中国多旋回叠合沉积盆地的形成演化、地质结构与油气分布规律

深入认识盆地的地质结构与构造演化,探讨盆地的油气分布规律,将为揭示中国大陆属性、资源能源分布、环境变化及油气勘探新领域奠立重要基础。本文立足于油气勘探的新资料,应用活动论构造历史观与比较大地构造学方法,分析了中国叠合沉积盆地的构造演化、构造分区、地质结构与油气成藏模式,探索油气分布规律。研究表明,中国叠合沉积盆地经历了中新元古代、寒武纪—泥盆纪(或中泥盆世)、(晚泥盆世—)石炭纪—三叠纪与侏罗纪—第四纪4个构造旋回的演化;据东西向两条构造锋线和南北(或北北东)向的两条改造锋线及西太平洋弧后盆地带,可将中国划分为北疆、内蒙古、松辽、塔里木—阿拉善、鄂尔多斯、渤海湾、青藏、四川、华南与海域等10个沉积盆地区;发育有前陆/克拉通、前陆/坳陷、坳陷/断陷、断陷/坳陷、反转断陷、被动陆缘、走滑叠合和改造残留等8种叠合盆地结构类型;发育安岳裂陷槽型、塔北型、苏里格复合三角洲型、玛湖凹陷型、陆梁隆起型、库车冲断带型、大庆长垣型、古潜山型、中央峡谷水道型、柴东生物气型、四川源内型与沁水向斜煤层气型等12种典型油气成模式;盆地内凹陷/断陷的油气分布具有空间有序性,叠合界面油气富集具优势性,油气叠合分布有强的非均一性,中西部前陆/克拉通叠合型盆地的油、气分区分布,海域被动陆缘/断陷叠合型盆地的油、气分带分布。中国多旋回叠合盆地具有独特的“三环带状”油气分布格局。

Multi-cycle superimposed sedimentary basins in China: Formation,evolution, geologic framework and hydrocarbon occurrence

Understanding basin's geological structure and tectonic evolution and exploring its oil and gas distribution pattern is key to revealing the geological features of China, and the energy resources distributions, environmental changes, and potential hydrocarbon exploration targets in China. Based on the new data of recent petroleum exploration and using the methodology of comparative geo-tectonics, this paper studies the superimposed sedimentary basins in China from the view point of mobile geo-tectonic history, focusing specifically on the basin's tectonic evolution, tectonic subdivision, geologic framework, and pool-formation models, and explores the basin's oil and gas distribution patterns. According to our analysis, the superimposed sedimentary basins in China evolve through four tectonic cycles during the Meso- to Neo-Proterozoic, Cambrian-Devonian (or Middle Devonian), (Late Devonian-) Carboniferous-Triassic, and Jurassic-Quaternary Periods. The sedimentary basins in China can be subdivided into ten sedimentary basin areas: northern Xinjiang, inner Mongolian, Songliao, Tarim-Alax, Ordos, Bohai Bay, Qinghai-Tibet, Sichuan, southern China, and oceanic area. They can be further characterized by eight structural styles as foreland/cratonic-basin, foreland/sag, sag/faulted-depression, faulted-depression/sag, inverted faulted-depression, passive margin, or strike-slip superimposed basins, or as modified residual basins. Twelve types of hydrocarbon pool-formation are developed, which are represented by the Anyue rift trough, northern Tarim, Sulig composite delta, Mahu sag, Luliang uplift, Kuqa thrust belt, Daqing anticline, paleo-buried hill, central canyon channel, eastern Qaidam biogas, Sichuan intra-source rock, and Qinshui syncline coalbed gas. Within a sag/faulted-depression superimposed basin, oil and gas distributions are typically ordered spatially, with the interface area most favorable for hydrocarbon accumulation. However, oil and gas distribution patterns are highly heterogeneous across different structural styles. For example, in the foreland/cratonic-basin superimposed basins of central and western China, oil and gas distribute separately in isolation, whilst in the passive-margin/faulted-depression superimposed basins of the oceanic area, oil and gas zones distribute respectively along the inner and outer sedimentary belts. The multi-cycle superimposed basins in China generally have a distinctive ‘three ring-like’ oil and gas distribution pattern within each basin area.