US5247993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Enhanced imbibition oil recovery process
Assignee: Union Oil Company of California
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Filing: 1992-06-16
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Granted: 1993-09-28
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Expires: 2012-06-16
Abstract
Abstract Oil production from a fractured, oil-bearing subterranean formation is enhanced by sequentially injecting (i) a wettability reversal agent-containing fluid and (ii) an overflush fluid through a well and into the formation. The well is then place into production after allowing a sufficient period of time for (a) the matrix face of the formation to change from preferentially oil wet to preferentially water wet and (b) a displacing fluid (e.g., hot water, steam) to imbibe into the fractured matrix and displace the oil from the matrix into the fracture cracks.
Inventors
- 👤 A. M. Sam Sarem
- 👤 Richard D. Hutchins
- 👤 Shlomo R. Frieman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:53
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/24; C; C09; C09K; C09K8/00; C09K8/58; C09K8/60
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
133 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of a fluid containing a wettability reversal agent through a well and into at least a portion of a fractured, oil-bearing subterranean formation, the wettability reversal agent being capable of changing at least a portion of the matrix face of the oil-bearing subterranean formation from preferentially oil wet to preferentially water wet; (b) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (c) placing the well into production.
Claim 2
Independent Claim
133 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of a fluid containing a wettability reversal agent through a well and into at least a portion of a fractured, oil-bearing subterranean formation, the wettability reversal agent being capable of changing at least a portion of the matrix face of the oil-bearing subterranean formation from preferentially oil wet to preferentially water wet; (b) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (c) placing the well into production.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein the fractured, oil-bearing subterranean formation comprises a tectonically fractured, oil-bearing subterranean formation.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein the fluid injected in step (a) comprises an aqueous liquid.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein the overflush fluid injected in step (b) comprises a hydrocarbon oil.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein the overflush fluid injected in step (b) comprises a diesel oil.
Claim 7
Independent Claim
125 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of a fluid containing a wettability reversal agent through a well and into at least a portion of a fractured, oil-bearing subterranean formation; (b) injecting a hot aqueous fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation; (c) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (d) placing the well into production.
Claim 8
Independent Claim
125 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of a fluid containing a wettability reversal agent through a well and into at least a portion of a fractured, oil-bearing subterranean formation; (b) injecting a hot aqueous fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation; (c) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (d) placing the well into production.
Claim 9
Dependent Claim
16 words
The method of claim 6 wherein the fluid injected in step (a) comprises an aqueous liquid.
Claim 10
Independent Claim
136 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of a fluid containing a wettability reversal agent through a well and into at least a portion of a fractured, oil-bearing subterranean formation, the wettability reversal agent being selected from the group consisting of alkaline alkali metal silicates, ammonium salts, alkali metal hydroxides, alkali metal tripolyphosphates, alkali metal carbonates, alkali metal bicarbonates, and mixtures thereof; (b) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (c) placing the well into production.
Claim 11
Independent Claim
136 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of a fluid containing a wettability reversal agent through a well and into at least a portion of a fractured, oil-bearing subterranean formation, the wettability reversal agent being selected from the group consisting of alkaline alkali metal silicates, ammonium salts, alkali metal hydroxides, alkali metal tripolyphosphates, alkali metal carbonates, alkali metal bicarbonates, and mixtures thereof; (b) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (c) placing the well into production.
Claim 12
Dependent Claim
18 words
The method of claim 8 wherein the fractured, oil-bearing subterranean formation comprises a tectonically fractured, oil-bearing subterranean formation.
Claim 13
Dependent Claim
17 words
The method of claim 8 wherein the overflush fluid injected in step (b) comprises a hydrocarbon oil.
Claim 14
Dependent Claim
17 words
The method of claim 8 wherein the overflush fluid injected in step (b) comprises a diesel oil.
Claim 15
Dependent Claim
29 words
The method of claim 8 wherein the overflush fluid injected in step (b) comprises (i) a hydrocarbon oil, (ii) an oil-soluble thickening agent, and (iii) a water-soluble thickening agent.
Claim 16
Dependent Claim
24 words
The method of claim 8 wherein the liquid phase of the fluid injected in step (a) has a pH of at least about 11.
Claim 17
Independent Claim
113 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of a fluid containing a wettability reversal agent through a well and into at least a portion of a fractured, oil-bearing subterranean formation, wherein the fluid injected in step (a) comprises steam; (b) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (c) placing the well into production.
Claim 18
Independent Claim
113 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of a fluid containing a wettability reversal agent through a well and into at least a portion of a fractured, oil-bearing subterranean formation, wherein the fluid injected in step (a) comprises steam; (b) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (c) placing the well into production.
Claim 19
Independent Claim
115 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) subjecting a well to at least one steam huff-n-puff cycle; (b) injecting a slug of a fluid containing a wettability reversal agent through the well and into at least a portion of a fractured, oil-bearing subterranean formation; (c) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (d) placing the well into production.
Claim 20
Independent Claim
115 words
A method for enhancing the production of oil from a fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) subjecting a well to at least one steam huff-n-puff cycle; (b) injecting a slug of a fluid containing a wettability reversal agent through the well and into at least a portion of a fractured, oil-bearing subterranean formation; (c) injecting a slug of an overflush fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the fractured, oil-bearing subterranean formation; and (d) placing the well into production.
Claim 21
Independent Claim
139 words
A method for enhancing the production of oil from a tectonically fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of an aqueous fluid containing a wettability reversal agent through a well and into at least a portion of a tectonically fractured, oil-bearing subterranean formation, the wettability reversal agent being selected from the group consisting of alkaline alkali metal silicates, ammonium salts, alkali metal hydroxides, alkali metal tripolyphosphates, alkali metal carbonates, and alkali metal bicarbonates; (b) injecting a slug of an overflush fluid through the well and into at least a portion of the tectonically fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the tectonically fractured, oil-bearing subterranean formation; and (c) placing the well into production.
Claim 22
Independent Claim
139 words
A method for enhancing the production of oil from a tectonically fractured, oil-bearing subterranean formation, the method comprising the sequential steps of: (a) injecting a slug of an aqueous fluid containing a wettability reversal agent through a well and into at least a portion of a tectonically fractured, oil-bearing subterranean formation, the wettability reversal agent being selected from the group consisting of alkaline alkali metal silicates, ammonium salts, alkali metal hydroxides, alkali metal tripolyphosphates, alkali metal carbonates, and alkali metal bicarbonates; (b) injecting a slug of an overflush fluid through the well and into at least a portion of the tectonically fractured, oil-bearing subterranean formation, the overflush fluid being capable of increasing the oil mobility and decreasing the water mobility in at least a portion of the tectonically fractured, oil-bearing subterranean formation; and (c) placing the well into production.
Claim 23
Dependent Claim
41 words
The method of claim 16 wherein the method further comprises the step (a.1) of injecting a hot aqueous fluid through the well and into at least a portion of the fractured, oil-bearing subterranean formation after step (a) but before step (b).
Claim 24
Dependent Claim
21 words
The method of claim 16 wherein prior to step (a) the well is subjected to at least one steam huff-n-puff cycle.
Claim 25
Dependent Claim
20 words
The method of claim 16 wherein after step (c) the well is subjected to at least one steam huff-n-puff cycle.
Claim 26
Dependent Claim
25 words
The method of claim 16 wherein the liquid phase of the aqueous fluid injected in step (a) has a pH of at least about 11.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-09-27 | 1997-03-29 | 1997-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-27 | 2001-03-29 | 2001-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-27 | 2005-03-29 | 2005-09-28 | $7700.00 | Window Closed / Lapsed |