METHOD FOR ELIMINATING FLOWS BEHIND THE CASING IN PETROLEUM PRODUCTION BOREHOLES Russian patent published in 2022 - IPC E21B33/138 

FIELD: petroleum industry.

SUBSTANCE: invention relates to the petroleum industry, namely, to methods for eliminating the circulation reservoir water behind the casing in petroleum boreholes. Proposed method for eliminating flows behind the casing in petroleum production boreholes includes the following stages: plugging the borehole, extracting the downhole equipment, implementing a complex of works in surveying the source of water inflow in the borehole, lowering a tubing string and pumping a pack of high-viscosity mud from the bottomhole to the upper perforations; after raising the tubing string, a packer plug is additionally lowered and installed in the interval of the upper perforations; a slot perforator is then lowered into the borehole on drill pipes, and the casing and cement stone are cut in the aquifier interval, creating slot-like channels; after the perforator is raised, a tubing string is lowered with a packer and a grouting composition is pumped into the slot-like channels, pushing the composition into the aquifer; after repair and insulation works are completed and the tubing string with the packer are raised, the borehole is left for the waiting-on-cement period (WOC); drill pipes are then lowered with a mill and the packer plug is drilled, flushing the metal chips and the viscoelastic composition to the surface; a casing of a smaller diameter is then lowered into the well, cemented and left for WOC.

EFFECT: provided reliable barrier for the ingress of reservoir waters in the behind-casing space between the casing and the rock.

1 cl, 7 dwg