塔北隆起侏罗系层序划分及沉积、储层特征

侏罗系储层为塔北隆起重要储层之一.储层分布主要受沉积环境的控制.塔北隆起侏罗系地层可划分为两个层序——层序1(JSQ1)、层序2(JSQ2).两个层序均由低位体系域、水进体系域、高位体系域组成.地层沉积环境主要为辫状三角洲、氧化宽浅湖泊环境.侏罗系地层为一套辫状三角洲—湖泊—河流相沉积,自下而上构成4个油组.储集砂体主要为辫状三角洲的分流河道、水下分流河道沉积,次为滨、浅湖沙滩沉积.水下分流河道砂体以中—粗砂岩为主,砾岩含量高,原生粒间孔发育,次生孔隙亦发育,储集性能好;滨、浅湖砂坝以粉砂岩、细砂岩为主,原生粒间孔不发育,次生溶孔亦不发育,储集性能差.垂向上,JⅣ油组优于JⅠ、JⅡ、JⅢ油组,JⅠ、JⅡ、JⅢ三个油组的储集性能相近;平面上,优质储层分布于辫状三角洲前缘亚相的水下分流河道中,相对较好的Ⅱ类储层分布于哈拉哈塘凹陷的HA4井区;Ⅲ类储集层分布于南喀—英买力、轮南低凸起、库尔勒鼻隆;Ⅳ类差储层分布于轮台断隆.

Sequence division,sedimentary characteristics and reservoir characteristics of Jurassic in Tabei uplift

Jurassic reservoir is one of the most important reservoirs in Tabei uplift,and reservoir distribution is controlled by sedimentary environment.The Jurassic is divided into 2 sequences:JSQ1 and JSQ2,and they all consist of low-stand system tract,trangressive system tract and high-stand system tract.Sedimentary environment is mainly braided delta and oxidized wide and shallow lake.The Jurassic is a set of braided delta-lake-fluvial facies deposits,and it consists of 4 oil series.Reservoir sand-bodies are mainly distributary channel and underwater distributary channel deposits,secondarily shore-lowerlake-sandy beach deposits.The underwater distributary channel sandstone are mainly medium-coarse sandstone,its content of conglomerate is high,the primary intergranular pore and secondary pore in it are all developed,and its reservoir property is good;shore-lowerlake sand bank is mainly siltstone and packsand,the primary intergranular pore and secondary dissolved pore in it are all not developed,and its reservoir property is bad.At vertical direction,the reservoir property of JⅣ oil series is better than that of JⅠ、JⅡand JⅢ,and the reservoir property of JⅠ、JⅡ、JⅢ is close.On the plane,good reservoir distributes in the underwater distributary channel of braided delta front subfacies,JⅡoil series of better property distributes in HA4 well-block in Halahatang sag;JⅢ oil series distributes in Nanka-Yingmaili,Lunnan uplifts and Kuerle nose-uplift;JⅣ oil series of worse property distributes in Luntai fault uplift.