考虑滑脱效应下XS火山岩气藏数值模拟研究

XS Volcanic Gas Reservoir Numerical Simulation Considering Klinkenberg Effect

由于火山岩储层存在着基质和裂缝双重介质、气藏渗透率较低的特点,导致气体渗流过程中存在滑脱效应的影响,常规砂岩气藏单一介质、达西渗流理论已经不适用于此类气藏。从物质守恒理论出发,建立了考虑滑脱效应的双重介质气、水两相渗流数学模型,利用有限差分方法进行数值求解,编写了数值模拟计算程序。利用XS气田实际单井相关参数进行数值模拟研究表明:模拟结果符合客观实际,考虑比不考虑滑脱效应影响时的稳产时间、稳产期产气量、稳产期采出程度、最终采收率等生产开发指标大,在开发生产过程中应考虑滑脱效应对火山岩气藏生产开发的影响。

Because of the characteristics of matrix and fractures and low permeability in volcanic reservoirs,the Klinkenberg effect was induced in gas percolation and the unique medium and Darcy flow theory in conventional sandstone reservoirs were not suitable for these kinds of gas reservoirs.Aimed at the problem mentioned above,a percolation mathematical model was established in the consideration of Klinkenberg effect,double-medium,two phases of gas and water,the numerical solution was performed by using the finite difference method,and numerical simulation procedure was prepared.single well parameters of the SN volcanic gas field were used for numerical simulation.The results indicate that the production indexes considering the starting pressure gradient are higher than that no consideration,including the accumulative gas production,recovery percent and the ultimate recovery during the stable time.So during the production Klinkenberg effect should be considered.