准噶尔盆地缘地层不整合油气成藏特征及勘探展望

基于大量地质与地球物理资料,分析了准噶尔盆地盆缘地层不整合样式结构特征,研究并总结了盆缘不整合的油气成藏特征及模式,提出了今后的勘探方向.认为:准噶尔盆地多期构造运动与频繁岩相变化使得盆缘不整合广泛发育,在宏观样式上具有削超、削平、平行等3种类型,垂向上具有三层或二层结构,并形成了多种渗透性组合形式.受不整合样式结构及渗透性组合、盆缘地质背景、盆内源岩发育状况等的影响,盆缘不整合成藏具有三大特征,一是不整合可形成地层圈闭及其他相关类型圈闭;二是多油气来源、多充注期次、原生与次生油藏共存;三是不整合自身具一定输导能力,但横向输导范围有限,相关油藏中的油气需要由断层、骨架砂体以及不整合等构成的"断—毯"式输导体系进行运移.盆缘不整合相关油气藏具有较大勘探潜力,需要根据各地区油气发现情况与勘探程度有针对性地开展相关研究与评价工作. 

Hydrocarbon accumulation characteristics and exploration prospects of stratigraphic unconformity in basin margin of Junggar Basin

Based on a large number of geological and geophysical data,it was analyzed in this paper the structural characteristics of stratigraphic unconformity styles in basin margin of the Junggar Basin.The hydrocarbon ac-cumulation feature and pattern were concluded,and the exploration prospect in the future was pointed out.Multiphase tectonic movements and frequent facies change in the Junggar Basin led to the wide development of unconformity in basin edge.In the macro style,three types of on lap truncation,leveled truncate and parallel conformity developed.In vertical direction,there were three or two layers,forming many combination forms of permeability.Influenced by unconformity style structure,permeability combination,geologic background in basin margin and source rock generation condition in basin,the accumulation of unconformity reservoir in basin margin has three characteristics.a) Unconformity trap can form stratigraphic trap and other related types.b) Hydrocarbon generates from multiple sources and charges during different phases.Primary and secondary reservoirs co-exist.c) Unconformity itself has a certain ability of conducting,but the scope of transverse conducting is limited and petroleum migrates along "fault-blanket" type migration systems formed by faults,framework sand body and unconformity.Basin edge unconformity reservoirs have great exploration potentials,so relevant research and eva-luation are needed to develop according to the exploration degree in each area.