考虑应力敏感性的低渗透气藏气井产能分析

Analysis on Gas Well Productivity of Low-Permeability Gas Reservoir with Stress-Sensitivity

低渗透气藏储层在开发过程中,由于受到的净覆压差增大,储层孔隙度、渗透率等物性会随之降低。结合国内某低渗气藏的室内岩心实验,用实验数据拟合回归出了孔隙度与净覆压的二次多项式,建立了覆压渗透率与净覆压、常压渗透率的经验公式。根据Forchheimier非达西渗流公式,建立了气藏在考虑应力敏感性时的二项式产能方程,对比分析了常压渗透率与覆压渗透率下的单井产能。结果表明,考虑应力敏感的气井,无阻流量降低了12.3%,累积产气量减少20.5%。

In the development process of low permeability gas reservoir,porosity and permeability reduce with the increase of net burden pressure.Combined with national indoor experiment for core of the low permeable gas reservoir,binomial relationships between porosity and net burden pressure is fitted by experimental data,and the empirical formula is established for the overburden pressure permeability and the net overburden pressure and the pressure permeability. Based on Forchheimier's non-Darcy flow equation,binomial deliverability equation considering stress-sensitivity,the single well productivity under station of the stable pressure permeability and overburden pressure permeability is compared and analyzed. The results showed that the AOF with net burden pressure permeability reduced 12. 3%,and the cumulative gas production reduced 20. 5%.