Patent US4903767A successfully refreshed from Google Patents.
US4903767A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Selective gelation polymer for profile control in CO2 flooding
Assignee: Mobil Oil AS
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Filing: 1988-12-30
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Granted: 1990-02-27
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Expires: 2008-12-30
Abstract
Abstract A process for the selective gelation of a polymer for profile control during carbon dioxide flooding. First, a size selective gel is formed ex-situ. Upon entering a thief zone or a more permeable low pH zone resultant from carbon-dioxide flooding, the gel forms a solid, firm gel. This gel comprises an aqueous composition of a partially and fully alkylated melamine resin and an xanthan polymer. Size selectivity is imparted by the partially alkylated resin and the polymer. Upon contact with the low pH environment, active melamine resin is released from the fully alkylated resin which reacts with the polymer to form a stable, solid gel. Once the solid gel has formed, steam-flooding, water-flooding or a carbon-dioxide oil recovery process is commenced in a zone where a solid gel has not formed.
Inventors
- 👤 Paul Shu
- 👤 Krishnaswamy Sampath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:10
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/16; E21B43/164; C; C09; C09K; C09K8/00; C09K8/50; C09K8/504; C09K8/506; C09K8/508; C09K8/512; C09K8/58; C09K8/594
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
250 words
A method for closing at least one zone in a subterranean formation where a carbon dioxide flooding process has caused the existence of carbon dioxide break-through fingers comprising: (a) introducing a gas selected from a member of the group consisting of carbon dioxide and gases containing carbon dioxide into a subterranean deposit containing carbon dioxide break-through fingers; (b) after said carbon dioxide break-through fingers have sorbed a predetermined amount of said gas, stopping the flow of said gas into said subterranean formation; (c) after stopping the flow of said gas into said subterranean formation, introducing an effective amount of a gel-forming composition into said subterranean formation and into said carbon dioxide break-through fingers, said gel-forming composition being operable, when contacting carbon dioxide break-through fingers containing an aqueous fluid which has absorbed substantial amounts of carbon dioxide, to form a gel in said fingers which is operable for retarding the flow of said gas through said fingers, said gel-forming composition comprising (i) an aqueous solution containing a water soluble xanthan polymer; and (ii) a partially and a fully alkylated melamine resin sufficient to cross-link said polymer; (d) injecting selectively said gel-forming composition into the break-through fingers of said formation where selectively is imparted by a higher viscosity resultant from said partially alkylated resin; and (e) allowing said composition to remain in the formation for a time sufficient for the fully alkylated resin to form an active resin which results in the creation of a stable solid gel which closes said fingers.
Claim 2
Independent Claim
250 words
A method for closing at least one zone in a subterranean formation where a carbon dioxide flooding process has caused the existence of carbon dioxide break-through fingers comprising: (a) introducing a gas selected from a member of the group consisting of carbon dioxide and gases containing carbon dioxide into a subterranean deposit containing carbon dioxide break-through fingers; (b) after said carbon dioxide break-through fingers have sorbed a predetermined amount of said gas, stopping the flow of said gas into said subterranean formation; (c) after stopping the flow of said gas into said subterranean formation, introducing an effective amount of a gel-forming composition into said subterranean formation and into said carbon dioxide break-through fingers, said gel-forming composition being operable, when contacting carbon dioxide break-through fingers containing an aqueous fluid which has absorbed substantial amounts of carbon dioxide, to form a gel in said fingers which is operable for retarding the flow of said gas through said fingers, said gel-forming composition comprising (i) an aqueous solution containing a water soluble xanthan polymer; and (ii) a partially and a fully alkylated melamine resin sufficient to cross-link said polymer; (d) injecting selectively said gel-forming composition into the break-through fingers of said formation where selectively is imparted by a higher viscosity resultant from said partially alkylated resin; and (e) allowing said composition to remain in the formation for a time sufficient for the fully alkylated resin to form an active resin which results in the creation of a stable solid gel which closes said fingers.
Claim 3
Dependent Claim
19 words
The method as recited in claim 1 wherein said aqueous fluid comprises fresh water, salt water or brackish water.
Claim 4
Dependent Claim
20 words
The method as recited in claim 1 where the polymer to resin ratio is from about 10:1 to about 1:5.
Claim 5
Dependent Claim
19 words
The method as recited in claim 1 where the polymer concentration is from about 0.1 to about 5.0 wt.%.
Claim 6
Dependent Claim
37 words
The method as recited in claim 1 where the fully alkylated resin, is a compound having the formula: ##STR3## where R is selected from a member of the group consisting of C 1 through C 4 alkyl.
Claim 7
Dependent Claim
16 words
The method as recited in claim 5 where R comprises ethyl, propyl, isopropyl, and butyl alkyl.
Claim 8
Dependent Claim
37 words
The method as recited in claim 1 where the partially alkylated resin is a compound having the formula: ##STR4## where R is selected from a member of the group consisting of C 1 through C 4 alkyl.
Claim 9
Dependent Claim
16 words
The method as recited in claim 7 where R comprises ethyl, propyl, isopropyl and butyl alkyl.
Claim 10
Dependent Claim
16 words
The method as recited in claim 1 where the fully alkylated melamine resinn is hexamethylmelamine resin.
Claim 11
Dependent Claim
25 words
The method as recited in claim 1 where a solid, firm gel is formed in a pH environment of from about 3 to about 5.
Claim 12
Dependent Claim
29 words
The method as recited in claim 1 where the gel composition remains in the formation from about 0.25 hours to about 5 days before forming a solid, firm gel.
Claim 13
Dependent Claim
35 words
The method as recited in claim 1 where the partially and fully alkylated melamine resin comprises ethyl, propyl, isopropyl, and butylated melamine resins which can be used in reservoirs having temperatures above about 200° F.
Claim 14
Dependent Claim
26 words
The method as recited in claim 1 where alcohol and a surfactant are added to the gel-forming composition so as to obtain a homogenous gelling mixture.
Claim 15
Dependent Claim
23 words
The method as recited in claim 1 where a solid, firm gel is formed in a pH environment of less than about 6.
Claim 16
Independent Claim
210 words
A method for selectively closing carbon dioxide break-through fingers in a subterranean formation comprising: (a) conducting a carbon dioxide oil recovery process in said formation until carbon dioxide break-through occurs during which process carbon dioxide is sorbed into aqueous formation fluids in an amount sufficient to create a substantially low pH environment; (b) ceasing said carbon dioxide oil recovery process; (c) introducing thereafter an effective amount of a gel-forming composition into said subterranean formation and into said carbon dioxide break-through fingers, said gel-forming composition being operable, when contacting carbon dioxide break-through fingers containing said fluids with a substantially low pH, to form a gel in said fingers which is operable for retarding the flow of carbon dioxide through said fingers, said gel-forming composition comprising (i) an aqueous solution containing a water soluble xanthan polymer, and (ii) a partially and a fully alkylated melamine resin sufficient to cross-link said polymer; (d) injecting selectively said gel-forming composition into the break-through fingers of said formation where selectively is imparted by a higher viscosity resultant from said partially alkylated resin; and (e) allowing said composition to remain in the formation for a time sufficient for the fully alkylated resin to form an active resin thereby creating a stable solid gel which closes said fingers.
Claim 17
Independent Claim
210 words
A method for selectively closing carbon dioxide break-through fingers in a subterranean formation comprising: (a) conducting a carbon dioxide oil recovery process in said formation until carbon dioxide break-through occurs during which process carbon dioxide is sorbed into aqueous formation fluids in an amount sufficient to create a substantially low pH environment; (b) ceasing said carbon dioxide oil recovery process; (c) introducing thereafter an effective amount of a gel-forming composition into said subterranean formation and into said carbon dioxide break-through fingers, said gel-forming composition being operable, when contacting carbon dioxide break-through fingers containing said fluids with a substantially low pH, to form a gel in said fingers which is operable for retarding the flow of carbon dioxide through said fingers, said gel-forming composition comprising (i) an aqueous solution containing a water soluble xanthan polymer, and (ii) a partially and a fully alkylated melamine resin sufficient to cross-link said polymer; (d) injecting selectively said gel-forming composition into the break-through fingers of said formation where selectively is imparted by a higher viscosity resultant from said partially alkylated resin; and (e) allowing said composition to remain in the formation for a time sufficient for the fully alkylated resin to form an active resin thereby creating a stable solid gel which closes said fingers.
Claim 18
Dependent Claim
28 words
The method as recited in claim 15 whhere after step (e) a carbon dioxide flooding or stimulation operation is initiated in said formation to recover additional hydrocarbonaceous fluids.
Claim 19
Dependent Claim
19 words
The method as recited in claim 15 where said aqueous fluid comprises fresh water, salt water or brackish water.
Claim 20
Dependent Claim
20 words
The method as recited in claim 15 where the polymer to resin ratio is from about 10:1 to about 1:5.
Claim 21
Dependent Claim
19 words
The method as recited in claim 15 where the polymer concentration is from about 0.1 to about 5.0 wt.%.
Claim 22
Dependent Claim
37 words
The method as recited in claim 12 where the fully alkylated resin, is a compound having the formula: ##STR5## where R is selected from a member of the group consisting of C 1 through C 4 alkyl.
Claim 23
Dependent Claim
16 words
The method as described in claim 20 where R comprises ethyl, propyl, isopropyl, and butyl alkyl.
Claim 24
Dependent Claim
37 words
The method as recited in claim 15 where the partially alkylated resin is a compound having the formula: ##STR6## where R is selected from a member of the group consisting of C 1 through C 4 alkyl.
Claim 25
Dependent Claim
16 words
The method as recited in claim 22 where R comprises ethyl, propyl, isopropyl and butyl alkyl.
Claim 26
Dependent Claim
16 words
The method as recited in claim 15 where the fully alkylated melamine resin is hexamethylmelamine resin.
Claim 27
Dependent Claim
25 words
The method as recited in claim 15 where a solid, firm gel is formed in a pH environment of from about 3 to about 5.
Claim 28
Dependent Claim
29 words
The method as recited in claim 15 where the gel composition remains in the formation from about 0.25 hours to about 5 days before forming a solid, firm gel.
Claim 29
Dependent Claim
35 words
The method as recited in claim 15 where the partially and fully alkylated melamine resin comprises ethyl, propyl, isopropyl, and butylated melamine resins which can be used in reservoirs having temperatures above about 200° F.
Claim 30
Dependent Claim
26 words
The method as recited in claim 15 where alcohol and a surfactant are added to the gel-forming composition so as to obtain a homogenous gelling mixture.
Claim 31
Dependent Claim
23 words
The method as recited in claim 15 where a solid, firm gel is formed in a pH environment of less than about 6.
Claim 32
Independent Claim
230 words
A method for selectively closing carbon dioxide break-through fingers in a subterranean formation comprising: (a) conducting a carbon dioxide oil recovery process in said formation until carbon dioxide break-through occurs during which process carbon dioxide is sorbed into aqueous formation fluids in an amount sufficient to create a substantially low pH environment of about 3 to about 5; (b) ceasing said carbon dioxide oil recovery process; (c) introducing thereafter an effective amount of a gel-forming composition into said subterranean formation and into said carbon dioxide break-through fingers, said gel-forming composition being operable, when contacting carbon dioxide break-through fingers containing said fluids with a substantially low pH, to form a gel in said fingers which is operable for retarding the flow of carbon dioxide through said fingers, said gel-forming composition comprising (i) an aqueous solution containing a water soluble xanthan polymer, and (ii) a partially and a fully alkylated melamine resin sufficient to cross-link said polymer; (d) injecting selectively said gel-forming composition into the break-through fingers of said formation where selectively is imparted by a higher viscosity resultant from said partially alkylated resin; (e) allowing said composition to remain in the formation for a time sufficient for the fully alkylated rresin to form an active resin thereby creating a stable solid gel which closes said fingers; and (f) conducting an enhanced oil recovery method in said formation and recovering hydrocarbonaceous fluids.
Claim 33
Independent Claim
230 words
A method for selectively closing carbon dioxide break-through fingers in a subterranean formation comprising: (a) conducting a carbon dioxide oil recovery process in said formation until carbon dioxide break-through occurs during which process carbon dioxide is sorbed into aqueous formation fluids in an amount sufficient to create a substantially low pH environment of about 3 to about 5; (b) ceasing said carbon dioxide oil recovery process; (c) introducing thereafter an effective amount of a gel-forming composition into said subterranean formation and into said carbon dioxide break-through fingers, said gel-forming composition being operable, when contacting carbon dioxide break-through fingers containing said fluids with a substantially low pH, to form a gel in said fingers which is operable for retarding the flow of carbon dioxide through said fingers, said gel-forming composition comprising (i) an aqueous solution containing a water soluble xanthan polymer, and (ii) a partially and a fully alkylated melamine resin sufficient to cross-link said polymer; (d) injecting selectively said gel-forming composition into the break-through fingers of said formation where selectively is imparted by a higher viscosity resultant from said partially alkylated resin; (e) allowing said composition to remain in the formation for a time sufficient for the fully alkylated rresin to form an active resin thereby creating a stable solid gel which closes said fingers; and (f) conducting an enhanced oil recovery method in said formation and recovering hydrocarbonaceous fluids.
Claim 34
Dependent Claim
37 words
The method as recited in claim 30 where the fully alkylated resin, is a compound having the formula: ##STR7## where R is selected from a member of the group consisting of C 1 through C 4 alkyl.
Claim 35
Dependent Claim
37 words
The method as recited in claim 30 where the partially alkylated resin is a compound having the formula: ##STR8## where R is selected from a member of the group consisting of C 1 through C 4 alkyl.
Claim 36
Dependent Claim
23 words
The method as recited in claim 30 where said gel-forming composition is injected into the formation via an injection or a production well.
Claim 37
Dependent Claim
19 words
The method as recited in claim 30 where said aqueous fluid comprises fresh water, salt water or brackish water.
Claim 38
Dependent Claim
31 words
The method as recited in claim 31 where R comprises ethyl, propyl, isopropyl and butyl alkyl which increase the effectiveness of said resin in reservoirs having temperatures above about 200° F.
Claim 39
Dependent Claim
28 words
The method as recited in claim 30 where after step (e) any ungelled composition is removed from the formation or diluted with water sufficient to prevent further gelation.
Claim 40
Dependent Claim
35 words
The method as recited in claim 30 where the partially and fully alkylated melamine resin comprises ethyl, propyl, isopropyl, and butylated melamine resins which can be used in reservoirs having temperatures above about 200° F.
Claim 41
Dependent Claim
26 words
The method as recited in claim 30 where alcohol and a surfactant are added to the gel-forming composition so as to obtain a homogenous gelling mixture.
Claim 42
Dependent Claim
23 words
The method as recited in claim 30 where a solid, firm gel is formed in a pH environment of less than about 6.
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