Supercritical water processing method for enhancing gas transportation capacity of shale matrix

Abstract

The invention discloses a supercritical water processing method for enhancing gas transportation capacity of a shale matrix. The supercritical water processing method for enhancing the gas transportation capacity of the shale matrix comprises the following steps that at least one horizontal well is drilled in a shale gas reservoir with initial formation pressure not lower than 22.1 MPa, and segmentation hydraulic fracturing is carried out; well soaking is carried out after shale gas well hydraulic fracturing construction is completed and then well opening is carried out to flow back hydrauliccracks and residual water in a shaft; an underground gas heating device is lowered, a gas heat transferring medium with pressure not lower than gas reservoir initial formation pressure and temperaturenot less than 374 DEG C is injected into a reservoir segment, air, oxygen and other oxidizing gas are used as the heat transferring medium, the hydraulic crack is used as a starting point, and reservoir detention fracturing liquid is gradually converted into supercritical water from the near to the distant; and the gas transferring medium is injected continuously to from an oxidized corrosion hole seam. According to the supercritical water processing method for enhancing the gas transportation capacity of the shale matrix, gas transportation space in the matrix can be expanded, matrix gas diffusion route is obviously shortened and the diffusion efficiency is improved, so that the effects of greenly, efficiently, safely and low-cost improving shale gas reservoir adsorbed gas recovery percentage are achieved.

Description

technical field [0001] The invention relates to a supercritical water treatment method for strengthening the transport capacity of shale matrix gas, and belongs to the technical field of energy and environment. Background technique [0002] my country's shale gas is widely distributed and has a large amount of resources. Compared with conventional natural gas reservoirs, shale gas reservoirs have the characteristics of small matrix pore throats and poor connectivity, high content of clay minerals, rich in organic matter and strong heterogeneity. For organic-rich shale reservoirs, adsorbed gas is one of the main storage modes of shale gas, accounting for 20% to 85% of the total gas content, and the output of adsorbed gas mainly depends on the diffusion of nanopores. Therefore, in shale matrix The gas diffusion efficiency directly determines the effective recovery of adsorbed gas, and increasing the diffusion rate and shortening the diffusion path is an effective way to impro...

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Problems solved by technology

However, the current shale gas recovery rate still has a lot of room for improvement, mainly as follows: (1) The fracturing fluid flowback rate is generally low, and the stagnant fracturing fluid is generally located in the matrix pores or closed fractures, which will inevitably cause flooding; Facies trap damage, especially restricting the gas transport capacity in matrix micro-nano pores and fractures; (2) Shale gas production has experienced gas transport processes at various scales, based on the fracture network formed by hydraulic fracturing, If the matrix gas diffusion path can be further shortened and the diffusion rate can be increased, the gas supply capacity of the shale matrix to hydraulic fractures can be significantly improved

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