渤海海域石臼坨凸起东段36-3构造古近系沙二段储集层特征及控制因素

摘要

利用岩心描述、常规薄片、铸体薄片和扫描电镜等化验分析资料,结合常规物性及勘探情况,对沙河街组二段储集层特征进行了系统分析,对储集物性、储集空间类型以及储层物性控制因素进行了深入的探讨.研究认为研究区沙河街组二段储集层为混积岩,岩性以生屑云岩为主,夹薄层砂砾岩；储层物性非常好,平均孔隙度为27.6％,平均渗透率为442×10-3μm2,储层类型为高孔-高渗型；储集空间以原生孔隙和次生孔隙为主,原生孔隙多为粒间孔和生物体腔孔.研究发现,沉积作用和成岩作用是控制储集层物性的两个主要的因素,其中溶解作用和白云石化作用是造成现今优质储集空间的主要原因.同时指出了优质储层的分布规律,认为沙河街组二段中发现的生屑云岩和含陆源碎屑云岩等白云岩储层是油气富集场所,是今后有利勘探区.%Various data including core description,conventional thin sections,casting thin sections and SEM,in combination with conventional physical properties of reservoirs and exploration results, were used to systemically analyze reservoir poroperm characteristics, reservoir space types and influencing factors of reservoir properties of the 2" member of Shahejie Formation. The study indicates that Shahejie Formation reservoirs are mixed carbon-ate/siliciclastic rocks dominated by bioclastic dolostone with thin sandy conglomerate interbeds. The poroperm characteristics are very good, with average porosity of 27. 6 % and permeability of 442 X 10 ~ jxm . The reservoir spaces are dominated by primary pores (mostly intergranular pores and skeletal pores) and secondary pores. Sedimentation and diagenesis are the two key factors controlling the physical properties of reservoirs. Dissolution and dolomitization contribute to high quality reservoir spaces. In addition, the distribution of high quality reservoirs is also delineated. It is believed that dolostone reservoirs are favorable for hydrocarbon accumulation, thus are potential exploration targets in the future.