US3929011A
Expired / Lapsed
US
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Determination of oil saturation in an anisotropic reservoir
Assignee: Marathon Oil Co
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Filing: 1974-12-13
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Granted: 1975-12-30
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Expires: 1994-12-13
Abstract
Abstract WHEREIN Soi is the average oil saturation between the injection well and observation well; Sob is the average oil saturation in the oil-water bank; Vobt and Vdbt are the cumulative volume of displacing fluid injected when the oil-water bank and the front of the displacing fluid arrives at the observation well, respectively; Sor is the average residual oil saturation left by the displacing fluid; foi is the fractional flow of oil prior to injection of the displacing fluid; and Vp is the pore volume of the reservoir in elliptical cylinder bounded by the observation well. Sob and Sor can be determined by laboratory methods. Oil saturation in an anisotropic reservoir is determined by injecting into the reservoir an oil and water displacing fluid, displacing it toward an observation well whereby a ''''stable'''' oil-water bank is formed and measuring the arrival times at the well of the stable oil-water bank and the front of the displacing fluid. Difference in the rate of bottom hole pressure change indicates arrival of the bank and the displacing fluid. The oil saturation is then determined by the formula:
Inventors
- 👤 Stanley C Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:53
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B49/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
A process of determining in situ the average oil saturation of an oil-bearing reservoir having an injection well in fluid communication with at least one observation well, comprising injecting into the reservoir a displacing fluid which will form a stable oil-water bank of the formation fluids within the reservoir and wherein the mobility of the displacing fluid is less than the mobility of the oil-water bank, determining the amount of the displacing fluid, comprised of a front portion and a back portion, required to displace the oil-water bank and the front portion of the displacing fluid to the observation well and thereafter determining the average oil saturation by the following formula:
Claim 2
Dependent Claim
111 words
A process of determining in situ the average oil saturation of an oil-bearing reservoir having an injection well in fluid communication with at least one observation well, comprising injecting into the reservoir a displacing fluid which will form a stable oil-water bank of the formation fluids within the reservoir and wherein the mobility of the displacing fluid is less than the mobility of the oil-water bank, determining the amount of the displacing fluid, comprised of a front portion and a back portion, required to displace the oil-water bank and the front portion of the displacing fluid to the observation well and thereafter determining the average oil saturation by the following formula:
Claim 3
Dependent Claim
13 words
The process of claim 1 wherein the reservoir is in a tertiary condition.
Claim 4
Dependent Claim
13 words
The process of claim 1 wherein the displacing fluid is a micellar dispersion.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein the back portion of the displacing fluid is an aqueous mobility buffer.
Claim 6
Dependent Claim
18 words
The process of claim 1 wherein the mobilities of the oil-water bank and the displacing fluid are similar.
Claim 7
Dependent Claim
159 words
A process of determining in situ the average oil saturation in an oil-bearing anisotropic reservoir that has been flooded to nearly residual oil saturation and an oil cut of less than 5 percent and which contains an injection well in fluid communication with a production well, comprising injecting into the injection well a displacing fluid, having a front portion, the front portion comprised of a micellar dispersion having sufficient properties to form a stable oil-water bank, comprised of a front portion, of the formation fluids within the reservoir, displacing it to the observation well and determining the volume amounts of the displacing fluid required to displace the front portion of the oil-water bank to the observation well, and also determining the volume amount of displacing fluid required to displace the front portion of the displacing fluid to the observation well, and thereafter determining the average oil saturation between the injection well and the observation well by the following formula:
Claim 8
Dependent Claim
159 words
A process of determining in situ the average oil saturation in an oil-bearing anisotropic reservoir that has been flooded to nearly residual oil saturation and an oil cut of less than 5 percent and which contains an injection well in fluid communication with a production well, comprising injecting into the injection well a displacing fluid, having a front portion, the front portion comprised of a micellar dispersion having sufficient properties to form a stable oil-water bank, comprised of a front portion, of the formation fluids within the reservoir, displacing it to the observation well and determining the volume amounts of the displacing fluid required to displace the front portion of the oil-water bank to the observation well, and also determining the volume amount of displacing fluid required to displace the front portion of the displacing fluid to the observation well, and thereafter determining the average oil saturation between the injection well and the observation well by the following formula:
Claim 9
Dependent Claim
20 words
The process of claim 6 wherein the back portion of the displacing fluid is comprised of an aqueous mobility buffer.
Claim 10
Dependent Claim
18 words
The process of claim 7 wherein the aqueous mobility buffer is an aqueous solution containing a polyacrylamide polymer.
References Cited (Backward Citations)
US3338094A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |