东营凹陷博兴油田沙四段滩坝砂岩储层特征研究

Beach-bar sandstone reservoirs from the fourth member of the Shahejie Formation in the Boxing Oil Field,Dongying depression,Shandong

东营凹陷南斜坡发育滩坝、水下扇和重力流水道等多类型的储集体,为一个多油层、多油气藏类型的复式油气聚集带。沙四段储集层为滨浅湖相滩坝砂体,油藏类型以岩性和构造岩性油气藏为主。博兴油田沙四段滩坝砂岩储层以长石粗粉砂岩、岩屑粉砂岩为主,砂体中发育有剩余粒间孔、粒间溶孔和粒内溶孔等储集空间类型,孔隙结构以低渗小孔喉为主,为中低孔隙度、低渗透率的储层。沉积微相和成岩作用是控制本区滩坝砂体储层物性的主要因素。

The beach-bar, submarine fan and gravity flow channel sandstone reservoirs are well displayed on the southern slope of the Dongying depression, Shandong, constituting a composite oil and gas accumulation zone with many types of oil reservoirs and oil and gas pools. The oil reservoirs in the fourth member of the Shahejie Formation consist of the littoral and shallow lacustrine beach-bar sandstone reservoirs including lithologic and structural- lithologic oil and gas pools, and thus are considered as the main exploration targets in the study area. These sandstone reservoirs are composed of feldspathic coarse sihstone and lithic sihstone with low to moderate textural maturity. The porosity types of the sandstone reservoirs significantly consist of residual intergranular pores, intergranular solution openings and intragranular solution openings. The pore structures are dominated by low permeability-micropore throats, indicating the medium- to low-porosity and low-permeability reservoirs. The sedimentary microfacies and diagenesis are considered as the main controlling factors of physical properties of the beach-bar sandstone reservoirs in the study area.