沾化凹陷沙三下亚段泥页岩孔隙类型及其影响因素

页岩储层有效性与孔隙类型及其发育程度关系密切。利用电镜、薄片、压汞等资料对沾化凹陷沙三下(Es_(3下))亚段泥页岩孔隙类型及其控制因素进行研究。结果表明,该层段主要发育黏土矿物晶间孔、黄铁矿重结晶孔、微裂缝和溶蚀孔隙,且不同类型孔隙发育所受的影响各不相同。然后结合纵向上划分的旋回和层序,分析泥页岩孔隙发育的规律,发现Es_(3下)亚段黏土矿物晶间孔和黄铁矿重结晶孔较发育,草莓状黄铁矿晶间孔仅发育于SQ2层序,且其大小随着湖平面的上升呈周期性减小的趋势;微裂缝与溶蚀孔作为有效的储集空间,前者主要发育在低位域,后者则多发育于较深地层,并以SQ1层序的湖侵体系域下部和低位域为主。该规律为在井筒剖面上寻找有利的泥页岩储层提供了依据。

Microscopic pore types and their influence factors of shale oil reservoirsin the Lower 3 rd Member of Shahejie Formation in Zhanhua Sag

The effectiveness of shale reservoir and pore types and growth level have a close relationship. Using electron microscope, thin section , mercury injection data and studying the pore types and controlling factors in shale reservoir of E_s3 formation in south slope of Dongying Sag. The result revealed that the clay intracrystalline pore, pyrite-recrystal pore, micro fractures and dissolved pore in the layer developed well, and the effects to developing of one pore types differs to another. Then combining the cyclic and sequence on vertical and analyzing the development rules of pore in shale, the result show that clay intracrystalline pore and pyrite-recrystal pore in E_s3 formation developed well, strawberry pyrite-recrystal pore just develop in SQ1, and with the rise of lake level, its scale have a phenomenon of tendency to periodic decrease. Micro fractures and dissolved pore as the effectiveSstorageSspaces, the former usually developed in lowSsystemStract (LST), while the latter developed in deep layers and mainly in lacustrineStransgressive system tracts (LTST) and LST in SQ2. The law provide the terms for finding favorable shale reservoir in well profile.