Coalbed methane recovery using membrane separation of oxygen from air
AssigneeAmoco Corporation
InventorsRajen Puri, Dan Yee
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Abstract
A method of recovering methane from a solid carbonaceous subterranean formation having a production well in fluid communication with the formation and an injection well in fluid communication with the formation, comprising the steps of passing a gaseous fluid containing at least 60 volume percent nitrogen and at least 15 volume percent oxygen through a membrane separator to produce an oxygen-depleted effluent, pressurizing the oxygen-depleted effluent to a pressure above a reservoir pressure of the solid carbonaceous subterranean formation, injecting the oxygen-depleted effluent into the formation through the injection well, and recovering a fluid comprising methane through the production well.
Claims25
A method for recovering methane from a solid carbonaceous subterranean formation having a production well in fluid communication with the formation and an injection well in fluid communication with the formation, the method comprising the steps of:
- (a) passing a gaseous fluid containing at least 60 volume percent nitrogen and at least 15 volume percent oxygen through a membrane separator to produce an oxygen-depleted effluent;
- (b) injecting the oxygen-depleted effluent into the formation through the injection well;
- (c) recovering a fluid comprising methane through the production well;
- and
- (d) operating the production well so that a pressure in the production well at a wellbore location adjacent to the formation is less than an initial reservoir pressure of the formation.
A method for recovering methane from a coalbed having a production well in fluid communication with the coalbed and an injection well in fluid communication with the coalbed, comprising the steps of:
- (a) passing a gaseous fluid containing at least 60 volume percent nitrogen and at least 15 volume percent oxygen through a membrane separator to produce an oxygen-depleted effluent having less than 95% by volume nitrogen;
- (b) injecting the oxygen-depleted effluent into the coalbed through the injection well;
- and
- (c) recovering a fluid comprising methane through the production well.
A method of recovering methane from a coalbed penetrated by a production well producing at a pre-injection methane recovery rate, the method comprising the steps of:
- (a) passing air containing about 15 to 25% by volume oxygen through a membrane separator to produce an oxygen-depleted effluent;
- (b) injecting the oxygen-depleted effluent through at least one injection well spaced from the production well and at an injection rate sufficient to increase the production of methane from the production well to at least two times the pre-injection methane recovery rate within ninety days of commencing to inject oxygen-depleted effluent;
- and
- (c) operating the production well so that a pressure in the production well at a wellbore location adjacent to the coalbed is less than an initial reservoir pressure of the coalbed.
A method for recovering methane from a solid carbonaceous subterranean formation having a production well in fluid communication with the formation and at least one injection well in fluid communication with the formation, the method comprising the steps of:
- (a) passing a gaseous fluid containing at least 60 volume percent nitrogen and at least 15 volume percent oxygen through a membrane separator to produce an oxygen-depleted effluent;
- (b) injecting the oxygen-depleted effluent into the formation through the injection well at a pressure above a formation parting pressure;
- (c) recovering a fluid comprising methane through the production well;
- and
- (d) operating the production well so that a pressure in the production well at a wellbore location adjacent to the formation is less than an initial reservoir pressure of the formation.
Dependencies are inferred from the claim text.