霸县凹陷古近系中深层有效储层成因机制

综合运用岩心观察、铸体薄片鉴定、图像分析、物性分析及流体包裹体分析等技术手段，在储层储集空间特征研究与有效储层物性下限计算的基础上，分析了霸县凹陷古近系中深层有效储层物性控制因素，总结了有效储层成因机制，建立了有效储层成因模式。结果表明，储集空间类型主要为原生孔隙，相对含量以大于50%为主。辫状河三角洲前缘水下分流河道与河口坝环境中杂基含量少，分选好，厚度大于2m的砂体是有效储层形成的有利物质基础。早期异常高压，抑制压实作用，保护原生孔隙，是有效储层形成的主控因素。溶解作用对象以硅酸盐矿物为主，主要发生在较厚层砂体距泥岩最近距离大于0.32m的储层中，能够改善储层物性，对有效储层的形成起建设性作用。油气充注晚于硅酸盐矿物溶解，但早于晚期碳酸盐胶结，能够有效抑制晚期碳酸盐胶结作用，保护储层原生孔隙与次生孔隙，是有效储层形成的关键要素。

Genetic Mechanism of Paleogene Middle-Deep Effective Reservoirs in Baxian Sag

On the basis of the reservoir characteristics study and petrophysical parameter cutoff calculation,we analyzed the controlling factors of Paleogene middle-deep effective reservoirs in Baxian Sag,summarized the genetic mechanism and established the genetic model of the effective reservoirs,by integrated use of drilling core observation,thin section analysis,and analysis of image,physical properties,fluid inclusion and other technical methods.The results showed that the reservoir spaces are mainly primary pores,whose relative contents are more than 50% in most reservoirs.It is the well sorted sandstones with little matrix contents and more than 2m thick in underwater distributary channel and mouth bar of braided delta front that make up the favorable material foundation of effective reservoirs.Early overpressure that restrained compaction and protected primary pore is the main controlling factor of effective reservoirs.The silicate mineral dissolution,especially feldspar,which happened in the reservoirs that are more than 0.32m from the nearest mudstones,could effectively improve the reservoir petrophysical properties.Hydrocarbon charge was later than feldspar dissolution,but earlier than the later carbonate cementation.So it could effectively inhibit the later carbonate cementation and protect primary and secondary pores.Therefore,it is the key elements to form effective reservoirs.