Shale gas reservoir fluid-solid coupling multi-scale numerical simulation method

Abstract

The invention discloses a shale gas reservoir fluid-solid coupling multi-scale numerical simulation method. The method comprises the following steps: obtaining spatial distribution and physical property parameters of organic matters and inorganic matters, constructing a physical model of a micro-scale shale matrix, solving a micro-scale seepage auxiliary equation and a mechanical auxiliary equation, and calculating equivalent seepage and mechanical parameters of the shale matrix core scale; acquiring a natural fracture distribution situation, constructing a rock core scale physical model containing a shale matrix and natural fractures, solving a seepage auxiliary equation and a mechanical auxiliary equation of the rock core scale, and calculating equivalent seepage and mechanical parameters of a shale gas reservoir macro-scale; on the basis, simulating a hydraulic fracture by adopting an embedded discrete fracture model, and establishing a shale gas reservoir macroscopic fluid-solid coupling model; and finally, based on the structured grid, solving the shale gas reservoir fluid-solid coupling model by adopting a mixed numerical discretization method combining simulated finite difference and extended finite elements so as to realize shale gas reservoir fluid-solid coupling numerical simulation with high simulation precision and small calculated amount.

Description

technical field [0001] The invention relates to the field of reservoir numerical simulation, in particular to a multi-scale numerical simulation method for fluid-solid coupling of shale gas reservoirs Background technique [0002] Shale gas resources are widely distributed and have large reserves, but the permeability of the reservoir matrix is ​​extremely low, and hydraulic fracturing is usually required for commercial exploitation. After fracturing, shale gas reservoirs develop a large number of fractures and are in a complex in-situ stress field In the joint action of the seepage field and the seepage field, the fluid-solid coupling effect is significant. At the same time, shale gas reservoirs contain multi-scale storage and seepage spaces: micro-scale organic and inorganic pores, core-scale natural fractures, and macro-scale artificial fractures. However, the current macroscopic numerical simulation methods for shale gas reservoirs are difficult to accurately capture th...

AI Technical Summary

Problems solved by technology

However, the current macroscopic numerical simulation methods for shale gas reservoirs are difficult to accurately capture the mechanical and seepage characteristics of micro-scale organic matter and inorganic matter and core-scale natural fractures, and based on lattice Boltzmann, directly solving N-S equations and discrete elements, etc. The calculation area of ​​the micro-scale numerical simulation method of the method is too small to be directly used for large-scale actual reservoir-scale problems

In addition, the existing fluid-solid interaction model solution methods usually use the finite volume method and finite element method to discretize the seepage field equation and the stress field equation. This method needs to be based on an unstructured grid or a locally refined grid to explicitly simulate the seepage of hydraulic fractures. and deformation features, so there are problems of difficult mesh division and large amount of calculation

Images