塔里木盆地阿克库勒地区三叠系湖底扇初探

岩芯观察表明，研究区南部三叠系中油组沉积物的粒度较粗，主要为砾岩、含砾砂岩等粗粒沉积，这种砾岩砾石成分复杂，分选性差，典型的基质支撑，发育鲍玛序列。综合测井及地震资料分析，确定该区中油组为湖底扇沉积。湖底扇可识别出扇中、扇缘和下切水道亚相，扇中亚相是湖底扇的主体，沉积物粒度最粗，可划分出辫状水道和水道间微相。扇缘亚相分布在湖底扇的最外缘，是湖底扇和盆地的过渡地带，发育鲍玛序列。下切水道亚相是湖底扇陆上物源的输送通道，主要为砂（砾）泥岩沉积，测井曲线上表现为两段下粗上细正韵律层，与湖底扇所反映的沉积特征相对应。湖底扇的物源来自研究区北部的辫状河流相沉积物，经盆地斜坡上的下切水道输送，在斜坡下部和盆底沉积，形成湖底扇。下切水道砂体和扇中砂体都是研究区有利的油气聚集区。

PROBE INTO SUBLACUSTRINE FAN OF TRIASSIC IN AKEKULE AREA,TARIM BASIN

Based on the observation of cores,grain sizes of the middle oil member are coarser in Akeyasu area at northern study area of Triassic,and the lithologies include conglomerate and pebbled sandstone.The compounds of pebbles are complicated with significantly various grain sizes and poor sorting,the sediments are supported by matrix,and Bouma sequences are well developed.Integrated with analysis of logging data and seismic data,the sedimentary facies of northern Akekule area are confirmed as sublacustrine fan.The fan can be divided into three subfacies that include middle fan,fringe fan and canyon,the middle fan is the principal part,in which,the depositional grain sizes are the coarsest,the middle fan can be divided into braided channels and interchannels mircrofacies.Fringe fan is distributed outmost of sublacustrine fan,being transitional belt between sublacustrine fan and basin.Canyons are transportation way of terrestrial source area for sublacustrine fan,and the main deposition is sandstone （pebble） and mudstone,logging data presents twostage positive rhythm layers,the feature is corresponding with depositional characteristic of sublacustrine fan.Sandstones of canyon and middle fan is all favorable petroleum accumulation bodies in the area.