Insulating foam steam stimulation method

Claim 1

A method for recovering oil from a subterranean oil-bearing reservoir, utilizing a single well operated by steam stiumlation, said reservoir having a permeable zone and an oil-bearing strata with a portion thereof to be stimulated by steam injection, which comprises: (a) injecting into said reservoir through said well a sufficient amount of steam to substantially eliminate any fluids from said well and from an expanse of said permeable zone which extends substantially radially from said well to the extent said permeable zone is in substantial proximity with said portion of said oil-bearing strata to be stimulated, (b) agitating with a pressurized, substantially non-condensible gas at or about the surface of said well a solution containing a sufficient amount of a surface active agent and a liquid to form a relatively stable, substantially non-condensible, thermally insulating foam having said non-condensible gas as a gas phase, (c) injecting said formed foam into said well until achieving a well bore injection pressure of said foam approaching a maximum stabilization injection pressure, but not exceeding the reservoir fracturing pressure, to position said foam in said permeable zone and substantially fill said expanse of said permeable zone with said foam to form a thermally insulating barrier to reduce loss of steam and heat from said oil-bearing strata to said permeable zone, (d) injecting into said reservoir through said well after formation of said thermally insulating barrier a sufficient amount of additional steam to heat said portion of said oil-bearing strata to stimulate oil production therefrom, (e) terminating substantially all steam injection into said reservoir and permitting heat to soak from said injected steam into said portion of said oil-bearing strata, and (f) withdrawing oil from said reservoir through said well.

Claim 2

A method for recovering oil from a subterranean oil-bearing reservoir, utilizing a single well operated by steam stiumlation, said reservoir having a permeable zone and an oil-bearing strata with a portion thereof to be stimulated by steam injection, which comprises: (a) injecting into said reservoir through said well a sufficient amount of steam to substantially eliminate any fluids from said well and from an expanse of said permeable zone which extends substantially radially from said well to the extent said permeable zone is in substantial proximity with said portion of said oil-bearing strata to be stimulated, (b) agitating with a pressurized, substantially non-condensible gas at or about the surface of said well a solution containing a sufficient amount of a surface active agent and a liquid to form a relatively stable, substantially non-condensible, thermally insulating foam having said non-condensible gas as a gas phase, (c) injecting said formed foam into said well until achieving a well bore injection pressure of said foam approaching a maximum stabilization injection pressure, but not exceeding the reservoir fracturing pressure, to position said foam in said permeable zone and substantially fill said expanse of said permeable zone with said foam to form a thermally insulating barrier to reduce loss of steam and heat from said oil-bearing strata to said permeable zone, (d) injecting into said reservoir through said well after formation of said thermally insulating barrier a sufficient amount of additional steam to heat said portion of said oil-bearing strata to stimulate oil production therefrom, (e) terminating substantially all steam injection into said reservoir and permitting heat to soak from said injected steam into said portion of said oil-bearing strata, and (f) withdrawing oil from said reservoir through said well.

Claim 3

A method for recovering oil from a subterranean oil-bearing reservoir, utilizing a single well operated by steam stimulation, said reservoir having a permeable zone and an oil-bearing strata with a portion thereof to be stimulated by steam injection, which comprises: (a) forming foam using a substantially non-condensible gas and a solution containing a sufficient amount of a surface active agent and a liquid, said formed foam being relatively stable, substantially non-condensible, thermally insulating and having said non-condensible gas as a gas phase, (b) injecting said formed foam into said well until achieving a well bore injection pressure of said foam approaching a maximum stabilization injection pressure, but not exceeding the reservoir fracturing pressure, to position said foam in said permeable zone and substantially fill with said foam an expanse of said permeable zone which extends substantially radially from said well to the extent said permeable zone is in substantial proximity with said portion of said oil-bearing strata to be stimulated, to form a thermally insulating barrier to reduce loss of steam and heat from said oil-bearing strata to said permeable zone, (c) injecting into said reservoir through said well after formation of said thermally insulating barrier a sufficient amount of steam to heat said portion of said oil-bearing strata to stimulate oil production therefrom, and (d) withdrawing oil from said reservoir through said well.

Claim 4

A method for recovering oil from a subterranean oil-bearing reservoir, utilizing a single well operated by steam stimulation, said reservoir having a permeable zone and an oil-bearing strata with a portion thereof to be stimulated by steam injection, which comprises: (a) forming foam using a substantially non-condensible gas and a solution containing a sufficient amount of a surface active agent and a liquid, said formed foam being relatively stable, substantially non-condensible, thermally insulating and having said non-condensible gas as a gas phase, (b) injecting said formed foam into said well until achieving a well bore injection pressure of said foam approaching a maximum stabilization injection pressure, but not exceeding the reservoir fracturing pressure, to position said foam in said permeable zone and substantially fill with said foam an expanse of said permeable zone which extends substantially radially from said well to the extent said permeable zone is in substantial proximity with said portion of said oil-bearing strata to be stimulated, to form a thermally insulating barrier to reduce loss of steam and heat from said oil-bearing strata to said permeable zone, (c) injecting into said reservoir through said well after formation of said thermally insulating barrier a sufficient amount of steam to heat said portion of said oil-bearing strata to stimulate oil production therefrom, and (d) withdrawing oil from said reservoir through said well.

Claim 13

A method for recovering oil from a subterranean oil-bearing reservoir, utilizing an injection well operated by steam stimulation and a laterally spaced production well, said reservoir having a permeable zone and an oil-bearing strata with a portion thereof to be stimulated by steam injection, which comprises: (a) injecting into said reservoir through said injection well a sufficient amount of steam to substantially eliminate any fluids from said injection well and from an expanse of said permeable zone which extends substantially radially from said injection well to the extent said permeable zone is in substantial proximity with said portion of said oil-bearing strata to be stimulated, (b) agitating with a pressurized, substantially non-condensible gas at or about the surface of said well a solution containing a sufficient amount of a surface active agent and a liquid to form a relatively stable, substantially non-condensible, thermally insulating foam having said non-condensible gas as a gas phase, (c) injecting said formed foam into said injection well until achieving a well bore injection pressure of said foam approaching a maximum stabilization injection pressure, but not exceeding the reservoir fracturing pressure, to position said foam in said permeable zone and substantially fill said expanse of said permeable zone with said foam to form a thermally insulating barrier to reduce loss of steam and heat from said oil-bearing strata to said permeable zone, (d) injecting into said reservoir through said injection well after formation of said thermally insulating barrier a sufficient amount of additional steam to heat said portion of said oil-bearing strata to stimulate oil production therefrom and to drive said oil toward said production well, and (e) withdrawing oil from said reservoir through said production well.

Claim 14

A method for recovering oil from a subterranean oil-bearing reservoir, utilizing an injection well operated by steam stimulation and a laterally spaced production well, said reservoir having a permeable zone and an oil-bearing strata with a portion thereof to be stimulated by steam injection, which comprises: (a) injecting into said reservoir through said injection well a sufficient amount of steam to substantially eliminate any fluids from said injection well and from an expanse of said permeable zone which extends substantially radially from said injection well to the extent said permeable zone is in substantial proximity with said portion of said oil-bearing strata to be stimulated, (b) agitating with a pressurized, substantially non-condensible gas at or about the surface of said well a solution containing a sufficient amount of a surface active agent and a liquid to form a relatively stable, substantially non-condensible, thermally insulating foam having said non-condensible gas as a gas phase, (c) injecting said formed foam into said injection well until achieving a well bore injection pressure of said foam approaching a maximum stabilization injection pressure, but not exceeding the reservoir fracturing pressure, to position said foam in said permeable zone and substantially fill said expanse of said permeable zone with said foam to form a thermally insulating barrier to reduce loss of steam and heat from said oil-bearing strata to said permeable zone, (d) injecting into said reservoir through said injection well after formation of said thermally insulating barrier a sufficient amount of additional steam to heat said portion of said oil-bearing strata to stimulate oil production therefrom and to drive said oil toward said production well, and (e) withdrawing oil from said reservoir through said production well.

Claim 15

A method for recovering oil from a subterranean oil-bearing reservoir, utilizing an injection well operated by steam stimulation and a laterally spaced production well, said reservoir having a permeable zone and an oil-bearing strata with a portion thereof to be stimulated by steam injection, which comprises: (a) forming foam using a substantially non-condensible gas and a solution containing a sufficient amount of a surface active agent and a liquid, said formed foam being relatively stable, substantially non-condensible, thermally insulating and having said non-condensible gas as a gas phase, (b) injecting said formed foam into said injection well until achieving a well bore injection pressure of said foam approaching a maximum stabilization injection pressure, but not exceeding the reservoir fracturing pressure, to position said foam in said permeable zone and substantially fill with said foam an expanse of said permeable zone which extends substantially radially from said injection well and a substantial part of the distance between said injection well and said production well, to form a thermally insulating barrier to reduce loss of steam and heat from said oil-bearing strata to said permeable zone, (c) injecting into said reservoir through said injection well after formation of said thermally insulating barrier a sufficient amount of steam to heat said portion of said oil-bearing strata to stimulate oil production therefrom and to drive said oil toward said production well, and (d) withdrawing oil from said reservoir through said production well.

Claim 16

A method for recovering oil from a subterranean oil-bearing reservoir, utilizing an injection well operated by steam stimulation and a laterally spaced production well, said reservoir having a permeable zone and an oil-bearing strata with a portion thereof to be stimulated by steam injection, which comprises: (a) forming foam using a substantially non-condensible gas and a solution containing a sufficient amount of a surface active agent and a liquid, said formed foam being relatively stable, substantially non-condensible, thermally insulating and having said non-condensible gas as a gas phase, (b) injecting said formed foam into said injection well until achieving a well bore injection pressure of said foam approaching a maximum stabilization injection pressure, but not exceeding the reservoir fracturing pressure, to position said foam in said permeable zone and substantially fill with said foam an expanse of said permeable zone which extends substantially radially from said injection well and a substantial part of the distance between said injection well and said production well, to form a thermally insulating barrier to reduce loss of steam and heat from said oil-bearing strata to said permeable zone, (c) injecting into said reservoir through said injection well after formation of said thermally insulating barrier a sufficient amount of steam to heat said portion of said oil-bearing strata to stimulate oil production therefrom and to drive said oil toward said production well, and (d) withdrawing oil from said reservoir through said production well.