塔里木盆地阿克库勒地区三叠系中油组沉积相研究

通过岩心观察、岩矿以及粒度等化验资料综合分析,确定阿克库勒地区三叠系中油组主要沉积相包括辫状河流相、湖泊相、湖底扇相以及三角洲相.中油组主砂体主要为辫状河流相和湖底扇相沉积,其中,湖底扇相属研究区内首次发现.湖底扇相可划分出扇中和扇缘2个亚相,辫状水道是扇中的主要微相,天然堤微相不发育.湖泊相发育滨浅湖和半深湖-深湖亚相.三角洲相分布在中油组主砂体上部的砂泥岩段中,由于上油组地层对中油组上部砂泥岩段的侵蚀作用较强烈,仅部分井残留三角洲沉积,所以三角洲不能构成研究区的有利储层.由北向南,中油组的沉积相平面组合为:辫状河流相—斜坡滨浅湖—半深湖(下切水道)—湖底扇相—深湖亚相.

Study on sedimentary facies of the middle oil group of the Triassic in Akekule area of Tarim Basin

It is held that the sedimentary facies in oil group mainly include braided stream,lacustrine,sublacustrine fan and delta according to the comprehensive analysis of core observation and the test data of rock,mineral and grain size.There are maily braided stream and sublacustrine fan in the main sandbody of the oil group,and the sublacustrine fan facies is found for the first time in studied area.The sublacustrine fan can be divided into two subfacies:mid-fan and fan-edge.The braided channel is the main mircrofacies of mid-fan.Natural levee mircrofacies don't present.There are shore-shallow lacustrine and half-deep-deep lacustrine subfacies in the lacustrine facies.Delta facies presents in the sand-mudstone layer at the upper of the main sandbody,and it presents only a part of wells because of the erosion of upper oil group to middle oil group.So the delta facies couldn't form favorable reservoir in the studied area.From north to south,the sedimentary facies of the middle oil group are braided stream-slope shore-shallow lacustrine-half-deep lacustrine(canyon)-sublacustrine fan-deep lacustrine.