吐-哈盆地台北凹陷侏罗系层序地层学研究

SEQUENCE STRATIGRAPHY OF JURASSIC IN TAIBEI SAG,TURPAN-HAMI BASIN

吐哈盆地台北凹陷侏罗纪沉积地层可分成４个层序１０个体系域，在古构造、古地形、古气候和古物源供给等因素控制下，层序内部发育低水位体系域、湖侵体系域和高水位体系域。根据地质、地震、测井及地球化学资料对吐哈盆地台北凹陷侏罗系的层序地层学特征进行了研究，认为台北凹陷侏罗纪沉积格局曾发生过显著变化，早中侏罗世由南而北依次发育河流、沼泽和湖泊相沉积，中侏罗世由南而北发育辫状河三角洲和湖泊相沉积，中晚侏罗世由南而北则发育辫状河三角洲、湖泊和扇三角洲相沉积。其中沼泽相煤岩和较深湖相泥岩是良好的烃源岩，辫状河三角洲、扇三角洲和河道砂体是物性较好的储层，湖相泥岩是有利的盖层，它们在垂向上构成了有利的生储盖组合。

sequences and 10 sedimentary system tracts could be identified in the sedimentary strata of the Jurassic in Taibei Sag of the Turpan Hami Basin. The lowstand system tract,transgressive system tract and highstand system tract developed under the control of ancient structure,paleotopagraphy, paleoclimate, sediment supply, and so on. In this paper,the sequence stratigraphy of the Jurassic in Taibei Sag is studied on the basis of geological,seismic, well logging and geochemical data. It is considered that sedimentary framework of the sag experienced great changes in Jurassic. From south to north,fluvial,swamp and lake deposits developed well in Early Middle Jurassic.Braid river deltaic and lake deposits developed in Middle Jurassic;and braid river,lake and fan deltaic deposits developed in Middle Late Jurassic.Among them, coal bed of swamp and mudstone of deep lake are good hydrocarbon soure rocks, braid river delta,fan delta and river channel sand bodies are good reservoirs, and lake mudstone is good cover rock. They constitute vertically favourable source reservoir cap rock assemblages.