溶解气驱油藏水平井IPR的数值模拟

NUMERICAL SIMULATION OF INFLOW PERFORMANCE RELATIONSHIPS FOR SOLUTIONGASDRIV E HORIZONTAL WELLS

目前，根据数值模拟计算，研究溶解气驱油藏水平井向井流动态关系时，都是沿用Ｖｏｇｅｌ研究方法即制作一定采出程度下水平井ＩＰＲ曲线，然后无因次化得到无因次ＩＰＲ曲线。经研究发现溶解气驱油藏动态受生产过程的影响较大，即用不同的流压生产，当达到相同的采出程度时，油藏平均压力并不相等。故前人用数模制作无因次ＩＰＲ曲线的方法存在较大的局限性，对此提出了用数模研究溶解气驱油藏水平井无因次ＩＰＲ曲线时，应先制作油藏平均压力为定值时的ＩＰＲ曲线，然后再无因次化的新方法。按此方法对一系列溶解气驱油藏模型进行了三维流动模拟计算，总结出了无因次ＩＰＲ曲线的曲度随油藏平均压力变化的规律，提出了描述溶解气驱油藏水平井无因次ＩＰＲ曲线的新的统一方程。

At present the Vogel's study methodology, in which an inflow performance relatio nship (IPR) curve for a solutiongasdrive well is generated at a constant rec overy factor, the dimensionless IPR curve can then be obtained, which has been a pplied to prepare IPRs of solutiongasdrive horizontal wells based on numerical res ervoir simulation. The research in this paper discovered that the production pro cesses have a significant influence on performance of a solutiongasdrive res ervoir, namely, the average reservoir pressures are not equal when the productio ns with different flowing bottomhole pressures reach the same recovery facto r. Therefore, there is a drawback in current methodlology of preparing IPR curve based on the numerical simulation calculations. An improved methodology is prop osed that the IPR curve of a horizontal well producing from a solutiongasdri ve reservoir is firstly prepared at a constant average reservoir pressure, the d imensionless IPR curve is then generated. Based on the new methodology, 3D flo w calculations for a wide variety of solutiongasdrive reservoir models are m ade. How the concavity of dimensionless IPR curves varies with the decrease in t he average reservoir pressure is found. Then a new equation is presented to fit the dimensionless IPR curves of solutiongasdrive horizontal wells.