应力敏感裂缝型油藏物质平衡方程计算新方法

对复杂的应力敏感裂缝型油藏来说,裂缝系统的储量大小对整个油田的开发起着至关重要的作用。以物质平衡方程为基础,研究了应力敏感裂缝型油藏储量的计算方法。采用实际覆压实验数据建立了数值模拟单井概念模型,使用模型模拟计算的压力、产量数据,该方法可分别计算出裂缝和岩块系统原油储量,与实际储量的对比验证了方法的正确性。结果表明,不考虑裂缝压缩系数变化时,采用物质平衡方程计算的裂缝储量明显小于实际值;考虑裂缝系统压缩系数变化后可以准确计算裂缝系统储量,计算误差在5%以内;该研究结果对应力敏感裂缝型油藏高效开发具有指导意义。

A New Calculation Approach of Material Balance Equation for Stress Sensitive Fractured Reservoirs

For complicated stress sensitive fractured reservoirs, the reserves of fracture system were vital to the development of the oilfield. Based on the principles of material balance, a new material balance equation for stress sensitive fractured reservoirs was presented to calculate the reserves. A conceptual single-well simulation model was built by using in-situ overburden pressure experiment data. And the reserves calculated from this approach using the pressure and production data from the simulation models were compared with the reserves of actual model, and it validates the approach. The results show the reserves calculated by the material balance equation are much smaller than the actual value if the compressibility of fracture is not changed with pressure; but the approach can accurately calculate the original oil in-place of fractured reservoirs if the fracture compressibility changing with pressure is considered, and the discrepancy is within 5%; it is of great significance to the effective development of stress sensitive fractured reservoirs.