초록 ▼

High pressure air passes through gas supply conduit (16), downwardly through pilot passage (54) of pilot valve (48) into internal piston valve chamber (58) and high pressure chamber (30). When the pressure in chambers (58) and (30) exceed 80% of the line pressure from supply conduit (16), pilot valv

High pressure air passes through gas supply conduit (16), downwardly through pilot passage (54) of pilot valve (48) into internal piston valve chamber (58) and high pressure chamber (30). When the pressure in chambers (58) and (30) exceed 80% of the line pressure from supply conduit (16), pilot valve (48) shifts vertically, exposing the upper end of piston valve (56) to high pressure, and thereby urging the piston valve downwardly to open the high pressure chambers (58) and (30) into the low pressure chamber (32), thus creating an abrupt charge of gas into the well. The movement of line pressure through high pressure passage (78) to a position behind the annular shoulder (82) of the piston valve (56) causes the piston valve to return to its start position, and the differential pressure across pilot valve (48) causes it to move back to its start position.

대표청구항 ▼

[ I claim:] [2.] A method of stimulating the flow of liquid through subterranean earth formations to a wellbore in the earth comprising the steps of:determining the level of liquid in the wellbore;estimating the pressure at which most of the subterranean earth formation about the wellbore will fract

[ I claim:] [2.] A method of stimulating the flow of liquid through subterranean earth formations to a wellbore in the earth comprising the steps of:determining the level of liquid in the wellbore;estimating the pressure at which most of the subterranean earth formation about the wellbore will fracture;inserting a gas expulsion tool into a well casing which extends into the wellbore to the depth below the level of the liquid in the wellbore and to the depth of the earth formation to be stimulated;expelling a surge of compressed gas from the gas expulsion tool in the well casing and through openings in the well casing and out beyond the wellbore at the depth of the earth formation to be stimulated at a pressure exceeding 50% of the estimated formation fracturing pressure.