Drilling fluid recycling method suitable for continental stratum containing high-activity clay

Abstract

The invention discloses a drilling fluid recycling method suitable for the continental stratum containing high-activity clay. The drilling fluid recycling method comprises that S1. the upper drilling fluid is processed, and the upper part is a strong mud making stratum; the step S1 comprises sub steps: S11. CaCl2 in a circulation tank is presses into an oil well, soil phases in the drilling fluid are flocculated, and the drilling fluid is ensured to be clean; S12. after flocculate is subjected to demulsification, and a filter press carries out solid-liquid separation; S13. when the well drilling process reaches the lower part of the strong mud making stratum, mud is appropriately made; S2. the middle-lower part drilling fluid is processed, the middle-lower part is an easily-collapsed stratum, before the well drilling process reaches the middle-lower part easily hydrated and collapsed stratum, an anti-collapse treating agent for restraining plugging is added, the well hole is ensured to be stable, a solid control device removes harmful solid phases to a recycling tank, then the harmful solid phases are put into a demulsification tank, demulsification and oxidation reactions are generated, and then the harmful solid phases are pressed and filtered by a filter press. According to the invention, after wastes are processed, the liquid can be recycled, solid matter can be used as a building material, 100 m<3> of drilling fluid in a single well is recycled, and 50% of the cost of the drilling fluid is saved.

Description

technical field [0001] The invention relates to a method for keeping drilling fluid from landing in continental formations containing high active clay, and belongs to the technical field of petroleum drilling. Background technique [0002] Drilling fluid is the circulating flushing medium used in the hole during the drilling process. Drilling fluid is the blood of drilling, also known as drilling flushing fluid. Drilling fluid can be divided into clear water, drilling fluid, clay-free flushing fluid, emulsion, foam and compressed air according to its composition. Clear water is the earliest drilling fluid, it does not need to be treated, it is easy to use, and it is suitable for areas with complete rock formations and sufficient water sources. Drilling fluid is a widely used drilling fluid, which is mainly suitable for unstable rock formations such as loose rock formations, developed cracks, easy to collapse and drop blocks, swelling and spalling when exposed to water. ...

AI Technical Summary

Problems solved by technology

The viscous micelles are demulsified by adding demulsifiers, and can only be separated by pressure filtration after oxidation by oxidants (oxidation of polymers such as PHP); the middle and lower parts use polymers, polysulfone and other drilling fluid systems, due to the high content of submicron particles and medium particle size The value is 1~2.5μm lower, and the liquid phase viscosity is high, resulting in slow drilling speed, drilling fluid can not be reused, and it is difficult to effectively separate solid-liquid waste, and most of the waste is discharged on site, which not only occupies a lot of land, but also seriously pollutes the environment

Existing technology can no longer meet the requirements of the country and enterprises for speed improvement, efficiency improvement and environmental protection

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