异地盐席发育区输导体系油气运聚物理模拟——以墨西哥湾博格斯盆地Perdido构造带为例

Physical simulation of hydrocarbon migration and accumulation in transport systems of allochthonous salt sheet development zone: a case study of Perdido Fold Belt in Burgos Basin, Gulf of Mexico

樊妍 向才富 杨松岭 逄林安 陈经覃 李爱山 陈亮 蒋善斌 司永康 杨明慧

FAN Yan XIANG Caifu YANG Songling PANG Lin'an CHEN Jingtan LI Aishan CHEN Liang JIANG Shanbin SI Yongkang YANG Minghui

1. 中国石油大学 地球科学学院, 北京 102249; 2. 中国海洋石油国际有限公司, 北京 100010

1. College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China; 2. CNOOC International Company Limited, Beijing 100010, China

博格斯盆地是墨西哥湾西部典型的含盐被动陆缘盆地，油气资源丰富，其Perdido构造带异地盐席发育区形成了由异地盐席底部构造、断层和古新统—始新统Wilcox组构成的油气输导体系。由于Perdido构造带水体较深且盐构造活动复杂，其异地盐席发育区的油气输导特征和输导效率不明。因此，定量评价Perdido构造带异地盐席发育区油气输导体系的输导效率、厘清不同类型输导体系输导效率的差异性及其影响因素对减少勘探风险尤为重要。基于地震、钻井和测井等资料，对Perdido构造带异地盐席发育区发育的下倾型、波浪型和上倾型三种形态的油气输导体系开展了油气运聚物理模拟实验。研究表明，与盐席底部砂泥岩相比，三种形态油气输导体系中Wilcox组均呈现更高的输导效率，是油气运移的优势通道。不同形态油气输导体系的输导效率在油气运移的不同时期存在差异，具体表现为始新世末期下倾型输导体系的输导效率最高；渐新世末期上倾型输导体系的输导效率最高。始新世末期和渐新世末期，研究区断层活动性强，促进油气输导。Perdido构造带异地盐席发育区的油气输导效率受输导体系的物性、油气运移距离和源储压差等因素的影响，其中，源储压差为主要控制因素，油气运移距离为次要控制因素，输导体系物性的影响相对较弱。

The Burgos Basin is a typical salt passive continental margin basin in the western Gulf of Mexico, rich in oil and gas resources. The allochthonous salt sheet development zone in the Perdido Fold Belt of the Burgos Basin has formed an oil and gas transport system comprising the underlying structures of allochthonous salt sheets, faults, and the Paleocene to Eocene Wilcox Formation. Due to the deep-water environment and complex salt tectonics, the hydrocarbon transport characteristics and efficiency in these allochthonous salt sheet development zones remain unclear. Therefore, to reduce exploration risks, it is important to quantitatively evaluate the transport efficiency of hydrocarbon transport systems in the allochthonous salt sheet development zone of the Perdido Fold Belt and to clarify transport efficiency differences among various types of transport systems and their influencing factors. Based on seismic, well drilling, and well logging data, the hydrocarbon migration and accumulation physical simulation experiments were carried out on three types of transport systems—downdip, wavy, and updip-developed in the allochthonous salt sheet zone of the Perdido Fold Belt. The results showed that compared to the sand and mudstone at the base of the salt sheets, the Wilcox Formation exhibited higher transport efficiency in all three transport systems, serving as the primary channel for hydrocarbon migration. The transport efficiency varied during different migration periods. Specifically, the downdip system demonstrated the highest transport efficiency at the end of the Eocene, and the updip system had the highest efficiency at the end of Oligocene. During these two periods, the study area experienced strong fault activities, facilitating hydrocarbon migration. The hydrocarbon transport efficiency in the allochthonous salt sheet development zone of the Perdido Fold Belt was affected by factors such as the physical properties of transport systems, hydrocarbon migration distance, and the pressure difference between source rock and reservoir. Among these, the pressure difference is the main controlling factor, followed by the migration distance, with the physical properties of transport systems having a relatively minor effect.

中国海油“十四五”重大科技项目“海外油气勘探开发关键技术”之课题2“'两岸一带’重点区油气勘探评价关键技术”(KJGG2022-0902)资助。

https://doi.org/10.11781/sysydz2025020347