Zhang Chuanying, Li Junjian, Ding Jialei, Zhang Miao, Diwu Pengxiang, Xu Fei
College of Petroleum Engineering, China University of Petroleum, 102249 Beijing, China.
College of Science, China University of Petroleum, 102249 Beijing, China.
ACS Omega. 2024 Jul 13;9(29):32235-32242. doi: 10.1021/acsomega.4c05231. eCollection 2024 Jul 23.
Sandstone-buried hill superimposed reservoirs, characterized by the coexistence of the sandstone matrix and the fracture pore matrix, present unique challenges in integrated development due to their connectivity and physical properties. Currently, research on the factors affecting the recovery of sandstone-buried hill superimposed reservoirs with both porous and fractured media is limited. In this study, a more realistic method for preparing fractured cores and calculating fracture permeability was proposed, and the effect of confining pressure on fracture permeability was investigated. Additionally, a three-tube experimental apparatus was designed to study the effects of connectivity, different permeability contrasts between sandstone and buried hills, and various development strategies on recovery. The results indicate that fracture permeability is significantly affected by the confining pressure. When sandstone and buried hills are not connected, the total recovery is the highest. As connectivity increases, the recovery from sandstone gradually decreases, while the recovery from the buried hill gradually increases, leading to a decrease in the overall recovery. The permeability contrast between sandstone and buried hill has a minimal impact on the overall recovery; however, a higher permeability contrast leads to increased sandstone recovery and decreased buried hill recovery. The highest overall recovery was achieved with injection solely into the sandstone, followed by general injection, with the lowest recovery from injection solely into the buried hill. This study provides new insights into the integrated development of sandstone-buried hill reservoirs.
砂岩潜山叠合油藏具有砂岩基质与裂缝孔隙基质共存的特点，因其连通性和物性在整体开发中面临独特挑战。目前，关于同时具有孔隙和裂缝介质的砂岩潜山叠合油藏采收率影响因素的研究较为有限。本研究提出了一种更符合实际的制备裂缝岩心和计算裂缝渗透率的方法，并研究了围压对裂缝渗透率的影响。此外，设计了一种三管实验装置，以研究连通性、砂岩与潜山之间不同的渗透率差异以及各种开发策略对采收率的影响。结果表明，裂缝渗透率受围压影响显著。当砂岩与潜山不连通时，总采收率最高。随着连通性增加，砂岩采收率逐渐降低，而潜山采收率逐渐升高，导致整体采收率下降。砂岩与潜山之间的渗透率差异对整体采收率影响最小；然而，较高的渗透率差异会导致砂岩采收率增加，潜山采收率降低。仅注入砂岩时整体采收率最高，其次是笼统注入，仅注入潜山时采收率最低。本研究为砂岩潜山油藏的整体开发提供了新的见解。
