Method for numerical simulation of fracture open degree of oil and gas reservoir

Abstract

The invention relates to the field of oil and gas field exploration and development, in particular to a numerical simulation method for fracture opening of oil and gas reservoirs. The roughness coefficient and coincidence coefficient of the fracture surface are obtained by acquiring the three-dimensional surface topography of the fracture surface. The 3D fractal interpolation algorithm is used torecover the 3D topography of one-sided fracture wall under the constraint of the roughness coefficient of fracture surface. Under the constraint of crack opening frequency distribution and coincidencecoefficient, the finite element geometric model of the two-sided crack wall is constructed. By determining the three-dimensional effective stress and rock mechanics parameters of oil and gas reservoir, the finite element geomechanics model is established, and the stress field is numerically simulated to obtain the residual opening and closure ratio of fracture. A method for analyze fracture opening degree of oil and gas reservoir by numerical simulation is provide from that viewpoint of finite element modeling, and the prediction results are of certain reference significance for optimizing oil and gas, key area of mineral exploration and modeling of dual porosity and dual permeability of natural fractured reservoir, and the like.

Description

technical field [0001] The invention relates to the field of exploration and development of oil and gas fields, in particular to a numerical simulation method for fracture opening of oil and gas reservoirs. Background technique [0002] For the selection of characterization parameters for the development degree of reservoir fractures, at present, the characterization and prediction of fracture parameters at home and abroad focus on the density (strength) of fractures in the target layer, while ignoring the characterization and prediction of the actual underground fracture opening. Fracture density is the most intuitive parameter in fracture characterization, so it is often used to characterize the degree of fracture development. In reality, opening contributes more significantly to porosity and permeability than fracture density and is a source of uncertainty in modeling naturally fractured reservoirs. This uncertainty is due to the difficulty of accurately quantifying subs...

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Problems solved by technology

Van et al. (2018) studied the unconventional siliciclastic reservoirs of the De Geerdalen Formation in Svalbard Islands, relying on micro-CT imaging to study the change of fracture opening under different confining pressure conditions, but the experimental measurement device was actually Only two-dimensional stress loading can be realized, and crack opening simulation under true three-dimensional conditions and multi-factor influences cannot be performed

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