Patent US3565175A successfully refreshed from Google Patents.
US3565175A
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Method for reducing gravity segregation of an aqueous flooding fluid
Assignee: Union Oil Company of California
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Filing: 1969-10-16
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Granted: 1971-02-23
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Expires: 1989-10-16
Abstract
Abstract Gravity segregation of an aqueous flooding fluid injected into a permeable subterranean reservoir containing lower density fluids is reduced by adjusting the viscosity of the aqueous flooding fluid injected into progressively lower levels of the reservoir so as to decrease the mobility of the fluid injected into each of the progressively lower levels sufficiently to offset the additional pressure exerted at the lower levels by the higher density aqueous flooding fluid tending to drive the aqueous fluids through the reservoir, whereby a substantially uniform vertical flood front is maintained. The viscosity of the fluid injected at each level may be continuously or incrementally decreased during injection.
Inventors
- 👤 James W Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:16
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/20; C; C09; C09K; C09K8/00; C09K8/58; C09K8/588
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
122 words
A method for reducing gravity segregation of an aqueous flooding fluid injected in to a relatively thick, subterranean reservoir containing fluids of lower density than said aqueous flooding fluid, which comprises simultaneously injecting a plurality of aqueous flooding fluids into alike plurality of vertically disposed contiguous permeable strata in said reservoir, the viscosity of the aqueous flooding fluid injected into each progressively lower stratum being adjusted so as to incrementally decrease the mobility of the flooding fluid in said lower stratum sufficiently to offset the additional pressure exerted by the higher density aqueous flooding fluids at the lower stratum tending to drive said aqueous flooding fluids through said stratum, whereby a flood front is established and substantially uniformly advanced through said reservoir.
Claim 2
Dependent Claim
18 words
packing off each of said injection tubes in the injection well between the termini of adjacent injection tubes;
Claim 3
Dependent Claim
47 words
simultaneously injecting an aqueous flooding fluid through said injection tubes into each of said permeable strata, the viscosity of said aqueous flooding fluid injected into each progressively lower stratum being adjusted so as to incrementally decrease the mobility of the flooding fluid in said lower stratum, and
Claim 4
Dependent Claim
28 words
The method defined in claim 2 wherein the viscosity of said aqueous flooding fluid is adjusted by the addition of a minor proportion of a water-soluble polymer thereto.
Claim 5
Dependent Claim
29 words
The method defined in claim 3 wherein said water-soluble polymer is acrylic acid-acrylamide copolymer, acrylic acid-acrylamide-diacetone acrylamide terpolymer, polyacrylamide, partially hydrolyzed polyacrylamide, hydroxyethyl cellulose, carboxymethyl cellulose, polyoxyethylene, or polysaccharide.
Claim 6
Dependent Claim
6 words
recovering oil from said producing well.
Claim 7
Dependent Claim
23 words
The method defined in claim 2 wherein each of said permeable strata has a vertical thickness of between about 5 and 75 feet.
Claim 8
Dependent Claim
48 words
The method defined in claim 2 wherein a plurality of slugs of said aqueous flooding fluid are sequentially injected into each of said permeable strata, the viscosity of each successive slug injected into each stratum being lower than the viscosity of the preceding slugs injected into that stratum.
Claim 9
Dependent Claim
34 words
The method defined in claim 6 wherein each slug of said aqueous flooding fluid is injected into said permeable stratum in the amount of between about 0.05 and 0.5 pore volume of said stratum.
Claim 10
Dependent Claim
75 words
The method defined in claim 6 wherein the viscosity of the aqueous flooding fluid injected into each stratum required to eliminate gravity segregation of the flooding fluid in the reservoir varies through out the radial extent of the stratum, and wherein each successive slug of said aqueous flooding fluid injected into each stratum has a viscosity based on the average value required over the radial extend of the reservoir to be flooded by that slug.
Claim 11
Dependent Claim
45 words
The method defined in claim 2 wherein a slug of said aqueous flooding fluid is injected into each of said permeable strata and displaced through each of said strata by the subsequent injection of a fluid selected from the group consisting of water and brine.
Claim 12
Dependent Claim
32 words
The method defined in claim 9 wherein said slug of aqueous flooding fluid is injected into each stratum in the amount of between about 0.05 and 0.5 pore volume of said stratum.
Claim 13
Dependent Claim
91 words
The method defined in claim 9 wherein a plurality of slugs of said aqueous flooding fluid are sequentially injected into each of said permeable strata, the viscosity of the aqueous flooding fluid injected into each stratum required to eliminate gravity segregation of the flooding fluid in the reservoir varies throughout the radial extend of the stratum and wherein each successive slug of aqueous flooding fluid injected into each stratum has a viscosity based on the average value required over the radial extend of the reservoir to be flooded by that slug.
Claim 14
Dependent Claim
26 words
The method defined in claim 2 wherein said aqueous flooding fluid is injected into each of said permeable strata at a substantially constant volumetric flow rate.
Claim 15
Independent Claim
122 words
A method for recovering oil from a relatively thick oil-bearing subterranean reservoir penetrated by at least one injection well and one or more production wells, which comprises: simultaneously injecting a plurality of aqueous flooding fluids through said injection well into a like plurality of vertically disposed contiguous permeable strata in said reservoir so as to displace reservoir oil from said strata, the rate of injection of aqueous flooding fluid into each stratum being selected to provide a substantially equal fluid velocity in each stratum, and the viscosity of said aqueous flooding fluid injected into each progressively lower stratum being adjusted so as to incrementally decrease the mobility of the flooding fluid in said lower stratum; and recovering oil from said production well.
Claim 16
Dependent Claim
67 words
The method defined in claim 13 wherein the viscosity of said aqueous flooding fluid injected into each of said permeable strata is adjusted so as to incrementally decrease the mobility of the flooding fluid in each progressively lower stratum sufficient to offset the additional pressure exerted by the higher density aqueous flooding fluid at the lower stratum tending to drive said aqueous flooding fluid through said reservoir.
Claim 17
Dependent Claim
31 words
The method defined in claim 13 wherein said aqueous flooding fluid is injected into each of said permeable strata at a substantially constant volumetric flow rate through out the flooding operation.
Claim 18
Dependent Claim
27 words
The method defined in claim 13 wherein the viscosity of said aqueous flooding fluid is adjusted by the addition of a minor proportion of a water-soluble polymer.
Claim 19
Dependent Claim
29 words
The method defined in claim 16 wherein said water-soluble polymer is acrylic acid-acrylamide copolymer, acrylic acid-acrylamide-diacetone acrylamide terpolymer, polyacrylamide, partially hydrolyzed polyacrylamide, hydroxyethyl cellulose, carboxmethyl cellulose, polyoxyethylene, or polysaccharide.
Claim 20
Dependent Claim
22 words
The method defined in claim 13 wherein each of said strata has a vertical thickness of between about 5 and 75 feet.
Claim 21
Dependent Claim
50 words
The method defined in claim 13 wherein said aqueous flooding fluid is injected into each stratum through a separate tubing string in the injection well and wherein packers are placed in said injection well near the terminus of each tubing string and adjacent the approximate boundaries of said permeable strata.
Claim 22
Independent Claim
177 words
A method for recovering oil from a relatively thick, subterranean reservoir penetrated by at least one injection well and one or more production wells, which comprises: simultaneously injecting through said injection well a plurality of aqueous flooding fluids into a like number of vertically disposed contiguous permeable strata so as to displace reservoir fluids of lower density than said aqueous flooding fluids from said strata, the rate of injection of aqueous flooding fluid into each stratum being controlled to provide a substantially equal fluid velocity in each stratum, and the viscosity of said aqueous flooding fluid injected into each progressively lower stratum being selected so as to incrementally decrease the mobility of the flooding fluid in said lower stratum sufficient to offset the additional pressure exerted at the lower stratum by the higher density aqueous flooding fluids tending to drive said aqueous flooding fluid through said reservoir; thereafter simultaneously injecting flood water into each of said strata at injection rates that provide a substantially equal flood velocity in each stratum; and recovering oil from said production well.
Claim 23
Dependent Claim
32 words
The method defined in claim 20 wherein the viscosity of each of said aqueous flooding fluids is adjusted by the addition of controlled proportions of a water soluble polymer to the solutions.
Claim 24
Dependent Claim
30 words
The method defined in claim 21 wherein said water-soluble polymer is acrylic aCid-acrylamide copolymer, acrylic acid-acrylamide -diacetone acrylamide terpolymer, polyacrylamide, partially hydrolyzed polyacrylamide, hydroxyethyl cellulose, carboxymethyl cellulose, polyoxyethylene, or polysaccharide.
Claim 25
Dependent Claim
22 words
The method defined in claim 20 wherein each of said strata has a vertical thickness of between about 5 and 75 feet.
Claim 26
Dependent Claim
54 words
The method defined in claim 20 wherein said aqueous flooding fluid in injected into each of the variously disposed strata through a separate tubing string in the injection well and wherein packers are placed in said injection well between the termini of the tubing strings and adjacent the approximate boundaries of said permeable strata.
Claim 27
Independent Claim
35 words
A method for recovering oil from a relatively thick, subterranean reservoir having a plurality of vertically disposed contiguous permeable strata penetrated by at least one injection well and one or more producing wells, which comprises:
Claim 28
Dependent Claim
171 words
The method defined in claim 25 wherein the viscosity of said aqueous flooding fluid injected into each progressively lower stratum is selected in accordance with the following equation: where Mu is the viscosity, in centipoises, of the aqueous flooding fluid injected into a selected stratum; Q is the volumetric flow rate, in barrels per day, of flooding fluid injected into said selected stratum; k is the average permeability, in darcies, of the selected stratum; Z is the vertical distance, in feet, from the bottom of the reservoir to the midpoint of the selected stratum; Delta gamma is the difference in density, in pounds per cubic foot, between the reservoir fluid and the flooding fluid; H is the vertical thickness, in feet, of the selected stratum; ria is an average radius, in feet, of the interface between the aqueous flooding fluid, and the displaced fluid; r w is the radius of the well bore, in feet; and Prime ('') represents value of the indicated parameter in the uppermost stratum of the reservoir.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |