Exxon Production Research Company

Hughes Tool Company LLC

Robert C West

Bolling A Abercrombie

Greg G Peters

Jack R Blann

Fluid, such as liquid water, is injected into the rock surrounding an in situ oil shale retort at sufficient pressure and flow rate so that the injected fluid flows toward the retort to block the path of hot liquid and gaseous kerogen decomposition products escaping from the retort and to return heat to the retort. The successful conduct of an oil shale retorting operation usually requires that the retort temperature be maintained at a temperature sufficient to decompose efficiently the kerogen contained in the oil shale. By reducing the heat loss from an active retort, the amount of energy required to maintain a desired temperature therein is reduced. The fluid injection method also maintains pressure in an in-situ oil shale retort, allowing in-situ oil shale retorting to be efficiently conducted at a desired pressure. The method also reduces the danger to mineworkers who may be engaged in adjacent mining operations due to the escape of hazardous gases from an active retort. The method allows a series of sequential in-situ oil shale retorts in an oil shale formation to be placed more closely together than previously practical by reducing hot fluid leakage from each active retort to one or more abandoned retorts adjacent thereto, thus improving the recovery factor from the formation. The method also minimizes contamination of the formation surrounding an active in-situ retort due to hazardous chemicals which may be contained in the kerogen decomposition products leaking from the retort.

In-situ retorting of oil shale

An artificial lifting device has a downhole valve which intermittently directs operating gas to the top of a collection chamber to promote the lifting of oil below the valve upwardly through an annulus defined between a cylindrical housing supporting the valve and an external cylindrical member through which the housing extends. Gas is alternately injected to the top of the chamber through an injection port and vented to the surface through a vent port. An exhaust conduit, separate from the source of pressurized gas running from the surface to the valve, communicates the vent port with the surface when the device is in the vent mode.

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Houston, TX, United States of America

Robert C West