Exploration breakthroughs and geological characteristics of continental shale oil: A case study of the Kongdian Formation in the Cangdong Sag, China
Exploration breakthroughs and geological characteristics of continental shale oil: A case study of the Kongdian Formation in the Cangdong Sag, China
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DOI：
10.1016/j.marpetgeo.2018.12.020
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发表时间：
2019-04
影响因子：
4.2
通讯作者：
Xianzheng Zhao;Lihong Zhou;X. Pu;Wenzhong Han;Fengming Jin;Dunqing Xiao;Zhannan Shi;Yuan Deng
中科院分区：
文献类型：
--
作者：
Xianzheng Zhao;Lihong Zhou;X. Pu;Wenzhong Han;Fengming Jin;Dunqing Xiao;Zhannan Shi;Yuan Deng
应用传统石油地质学和沉积岩石学方法，对孔二段细粒相区的石油地质和沉积特征进行了研究。以渤海湾盆地沧东凹陷湖盆中心500 m连续取心、万余个岩心样品的系统分析和测井资料为基础，建立了新的页岩油气成藏理论，确定了页岩油的分布，为页岩油勘探部署提供了依据。结果表明，在最大湖泛期，研究区沉积了广泛分布的半深-深湖亚相细粒沉积物（页岩）。该沉积物由长英质页岩、混合页岩和碳酸盐岩组成，但没有粘土页岩。页岩岩石成分多，优势矿物少;碎屑矿物含量高，粘土矿物含量低;方沸石富集，黄铁矿贫乏;脆性矿物富集，石英贫乏;岩石类型多样，页岩油有限;致密储层多，无裂缝储层少;优质烃源岩多，非烃源岩少;高频旋回多，块状沉积少。结果表明，碳酸盐岩在平面上呈条带状分布，局部富集，与陆相封闭湖盆中部仅发育烃源岩而不发育储集层的认识相矛盾。研究区页岩油成藏条件良好，烃源岩和储层配置良好，甜点面积达260 km 2，具有较高的勘探价值。在地质知识指导和工程技术支持下，多口威尔斯探井获得了工业油流。
Petroleum geology and deposition features of the fine grain phase region in the second member of the Kongdian Formation were investigated using traditional petroleum geology and sedimentary petrology. New theories for shale oil and gas formation, based on data from 500 m continuous coring, systematic analysis of over ten thousand core samples, and logging data in the center of the lake basin in the Cangdong Sag (Bohai Bay Basin, China) were developed to determine the distribution of shale oil and provide a basis for shale oil exploration deployment. Results showed that a wide distribution of semi-deep to deep lake sub-facies fine-grained sediment (shale) was deposited in the study area during the largest lake flooding period. This sediment consists of felsic shale, mixed shale, and dolomites, but no clay shale. The shale features multiple rock components with few dominant minerals; high clastic mineral content and low clay mineral content; rich analcite and lean pyrite; rich brittle minerals with lean quartz; diverse rock types with limited shale oil; more tight reservoirs and fewer reservoirs with no fractures; more high-quality source rock with less non-hydrocarbon source rock; and more high frequency cycles with fewer monolithic deposits. Results indicate that dolomites are located in strips on the plane and are locally enriched, contradicting the understanding that only hydrocarbon source rock, and no reservoirs, develop in the middle of a continental closed lake basin. The study region demonstrates good conditions for shale oil formation, a favorable configuration of source rock and reservoirs, and 260 km2of sweet spots, indicating high exploration value. Several prospecting wells have obtained industrial oil flow with guidance based on geological knowledge and engineering technology support.