中国中西部沉积盆地致密油富集机理及其主控因素  

Enrichment of tight oil and its controlling factors in central and western China

作　　者：宋岩[1,2] 罗群[1,2] 姜振学[1,2] 杨威[1,2] 刘冬冬[1,2] SONG Yan;LUO Qun;JIANG Zhenxue;YANG Wei;LIU Dongdong(Unconventional Oil and Gas Science and Technology Institute,China University of Petroleum,Beijing 102249,China;China State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China)

机构地区：[1]中国石油大学(北京)非常规油气科学技术研究院,北京102249 [2]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249

出　　处：《石油勘探与开发》2021年第2期421-433,共13页Petroleum Exploration and Development

基　　金：国家自然科学基金:“致密油储层层理缝启闭与石油充注”(41672118);中国石油大学(北京)-中国石油战略合作科技专项课题6“吉木萨尔页岩油甜点形成机制与分类预测技术研究”(ZLZX2020-01-06)。

摘　　要：以鄂尔多斯盆地中南凹陷、准噶尔盆地吉木萨尔凹陷、酒泉盆地青西凹陷致密油为研究对象,基于野外观测、致密油解剖、样品分析测试、模拟实验与综合分析,揭示了致密油"启动压力启动、压差推进、弥漫式快慢交替、阶梯状大面积充注与裂缝优势通道快速运移并存、优势缝-孔耦合空间富集"的机理。指出孔隙结构的多尺度层次性是致密油阶梯式充注的根本原因。总结出"广覆式高生烃强度的源岩是致密油富集的物质基础,优势源储组合是致密油富集的基本单元,裂缝和层理有利于致密油的局部快速运移,缝-孔耦合控制致密油的富集"是致密油富集的主控因素。建立了大型淡水湖碎屑岩"源储共生,四优富集,环心展布,规模连片"和小型咸化湖混积岩"源储一体,四优富集,中心分布,虽小而肥"的两种典型致密油运聚富集模式。Taking the tight oil of the Zhongnan sag in the Ordos Basin,Jimusar sag in the Junggar Basin and Qingxi sag in the Jiuquan Basin as study objects,based on field survey,dissection of tight oil reservoirs,sample test,modeling experiment and comprehensive analysis,this study reveals that the tight oil accumulates at start-up pressure,advances under differential pressure,diffuses at alternating fast and low speeds,charges in stepped large area and migrates rapidly through fractures,and enriches in dominant fractures and pores.The root cause of ladder-like charge is the multiple scales of pores.The widespread source rock with high hydrocarbon generation intensity is the material basis for tight oil enrichment;the dominant source reservoir assemblage is the basic unit for tight oil enrichment;fractures and beddings are conducive to local rapid migration of tight oil;fractures and pores work together to control the enrichment of tight oil.Two typical accumulation models of tight oil are established,namely"source reservoir in coexistence,four optimal factors controlling enrichment around central area,and large-scale continuous distribution"for a large freshwater lake clastic rock basin and"source reservoir integration,four optimal factors controlling enrichment,central area distribution,small in size but high in enrichment degree"for a small salty lake diamictite depression.

关 键 词：致密油 富集机理 主控因素 富集模式 中西部地区 

分 类 号：TE122[石油与天然气工程—油气勘探]