Saturated salt water drilling fluid for deep well salt mine drilling and preparation method of drilling fluid

Abstract

The invention discloses a saturated salt water drilling fluid for deep well salt mine drilling and a preparation method of the drilling fluid. The saturated salt water drilling fluid comprises the following raw materials in parts by weight: 100 parts of water, 2-4 parts of bentonite, 1-2 parts of sepiolite, 0.5-1 part of hectorite, 1-4 parts of FT-1 sulfonated bitumen powder, 0.2-1 part of an inorganic salt recrystallization inhibitor, 0.4-2 parts of a GTQ salt-resistant copolymer, 0.3-0.5 part of KHm potassium humate, 0.1-0.5 part of a water-based defoaming agent, 0.2-1 part of sodium carbonate, 0.1-0.3 part of sodium hydroxide, 2-10 parts of magnesium chloride, 7-15 parts of potassium chloride and 20-35 parts of sodium chloride. According to the saturated salt water drilling fluid, the influence on the performance of the drilling fluid caused by complicated environments of high-concentration inorganic salt, high temperature and the like in deep well salt mine construction can be eliminated and a technical guarantee is provided for rock salt stratum coring operation; and the saturated salt water drilling fluid is relatively good in rheological property, is capable of effectively preventing corrosion on a salt well wall and a rock core in core drilling, and is stable in performance at a high temperature and suitable for deep well salt mine sampling drilling.

Description

technical field [0001] The invention relates to a saturated brine drilling fluid suitable for deep brine drilling and exploration field and a preparation method thereof. Background technique [0002] Underground brine is an important natural resource, which is of great significance to chemical industry and manufacturing industry. When drilling into the salt-gypsum formation, the drilling fluid needs to face the pollution of the salt-gypsum layer, the dissolution of the salt layer when it encounters water, the shale of broken and soluble salt hydrates, expands, falls off or even collapses. The downhole is complicated, and it will cause the occurrence of stuck pipe accidents. At the same time, it is also possible that the formation loss leads to relatively low drilling fluid density, and it is difficult to control the creep of the brine formation, resulting in plastic flow. The low drilling fluid column pressure makes the already unstable wellbore more unstable and accidents ...

AI Technical Summary

Problems solved by technology

In addition, the degradation or cross-linking reaction of organic treatment agents in drilling fluids under high temperature conditions can easily lead to drastic changes in the above properties, suspension of rock powder and deterioration of fluidity

Surface saturated brine drilling fluid will turn into an undersaturated state under high temperature conditions at the bottom of the hole, which will lead to the dissolution of core samples and reduce the efficiency of coring

In a high-temperature environment, under the action of the high-concentration electrolyte in the saturated brine drilling fluid, the organic treatment agent will cause the drilling fluid to generate air bubbles, resulting in a decrease in density

In addition, in the saturated brine drilling fluid under high temperature conditions, the corrosion effect of the electrolyte on the drilling tool is enhanced, which will cause pitting corrosion and stress corrosion of the drill string, resulting in serious well accidents

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