Deepwater high-density drilling fluid capable of resisting high temperature of 220 DEG C

Abstract

The invention discloses a deepwater high-density drilling fluid capable of resisting a high temperature of 220 DEG C, wherein the drilling fluid comprises: 100 parts of seawater, 0.1-0.2 part of sodaash, 0.2-0.3 part of caustic soda, 1.2-1.5 parts of bentonite, 0.2-0.3 part of a flow type regulator, 2.0-3.0 parts of a tackifying and shear strength improving agent, 5.0-8.0 parts of a high-temperature-resistant filtrate reducer, 2.0-4.0 parts of a high-temperature anti-collapse agent, 15.0-20.0 parts of a hydrate inhibitor and 420-650 parts of a weighting agent. According to the invention, thedeepwater high-density drilling fluid has good sedimentation stability, good rheological property, good water loss wall-building property and other properties under high-temperature conditions, and meets the exploration and development of deepwater high-temperature and high-pressure wells.

Description

technical field [0001] The invention belongs to the technical field of drilling fluid for petroleum drilling, and in particular relates to a deep-water high-density drilling fluid resistant to high temperatures of 220°C. Background technique [0002] Deepwater drilling generally refers to areas where the water depth exceeds 900 meters in offshore operations. Among them, offshore operations when the water depth is greater than 1,500 meters are called ultra-deepwater drilling. In recent years, with the increasing proportion of offshore oil reserves, offshore oil exploration has gradually developed into deep water areas. However, various complex problems caused by water depth problems have brought more serious challenges to drilling and completion. [0003] Deepwater development wells further narrow the drilling window and require higher drilling fluids. The depth of deep water is relatively large, the upper rock cover is replaced by seawater, the pressure of the overlying f...

AI Technical Summary

Problems solved by technology

The conditions of low temperature and inclined wells in the seawater section change the rheology of the drilling fluid in the riser, which can increase the viscosity and density of the drilling fluid and produce a gel effect. High frictional resistance is generated in the wellbore flow and the formation at the casing shoe is compressed. The risk of leakage increases, causing high-temperature degradation and cross-linking of part of the treatment agent in the drilling fluid, weakening the anti-pollution ability of the system, making the water solubility of the treatment agent worse, affecting the rheology and fluid loss performance of the entire drilling fluid, seriously When the entire system collapses, it is necessary to prevent the drilling fluid from gelling in the low-temperature section and cause lost circulation, and to prevent the drilling fluid from degrading in the high-temperature section, resulting in a decline in rock-carrying capacity.

In foreign countries, the water-based drilling fluid system for deepwater high-temperature and high-pressure development wells with a temperature resistance of about 180°C and a specific gravity of about 2.1 has been widely used, but domestic research is still blank

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