西非科特迪瓦盆地重力场特征与构造区划  

Gravity field characteristics and structural division of the Cote d’Ivoire Basin in West Africa

作　　者：张科 张义娜 李全 陈全红 盖海洋 ZHANG Ke;ZHANG Yina;LI Quan;CHEN Quanhong;GAI Haiyang(CNOOC International Ltd.,Beijing 100027,China)

机构地区：[1]中国海洋石油国际有限公司,北京100027

出　　处：《西安科技大学学报》2021年第6期1025-1031,共7页Journal of Xi’an University of Science and Technology

基　　金：国家重大专项(2017ZX05032-002);国家自然科学基金项目(92055203)。

摘　　要：为系统解析西非科特迪瓦盆地构造特征、厘定洋陆边界并划分构造单元,明确有利勘探区带,基于新采集地震资料和最新高精度卫星重力数据,应用位场分离技术获取布格重力异常划分科特迪瓦盆地洋陆边界;利用位场边缘识别技术计算布格重力异常总水平-垂向导数推测控盆断裂6组,其中3组为近东西走向,3组为近南北走向;利用剩余布格重力异常反演科特迪瓦盆地沉积厚度,根据异常所对应的隆起和坳陷结合布格重力异常和总水平-垂向导数划分东部离散边缘、北部转换离散边缘和洋盆共3个二级构造单元。首次明确了科特迪瓦盆地“东西分段、南北分带”的构造特点、厘定了洋陆边界、划分了构造单元,指出东部离散边缘区为有利勘探区。结合区域地质研究认为东部离散边缘区含油气系统证实,勘探潜力较大,为盆地未来勘探方向。借助高精度卫星重力资料,以区域地质及地震资料为约束,有效解决巨型低勘探盆地构造区划的难题,指明盆地勘探方向,对类似靶区具有较好的借鉴和推广意义。The research attempts to systematically analyze the structural characteristics of the Cote d’Ivoire Basin in West Africa,determine the COB,divide the structural units and identify the favorable exploration zones.Based on the new seismic data and the latest high-precision satellite gravity data,the potential field separation technology is adopted to obtain the Bouguer gravity anomaly with the ocean land boundary of the Cote d’Ivoire Basin divided.The potential field edge recognition technology is also used to calculate the total horizontal vertical derivative of the Bouguer gravity anomaly with six groups of basin controlling faults inferred,three of which are nearly East-West strike and three of which are nearly north-south strike.And there sidual Bouguer gravity presents the deopsit thickness.According to the uplift and depression corresponding to the anomaly,combined with Bouguer gravity anomaly and total horizontal vertical derivatives,three secondary structural units are divided into eastern discrete edge,northern transformed discrete edge and ocean basin.In this study,for the first time,the structural characteristics of“East-West segmentation and North-South zonation”in the basin have been clarified,the COB been determined,and the structural units been divided.It is pointed out that the eastern discrete edge area is a favorable exploration area.With the regional geological research in view,the petroleum system in the eastern discrete marginal area confirms that the exploration potential is large,which is the future exploration direction of the basin.With the help of high-precision satellite gravity data and the constraints of regional geological and seismic data,this study effectively solved the problem of structural division of huge low exploration basin to determine the exploration direction of the basin,aguiding significance for similar target areas.

关 键 词：科特迪瓦盆地 构造解析 洋陆边界 位场边缘识别技术 布格重力异常 布格重力异常总水平-垂向导数 

分 类 号：TE121[石油与天然气工程—油气勘探]