An environmentally friendly oxidation-imbibition method for enhanced oil recovery with zero flowback of fracturing fluid in shale gas wells

Abstract

The invention discloses an environment-friendly oxidation-imbibition method for zero flowback of shale gas well fracturing fluid and improved recovery. In this method, oxidant is added to the fracturing fluid, and after the fracturing of the gas well, the shale and the oxidizing fracturing fluid are used to oxidize the organic matter on the fracture surface or pore surface, thereby increasing the contact area between the fracturing fluid and clay minerals, and improving the shale The imbibition ability of fracturing fluid enables the fracturing fluid in the fracture to imbibe and disperse into the pores, and the fracturing fluid in the pores dissolves organic matter and disperses into the intercrystalline pores of clay minerals, realizing zero flowback of fracturing fluid. The present invention uses oxidative fracturing fluid to improve the imbibition capacity of shale reservoirs, not only increases the effective seepage channel and gas desorption-diffusion capacity, but also avoids the environmental problems induced by fracturing fluid flowback, and returns to the shale gas well after shale gas well pressure. When the drainage is put into production, the oxidant trapped in the reservoir can continuously improve the shale gas transmission channel, which is conducive to realizing the low-cost and high-efficiency development goal of shale gas wells.

Description

technical field [0001] The invention belongs to the technical field of petroleum and natural gas exploitation, and relates to a method for increasing the recovery rate of shale gas reservoirs in the environment of zero flowback of fracturing fluid in shale gas wells. Background technique [0002] Shale gas is a typical unconventional natural gas with huge global resources and great exploitation value. Because the seepage channel of the shale matrix is ​​mainly in the nanometer scale, the permeability of the matrix is ​​mainly between nadarcy and microdarcy, the seepage resistance of shale gas is huge, the adsorption / free gas coexists, the gas transmission capacity is low, hydraulic fracturing is At present, the main means of exploiting shale gas, but the scale of fracturing in shale gas reservoirs is large, the amount of fracturing fluid used is large, and the flowback of fracturing fluid is difficult. A large amount of fracturing fluid flowback will cause serious pollution...

AI Technical Summary

Problems solved by technology

However, there is still the problem of fracturing fluid flowback in this patent, which has caused a great burden to the environment

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