Mobil Oil Corporation

Robert S Timmer

Alfred R Jennings, Jr

Eve S Sprunt

Paul S Northrop

A method for recovering hydrocarbons (e.g. oil) from a low permeability subterranean reservoir of the type comprised primarily of diatomite. A first slug or volume of a heated fluid (e.g. 60% quality steam) is injected into the reservoir at a pressure greater than the fracturing pressure of the reservoir. The well is then shut in and the reservoir is allowed to soak for a prescribed period (e.g. 10 days or more) to allow the oil to displaced by the steam into the fractures by imbibition. The well is then produced until the production rate drops below an economical level. A second slug of steam is then injected and the cycles are repeated with the volume of each subsequent slug of steam being progressively smaller that the one before it (i.e. about 80%) and the respective soak period being increased by about 20% over that of the previous cycle.

Method for producing low permeability reservoirs using steam

An oxygenated foam is injected into a loosely consolidated, clay-containing sandstone formation surrounding a well penetrating a hydrocarbon-bearing reservoir. Combustion is initiated between the oxygenated foam and hydrocarbons within the reservoir to burn the formation and form said consolidated zone around the well that acts as a barrier to the passage of sand into the well along with produced hydrocarbons.

Method of sand consolidation

An oxygenated foam is injected into a hydrocarbon-bearing reservoir within a diatomite-containing subsurface formation to hydraulically form a fracture within the reservoir. Combustion is initiated between the oxygenated foam and hydrocarbons within the reservoir to burn the formation and alter diatomite within the burned area into a hardened, more highly permeable material. The reservoir may again be fractured to shatter the hardened diatomite to further increase reservoir permeability and form a self-propped fracture within the reservoir.

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Bakersfield, CA, United States of America

Robert S Timmer