Method for the enhanced recovery of oil and natural gas
AssigneeUnion Oil Company of California
InventorVirgil A. Josendal
Life of this patent
Estimating the term…
Abstract
A method for the enhanced recovery of both natural gas and liquid petroleum from hydrocarbon-containing subterranean formations, particularly dipping subterranean formations, by the consecutive steps of introducing a gaseous displacement fluid to recover natural gas and thereafter introducing an oil-miscible displacement fluid to recover undrained oil and/or other liquid petroleum.
Claims28
A method for the recovery of hydrocarbons from a subterranean formation containing both natural gas and liquid petroleum, said formation having an upper first zone containing said natural gas, said method comprising the steps of:
- (a) introducing a gaseous displacement fluid through a first well communicating with said first zone so as to displace at least a portion of said natural gas from said first zone to a second well and recovering said portion of natural gas through said second well;
- and
- (b) thereafter introducing an oil-miscible displacement fluid into said formation at a selected pressure so as to displace at least a portion of said liquid petroleum to a recovery well, and recovering said portion of liquid petroleum through said recovery well.
A method for the recovery of natural gas, undrained oil, and liquid petroleum from a dipping subterranean hydrocarbon-containing formation having an updip first zone containing natural gas and undrained oil overlying a second zone containing liquid petroleum, said method comprising the steps of:
- (a) injecting a gaseous displacement fluid through a first well into said first zone so as to displace at least a portion of said natural gas from said first zone to an updip second well and recovering said portion of natural gas through said second well, said gaseous displacement fluid being selected from the group consisting of nitrogen and nitrogen-containing gases and having a density which is greater than or equal to the density of said natural gas under the conditions prevailing in said first zone;
- and
- (b) thereafter injecting an oil-miscible displacement fluid into said first zone at a selected pressure so as to displace at least a portion of said undrained oil from said first zone and at least a portion of said liquid petroleum from said second zone to a downdip third well and recovering said portions of undrained oil and liquid petroleum through said third well, said oil-miscible displacement fluid being selected from the group consisting of carbon dioxide, nitrous oxide, and sulfur oxides.
A method for the recovery of natural gas, undrained oil and liquid petroleum from a dipping subterranean hydrocarbon-containing formation having an updip first zone containing natural gas and undrained oil overlying a second zone containing liquid petroleum, said method comprising the steps of:
- (a) injecting a gaseous displacement fluid through a second well into said first zone so as to displace at least a portion of said natural gas from said first zone to a downdip first well and recovering said portion of natural gas through said first well, said gaseous displacement fluid being selected from the group consisting of nitrogen and nitrogen-containing gases and having a density which is less than or equal to the density of said natural gas under the conditions prevailing in said first zone;
- and
- (b) thereafter injecting an oil-miscible displacement fluid into said first zone at a selected pressure so as to displace at least a portion of said undrained oil from said first zone and at least a portion of said liquid petroleum from said second zone to a downdip third well and recovering said portions of undrained oil and liquid petroleum through said third well, said oil-miscible displacement fluid being selected from the group consisting of carbon dioxide, nitrous oxide, and sulfur oxides.
A method for the recovery of natural gas, undrained oil, and liquid petroleum from a dipping subterranean hydrocarbon-containing formation having an updip first zone containing natural gas and undrained oil overlying a second zone containing liquid petroleum, said method comprising the steps of:
- (a) treating air so as to generate (1) a gaseous displacement fluid consisting essentially of nitrogen and (2) an oxidizing fluid consisting essentially of oxygen;
- (b) reacting said oxidizing fluid with carbonaceous matter to generate an oil-miscible displacement fluid comprising carbon dioxide;
- (c) injecting said gaseous displacement fluid into said first zone through a first well communicating with said first zone near the interface of said first and second zones so as to displace at least a portion of said natural gas from said first zone to an updip second well, and recovering said portion of natural gas through said second well, said gaseous displacement fluid having a density greater than or equal to the density of said natural gas under the conditions prevailing in said first zone;
- (d) thereafter injecting at least a portion of said oil-miscible displacement fluid into said first zone at a selected pressure so as to form a miscible transition fluid with at least a portion of said undrained oil, said selected pressure being between about the miscible displacement pressure in the absence of said gaseous displacement fluid and about the miscible displacement pressure of said gaseous displacement fluid;
- (e) thereafter injecting a drive fluid into said first zone so as to displace at least a portion of said miscible transition fluid and at least a portion of said liquid petroleum from said second zone to a downdip third well and recovering said portions of liquid petroleum and undrained oil through said third well.
Dependencies are inferred from the claim text.