文13西块油藏岩石形变对采收率影响研究

Study on effect of rock deformation on recovery of west Wen-13 Block Reservoirs

低渗透、异常高压油藏弹性能量充足,储层欠压实,岩石易发生弹塑性变形。根据这些油藏特性,从达西定律的角度推导出了室内一维岩芯中最终采出程度与岩石物性变化的近似关系式,并引入渗透率变化因子分析采收率的影响因素,进而以文13西块油藏岩石为例,通过不同流体介质的渗透率压敏性试验,以及不同加压方式下渗透率变化试验,结合降压弹性开采试验和水驱物理模拟试验,以渗透率变化因子为基础,分析并讨论该类油藏的开采方法。结果表明:该类油藏在保持较慢降压速度、较高孔隙压力水平时,能够获得较高的油藏采收率。

Low-permeable abnormal high-pressure reservoirs own some characters that elastic energy is abundant,and reservoirs are under-compacted,and rocks are prone to elastoplastic deformation.According to these features,an approximate relationship of final recovery and petrophysical property based on Darcy＇s law is achieved;and the concept of permeability variation factor is introduced to analyze the affecting factors on recovery rate.Taking West Wen-13 block for example,exploitation methods of such reservoirs are analyzed and discussed by means of permeability variation factor,combining with pressure sensitive experiment of different fluid permeability,experiments of permeability change in different pressure loading modes,and depressurizing elastic drive and water flooding experiments.The results show that a higher oil recovery can be obtained by maintaining slower depressurizing speed and higher pore pressure.