US3757575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Well-logging method
Assignee: BP America Production Co
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Filing: 1971-07-09
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Granted: 1973-09-11
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Expires: 1991-07-09
Abstract
Abstract This invention relates to determining the oil saturation in an underground rock reservoir by use of a log-inject-log technique. The formation rock adjacent the well bore is prepared such that the saturation conditions there are representative of those in the interwell area. A log such as an electric or thermal decay time log is then run. A driving fluid such as alcohol or a micellar fluid is injected to drive all of the fluid from the pore space in the volume of rock being logged. Then the driving fluid is displaced by a second driving fluid which has the same resistivity or thermal neutron capture cross-section as the formation water. The formation is then again logged by the same equipment as the first log run. The formation water saturation at the time the first log was run is then determined from these two logs.
Inventors
- 👤 R Murphy
- 👤 W Owens
- 👤 D Dauben
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:03
CPC Classifications
E; E21; E21B; E21B49/00
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
136 words
A method of measuring water saturation in a subsurface zone penetrated by a well bore which comprises the steps of: a. running a logging instrument in said well bore to measure the water saturation of the rock in said zone adjacent said well bore, b. injecting a driving fluid through said well bore into said zone to displace oil out of the rock immediately surrounding the well bore, said driving fluid being a fluid easily driven through the rock by a second driving fluid having the same logging characteristics as the water in the rock at the time of Step (a), c. injecting said second driving fluid through said well bore into said zone to drive said first driving fluid from the zone immediately adjacent the well bore, and d. after Step (c), repeating Step (a).
Claim 2
Independent Claim
136 words
A method of measuring water saturation in a subsurface zone penetrated by a well bore which comprises the steps of: a. running a logging instrument in said well bore to measure the water saturation of the rock in said zone adjacent said well bore, b. injecting a driving fluid through said well bore into said zone to displace oil out of the rock immediately surrounding the well bore, said driving fluid being a fluid easily driven through the rock by a second driving fluid having the same logging characteristics as the water in the rock at the time of Step (a), c. injecting said second driving fluid through said well bore into said zone to drive said first driving fluid from the zone immediately adjacent the well bore, and d. after Step (c), repeating Step (a).
Claim 3
Dependent Claim
21 words
A method as defined in claim 1 in which said Step (a) and (d) is the running of an electric log.
Claim 4
Dependent Claim
15 words
thereafter reducing to zero the oil saturation of the rock immediately surrounding the well bore,
Claim 5
Dependent Claim
15 words
thereafter reducing to zero the oil saturation of the rock immediately surrounding the well bore,
Claim 6
Dependent Claim
31 words
filling the pore space of the rock adjacent the well bore with a fluid having the same logging characteristics as the water in the rock at the time of Step 1),
Claim 7
Dependent Claim
31 words
filling the pore space of the rock adjacent the well bore with a fluid having the same logging characteristics as the water in the rock at the time of Step 1),
Claim 8
Dependent Claim
21 words
A method as defined in claim 1 in which Step (a) is the running of a thermal neutron decay time log.
Claim 9
Dependent Claim
25 words
A method as defined in claim 1 in which said first driving fluid is a micellar solution having mutual solubility in oil and in water.
Claim 10
Dependent Claim
18 words
after Step 3 again measuring the water saturation of the rock in said zone adjacent said well bore.
Claim 11
Dependent Claim
18 words
after Step 3 again measuring the water saturation of the rock in said zone adjacent said well bore.
Claim 12
Dependent Claim
20 words
A method as defined in claim 4 which comprises the step of injecting a fresh water slug before Step (c).
Claim 13
Dependent Claim
18 words
A method as defined in claim 5 which includes the step of injecting fresh water after Step (c).
Claim 14
Dependent Claim
31 words
A method as defined in claim 1 in which both an electric log and a thermal neutron decay time log are run first before and then after Steps 3 and 4.
Claim 15
Dependent Claim
17 words
A method as defined in claim 1 in which said first driving fluid is an alcohol solution.
Claim 16
Dependent Claim
26 words
A method as defined in claim 1 in which the said first driving fluid is an alcohol solution having mutual solubility in oil and in water.
Claim 17
Dependent Claim
25 words
A method as defined in claim 9 which includes injecting fresh water immediately before the injection of the said alcohol solution and before Step (c).
Claim 18
Dependent Claim
41 words
A method as defined in claim 1 in which before Step (a) the well is conditionEd to produce as near as possible the same fluid saturation adjacent the bore as that present in the rock formation remote from the well bore.
Claim 19
Dependent Claim
40 words
A method as defined in claim 1 when used in a zone having gas saturation, the method including the step of running logs to determine the gas saturation, such logs to be run after Step (a) and before Step (b).
Claim 20
Independent Claim
20 words
A method of measuring water saturation in a subsurface zone penetrated by a well bore which comprises the steps of:
Claim 21
Independent Claim
20 words
A method of measuring water saturation in a subsurface zone penetrated by a well bore which comprises the steps of:
References Cited (Backward Citations)
US3558888A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |