渤海BZ油田低渗储层质量主控因素及开发实践

The quality control factors and development practices of low permeability reservoirs in BZ oilfield,Bohai sea

渤海BZ油田沙河街组发育异常高压低渗油藏,单井产能差异大、储层质量控制因素认识不清制约了该区低渗油藏的开发。在对BZ油田沙河街组储层特征分析的基础上,深入剖析了储层质量的控制因素,探讨了单井产能差异的原因。研究表明:该区低渗储层质量受控于原始沉积条件、成岩压实和胶结作用、构造断裂及背斜等因素,将这些因素与开发井初期产能结合,得到了沉积、成岩、构造有利区,其中沉积有利区位于研究区西南区域,成岩有利区带位于构造相对较高的层位及区域,构造有利区带位于发育背斜、且位于背斜核部的区域,而断层附近受晚期碳酸盐胶结作用影响储层质量较差。针对几个有利区分别提出了开发策略,并先后成功指导了6口井的挖潜,增油效果显著。本文研究为该油田下步难动用储量的有效动用奠定了基础。

The Shahejie Formation of BZ oilfield in Bohai sea has developed abnormal high-pressure and low permeability reservoirs,the single-well productivity varies greatly,and the understanding on reservoir quality control factors is unclear,which hinder the development of low-permeability reservoirs in this area.Based on the analysis of reservoir characteristics of Shahejie Formation in BZ oilfield,the control factors of reservoir quality were deeply analyzed,and the reasons for the difference on single well productivity were discussed.The research suggests that the quality of low permeability reservoirs in this area is controlled by the factors such as original sedimentary conditions,diagenetic compaction and cementation,structural fractures and anticlines.By combining those factors with the initial productivity of development wells,the sedimentary,diagenetic and tectonic favorable zones were delineated,respectively.Among them,the sedimentary favorable zone is located in the southwestern part of the study area,the diagenetic favorable zone is located in the stratum and region with relatively high structure,and the tectonic favorable zone is located in the anticline nucleus where anticline was developed.Due to the late carbonate cementation,the quality of reservoirs in the vicinity of fault is inferior.The development strategies were proposed respectively for several favorable zones,the potential exploitation of 6wells has been successfully guided,and the oil-increasing effect was remarkable.This paper lays a foundation for the effective use of difficult-to-use reserves in this oilfield.