鄂尔多斯盆地深层寒武系烃源岩展布特征及其勘探意义  

Distribution Characteristics and Exploring Significance of Cambrian Source Rock in the Deep of Ordos Basin,China

作　　者：陈启林[1] 白云来[1] 廖建波[1] 刘晓光 龙礼文[1] 马玉虎[1] 

机构地区：[1]中国石油勘探开发研究院西北分院,甘肃兰州730020 [2]重庆市地质矿产勘查开发局107地质队,重庆401120

出　　处：《天然气地球科学》2015年第3期397-407,共11页Natural Gas Geoscience

基　　金：国家重大科技专项"岩性地层油气藏成藏规律;关键技术及目标评价"(编号:2011ZX05001);中国石油天然气股份有限公司重大专项(编号:2008E-0702;2008E-0706)联合资助

摘　　要：鄂尔多斯盆地深层寒武系海相沉积是重要的勘探领域。从基础地质研究入手,通过系统研究盆地周边露头剖面及盆地内钻遇寒武系的探井资料、重点分析寒武系岩性岩相特征及分布特点、采集寒武系暗色岩石样品并进行TOC、氯仿沥青＂A＂等分析测试。结果表明,鄂尔多斯盆地深层寒武系分布稳定,厚度约为50-800m,主要由缓坡—台地相碳酸盐岩及混积缓坡—深水相泥岩、碳酸盐岩组成;盆地南中部寒武系馒头组黑色泥岩及三山子组深灰色、灰黑色纹层状白云岩形成于还原环境,有机质含量相对较高（TOC最高值为0.34%）,具有一定的生烃潜力。寒武系及其暗色岩类在贺兰奥拉谷和歧山—延安奥拉谷厚度明显增大,TOC值也明显增高,在环县、定边地区也有TOC高值区出现,表明了奥拉谷是鄂尔多斯盆地寒武系主要烃源岩发育区,预测可与中央古陆隆起带及其斜坡区形成有效的生烃—聚集成藏组合,鄂尔多斯盆地寒武系是值得进一步研究和勘探的重要层系。The Cambrian is an important prospecting field in the deep of Ordos Basin. According to the basra geological data in this area, and systematical study on the field geological outcrop profiles surrounding the basin and the Cambrian cores,the characteristics of the Cambrian lithology, lithofacies and distribution are emphatically analyzed. The Cambrian dark rocks were sampled and tested on TOC. The results show that the Cambrian has stable distribution with 50-800m thickness,belonging to ramp-platform facies and mixing ramp-deep water facies. Carbonate is developed in the ramp-platform facies mudstone and carbonate are developed in the mixing ramp-deep water facies. The Mantou Formation black mudstone and the Sanshanzi Formation lamellar dolomite have 0.34 % TOC in the southern central basin. Especially, the above lamellar dolomite flings off odour （H2S） which means it formed in a reducing environment. On the both sides of ＂the central ancient land＇,namely the Helan aulacogen and the Qishan-Yanan aulacogen,Cambrian and its mudstones are thicker,and the total organic carbon is higher too. Besides, the areas with high total organic carbon appear in the Huanxian County,Gansu Province and Dingbian County,Shaanxi Province which lie on ＂the central ancient land＂ too. These show the aulacogens may be a developed area of main Cambrian source rocks. The aulacogens,＂the central ancient land＂ and its slope area may form some effective reservoir-forming assembIages. The Cambrian in the Ordos Basin possesses the hydrocarbon-generating capabili- ty and needs further study and exploration.

关 键 词：寒武系 勘探 鄂尔多斯盆地 深层 奥拉谷 

分 类 号：TE122.115[石油与天然气工程—油气勘探]