Low-density water base drilling fluid capable of resisting ultra-high temperature of 248 DEG C as well as preparation method and application thereof

Abstract

The invention relates to a low-density water base drilling fluid capable of resisting ultra-high temperature of 248 DEG C as well as a preparation method and application thereof. The drilling fluid isprepared from the following raw materials: 100 parts of pulp blending water, 0.2-0.3 part of sodium carbonate, 1.5-4 parts of sodium bentonite, 0-0.5 part of caustic soda flake, 0.3-0.5 part of deoxidant, 0.3-0.7 part of zwitter-ion hydrophobic associated polymer filtrate reducer, 0.5-1.2 parts of anionic type polymer filtrate reducer, 3-5 parts of sulfomethylation formoldehyde resin type II, 3-5parts of sulfomethylation lignite resin, 2-4 parts of high softening point sulfonated bitumen, 1-3 parts of modified graphitic lubricant, 1-3 parts of polymeric alcohol, 0-6 parts of No.5 white oil,0-1 part of emulsifier, 0-2 parts of polycarboxylate flow type conditioning agent, 3-5 parts of ultra-high temperature blocking agent and 0-20 parts of API (American Petroleum Institute) standard barite. The drilling fluid is suitable for a stratum of which the temperature is 248 DEG C. The ultra-high temperature low-density water base drilling fluid disclosed by the invention has the advantages of high thermal stability under an ultra-high temperature condition, simpleness in performance maintenance and low cost, and the rheological property of the drilling fluid is easy in regulation and control.

Description

Technical field: [0001] The invention relates to an ultra-high temperature-resistant low-density polysulfide water-based drilling fluid for ultra-deep well drilling and its preparation method and application, belonging to the technical field of drilling fluid in oil and natural gas drilling engineering, deep exploration drilling engineering and geothermal well drilling engineering . Background technique: [0002] With the development of my country's oil and gas industry, oil and gas exploration areas are gradually expanding from land to deep sea, and target layers are expanding from shallow to deep and ultra-deep layers. Ultra-deep layers will be one of the most important development areas for my country's oil industry in the future. During the drilling process of ultra-deep wells, the bottom of the well is under ultra-high temperature and high pressure conditions. The drilling section is long and there are large sections of open holes, and many complex formations must be dr...

AI Technical Summary

Problems solved by technology

[0004] For ultra-deep well ultra-high temperature and low-pressure reservoir drilling, currently used ultra-high temperature and low-density water-based drilling fluid has poor ultra-high temperature stability, viscosity reduction problems, easy drilling fluid loss and ultra-deep well slim hole drilling. Drilling fluid rheological control problems, wellbore stability problems, leakage prevention and plugging and other drilling fluid technical problems, the present invention provides an ultra-high temperature resistant low-density polysulfide water-based drilling fluid and its field application method to solve the problem of low pressure in ultra-deep wells Water-based drilling fluid technical bottlenecks under harsh conditions such as ultra-high temperature and low density during oil and gas reservoir drilling

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