METHOD FOR ASSESSMENT OF CEMENTATION QUALITY OF OIL AND GAS WELLS Russian patent published in 2017 - IPC E21B47/05 

FIELD: oil and gas industry.

SUBSTANCE: method for assessing the cementation quality of oil and gas wells involves acoustic sector scanning of the space behind the string with measurement of amplitudes of the reflected signal from the inner wall of the casing. Identify the communicated cementation defects among a plurality of chaotically distributed regions with different cementation state and assess quality of their length along the column and the extent of their perimeter opening. Perform sequential analysis of data by sector at each depth quantum. Select sectors with cementation defects along the perimeter and behing the string space. In the case sectors coincide with cementation defects of the next and previous quantum of depth, the next quntum sectors are assigned to the sectors of the previous quantum. According to duration of sectors` coincidence with such defects, the duration of through channels with cementation defects in a given interval of research is estimated, and by the number of sectors on each quantum, the perimeter of their opening in degrees is assessed. The opening of isolated sectors with cementation defects is also estimated in degress along the perimeter on a separate quanta of depth, not adjacent to the selected through channels. The separate contribution of through channels with cementing defects and isolated cementing defects in the total cementation defect are determined.

EFFECT: increased reliability and accuracy of cementation quality assessment in oil and gas wells casing columns.

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