A Simulation Experimental Study on the Gas-Water Saturation Characteristics in the Process of Constant-Speed Gas Production Based on the Microscopic Model

Abstract

This paper presents the important findings of research work that was undertaken on the residual water saturation of gas reservoirs that arises from the decrease in pore pressure during a constant-speed gas production process. To study the changes and distribution regularities of water-gas saturation, we used a micro-glass model to conduct a simulation study of the process of constant-speed gas production under pore pressures of 0.5 MPa, 1 MPa and 5 MPa. The results indicate that the total displacement power of the gas reservoir directly affects the development effect. The higher the pore pressures of the gas reservoir whose part of bound water may flow, the more difficult is the development of the reservoir due to the presence of more movable water, resulting in a poorer development effect. For a lower pore pressure of a gas reservoir, the bound water of the gas reservoir is generally immobile, that is, the gas production is single-phase gas seepage, resulting in an improved development effect. Implementing a reasonable development plan for a water-bearing gas reservoir with low permeability is clearly of great significance to ensure its effective development.
Key words: Microscopic model; Constant speed; Gas production; Gas-water saturation; Variation characteristics; Simulation experiment