Prediction method for yield change trend of high-water-content tight gas reservoir gas well

Abstract

The invention relates to a prediction method for a yield change trend of a high-water-content tight gas reservoir gas well. The prediction method comprises the steps that 1, production data of a production well are obtained and preprocessed; 2, a gas-water two-phase density diffusion equation taking density as a main variable is established; 3, the gas-water two-phase density diffusion equation with the density as the main variable is solved, and a flow state equation of the whole seepage process based on density diffusion is obtained; 4, a flow state is judged, a flow state model is selected,reservoir reconstruction parameters and reservoir physical property parameters are solved in combination with the preprocessed production data, and the yield change rule of the gas well under different working systems is predicted. According to the method, the dimensionless viscosity-compression coefficient ratio lambda changing along with time and the time average value beta approximate linearization density-diffusion coefficient are introduced, the real-time dynamic water-gas ratio is introduced, joint analysis of water-gas two-phase flow is achieved, physical characteristics of a functionare reserved, the method is convenient and rapid, and parameter calculation and dynamic analysis can be achieved.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a prediction method for determining the production change trend of a gas well in a high water-cut tight gas reservoir based on a density diffusion equation. Background technique [0002] The prediction of gas well production change trend is one of the important research contents of gas reservoir dynamic analysis. At present, the commonly used production forecast methods at home and abroad include the traditional production decline curve method, the forecast production model method and the modern production decline analysis method, etc. [0003] The traditional production decline curve method is based on the statistical research of the actual mine data by J.J.Arps, who proposed a production decline analysis method, classified the decline curves, and summarized them into three types: exponential decline, hyperbolic decline, and harmonic decline. T...

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Problems solved by technology

For the unsteady state, that is, the gas-water two-phase flow process that changes with time, since the gas-water two-phase unsteady seepage equation is a nonlinear partial differential equation, it is difficult to obtain an accurate analytical solution using analytical methods

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