致密气藏开发气水相对渗透率的逾渗计算

PERCOLATION CALCULATION OF GAS AND WATWR RELATIVE PERMEABILITY IN TIGHT GAS RESERVOIR DEVELOPMENT

在开发过程中边底水及工作液的侵入会使气藏含水饱和度上升,出现气液两相流。致密气藏复杂的地质结构,使开发中面临气水两相渗透率难以准确计算的难题。逾渗理论应用于流体在多孔介质中的传递计算,可解决多相渗透率计算问题。应用逾渗分析,把致密气藏孔隙网络合理简化为逾渗模型,借助β树模型结构,能够对致密气藏开发过程中气水两相渗透率变化规律进行研究。示例计算和对比分析表明,设定适当的网络参数,运用逾渗理论求取相对渗透率是可行的,这为致密气藏开发中流体渗流的理论计算提供了一条新的途径。

Water saturation will increase owing to edge and bottom water and treatment fluid invasion in gas reservoirs development.This results in gas-liquid two-phase flow.In the course of tight gas reservoirs development,gas-liquid two-phase flow permeability can not be accurately calculated for the complex geological structure.Percolation theory is applied for calculating the fluids transfer in porous medium,it can successfully calculate multiphase permeability.Through reasonable simplified tight gas reservoir pore network into percolation model,with β-model structure,gas and water permeability change laws were studied in the development of tight gas reservoirs.Example of calculation and comparison showed that by setting the appropriate network parameters and using percolation theory,achieved relative permeability was feasible.It provided a new method to fluid flow theoretical calculation in the development of tight gas reservoir.