A horizontal well gas-water two-phase numerical simulation method based on non-structural grids

Abstract

The invention discloses a horizontal well gas-water two-phase numerical simulation method based on non-structural grids. The horizontal well gas-water two-phase numerical simulation method comprises the following steps of S1 carrying out the three-dimensional geologic body generation and grid dispersion of a low-permeability fractured reservoir horizontal well; S2 establishing a fractured tight reservoir multiphase flow seepage model; S3 carrying out the non-structural grid unit feature analysis and integral numerical calculation format establishment; S4 considering a horizontal well point grid quasi-steady-state well model of the flow characteristics in the horizontal well shaft; and S5 solving the established stratum seepage and wellbore internal flow coupling model, and analyzing the water saturation, stress sensitivity and other parameter sensitivities. According to the method, the horizontal well shaft flowing condition and the low-permeability reservoir micro-crack development characteristics are considered; a finite volume control method is adopted, a gas-water two-phase flow numerical solution of the low-permeability fractured reservoir is obtained on the basis of non-structural grids, and the problems that a traditional structural grid simulator is high in grid orientation, neglects stress sensitivity, ignores flow characteristics in a horizontal shaft and the like aresolved.

Description

technical field [0001] The invention relates to the field of exploration and development of unconventional low-permeability reservoirs, in particular to a method for numerical simulation of gas-water two-phase in horizontal wells based on unstructured grids. Background technique [0002] With the exhaustion of conventional high-permeability reservoirs, in order to meet the growing energy demand, the exploration and development of unconventional low-permeability reservoirs has become a hot and difficult point. Field practice shows that for low-permeability tight reservoirs, due to low permeability, tight reservoirs, and low effective thickness, the use of horizontal well technology to expand the drainage area has become an important means of high-efficiency production in low-permeability reservoirs. At the same time, in the low-permeability gas reservoirs in the middle and late stage of development, different degrees of water breakthrough make the wellbore flow and formation ...

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Problems solved by technology

[0003] The invention considers the wellbore flow of horizontal wells and the development characteristics of micro-fractures in low-permeability reservoirs, adopts the finite control volume method, and based on unstructured grids, obtains the numerical solution of gas-water two-phase flow in low-permeability fractured reservoirs, trying to solve the problem of traditional structural grids. Due to the problems of strong grid orientation, ignoring stress sensitivity and flow characteristics in horizontal wellbore in the grid simulator, a numerical simulation method of gas-water two-phase in horizontal well based on unstructured grid is proposed

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