Environment-friendly continuous transformation method for shale gas well after hydraulic fracturing

Abstract

The invention relates to an environment-friendly continuous transformation method for a shale gas well after hydraulic fracturing. Shale gas production undergoes a desorption-diffusion-seepage process, a complex seam net is formed through hydraulic fracturing, only the gas seepage capacity is improved, and gas desorption-diffusion is almost not influenced, so that the gas well post-fracturing exploitation initial-stage yield is decreased gradually and quickly. Meanwhile, the dosage of single well fracturing fluid is large, the flowback rate after fracturing is generally lower than 30%, and reservoir damage is induced by retained fracturing fluid. Due to the fact that the characteristic that organic matter and pyrite in shale are easy to decompose under the conditions of reduction environment deposition and oxidation, shale matrix is further transformed by adding an oxidizing agent into the fracturing fluid and inducing the shale pore crack dissolving and expanding effect through oxidative corrosion in combination with the characteristic that a large amount of fracturing fluid is retained, and gas desorption-diffusion capability is improved, the gas well hydraulic fracturing effectis enhanced, and the gas reservoir recovery rate is increased. The invention belongs to the technical field of petroleum and natural gas exploitation, and relates to an environment-friendly continuoustransformation method for a shale gas well after hydraulic fracturing.

Description

technical field [0001] The invention belongs to the technical field of petroleum and natural gas exploitation, and relates to a method for enhancing the effect of hydraulic fracturing of shale gas wells, which is mainly used for consolidating the effect of hydraulic fracturing of shale gas wells and increasing the output of shale gas. Background technique [0002] Hydraulic fracturing breaks the shale matrix and opens natural fractures at the same time, forming a complex artificial fracture network inside the gas layer, shortening the seepage distance of gas from the matrix to the fractures, increasing the drainage area, and realizing the economic development of shale gas reservoirs. The shale matrix seepage channel is mainly in the nanometer scale, and the matrix permeability mainly ranges from nadarcy to microdarcy, the gas seepage resistance is huge, and the adsorption / free gas coexists, and the gas transmission capacity is low. The purpose of hydraulic fracturing is to g...

AI Technical Summary

Problems solved by technology

[0003] The production of shale gas needs to go through the process of desorption-diffusion-seepage. The current hydraulic fracturing technology mainly focuses on improving the seepage capacity of shale gas reservoirs. Insufficient consideration, ignoring the insufficient gas supply caused by low gas desorption-diffusion ability, resulting in an exponential decline in gas well production after shale gas well pressure in the initial stage of production

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