Ultra-low temperature resistant calcium-based low-solid drilling fluid for drilling in permafrost or severe cold areas

Abstract

The invention relates to ultra-low temperature resistant calcium-based low-solid drilling fluid for drilling in permafrost or severe cold areas. The ultra-low temperature resistant calcium-based low-solid drilling fluid is composed of 100 parts of water, 10-30 parts of calcium chloride, 1-10 parts of multifunctional complexing agent, 0.5-2.0 parts of viscosity reducer, 0.1-1.0 parts of filtrate reducer, 1-5 parts of lubricant and 1-3 parts of antifoaming agent. The drilling fluid provided by the invention has good rheological property in an ultra-low temperature environment and quite good wall protection capability and carrying ability, thereby providing a technical support for drilling constructions in permafrost and severe cold areas in winter of our country.

Description

technical field [0001] The invention relates to a drilling fluid for drilling in permafrost regions or severe winter regions and a preparation method thereof. Background technique [0002] When drilling in Xinjiang, Qinghai, Tibet, Heilongjiang and other places, they often encounter permafrost and extremely cold and ultra-low temperature environments in winter. When drilling in such a low-temperature environment, because the temperature in the borehole and the environment reach or even exceed -30°C (ultra-low temperature), the drilling fluid often freezes, resulting in the failure of the drilling fluid to circulate, and the drilling tools are frozen in the hole and cannot be used. Continue construction. When the permafrost melts after overwintering, the drilling fluid may also experience formation instability due to the loss of cement and the ability to retain walls. Therefore, there is an urgent need to study a drilling fluid suitable for use under ultra-low temperature ...

AI Technical Summary

Problems solved by technology

At present, most cryogenic drilling fluids use hydrocarbon-based liquids with various additives (TC21 aviation fuel, diesel fuel, etc.), ethanol aqueous solutions, ethylene glycol aqueous solutions and other solid-free drilling fluids. Not only does it pollute the environment, but it also costs a lot

In addition, the solid-free drilling fluid has relatively poor adaptability to the formation, and has certain limitations in use

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