哈密坳陷三叠系层序地层与沉积特征

哈密坳陷三叠系是重要的烃源岩和储层,综合地震、测井、沉积和古生物等资料对其进行层序地层综合划分,将其分为1个二级层序和4个三级层序,各三级层序分别由3个体系域组成,主要发育低位体系域、水进体系域和高位体系域。哈密坳陷三叠系主要发育辫状河、曲流河、辫状河三角洲、曲流河三角洲和湖泊5种沉积相,其中曲流河三角洲相和辫状河三角洲相是主要的储集体发育相带,湖泊相是有利的烃源岩和盖层发育相带。早、中三叠世哈密坳陷中南部缓坡带广泛发育辫状河相,北部、西北部主要发育曲流河相;晚三叠世黄山街组和郝家沟组沉积时期主要发育辫状河三角洲相,克拉玛依组沉积晚期哈密坳陷北部主要发育曲流河三角洲相,是寻找岩性油气藏的有利区带。

Triassic sequence stratigraphy and sedimentary characteristics in Hami depression

The Triassic of Hami depression is an important source rock and reservoir stratum. It is divided into one second-class sequence and four third-class sequences. Each third-class sequence is consisted of two or three system tracts, including lowstand system tract, highstand system tract, transgressive system tract. The Triassic of Hami depression is mainly developed as braided river, meandering river, braided river delta, meandering river delta and lacustrine facies. Among these, the meandering river delta and braided river delta are main reservoir facies belt, the lacustrine facies is favorable source rock and cap rock facies belt. From early to middle Triassic epoch, south central gentle slope of Hami depression is extensively developed as braided river facies, north and the north-west of Hami depression is developed as meandering river facies. In late Triassic Huangshanjie group and Haojiagou group period, the braided river deltas are developed, in late Karamay group, the meandering river delta is developed, which is the favorable belt for locating lithologic reservoirs.