METHOD OF DETERMINING TIGHTNESS OF ANNULAR SPACE Russian patent published in 2025 - IPC E21B47/05 E21B47/11 G01V5/04 

FIELD: mining.

SUBSTANCE: invention relates to construction and operation of oil and gas wells, in particular to diagnostics of tightness of annular space in production, exploration, observation and other wells. In particular, disclosed is a method for determining tightness of annular space, which consists in conducting background pulsed neutron gamma-ray logging or pulsed neutron gamma-ray spectrometric logging. Instrument assembly is lowered on a cable with a container with gadolinium chloride solution into the investigated interval on a geophysical cable and installed at depth of 50-150 m above the perforation interval. Then, solution with gadolinium chloride is pumped into borehole space. Then, a control measurement of pulsed neutron gamma-ray logging or pulsed neutron gamma-ray spectrometric logging is obtained. Thereafter, solution with gadolinium chloride in production or injection well is forced into formation by adding water to well until solution with gadolinium chloride passes into perforation interval and annular space. Further, repeated measurement of pulsed neutron gamma-ray logging or pulsed neutron gamma-ray spectrometric logging is carried out. Data obtained during measurements are compared with background data and based on this comparison, presence or absence of behind-the-casing flows and absorption intervals are determined.

EFFECT: disclosed is a method for determining tightness of annular space.

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