东尼日尔盆地Tenere坳陷上白垩统海相烃源岩评价及勘探潜力  

Evaluation and Exploration Potential of Upper Cretaceous Marine Source Rocks in Tenere Depression, Eastern Niger Basin

作　　者：刘邦[1] 潘校华[1] 万仑坤[1] 毛凤军[1] 刘计国[1] 程顶胜[1] 

机构地区：[1]中国石油勘探开发研究院

出　　处：《海相油气地质》2012年第1期29-34,共6页Marine Origin Petroleum Geology

基　　金："十一五"国家科技重大专项之课题"海外重点裂谷盆地油气成藏规律及目标优选"(编号:2008ZX05029-001)资助

摘　　要：东尼日尔盆地是中西非裂谷系中典型的中—新生代裂谷盆地。Tenere坳陷位于盆地西北部,包括西部凹陷、东Ⅰ凹陷和东Ⅱ凹陷。对Saha-1井上白垩统岩屑样品的分析揭示,干酪根显微组分以不发荧光或弱荧光的无定形体为主,岩石抽提物中C29甾烷优势明显,说明该井上白垩统泥岩有机质输入以陆源植物为主。岩石热解分析表明上白垩统Yogou组泥岩大多数为中等—好烃源岩,有机质以Ⅱ2-Ⅲ型为主,Donga组泥岩大部分为差—中等烃源岩,以Ⅲ型为主;岩石热解峰温指示烃源岩成熟门限深度为2300 m左右。生烃史模拟显示,Saha-1井Yogou组泥岩尚未开始生烃,Donga组在白垩纪末期开始生烃,下部已进入生气阶段。综合研究认为Tenere坳陷的西部凹陷勘探潜力较大,而东Ⅰ凹陷和东Ⅱ凹陷潜力有限。Eastern Niger Basin is a typical Mesozoic-Cenozoic intracontinental rift basin of the Central-Western African rift system.The Tenere Depression,located in the northwestern part of the basin,includes the Western Sag,EasternⅠ Sag and EasternⅡ Sag.Analysis of mudstone cuttings from Well Saha-1 has revealed that kerogen macerals are dominated by amorphinite without or with weak fluorescence and C 29 regular sterane are predominant in rock extracts.On these characteristics,it is suggested that the organic matter of the Upper Cretaceous mudstones mainly derived from terrigenous plants.Rock-Eval pyrolysis data reveals that the Upper Cretaceous Yogou mudstone generally is moderate to good hydrocarbon source rock with predominant Type Ⅱ 2 to Type Ⅲ of kerogen while the Donga mudstone is mainly poor to moderate source rocks with Type Ⅲ of kerogen.The T max values indicate that the depth of hydrocarbon-generating threshold is about 2300m.Thermal-burial history modeling implies that of Yogou mudstone（Well Saha-1） is not mature.Donga mudstone has reached the oil-generating threshold at the end of Cretaceous and the lower part of Donga is in gas-generating stage.By integrated study,it is suggested that better potential for hydrocarbon exploration exists in Western Sag compared with that in the EasternⅠ Sag and EasternⅡ Sag.

关 键 词：东尼日尔盆地 Tenere坳陷 上白垩统 海相地层 烃源岩评价 勘探潜力 

分 类 号：TE112.115[石油与天然气工程—油气勘探]