Abstract: Jungar Basin is a large sedimentary basin with abundant oil and gas resources and the petroliperous characters in every structural element.Based on the crystalline basement of the Pre-Cambrian and the folded basement of the Pre-Carboniferous,the basin has undergone four history stages including foreland basin from the Late Carboniferous to the Middle Triassic period,moderate extension and depressive basin from the Late Triassic to the early phase of the Middle Jurassic period,trans-compressive basin of the late phase of the Middle Jurassic to the Cretaceous period,foreland basin of the Cenozoic Era.In the four tectonic evolutional stages,the superimposition of the different proto-types of sedimentary basins has resulted in the wedge-shaped geological structure being the thickest in the south and the thinnest in the north,which controls the accumulation pattern of oil and gas.The basin was vertically subdivided into four reservoir intervals by the thick mudstones in Baijiantan Formation of the Upper Triassic series,the thick mudstones of the Tugulu Group of the lower Cretaceous series and the extensive abnormal pressure sealing beds or the basin-scale compartment,including the Carboniferous to the Middle Triassic (C-T₂),the Upper Triassic to the Lower Jurassic (T₃-J₁s),the Middle Jurassic to the Lower Cretaceous (J₂-K₁) and the Upper Cretaceous to the Neogene System (K₂-N).The vertical migration of oil and gas along the faults and the interval vertical breakthrough of abnormal high-pressure fluid system has resulted in a typical hydrocarbon migration and accumulation model as well as resulted in hybrid pools sourced from the different source rocks or source kitchens of different ages.The distributions of oil and gas fields show that the four basement fracture belts trending in north-north-east direction have become the proper paths of oil and gas migration.Along these paths,there has occurred four favorable belts for oil and gas accumulation.The formation of oil and gas fields and the difference of hydrocarbon abundance are chiefly controlled by the coupling style between the basement faults and the sedimentary cover faults.The Jurassic System and the Cretaceous System are favorable for the development of oil and gas reservoirs with the features of distant source,gentle slopes and secondary characters,while the Permian System and the Triassic System are favorable for the reservoirs with the near source,steep slopes and primary characters.The accommodation positions of fault and lithological body such as sandbody,sandy-conglomerate and conglomerate bodies are the main sites for hydrocarbon entrapment.Oil and gas in the Jurassic System and Cretaceous System predominantly occurred in the north-east or north-east-east trans-compressive structural belts.Those belts may be the important plays for the coming petroleum exploration in Jungar Basin.

Key words: Jungar Basin, paleo-uplift, fault system, abnormal pressure, primary reservoir, secondary reservoir, oil and gas enrichment

摘要： 准噶尔盆地是一个"满盆"含油、全层系多层组含油、油气资源丰富的大型沉积盆地.它是在前寒武系结晶基底与前石炭系褶皱基底基础上,经历了晚石炭世-中三叠世前陆盆地阶段、晚三叠世-中侏罗世早期(J₂x)弱伸展拗陷盆地阶段、中侏罗世晚期(J₂t)-白垩纪压扭盆地阶段与新生代前陆盆地阶段的演化历史.4个构造发展阶段不同类型的原型盆地的叠合,形成了南厚北浅的楔形地质结构,决定了油气聚集的基本面貌;不同时期、不同性质的古隆起纵横叠置,制约着相应地质时期油气运聚的基本格局.在垂向上,以上三叠统白碱滩组泥岩、下白垩统吐谷鲁群泥岩与广泛分布的异常压力封隔层为界可将盆地划分为C-T₂,T₃-J₁s,J₂-K₁与K₂-N-4个各具特色的成藏区间;油气沿断裂的垂向运移与异常高压流体系统的幕式突破,导致了以垂向运移为主导的运聚模式,多源、多期油气混合成藏.现有油气田的分布及勘探趋势表明4个NNE向基底断裂带为油气优势运移通道,沿着它们形成了4个油气富集的黄金带.这些基底断裂与盖层断裂之间的耦合方式是制约形成油气田及导致含油气丰度差异的关键条件.准噶尔盆地侏罗系-白垩系与二叠系-三叠系分别发育"远源、缓坡、次生"与"近源、陡坡、原生"两种典型的断裂-岩性体油气藏类型,断裂与岩性体(砂体、砂砾岩、砾岩体等)的有机组合部位是油气富集的主要场所.侏罗系-白垩系的油气主要富集在NE、NEE向压扭性构造带上,它们是腹部地区下一步勘探的主要方向.

关键词: 准噶尔盆地, 古隆起, 断裂系统, 异常压力, 原生油气藏, 次生油气藏, 油气富集