METHOD FOR ELIMINATING ANNULAR FLOWS AND BREACHING WHEN CEMENTING CONDUCTORS UNDER PERMAFROST CONDITIONS Russian patent published in 2024 - IPC E21B43/00 E21B33/14 C09K8/42 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to a method for eliminating annular flows and breaching when cementing conductors under permafrost conditions. The method includes auger drilling of a wellbore to the depth of the shoe installation. Also includes lowering centred at the bottom and wellhead, with unloading at the bottom. The method also includes installing a device on the conductor head that is capable of sealing the inner part of the column and uniformly distributing the injected cement slurry into the annulus. The method also includes preparing a cement slurry with a density of no more than 1400 kg/m³ and heating this solution to 25-30 °C and pumping it into the annular space to the mouth. After that, the device in use is removed, and a device designed to seal the intracolumn space is installed on the direction head. At a distance of up to 0.5 m from the head, a threaded pipe is welded into the direction wall to connect a column of flexible pipes to the sump tank. After which, a cementing unit connected to the surge tank pumps a mineralized buffer liquid heated to a temperature of 50 °C, inward direction to the bottom. To prepare the cement slurry, expandable cement material without thickening-setting accelerators in its composition is used.

EFFECT: improved quality of primary cementing of conductors and elimination of annular flows and breaching.

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