摘要
基于鄂尔多斯盆地中生界沉积充填特征和油气成藏要素研究,开展中生界全油气系统划分,分析常规—非常规油气运聚特征及成藏主控因素,建立全油气系统模式。研究表明:(1)中生界发育以三叠系延长组7段优质烃源岩为核心的、以低渗透油藏—非常规油气为主的全油气系统,可划分出源内滞留油气聚集域、近源致密油气聚集域、远源常规油气聚集域及过渡型油气聚集域4类油气聚集域,它们共同构成了一个连续共生、有序成藏的油气聚集整体,其中非常规油气资源占比显著高于常规油气资源;(2)沉积充填体系空间上的核心区即全油气系统核心富油区,由核心区向外围页岩油→致密油→常规油依次渐变,成藏动力变化趋势为超压驱动→浮力或超压+毛管压力主导,油气聚集规模变化特征为大面积连片的亿吨级→离散的十万吨—百万吨级,气油比和甲烷含量呈明显降低趋势;(3)沉积充填体系为全油气系统提供物质基础和空间格架,由叠置砂体、断裂和不整合面构成的输导体系成为远源常规油气聚集域和过渡型油气聚集域的油气运移优势路径,优质烃源岩奠定了页岩油雄厚的资源基础,微纳米孔喉—裂隙网络构成非常规聚集空间,油气运移聚集的过程主要受成藏期超压强排烃和后成藏期负压再富集所控制,油气富集与长期保存依赖于“稳定构造+多旋回沉积+双重自封闭”三元协同控制机制;(4)全油气系统模式可概括为“四域一体、双压驱动、双重自封闭”。
Based on the investigation of sedimentary filling characteristics and pool-forming factors of the Mesozoic in the Ordos Basin,the whole petroleum system in the Mesozoic is divided,the migration&accumulation characteristics and main controlling factors of conventional–unconventional hydrocarbons are analyzed,and the whole petroleum system model is established.First,the Mesozoic develops the whole petroleum system dominated by source rocks of the 7th member of Triassic Yanchang Formation and low-permeability oil reservoirs to unconventional oil and gas.It can be divided into four hydrocarbon accumulation domains,including intra-source retained hydrocarbon accumulation domain,near-source tight hydrocarbon accumulation domain,far-source conventional hydrocarbon accumulation domain and transitional hydrocarbon accumulation domain.Second,the core area of sedimentary filling is the oil-rich core of the whole petroleum system.From the core to the periphery,the reservoir type evolves as shale oil→tight oil→conventional oil,the accumulation power is dominated by overpressure→buoyancy or overpressure and capillary force,the accumulation scale changes from extensive hundreds of millions of tons to a dispersed hundreds of thousands-million of tons,and the gas-oil ratio and methane content decrease.Third,the sedimentary filling system provides the material basis and spatial framework for the whole petroleum system,the superimposed sand body,fault and unconformity constitute the dominant migration pathway of hydrocarbons in the far-source conventional hydrocarbon accumulation domain and the transitional hydrocarbon accumulation domain,the high-quality source rocks provide a solid resource basis for shale oil,and the micro-nano pore throat-fracture network constitute unconventional accumulation space.The hydrocarbon migration and accumulation process is mainly controlled by intense expulsion of hydrocarbon under overpressure in the pool-forming stage and the in-situ re-enrichment controlled by underpressure in post-pool-forming stage.The oil-gas enrichment and long-term preservation depends on the coordination among three factors(stable geological structure,multi-cycle sedimentation,and dual self-sealing).Fourth,the whole petroleum system model is defined as four domains,overpressure+underpressure drive,and dual self-sealing.
作者
邓秀芹
白斌
DENG Xiuqin;BAI Bin(National Engineering Laboratory for Exploration and Development of Low Permeability Oil&Gas Fields,Xi’an 710018,China;Exploration and Development Research Institute of PetroChina Changqing Oilfield Company,Xi’an 710018,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;National Key Laboratory for Multi-resource Collaborated Green Development of Continental Shale Oil,Daqing 163712,China)
出处
《石油勘探与开发》
北大核心
2025年第5期1017-1027,共11页
Petroleum Exploration and Development
基金
中国石油天然气集团有限公司前瞻性基础性技术攻关项目(2021DJ2203)
新型油气勘探开发国家科技重大专项“鄂尔多斯盆地全油气系统与新领域勘探技术”(2025ZD1400200)。
关键词
全油气系统
鄂尔多斯盆地
中生界
油气聚集域
连续性聚集
序列成藏
成藏动力
双重自封闭保存
whole petroleum system
Ordos Basin
Mesozoic
hydrocarbon accumulation domain
continuous accumulation
orderly accumulation
accumulation power
dual self-sealing preservation
