准噶尔盆地西北缘中拐—五八区二叠系上乌尔禾组砂砾岩储层特征

利用岩心、薄片、扫描电镜及能谱分析等资料,依据沉积学原理和方法对准噶尔盆地西北缘中拐—五八区二叠系上乌尔禾组砂砾岩储层进行了研究,认为该组砂砾岩储层主要发育于"复合扇"沉积序列的多期冲积扇相中,可进一步分为扇根、扇中和扇缘亚相。砂砾岩储层以砾岩—粗砂岩为主,含少量细砂岩,砾石成分以凝灰岩、安山岩岩屑为主;成岩作用以压实作用、胶结作用和溶蚀作用为主,沸石类胶结物的溶蚀作用对储层物性起建设性作用;成岩阶段主要为晚成岩阶段A期,其孔隙度主要为5%～15%,平均为9.4%,渗透率主要为0.1～80.0mD,平均为3.1mD,总体上属Ⅱ—Ⅲ类储层。

Characteristics of glutenite reservoir of Permian Upper Wuerhe Formation in Zhongguai-Wuba area in the northwestern margin of Junggar Basin

Based on the data of cores,thin sections,scanning electron microscope and energy spectrum analysis,combined with the principles and methods of sedimentology,this paper studied the glutenite reservoir of Permian Upper Wuerhe Formation in Zhongguai-Wuba area in the northwestern margin of Junggar Basin.The result shows that the glutenite reservoir is mainly developed in multi-alluvial fan facies with ＂composite fan＂ sedimentary sequences,which can be further divided into fan-root,fan-bosom and fan-edge subfacies.Glutenite reservoir is mainly consisted of conglomerate,gravel,sandy conglomerate and conglomeratic coarse sandstone,and also contains a few sandstone and fine sandstone.The gravels in conglomerate are mainly tuff and andesite.Reservoir diageneses are mainly compaction,cementation and dissolution,zeolite dissolution is constructive to the reservoir perperties,and diagenetic stage is mainly of late diagenetic stage A.The porosity ranges from 5% to 15%,and the average porosity is 9.4%.The permeability ranges from0.08 to 80.00 mD,and the average permeability is 3.05 mD.On the whole,it belongs to the better-medium type reservoir.