北部湾盆地迈陈凹陷油气成藏期次、特征及模式

Hydrocarbon Accumulation Stages, Features and Patterns in Maichen Sag, Beibuwan Basin

刘宏宇

LIU Hongyu

中国石油化工股份有限公司江苏油田分公司勘探开发研究院, 江苏扬州 225009

Exploration and Development Research Institute of Jiangsu Oilfield Company, Sinopec, Yangzhou Jiangsu 225009, China

北部湾盆地迈陈凹陷在斜坡带、断裂带等不同区带分别发现油气藏，为查明不同区带油气藏的油气成藏期次与特征，利用流体包裹体分析技术在迈陈凹陷开展了储层流体包裹体特征描述和成藏期次、成藏过程的研究。研究表明，迈陈凹陷至少存在3期油气充注成藏，分别是早中新世下洋组沉积时期、中中新世角尾组沉积之后、中新世末灯楼角组沉积之后。三期油气成藏具有不同的成藏特点：I期成藏油气沿断裂呈"管流"运聚成藏，Ⅱ期成藏油气沿连通裂隙呈"网流"运聚成藏，Ⅲ期成藏油气沿有限连通孔隙"渗流"运聚成藏。结合实例建立了迈陈凹陷不同区带的成藏模式：斜坡带为侧向运移为主、垂向运移为辅的油气成藏模式，断裂-深凹带为垂向运移为主、侧向运移为辅的油气成藏模式。

There are several oil and gas pools found in different zones (the slope zone, fault zone, etc.) in Maichen Sag, Beibuwan basin. In order to identify the stages and features of hydrocarbon accumulation in different zones, the feature of reservoir fluid inclusions, the accumulation stages and process have been studied by using fluid inclusion technology. The research results show that there are at least three stages of hydrocarbon charging and accumulation in Maichen Sag, which are the early Miocene, Middle Miocene and the late Miocene. Three-stage hydrocarbon accumulation has different features. During Stage I, oil and gas migrated and accumulated along faults as "pipe flow". During Stage Ⅱ, oil and gas migrated and accumulated along the connected fractures as "network flow". During Stage Ⅲ, oil and gas migrated and accumulated along the limited connected pores. Then the accumulation patterns of different zones have been established by examples. The slope zone is an accumulation pattern with lateral migration as the major and vertical migration as the minor. The deep depression zone and the fault zone are characterized by vertical migration as the major and lateral migration as the minor.

中国石化科技项目“北部湾盆地中部地区油气成藏条件与勘探潜力”（P14088）和中国石化江苏油田分公司科技项目“北部湾盆地徐闻探区油气成藏动力学系统及勘探方向”（JS13002）资助。

https://doi.org/10.3969/j.issn.1008-2336.2019.02.001