METHOD OF WELLS CEMENTING Russian patent published in 2008 - IPC E21B33/14 

FIELD: mining.

SUBSTANCE: invention concerns mining, particularly a method of cementing of oil, gas and water wells. The method involves landing of a casing pipe into a well, pumping cement slurry into the casing pipe, flush, displacement of the cement slurry to casing annulus and letting it solidify. During flush the cement slurry column in the casing annulus is reciprocated up and down multiple times, ceasing flush for that, further the pressure above bypass plug in the casing pipe is reduced, cement slurry is partially let back into the casing pipe and flushed to the casing annulus again. Reciprocation cycle for the cement slurry column in the casing annulus is repeated multiple times and finished with flush of all cement slurry into the casing annulus. Cement column reciprocation is implemented at various height and speed; before the beginning of the cement slurry gelling the reciprocation height and speed is minimised, while the slurry is flushed into the casing annulus completely before it begins gelling.

EFFECT: improved cementing quality due to the cement slurry reciprocation in casing annulus during a casing pipe cementation, removal of boring fluid residues from the well, casing pipes and cavities walls, elimination of shrinkage strain of solidifying cement grout, reduction of time passing since cement slurry halts till it begins to solidify in the hole clearance.

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