流体动力与输导体系联合约束下的油气运聚成藏机理分析——以珠江口盆地白云凹陷深层为例  

Analysis on hydrocarbon migration and accumulation mechanism under combined constraints of fluid dynamics and transport system:A case study from the deep Baiyun Depression,Pearl River Estuary Basin

作　　者：王震亮[1] 王晨 何星辰 祁妙 WANG Zhenliang;WANG Chen;HE Xingchen;QI Miao(State Key Laboratory of Continental Dynamics,National and Local Joint Engineering Center for CO2 Capture and Storage Technology,Department of Geology,Northwest University,Xi′an 710069,China)

机构地区：[1]西北大学地质学系/大陆动力学国家重点实验室/CO_(2)捕集与封存技术国家地方联合工程中心,陕西西安710069

出　　处：《西北大学学报（自然科学版）》2022年第6期1013-1027,共15页Journal of Northwest University（Natural Science Edition）

基　　金：中海油研究总院有限责任公司项目(CCL2020RCPS0051ESN);国家自然科学基金青年项目(42102169)。

摘　　要：珠江口盆地白云凹陷油气勘探潜力巨大。该文利用钻测井和三维地震资料,使用三维盆地模拟技术和油气成藏综合研究方法,以白云凹陷深层流体动力和输导体系为基础,分析深层油气运移、成藏条件和动态过程,明确深层的油气运聚成藏模式,以便为白云凹陷深层有利区带的预测提供较为可靠的科学证据。研究认为,主力烃源岩恩平组因欠压实和生烃增压等机制而形成明显超压,油气可藉此克服毛细管阻力,排出烃源岩外。主洼中心在距今8 Ma时流体压力大于泥岩的破裂压力,可使烃源岩破裂,发生幕式混相排烃。恩平组上段气势梯度表现为主洼大部分及周缘气势梯度较大,东洼出现小范围内气势梯度为全区最高,表现出不同地区间油气运移动力的强弱差别。恩平组内断层全部开启,具有良好的输导性能,可作为油气运移通道。珠海组内以主洼东部断层开启最多,输导性能最好。断层与砂体倾向相同的断砂组合,其输导性能最强,而断层呈一定角度与构造脊相交的断脊组合更有利于油气运移。综合考虑流体动力和输导体系,分别建立了恩平组和珠海组内的油气运聚成藏模式。恩平组内突出表现为油气在一定范围的近源、侧向运移和聚集成藏,主洼和东洼生成的油气在流体势场驱动下向北坡、主洼东部和西南部运移,晚期运移动力充足;珠海组内油气以垂向运移为主,侧向运移规模较小,在砂岩储层与断层垂向输导部位匹配处,有利于油气聚集成藏。There is a great potential for oil and gas exploration in Baiyun depression,Pearl River Estuary Basin.By using drilling,logging and 3D seismic data,and 3D basin simulation technology and comprehensive research methods,based on deep fluid dynamics and transport systems in deep Baiyun depression,the hydrocarbon migrating and accumulating contexts and dynamic process are analyzed,deep hydrocarbon accumulating modes are predicted,in order to provide more reliable scientific evidences for the prediction of the deep favorable zone in deep Baiyun depression.It is concluded that the main source rocks in Enping Formation existed mechanisms of under-compaction and hydrocarbon generation pressurization,resulted in obvious overpressure,whereby hydrocarbon could overcome the capillary pressure and expelled out of the source rocks.The fluid pressure in the center of the main sag was greater than the fracturing pressure of mudstone after 8 Ma BP,caused the source rock to fracture and episodic miscible expulsion of hydrocarbon.It showed that the gas potential gradient in upper member of Enping Formation is large in most areas of the main sag and its surrounding areas,and the gas potential gradient in the east sag is the highest in the whole region in a small range,indicating the difference in the strength of hydrocarbon migrating force between different areas.The faults in Enping Formation are all open and have good transport performance,which can be used as hydrocarbon migrating pathway.In the Zhuhai Formation,the faults in the east of the main sag are most open and have the best transport performance.The assemblage type between fault and sand body with the same inclination of fault and sand body has the strongest transport capacity in Enping Formation,while the configuration type between fault and structural ridge with the fault intersecting the tectonic ridge at a certain angle is more helpful to hydrocarbon migration.Overall consideration of fluid dynamics and transport systems,the hydrocarbon accumulating modes in Enping Fo

关 键 词：流体动力 输导体系 过剩压力 气势梯度 运聚成藏模式 白云凹陷深层 

分 类 号：TE12[石油与天然气工程—油气勘探] P612[天文地球—矿床学]