准噶尔盆地石西油田石南4井区侏罗系头屯河组储层特征及有利区展望

石西油田石南4井区侏罗系头屯河组为辫状河三角洲沉积背景,自下而上是湖平面先下降后快速上升的沉积序列,形成一套陆源碎屑岩。底部以中砂岩和泥岩为主,中部以粗、中砂岩相占绝对优势,顶部为厚层块状泥岩。基于岩石薄片、铸体薄片、扫描电镜、X衍射等资料,首次对研究区储层的岩矿特征、孔隙结构以及物性特征进行详细研究。结果表明,头屯河组储集层岩矿类型以岩屑砂岩为主,其中胶结物以碳酸盐胶结为主,胶结类型以孔隙式胶结为主,杂基以泥质为主;黏土矿物以高岭石居多,高岭石、绿泥石含量与储层孔隙度有良好正相关性,储层具中偏强碱敏性和中等水敏性特征;储层孔隙类型有原生和次生孔隙2类,原生孔隙以常与石英、绿泥石矿物相伴生的粒间孔隙为主,次生孔隙以多同长石、高岭石矿物相共生的粒间溶孔为主,储集层属中孔低渗储层。基于储层特征及沉积微相主控因素,将头屯河组储层分为Ⅰ类优质、Ⅱ类储层,同时对研究区进行了储层有利区预测与潜力区识别,该潜力区可作为石南4井区后续滚动开发的重点区域。

The Reservoir Characteristics and Favorable Zone Prospect of the Jurassic Toutunhe formation in WellBlock Shinan-4,Shixi Oilfield,Junggar Basin

The Jurassic Toutunhe formation in WellBlock Shinan-4 of Shixi Oilfield is the braid-like sedimentary river delta.From the bottom to the top,the sedimentary sequence is lake level first descending and then quickly rising,thus formed a set of terrigenous clastic rocks.Middle sandstone and mudstone are dominant at the bottom,coarse and medium sandstone facies in the middle,and thick massive mudstone at the top.Through analyzing the data of rock slice,cast thin section,scanning electron microscope and X diffraction,this paper studies in detail the characteristics of rock and ore,pore structure and physical properties of the reservoir in the study area.The results show that the rock types of reservoir in Toutunhe formation are mainly lithic sandstone.The cementation is mainly carbonate cementation,and the main type of cementation is porous cementation.The hetero-group is mainly argillaceous.The clay minerals are mostly kaolinite,and the contents of kaolinite and chlorite are positively correlated with reservoir porosity.The reservoir has the characteristics of strong alkali sensitivity and moderately water sensitivity.The types of reservoirs are primary pore and secondary pore.The primary pore is mainly intergranular pore associated with quartz and chlorite minerals;the secondary pore is mainly intergranular solution pore associated with feldspar and high-collar minerals.The reservoirs belong to medium porosity and low permeability reservoirs.Based on the reservoir characteristics and main controlling factors of sedimentary microfacies,the reservoir sand bodies of Toutunhe Formation is divided into high quality reservoir type I and reservoir type II.At the same time this paper predicts the favorable reservoir areas and identifies the favorable potential areas.The potential areas can be the key areas in the follow-up progressive development of WellBlock Shinan-4.