塞内加尔盆地北部次盆白垩系烃源岩地球化学特征及分布  

Geochemical characteristics and distribution of Cretaceous source rocks in Northern Sub‑basin of Senegal Basin

作　　者：李越哲 殷杰[1] 王振奇[1] LI Yuezhe;YIN Jie;WANG Zhenqi(School of Geosciences,Yangtze University,Wuhan 430100,China)

机构地区：[1]长江大学地球科学学院,湖北武汉430100

出　　处：《大庆石油地质与开发》2023年第3期30-39,共10页Petroleum Geology & Oilfield Development in Daqing

基　　金：国家科技重大专项“西非北段被动大陆边缘盆地油气成藏条件与规律研究”(2017ZX05032-002-001)。

摘　　要：塞内加尔盆地是西非海岸最大的含油气盆地之一,但总体勘探程度较低,还有较多待解决问题,制约了盆地的油气勘探进程。通过对塞内加尔盆地北部次盆白垩系的钻井、测井及地球化学资料综合分析,对研究区2套烃源岩地球化学特征进行评价,并利用测井相、地震相预测了主力烃源岩的分布。结果表明:下白垩统Albian阶烃源岩w(TOC)平均值为1.2%,干酪根类型以Ⅱ型为主,上白垩统Cenomanian-Turonian阶烃源岩w(TOC)平均值为1.4%,干酪根类型以Ⅱ、Ⅲ型为主;白垩系烃源岩Ro为0.60%~1.00%,有机质处于低熟—成熟阶段;白垩系烃源岩主要分布在次盆北部陆架边缘D1井、L井附近,以及南部凹陷的深水沉积区域,其中Albian阶烃源岩发育厚度较大,连续性较好。研究成果可为北部次盆下一步勘探有利区确定和井位部署提供依据。Senegal Basin is one of the largest hydrocarbon-bearing basins on West African coast,but its overall exploration degree is low and there are many problems to be solved that constrain hydrocarbon exploration process of the basin.Based on comprehensive analysis of drilling,logging and geochemical data of Cretaceous strata in Northern Sub-basin of Senegal Basin,the geochemical characteristics of 2 sets of source rocks in studied area are evaluated,and distribution of main source rocks is predicted by using logging facies and seismic facies.The results show that averaged w(TOC)of Lower Cretaceous Albian source rocks is 1.2%and the main kerogen type is TypeⅡ.Averaged w(TOC)of Upper Cretaceous Cenomanian-Turonian source rocks is 1.4%,and the main kerogen types are TypeⅡand TypeⅢ.Ro value of Cretaceous source rocks is 0.60%~1.00%,and organic matters are in low-mature stage to mature stage.The Cretaceous hydrocarbon source rocks are mainly distributed near Well D1 and Well L located in northern shelf margin of the sub-basin,and in deep-water depositional areas of southern sag,including Albian source rocks with large development thickness and good continuity.The research provides reference for further determination of favorable exploration areas and well location deployment in Northern Sub-basin.

关 键 词：地球化学 白垩系烃源岩 海相烃源岩 烃源岩分布 塞内加尔盆地 北部次盆 

分 类 号：TE122.1[石油与天然气工程—油气勘探]