Environmentally-friendly oxidation-imbibition method for increasing recovery rate under zero flowback of fracturing fluid in shale gas well

Abstract

The invention discloses an environmentally-friendly oxidation-imbibition method for increasing the recovery rate under zero flowback of fracturing fluid in a shale gas well. According to the method, an oxidant is added into the fracturing fluid, after the gas well is fractured, by utilizing the effect of shale and the oxidized fracturing fluid, organic matter on the crack surface or the pore surface is oxidized, the contact area of the fracturing liquid and a clay mineral is increased, the imbibition ability of the shale on the fracturing liquid is improved, thus the fracturing fluid in a crack is subjected to imbibition and dispersed towards a pore, the fracturing fluid in the pore corrodes the organic matter and is dispersed towards a clay mineral intergranular pore, and thus zero flowback of the fracturing fluid is achieved. According to the environmentally-friendly oxidation-imbibition method, the imbibition ability of a shale reservoir is improved through the oxidized fracturing fluid, an effective seepage channel is additionally formed, the gas desorption and diffuse ability is improved, and the environment problem induced by flowback of the fracturing fluid is also avoided;and when the shale gas well is subjected to flowback after being fractured and is put into production, the oxidant bedetained in the reservoir can continuously improve the shale gas transmission channel, and the low-cost and efficient development goal of the shale gas well is achieved advantageously.

Description

Technical field [0001] The invention belongs to the technical field of petroleum and natural gas exploitation, and relates to a method for improving the recovery rate of a shale gas reservoir in a shale gas well fracturing fluid zero flowback environment. Background technique [0002] Shale gas is a typical unconventional natural gas with huge global resources and great exploitation value. Because the shale base block seepage channels are mainly nano-scale, the permeability of the base block is mainly from Nadarcy to Weidarcy, the shale gas seepage resistance is huge, the adsorption / free gas coexists, the gas transmission capacity is low, and hydraulic fracturing is At present, the main means of shale gas exploitation, but the scale of shale gas fracturing is large, the amount of fracturing fluid is large, and the flowback of fracturing fluid is difficult. The flowback fluid of fracturing fluid contacts with organic-rich shale and contains high organic matter. A large amount of ...

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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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