A simulation method of single fracture propagation based on quasi-continuous geomechanical model

Abstract

The invention discloses a simulation method of single propagation expansion based on a quasi-continuous geomechanical model, which comprises the following steps: acquiring geological parameters, including three-dimensional geological information and rock physical property information; Correcting petrophysical information; Establishing three-dimensional geological model of stratum; establishing FEMfluid-solid coupling model; obtaining the pressure field, displacement field, stress field and strain field of the three-dimensional geological model by solving the fluid-solid coupling equations ofthe finite element method; judging whether cracks are produced or not according to the stress strength criterion; obtaining The fracture width, permeability matrix and flexibility matrix, and then calculating the influence of fracture on pressure field and displacement field. The simulation of single fracture propagation based on quasi-continuous geomechanical model is realized. The invention hasthe advantages of quick solution, high accuracy and good reliability, and effectively solves the problem of dynamic display of fractures in the process of hydraulic fracturing simulation.

Description

technical field [0001] The invention belongs to the technical field of hydraulic fracturing simulation, and in particular relates to a single fracture expansion simulation method based on a quasi-continuous geomechanics model. Background technique [0002] Reservoir stimulation is an effective method to increase production in the development of low permeability oil and gas reservoirs. Reservoir stimulation simulation technology can predict the size, shape, scale and even complexity of artificial fractures in reservoirs by simulating fracture propagation, which has guiding significance for on-site fracturing implementation and is a necessary technology for realizing economic benefits of oilfields. [0003] Reservoir stimulation models include 2D, pseudo-3D (P3D) and full 3D (PL3D) models. The earliest two-dimensional model is also called analytical model, which includes KGD model [1], PKN model [2] and radial model [3]. The KGD model assumes that the fracture height remains...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that this method is limited to solving two-dimensional problems. When it is extended to three-dimensional, there is no good solution for how to choose the integration path of J integral.

The disadvantage of this method is that it is difficult to control the selection of particle size and the acquisition of mechanical parameters between particles, and the calculation amount is large.

However, when applied to fracture propagation simulation, the disadvantages of this method are that 1) the direction of fracture propagation cannot be determined, 2) it is not suitable for hard shale, and 3) it can only set fuzzy strain boundaries.

However, this method still has shortcomings: 1) it can only deal with homogeneity problems, 2) since the deformation and force state of a certain element on the boundary also affect other elements on the boundary, the coefficients of the formed algebraic equations are dense matrices , and the coefficient matrix has asymmetry, resulting in a particularly low solution rate when simulating fracturing expansion for a long time

The problem with this model is that it cannot determine the location and propagation direction of fractures, and it cannot further perform cross simulation of fractures and simulation of proppant migration.

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