Cavity induced stimulation of coal degasification wells using foam
AssigneeAtlantic Richfield Company
InventorsXiaowei Weng, Carl T. Montgomery, Thomas K. Perkins
Life of this patent
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Abstract
An improved method for stimulating coal degasification wells comprising the injection of a foam into a coal seam which contains natural or induced fractures. Thereafter, high pressure gas is injected into the coal seam and suddenly released to cause disintegration of coal surrounding the borehole.
Claims15
A cavity induced stimulation method of the type in which injection and release of high pressure gas from a subterranean coal seam adjacent a wellbore is used to form a cavity adjacent the wellbore for improving the production of fluids from the subterranean coal seam comprising:
- (a) completing a wellbore into said coal seam;
- (b) flowing a foam forming fluid down the wellbore to said coal seam and into said coal seam;
- (c) flowing a gas down the wellbore and into said coal seam at high pressure to generate foam in situ and to generate an area of high pressure gas in the coal seam adjacent the wellbore;
- and,
- (d) releasing the pressure in said wellbore to generate a cavity in the coal seam adjacent the wellbore.
A cavity induced stimulation method of the type in which injection and release of high pressure gas from a subterranean coal seam adjacent a wellbore is used to form a cavity adjacent the wellbore for improving the production of fluids from an existing well which has been completed in the subterranean coal seam and used to hydraulically stimulate the coal seam comprising:
- (a) flowing a foam forming fluid down the wellbore to said coal seam and into said coal seam;
- (b) flowing a gas down the wellbore and into said coal seam at high pressure to generate foam in situ and to generate an area of high pressure gas in the coal seam adjacent the wellbore;
- and,
- (c) releasing the pressure in said wellbore to generate a cavity in the coal seam adjacent the wellbore.
Dependencies are inferred from the claim text.