METHOD OF TESTING GAS WELL CASING STRINGS FOR TIGHTNESS Russian patent published in 2000 - IPC

FIELD: oil-and-gas producing industry; applicable in testing of casting strings of gas and oil wells for tightness after drilling in completion and repair, and isolation operations. SUBSTANCE: essence of invention consists in that with tubing and drilling pipes run down to well bottom and after replacement of drilling mud with process water, pressure in annular space is gradually raised by injection of air by compressor with discharge of displaced water into measuring vessel up to casing test pressure value. Variations of pressure in annular space and level in measuring vessel are observed for 12 h, then pressure is released and level change is controlled over by downhole instrument every two hours. EFFECT: higher level of control over casing string defects due to high permeability of gas. 2 dwg