中国中西部大型盆地差异演化与碎屑岩油气响应

Differential characteristics of large-scale basin evolution and hydrocarbon response of clastic strata in central-western China

方成名 黄泽光

Fang Chengming Huang Zeguang

中国地质大学(武汉) 资源学院, 武汉 430074 2. 中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126

School of Earth Resource, China University of Geosciences(Wuhan), Wuhan, Hubei 430074, China 2. Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China

以碎屑岩油气成藏体系为核心，将中西部大型盆地（四川、鄂尔多斯、准噶尔和塔里木）置于统一时空体系，分析晚古生代以来原型及其更迭对成藏体系形成、分布的控制与油气响应，明确勘探方向。研究认为，构造体制转换期的原型沉降结构差异约束了主力烃源岩及源内、内源近源成藏体系的形成与分布，原型更迭产生的构造形变决定了内源远源、外源与混源成藏体系的时空展布。不同成藏体系的油气行为受中、新生代陆内体制原型的叠加改造控制，表现为：①转换期前渊叠加产生的差异性构造沉降控制了内源近源成藏体系大面积岩性油气藏的形成和近隆起/斜坡相对富集；②燕山晚期以来的掀斜隆升改造致使早期近源油气藏发生调整与贫化；③燕山期以来的断裂改造控制了近源成藏体系油气局部富集高产与内源远源、外源成藏体系油气藏的形成。中部盆地碎屑岩油气勘探主攻方向为燕山期隆起斜坡区内源近源、源内成藏体系，西部盆地优先选择活动隆起压扭性断裂发育区的内源远源、外源成藏体系。

Taking the petroleum accumulation system of clastic strata as the core, and the large-scale basins in the central-western China (Sichuan, Ordos, Junggar and Tarim) as a unified space-time system, we discussed the formation and distribution of accumulation systems and their petroleum response under the control of the superposition of basins since the Late Paleozoic. The formation and distribution of main hydrocarbon source rock strata, self-sourced and self-and-near-sourced petroleum accumulation systems were constrained by the differential structure of prototype compaction during a tectonic transition period. The self-and-far-sourced, externally sourced and hybrid-sourced petroleum accumulation systems were controlled by the tectonic deformation caused by basin superposition. The superposition of intercontinental systems in the Mesozoic to Cenozoic controlled petroleum behavior in different accumulation systems. First, differential tectonic subsidence which generated by foredeep overlap during a tectonic transition period controlled the formation of large lithologic hydrocarbon reservoirs and relative enrichment near tectonic uplift/slope zones in self-and-near-sourced petroleum accumulation systems. Second, the late Yanshanian uplift tilting made the early near-sourcing hydrocarbon reservoirs adjust or dilute. Finally, fault activities ever since the Yanshanian controlled the partial enrichment and high-yielding of hydrocarbon in self-sourced petroleum accumulation systems, and the formation of self-and-far-sourced and externally sourced petroleum accumulation systems. The self-and-near-sourced and self-sourced petroleum accumulations in the Yanshanian uplift or slope are the main hydrocarbon exploration targets in clastic strata in the central basin. In the western basin, we should focus on the externally-sourced and self-and-far-sourced petroleum accumulation systems on the compression-wrench fault belts of active uplifts.

国家“十二五”重大科技专项“大型油气田及煤层气开发”（2011ZX05002-006）和中国石化科技项目（P15098）资助。

https://doi.org/10.11781/sysydz201606703