Method for computing unsteady state output of shale gas reservoir complex fracture network

Abstract

The invention belongs to the technical field of mineral resources, and particularly relates to a method for computing unsteady state output of a shale gas reservoir complex fracture network. The method comprises the following steps that S1, basic parameters of shale gas reservoir strata and shale gas are collected, and a shale substrate porous media capillary tube permeability model is established; S2, shale gas reservoir microseism fracture imaging data is collected, a box method is applied to acquire fractal dimensions, a two-dimensional discrete fracture network model is established, and animproved cubic law is adopted to calculate the complex fracture network permeability; S3, it is considered that a shale gas reservoir fracturing horizontal well outer region is a substrate area infiltration area and a shale gas reservoir fracturing horizontal well inner region is a complex fracture network area flow area, and a shale gas reservoir fracturing horizontal well steady-state productivity model is established; according to a shale gas pressure propagation radius equation and a shale gas reservoir material balance equation, a continuous quasi-steady method is applied to establish ashale gas reservoir fracturing horizontal well unsteady state model. The method for the computing unsteady state output of the shale gas reservoir complex fracture network has the advantages that theconsideration factors are close to the actual conditions of strata, and computed results are more accurate.

Description

technical field [0001] The invention relates to a method for calculating the unsteady output of a complex fracture network in a shale gas reservoir, belonging to the technical field of mineral resources. Background technique [0002] The potential of shale gas resources is huge, and it has attracted extensive attention in recent years. With the rapid improvement of drilling and fracturing technology, shale gas has become an important part of oil and gas exploration and development. Horizontal well fracturing to form a complex fracture network is a key technology for developing shale gas. After fracturing in shale reservoirs, a complex fracture network will be formed in the stimulated area, while the untreated area is still a matrix pore area. During the production process of shale gas fractured horizontal wells, according to the flow characteristics of shale gas, the seepage field of shale gas wells after fracturing can be divided into two flow fields: inner and outer flow...

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Problems solved by technology

[0003] The current source function method commonly used to calculate the production of shale gas fractured horizontal wells assumes that the pressure caused by production will be transmitted to the reservoir boundary at the beginning, which is not consistent with the actual situation; and the calculated shale matrix permeability The single capillary model is established, which is inconsistent with the actual situation of the formation; the permeability of the complex fracture network is measured through experiments, which cannot reflect the actual situation of the actual complex fracture network, resulting in large errors between the calculation results and the actual production

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