塔里木盆地巴楚及塔中地区二叠系层序地层学分析

通过钻井、测井以及野外剖面等资料的综合分析,塔里木盆地巴楚及塔中地区二叠系可识别出6个层序边界.除B4为Ⅱ型层序边界外,其他各层序边界均为Ⅰ型层序边界,并以侵蚀下切为特征.根据6个层序边界可将二叠系划分为5个三级层序,这些层序均符合Vail经典层序地层学模式.SQ4层序可识别出湖侵体系域和高位体系域,SQ1、SQ2、SQ3、SQ5层序可识别出低位体系域、海(湖)侵体系域和高位体系域.低位体系域为河流相性质的侵蚀沟谷充填沉积,海(湖)侵体系域为滨浅湖和半深湖沉积,高位体系域为半深湖-滨浅湖以及三角洲沉积,另外,SQ3层序高位体系域上部还发育火山岩.河流相侵蚀沟谷充填沉积和三角洲沉积主要分布在塔东隆起西部斜坡上.

Analysis of Sequence Stratigraphy of Permian inBachu and Tazhong of Tarim Basin

Based on analysis of drilling data, logging data and outcrop section data, 6 sequence boundaries were recognized in Permian in Tarim Basin. Except that boundary B4 belonged to type Ⅱ sequence boundary, the others boundaries were type Ⅰ sequence boundary, characteried by erosion and down-cutting. According to 6 sequence boundaries, 5 three order sequences could be recognized in Permian, and all the sequences corresponded with classic sequence models of vail. Sequence SQ4 could be used to recognize trangressive system tract (TST) and highstand system tract (HST). Sequences SQ1, SQ2, SQ3, SQ5 could be adopted to recognize lowstand system tract (LST), trangressive system tract (TST) and highstand system tract (HST). LST was deposited by incised channel characterized by fluvial facies. TST was deposited by lacustrine shore and semi-deep to deep lacustrine. HST was deposited by semi-deep to deep lacustrine and delta. What's more, lava rocks were presented at the top part of HST in sequence SQ3. The incised channel infilling distributed mainly around basin,and delta mainly in southwest and south area.