery of nearly all the remaining stranded oil in place.
  • [0003]
    The oil coating on the reservoir minerals can be flushed off much more effectively than by carbon dioxide flooding. By heating the oil to an elevated temperature along with reservoir pressurization, the oil can be flushed off of the sand, for example, in the reservoir. In the present invention, hot fluids are injected near the top of the reservoir such that fluid flow is downward toward the reservoir floor by gravity drainage aided by the downward fluid flow. Inert gases present in injected fluids provide reservoir repressurization. Preferably, fluid is injected through a horizontal well to best distribute the flow across the reservoir ceiling. Advantageously, the hot combustion gases are produced using a downhole combustor. If available, carbon dioxide is added to combustion products for sequestration.
  • [0004]
    FIG. 1 depicts an isometric of horizontal injection well with branches protruding into the reservoir.
  • [0005]
    In the present invention 10, as shown in FIG. 1, hot fluids such as steam or combustion gases may be produced at the surface and injected downhole via injection well 12. However, heat losses advantageously may be reduced by generating the heated fluids downhole as by a downhole combustor with fuel and air supplied from the surface. Combustion gases produced by downhole combustion typically are reduced in temperature by addition of an inert fluid such as nitrogen or carbon dioxide. Steam may be produced by spraying water into the hot combustion products. Hot fluids also may be generated by in-situ combustion with air supplied from the surface.
  • [0006]
    Hot fluid is provided near the reservoir ceiling 14 using any conventional method known in the art such that the flow forms a gas blanket layer which flows downward toward the reservoir floor. Thus heated oil drains toward the reservoir floor 16. Typically the fluid is injected via a horizontal well 18. To distribute the fluid over a wider area, the horizontal well may have horizontal branches 20 as shown in FIG. 1.
  • [0007]
    Temperature of the injected fluid in most cases is below that which would result in significant cracking of the oil. However, if significant reduction in the oil viscosity is desired, the temperature of the injected fluid is controlled to a value which will result in cracking of the oil. Temperatures high enough for cracking can be provided by use of in-situ combustion. Cracking of the oil is desirable where the viscosity of the stranded oil is higher than that originally produced in primary production. Oil draining to the reservoir floor may be recovered through an existing production well. However, it may be advantageous to provide a new horizontal production well located on or near the reservoir floor.
  • [0008]
    After the heated fluid has heated an upper portion of the reservoir flushing the oil downward, heat from oil depleted layers may be utilized to heat a cold fluid such as nitrogen or carbon dioxide thus providing heated fluid for recovery of oil from lower levels.
  • [0009]
    While the present invention has been described in considerable detail with reference to a preferred method for the recovery of stranded oil left behind in an oil reservoir after recovery of oil by conventional means as described herein, other methods exhibiting the characteristics taught herein are contemplated. Therefore, the spirit and scope of the invention should not be limited to the description of the preferred embodiment described herein.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3284281 *Aug 31, 1964Nov 8, 1966Phillips Petroleum CoProduction of oil from oil shale through fractures
US3537528 *Oct 14, 1968Nov 3, 1970Shell Oil CoMethod for producing shale oil from an exfoliated oil shale formation
US5456315 *Feb 1, 1994Oct 10, 1995Alberta Oil Sands Technology And ResearchHorizontal well gravity drainage combustion process for oil recovery
US20040050547 *Sep 16, 2002Mar 18, 2004Limbach Kirk WaltonDownhole upgrading of oils
US20070039729 *Jul 17, 2006Feb 22, 2007Oil Sands Underground Mining CorporationMethod of increasing reservoir permeability
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7909094May 14, 2008Mar 22, 2011Halliburton Energy Services, Inc.Oscillating fluid flow in a wellbore
US9163491Sep 27, 2012Oct 20, 2015Nexen Energy UlcSteam assisted gravity drainage processes with the addition of oxygen
US9328592May 8, 2013May 3, 2016Nexen Energy UlcSteam anti-coning/cresting technology ( SACT) remediation process
US20130175031 *Jul 6, 2012Jul 11, 2013Nexen Inc.Sagdox geometry
CN101956548A *Sep 25, 2010Jan 26, 2011北京奥瑞安能源技术开发有限公司Coal bed methane multi-branch horizontal well system and modification method thereof
CN101975050A *Sep 17, 2010Feb 16, 2011北京奥瑞安能源技术开发有限公司Construction method of coal bed gas horizontal well and vertical drainage well in multi-objective layer geologic environment
U.S. Classification166/257, 166/50, 166/303
International ClassificationE21B43/24, E21B43/243
Cooperative ClassificationE21B43/243, E21B43/2406, E21B43/2408
European ClassificationE21B43/243, E21B43/24S2, E21B43/24S
Legal Events
Oct 15, 2008ASAssignment
Effective date: 20081004