新疆塔河油田石炭系层序地层分析及低水位岩性圈闭预测

对新疆塔河油田石炭系岩性圈闭的地震和钻井层序地层分析结果表明,石炭系由SQ1、SQ2、SQ3三个三级层序组成,分别以障壁岛-泻湖体系、潮控碎屑滨岸体系、辫状河三角洲体系为特征,总体反映了陆源供给由弱到强、研究区北部抬升的阶段性过程.在SQ2层序发育时期,地形平缓,砂体储层发育于海进体系域和高水位体系域的下部,导致与沉积作用相关的岩性圈闭发育.SQ1、SQ2层序的发育主要受海平面变化的控制;SQ3层序的形成主要受控于大塘中-晚期的构造挤压和抬升作用.SQ1层序内的鼻状凸起的两侧--西北部和东南部斜坡区、SQ3层序内的由北部褶皱隆起和南部差异压实联合作用形成的次级凹陷,是形成低水位岩性圈闭的有利场所.

SEQUENCE STRATIGRAPHY AND PREDICTION OF LITHOLOGIC TRAPS IN THE LOW SYSTEM TRACTS OF THE CARBONIFEROUS IN TAHE OIL FIELD,XINJIANG

The lithologic traps of the Carboniferous in Tahe Oil Field,Xinjiang have been paid fully attention to.In this paper,the sequence stratigraphy of the Carboniferous had been analyzed according to seismic and well data.Three third-grade sequences, namely SQ1,SQ2,SQ3,were identified.It is found that barrier island-lagoon system mainly developed in the SQ1;tide-dominated clastic shoreline system developed in the SQ2;and braided delta system mainly developed in the SQ3.This could show that terrigenous supplements became weak to strong,and that the north of the research area was uplifted.In the period of SQ2 development,the topography took on a wide and low-tilt slope.It is very unusual that sand-bodies in the SQ2 were distributed in the transgression system tract and the below of high system tract,so some lithologic traps associated with sedimentary were abundant.The study indicates that the SQ1 and SQ2 resulted from sea-level fluctuation,and the SQ3 from a tectonic uplifting in the middle or later period of Datang.Northwestern and southeastern slopes existed on the two sides of nose convex during the development of the SQ1.A sub-sag had been produced by southern differential compaction and northern folding before the SQ3.It is proposed that the slopes and the sub-sag are favorable for lithologic traps forming.