准噶尔盆地非构造油气藏成因类型及成藏主控因素(为庆祝克拉玛依油田勘探开发50周年而作)

准噶尔盆地非构造油气藏发现早、类型多、规模大、分布广、差异大,占已探明石油地质储量的76.1%,一直是新疆石油勘探开发的主要对象.已发现的非构造油气藏储集体成因类型主要包括4类：一是西北缘同生断阶陡坡带洪积扇砾岩、砂砾岩为储集层的断层-岩性及岩性-地层油气藏;二是准东断坡近岸三角洲水下扇、浊积扇砂砾岩、砂岩为储集层的构造-岩性及岩性-地层油气藏;三是腹部古凸起控制的侏罗系-白垩系缓坡带河流-三角洲砂岩为储集层的构造-岩性及岩性-地层油气藏;四是海西运动期基底潜山风化壳油气藏.它们以上三叠统白碱滩组（黄山街组）盆地级区域盖层为界,划分为上、下两大成藏组合.下组合油气来源为自源、近源,其非构造油气藏形成主要是储集体岩相、物性、输导体系3因素控制;上组合油气来源主要为二叠系远源及二叠系和侏罗系烃源的混源,其非构造油气藏的形成,主要受输导体系、构造背景、储集体岩相、圈闭及物性5因素控制.

Main Factors of Petroleum Accumulations and Origin Types of Non-Structural Reservoirs in Junggar Basin

Junggar basin is characterized by early discovery, multiple types, large scale, wide distribution and big differences of oil-gas reservoirs, accounting for 76.1% of proved OOIP. It has been playing a major target for petroleum exploration and development in Xin- jiang region. For discovered non-structural reservoirs, their origin types mainly include: the fractured-lithologic and lithologic-stratigraphic reservoirs dominated by torrential fanglomerate and glutenite of steep slope in depositional fault bench in northwestern margin of Junggar basin, the structural-lithologic and lithologic-stratigraphic reservoirs by delta submarine fan, turbidite fan glutenite and sandstone in nearshore fault slope in Zhundong (east Junggar area, the structural-lithologic and lithologic-stratigraphic reservoirs by fluvial-delta sand- stone in Jurassic-Cretaceous gentle slope controlled by paleo-swell in hinterland of Junggar basin, and the buried-hill-weathered-crust reservoirs of Hercynian episode in basement of Junggar basin. The basin-scale regional cap rocks of Baijiantan formation (Huangshanjie formation) of Upper Triassic are their boundaries, and upper and lower reservoir assemblages can be divided. The lower assemblage con- tains hydrocarbon from self source and adjacent source, and its main factors of forming non-structural reservoir are lithofacies, petrophysi- cal property and transport system. The upper assemblage has hydrocarbon sources mainly from Permian remote source and Permian- Jurassic mixed source, its primary control factors of shaping non-structural reservoir are transport system, tectonic setting, lithofacies, trap and petrophysical property.