异常高压致密气藏两相渗流数值模拟技术

A Flow Numerical Simulation Technology on Gas-water Two Phase in Tight Gas Reservoirs with Abnormally High Pressure

异常高压致密气藏压力系数高、孔隙结构及渗流机理复杂,相渗曲线随压力发生改变,导致利用常规相渗曲线的测试结果已不能正确反映地层条件下的气水渗流规律,预测的开发指标好于实际生产的结果。因此,需要研究地层条件下的相渗曲线,探讨异常高压致密气藏两相渗流规律。结合气藏高温、高压的特性,研制了异常高压致密气藏岩心驱替装置(120 MPa、150℃),回归了36块岩心归一化的岩心相渗端点与压力的关系,建立了异常高压致密气藏两相渗流数学模型及数值模型。研究结果表明,在异常高压条件下,束缚水饱和度降低,流动阻力增大,采收率降低,开发效果变差。

Pore structure and seepage mechanism are very complicated in tight gas reservoirs with abnormally high pressure. Because of different relative-permeability-curve in different pressure conditions,development indexes calculated by the traditional relative-permeability-curve are better than the real. So the relative-permeabilitycurve based high pressure and temperature are tested,and the seepage law on gas-water two phase in tight gas reservoirs with abnormally high pressure is studied. The core flooding device（ 120 MPa and 150 ℃） was set on tight gas reservoirs with abnormally high pressure. The mathematical model and numerical model were set on the porous media Seepage with tight gas reservoirs,based on the relative-permeability-curve of 36 pieces of core tested in different pressures. The results show that the higher pressure is,the higher irreducible water saturation is,the bigger flowing resistance is,the lower the recovery factor is,and the poor the development effect is