METHOD OF TIGHTNESS TESTING FOR UNDERGROUND RESERVOIR ARRANGED IN SOLUBLE ROCKS THROUGH DRILL WELL Russian patent published in 2012 - IPC G01M3/00 B65G5/00 

FIELD: mining.

SUBSTANCE: underground reservoir filled with a brine is equipped with a casing pipe and a hanger pipe, test intervals are identified, interval injection of a test fluid is carried out into a tube space of casing and hanger pipes until the test fluid-brine interface reaches the lower elevation of the test interval with simultaneous displacement of brine to day surface. Application of test pressure is carried out with a time delay for each identified test interval and detection of pressure drop rate. Then the test pressure is repeatedly applied with additional pumping of the test fluid, afterwards value is determined, as well as leakage intensity by pressure drop rate and volume of added test fluid. At the same time, according to the invention, prior to application of test pressure, a hanger pipe block is installed under the casing pipe block, the lower elevation of the investigated interval is identified by volume of brine displaced from the underground reservoir and by values of test fluid and brine pressures measured at the wellhead in the period of underground reservoir pressurising. At the same time application of test pressure is carried out in stages by means of increasing it in the following sequence: 0.5 P_test, 0.75 P_test, P_test, where P_test - test pressure, with staged soaking of the underground reservoir in time under the specified pressures until the temperature background is balanced for the injected test fluid, brine and rock that holds the underground reservoir. Pressure drop rate is identified at each stage of the underground reservoir soaking in time under applied pressure, and value and intensity of leakage within the range of the identified test interval are set by averaged value of added test fluid volume during the period of staged application of pressure to the value of the test one.

EFFECT: increased reliability of testing for tightness of underground reservoirs.

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