Fracturing process for removing breakdown fluid contamination

Abstract

The invention relates to a mining technology for the petroleum, natural gas and the coal seam gas, in particular to a compression fracture process which avoids the fracturing fluid pollution and solves the problem that the fracture conductivity is reduced caused by the dense filter cake formed on the surface of the strata fracture by the thickener added in the fracturing fluid applied in all the compression fracture constructions found in the prior art. The construction steps include that the pad fluid is injected into the oil gas storage strata; the sand-laden fluid is injected continuously when the oil gas storage strata generates fractures; subsequently, the displacement fluid is injected; then the pump on the ground is stopped; 60 minutes later after the fracture closing time T3 and the pressure is lower than the fracture closing pressure P3, the oxidant solution such as the chlorine dioxide result solution, the potassium permanganate, the hydrogen peroxide solution or the persulphate which can degrade the polymers is injected into the fractures as the fracturing post pad fluid; finally, the displacement fluid is injected to extrude all the compression fracture post pad fluid to the strata fractures. The compression fracture process can radically avoid the pollution block of the fracturing fluid, exert the potential of the fracturing technology and increase the yield.

Description

technical field [0001] The invention relates to a technology for exploiting oil, natural gas and coal bed gas, in particular to a fracturing process for decontaminating fracturing fluid. technical background [0002] Hydraulic fracturing is the main means to improve or transform the permeability of oil layers, and it is also the main means of increasing oil production in low-permeability and ultra-low-permeability oilfields. Hydraulic fracturing technology is also widely used in the exploitation of natural gas and coalbed methane. The ideal process of this method is to inject high-viscosity liquid, also known as fracturing fluid, into the oil well with a displacement that greatly exceeds the absorption capacity of the formation by using the surface high-pressure pump group, so that the hydraulic pressure in the well will continue to rise. After the cracking fluid pressure is greater than the formation pressure and rock tensile strength, the oil-bearing formation near the bot...

AI Technical Summary

Problems solved by technology

[0008] In order to solve the problems existing in the prior art in all fracturing fluids used in fracturing construction, the dense filter cake formed by the added thickener on the surface of formation fractures leads to the reduction of fracture conductivity, and provides a A fracturing process that solves fracturing fluid pollution (or clogging), and opens up a new effective way to improve the effect of fracturing stimulation

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