准噶尔盆地腹部调整性油气藏主控因素及勘探思路

THE MAIN CONTROLLING FACTORS AND EXPLORATION THINKING OF ADJUSTMENT RESERVOIRS IN CENTER OF JUNGGAR BASIN

准噶尔盆地腹部油气勘探以隐蔽、调整型油气藏为主，勘探风险较大．研究认为主要勘探目的层侏罗系三工河组二段沉积背景与后期车-莫古隆起的演化是后期油气调整的主控因素．三工河组二段自下而上分为下亚段（J1s2^2）和上亚段（J1s2^1），下亚段沉积环境主要为辫状河三角洲前缘亚相，上亚段为曲流河三角洲前缘亚相．沉积后受车-莫古隆起掀斜调整改造作用，早期形成的储存于侏罗系的原生油藏随车-莫古隆起调整而改造，下亚段辫状河道砂体叠置、砂体连通性好，油气逸散严重．上亚段砂泥交互沉积，受后期调整作用小．针对不同的勘探对象，提出了下亚段主要寻找构造（断块＋低幅度背斜）油气藏为主，上亚段寻找岩性油气藏为主的勘探思路．

In center of Junggar basin, the petroleum exploration aims at subtle and adjustment reservoirs and its exploration risk is high. According to the researches, the sedimentary background of Member 2 of Sangonghe Formation, Jurassic and the later evolution of Che-Mo paleo-uplift is the main controlling factors to the hydrocarbon adjustment. Member 2 of Sangonghe Formation consists of J1s22 and J1s21. The sedimentary background is mainly braided delta front in J1s22, while it＇s mainly meandering fiver delta front in J1s21. Because of the tilting and transformation of Che-Mo paleo-uplift, the early primary reservoirs stored in Jurassic are also transformed with the adjustment of Che-Mo paieo-uplift. The braided fiver sand bodies in J1s22 overlays and their connection is good, so the oil and gas diffuses seriously, but the sand and mud deposits interactively in J1s21 and its adjustment is small. In view of different exploration targets, the author puts forward the following exploration thinking. In J1s22, the main target is to find structural （fault block and low amplitude anticline） reservoirs, while in J1s21, the main target is to find lithologic reservoirs. And according to this thinking, we have obtained good effect in petroleum exploration practice of Central Zhunggar basin.