Porous medium equivalent simplified model construction method for tight reservoir numerical simulation

Abstract

The invention relates to a porous medium equivalent simplified model building method for tight reservoir numerical simulation, which comprises the following steps: building a compact porous medium sandstone particle accumulation three-dimensional simplified geometrical morphology model based on the idea of reducing the pore space of a reservoir under the synergistic effect of compaction and cementation of rock mineral particles; firstly, an equal-diameter spherical sandstone particle tangent infinitesimal body is established; a sandstone particle size distribution rule is represented through a Rayleigh distribution function, a form of combining large ball accumulation with particle size obeying Rayleigh distribution with small ball filling is established, and the particle size is longitudinally and randomly arranged in a staggered manner to form a three-dimensional sphere accumulation model; a synergistic coefficient is introduced to characterize the influence of the compaction effect of the dense porous medium and the cementation effect of the cement on the pore form; and fitting the cooperation coefficient in combination with a lattice Boltzmann simulation method to realize construction of a three-dimensional simplified geometric morphology model of the tight reservoir pore structure. According to the invention, the differential characterization and alternate distribution of geological causes and pore throats of tight reservoirs can be embodied, and the porosity and the seepage capacity are realized.

Description

Technical field: [0001] The invention relates to a method for modeling and simplifying the real physical structure of dense porous media in the numerical simulation technology of tight reservoirs, and in particular to a method for constructing equivalent simplified models of porous media for numerical simulation of tight reservoirs. Background technique: [0002] Tight oil and gas reservoirs have the characteristics of low porosity and low permeability. Conventional micro-pipe flow experiments cannot meet the requirements of the distribution range of pore throats in tight gas reservoirs. Microscopic numerical simulation methods are needed to determine the law of fluid flow in tight porous media. and influencing factors. The most typical characteristics of tight sandstone reservoirs are poor sandstone particle sorting and mutual filling of large and small particles, resulting in dense accumulation of mineral particles; on the basis of low porosity, low permeability and poor p...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a porous medium equivalent simplified model construction method for tight reservoir numerical simulation, this porous medium equivalent simplified model construction method for tight reservoir numerical simulation can reflect the tight reservoir geological origin and pores The differential characterization and alternate distribution of throats can solve the problem that existing methods cannot truly reflect the real flow resistance of tight reservoir fluids

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