METHOD OF ISOLATION OF ABSORPTION ZONES DURING WELL DRILLING Russian patent published in 2021 - IPC E21B33/138 E21B43/32 

FIELD: oil and gas.

SUBSTANCE: invention relates to the oil and gas industry and is intended for repair and insulation works in absorption zones when drilling wells. The method of isolation of absorption zones during well drilling includes stopping drilling after opening the absorption zone, which does not allow further deepening of the well, removing the drilling tool from the well, lowering the production string into the well, through which the blocking composition is injected in portions into the absorption zone in the form of a plugging solution with a clogging filler taking into account the injection pressure. At the same time, before injection, the well is flushed with a fluid flow sufficient to wash out the rock from the absorption zone, the subsequent replacement of the wellhead pump with a concrete pump with increased throughput - a screw pump, gerotor pump or BN-70D concrete pump, and determination of the required screen size to isolate the absorption zone around the well based on the screen size and the injectivity of the loss zone. The initial volume of the plugging solution with the bridging filler is determined, which is selected from the maximum throughput of the pump and / or process pipes. The initial volume of the bridging composition is crushed by the buffer fluid into the absorption zone with a pressure not exceeding the permissible pressure, excluding the violation of the integrity of the rocks exposed by drilling. If necessary, the remnants of the clogging compound are washed out of the well. After technological exposure sufficient for the setting of the bridging composition and / or the deposition of the bridging filler, the injectivity of the disturbance zone is determined, from which the required volume of the bridging composition and its composition for pushing the buffer liquid into the absorption zone are determined.

EFFECT: expansion of functionality due to possibility of clogging high-injectivity absorption zones by pumping portions of drilling or cement slurry with a large filler.

2 cl