METHOD FOR SYSTEM ESTIMATION OF QUALITY OF WELL PERFORATION Russian patent published in 1997 - IPC

FIELD: oil and gas production. SUBSTANCE: downhole device with measuring electrodes is sunk in cemented casing string below perforation interval. During its rise, curve of change in electric potential between measuring and grounded electrodes is registered and, from the peculiar features of change in electric potential of string after perforation, one estimates perforation quality. Additionally, before and after perforation, device for electromagnetic crack detection in casing strings and acoustic control of cementation is sunk in casing string below the head of proximate bed-collector lying below perforation interval. When being raised, curves of change in measured parameters are registered and, from configuration and extension of changes in curves registered after perforation, one judges about borders of perforated interval and degree of alteration in its insulation caused by perforation. Quality of perforation is estimated from whole complex of curves describing changes in electric potential of string, indications of electromagnetic crack detection of string, and acoustic control of well cementation. EFFECT: facilitated well perforation quality control. 2 dwg