准噶尔盆地侏罗系沉积构造与油气分布

准噶尔盆地陆相侏罗系煤系地层的油气勘探自８０年代后期以来获得了突破性的进展。对全盆地侏罗系沉积构造及其油气藏分布规律提出如下认识：大型鼻状构造与三角洲砂体的叠合控制侏罗系油气聚集，中下侏罗统属于不稳定的浅水湖泊群—沼泽沉积，湖相泥岩是主要烃源岩。三工河组、西山窑组和头屯河组具有自生自储条件，三角洲水下分流河道砂岩和河口沙坝是主要储集层。侏罗系自生油气以短距离侧向运聚为主，富集在大型鼻状构造的脊部、转折平台以及平台上的局部高点，以岩性油气藏为主，其次是断背斜、断鼻油气藏。切割大型鼻状构造的断层是深部二叠系油气进入侏罗系储集层的通道，在特定地区形成混源。油气藏最早在侏罗纪末开始形成，经历了多阶段充注和调整，第三纪盆地南部剧烈沉降，促使油气进一步聚集成藏。图２ 表１ 参１９ （刘银河摘）

Jurassic sedimentation, tectonics and petroleum distribution in Junggar basin.

In Junggar basin, the conjunction of large nose with deltaic sand body controls the accumulation of oil and gas in Jurassic. The Middle and Lower Jurassic belongs to the sedimentation of river, shallow lakes and marsh which show unstable and movable. Dominant source of oil is from mud rock deposited in deeper lake. Sangonghe, Xishanyao and Toutunhe Formations have the ability of self generation and self reservoir. Main reservoir bed is channel sand body and river mouth bar of delta. Oil and gas originated from Jurassic migrated in short lateral distance, accumulating in the axis of the nose, the flat changing part and the local higher point, forming lithologic pool and other kinds of fault anticline and fault nose pool. The faults which cut the nose are the path of oil and gas originated from deep Permian strata and mixed with the Jurassic self generated oil and gas. The earliest pool was formed at the end of Jurassic which have been filled and adjusted in many times and further more accumulating happened in Tertiary when the basin's south part sharply depressed.