Amoco Corporation

The Standard Oil Company

Standard Oil Company (indiana)

Bp Amoco Corporation

Rajen Puri

Dan Yee

John P Seidle

Joseph J Chaback

Michael H Stein

Richard F Volz, Jr

Paul T Pendergraft

Bruce W Gash

Robert S Metcalfe

Thomas S Buxton

Luis E Arri

Om Majahan

A method is disclosed 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. In the method an oxygen-depleted effluent, produced by a cryogenic separator is injected into the formation through the injection well. A first methane-containing gaseous mixture is recovered from the formation through the production well-during at least a portion of the time the oxygen-depleted effluent is being injected into the formation. The first methane-containing gaseous mixture has a first methane-desorbing gas volume percent. The injection of oxygen-depleted effluent is ceased and thereafter a second methane-containing gaseous mixture is recovered from the formation which has a second methane-desorbing gas volume percent which is less than the first methane-desorbing gas volume percent.

Method for recovering methane from a solid carbonaceous subterranean

A method is disclosed 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. In the method an oxygen-depleted effluent, produced by a cryogenic separator is injected into the formation through the injection well. A first methane-containing gaseous mixture is recovered from the formation through the production well during at least a portion of the time the oxygen-depleted effluent is being injected into the formation. The first methane-containing gaseous mixture has a first methane-desorbing gas volume percent. The injection of oxygen-depleted effluent is ceased and thereafter a second methane-containing gaseous mixture is recovered from the formation which has a second methane-desorbing gas volume percent which is less than the first methane-desorbing gas volume percent.

A method for treating a mixture of gaseous fluids within a solid carbonaceous subterranean formation. In some embodiments, the invention provides for the disposal of a strongly adsorbing gaseous fluid within the formation. In other embodiments, the invention provides a means for fractionating a mixture of gaseous fluids within the formation. In still other embodiments, the invention provides for the recovery of a raffinate from the formation which is enriched in relatively weaker adsorbing gaseous fluids. In still other embodiments, the invention provides for the recovery of methane from the formation.

A method for determining the reservoir properties of a solid carbonaceous subterranean formation is disclosed. The method uses field data obtained from an injection/flow-back test, which utilizes a gaseous desorbing fluid, in conjunction with reservoir modeling techniques to determine the reservoir quality and the enhanced methane recovery characteristics of the formation.

Method for determining the reservoir properties of a solid carbonaceous

Method for treating a mixture of gaseous fluids within a solid

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.

Coalbed methane recovery using membrane separation of oxygen from air

A method is disclosed for using a pressure swing adsorption separator system to provide an oxygen-depleted gaseous effluent for injecting into a suitable solid carbonaceous subterranean formation, such as a coalbed, to enhance the recovery of methane from the formation.

Coalbed methane recovery using pressure swing adsorption separation

A method is disclosed for increasing the production of methane from a solid carbonaceous subterranean formation having a standard initial production rate of a methane-containing gas of X standard cubic feet per unit time. The method comprises the steps of injecting an inert methane-desorbing gas into the formation; terminating injection of the methane-desorbing gas; and thereafter recovering greater than X standard cubic feet per unit time of a methane-containing gas from the formation. In some embodiments, a number of well systems exceeding the number of available inert gas production and injection units can be operated in accordance with the present invention to yield greater methane-containing gas production than would be obtained if the available injection systems were dedicated continuously to particular well systems.

Method for producing methane-containing gaseous mixtures

Processes are disclosed for separating an oxygen-containing gas into oxygen-enriched and oxygen-depleted streams. The oxygen-depleted stream is injected into a methane-containing solid carbonaceous subterranean formation to produce a methane-containing gaseous mixture. The oxygen-enriched stream is reacted with a stream containing an oxidizable material which can be the methane-containing mixture.

A method for reducing the inert gas fraction volume percent present in a methane-containing mixture produced by injecting an inert gas into a solid carbonaceous subterranean formation is disclosed. The method reduces the inert gas fraction by suspending the injection of the inert gas or by reducing a rate of injection of the inert gas. Additional methods are disclosed in which the inert gas volume percent of a gaseous mixture produced from more than one well can be maintained below the inert gas volume percent present in a gas obtained from at least one of the wells.

Method for reducing the inert gas fraction in methane-containing gaseous

A method for generating oxygen-depleted air for injection into a subterranean coal seam for increasing production of methane. Air and produced fluids comprising methane are input into a fuel cell power system; and fuel cell power system exhaust comprising oxygen-depleted air is injected into the coal seam.

Generating oxygen-depleted air useful for increasing methane production

A method of recovering methane from a solid carbonaceous subterranean formation by injecting a fluid that desorbs methane through at least one injection well into a subterranean formation and recovering desorbed methane through at least one production well. The initial rate of injection of the desorbing fluid can be increased without exceeding formation pressure limitations by injecting a preflush fluid having a desorbing efficiency less than a desorbing efficiency of the first fluid. This increase in injection of the desorbing fluid results in an increase in the recovery rate of methane.

Recovery of methane from solid carbonaceous subterranean formations

A method of recovering methane from a solid carbonaceous subterranean formation includes injecting a gas that desorbs methane through an injection well into a subterranean formation and recovering methane from a first and a second production wells, or from a first and a second layer. Areal and/or vertical sweep efficiency of the injected desorbing gas can be increased by selectively restricting the flow of recovered fluids from the first or the second production well with the highest monitored ratio of injected desorbing gas. The restriction of flow forces the desorbing gas into higher permeability areas of the subterranean formation.

Recovery of methane from solid carbonaceous subterranean of formations

The irreducible water saturation profile across the length of a core sample of coal is determined from four series of X-ray attenuation measurements made over the length of the core sample. The X-ray attenuation measurements are made while the core sample is at a pressure simulating a formation overburden pressure. The first series of X-ray attenuation measurements are made while the core sample is saturated with distilled water or formation brine. The distilled water or formation brine is then displaced with humidified, inert, substantially nonadsorbing gas and a second series of X-ray attenuation measurements are made. The core sample is then saturated with an aqueous sodium iodide solution and a third series of X-ray attenuation measurements are made. The aqueous sodium iodide solution is then displaced with a humidified, inert, substantially nonadsorbing gas and a fourth series of X-ray attenuation measurements are made.

Method of determining the porosity and irreducible water saturation of a

A method of producing methane by injecting inert gas, such as nitrogen, through an injection well into a solid carbonaceous subterranean formation (e.g., coal) and recovering methane from a production well(s). Methane desorption is achieved by reduction in methane partial pressure rather than by reduction in total pressure alone.

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Aurora, CO, United States of America

Rajen Puri