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| 鄂尔多斯盆地西缘马家滩地区延长组烃源岩研究 |
| 陈庆龙1,蒲仁海1,郭玮2,3,白清华2,3 |
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(1. 西北大学大陆动力学国家重点实验室, 地质学系, 陕西 西安 710003;
2. 中国石油长庆油田分公司勘探开发研究院, 陕西 西安 710003;
3. 低渗透油气田勘探开发国家工程实验室, 陕西 西安 710003) |
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| 摘要: |
| 鄂尔多斯盆地延长组深湖相页岩在盆地内部均有分布，但在其西缘冲断带地区是否仍然存在、如何分布、是否具有生烃潜力，这些问题尚待进一步研究。本文根据近期在石沟驿向斜所钻的驿探1及其周边钻井、露头和地震资料对延长组暗色页岩厚度、层位、展布和生烃条件进行了研究。烃源岩测井响应、地震层位追定、地震正演模型及烃源岩热解等分析结果表明：（1）青铜峡-固原断裂以东的西缘冲断带中部马家滩地区仍然发育2-4层延长组黑色烃源岩，呈高伽马、高时差和低电阻率测井响应特征，但其单层厚度较薄，一般只有3-5m，累计厚度最大20m左右，一般分布在长10、长9、长8和长7等层位，在地震剖面上以强振幅响应；（2）与盆地内部不同，马家滩地区在延长组底部长10出现薄层黑色页岩，并成为区分上、中三叠统的标志；（3）马家滩地区深浅湖呈"十字"分布，与盆地主体湖盆并不连通，单独存在。主体生油岩为长9-长10段烃源岩；（4）驿探1井热解样品均达到较好-好的烃源岩条件，具备较好生烃潜力。 |
| 关键词: 鄂尔多斯盆地 上三叠统延长组 马家滩地区 烃源岩 正演模型 |
| DOI： |
| 附件 |
| 投稿时间：2019-09-12修订日期：2019-10-12 |
| 基金项目:中国石油天然气股份有限公司科技重大专项"长庆油田5000×104t持续高效稳产关键技术研究与应用"（编号：2016E-0502） |
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| An approach to the source rocks from the Upper Triassic Yanchang Formation in the Majiatan region on the western margin of the Ordos Basin |
| CHEN Qinglong1, PU Renhai1, GUO Wei2,3, BAI Qinghua2,3 |
(1. State key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710000, Shaanxi, China;
2. Research Institute of Petroleum Exploration and Development, Changqing Oil Field Company, CNPC, Xi'an 710000, Shaanxi, China;
3. National Engineering Laboratory of Exploration and Development of Low-Permeability Oil and Gas Fields, Xi'an 710000, Shaanxi, China) |
| Abstract: |
| The deep lacustrine shales occur mostly in the interior of the Ordos Basin. However, there remains uncertain about how and whether they occur or have the hydrocarbon potential in the thrust zones on the western margin of the ordos Basin. The present paper gives a detailed study of thickness, horizon, distribution and hydrocarbon potential of the black shales from the Yanchang Formation on the basis of outcrops and seismic data from the Yitan-1 well and other wells in the Shigouyi geosyncline. The results of well logs, seismic horizon tracing, seismic forward modeling and pyrolytic analysis of the source rocks led us to draw the following conclusions. (1) There are still 2 to 4 beds of the black source rocks in the Yanchang Formation, Majiatan region in the central part of the thrust zone east of Qingtongxia-Guyuan fault. These black source rocks are characterized by high gamma, high time difference and low-resistivity well logs, 3 to 5 m in thickness for a single bed with a total thickness of about 20 m in the Chang-10, Chang-9, Chang-8 and Chang-7 horizons, and also with high amplitude responses. (2) The thin-bedded black shales in the Chang-10 horizon at the bottom of the Yanchang Formation in the Majiatan region are interpreted as the indicator for the distinction from the Upper and Middle Triassic strata. (3) The deep and shallow parts of the lake exhibit the "cross" distribution, isolated and discontinous with the main body of the lake basin. The Chang-10 and Chang-9 horizons are believed to be major source rocks. (4) The samples collected from the Yitan-1 well for the pyrolytic analysis indicate better to good source rocks with good hydrocarbon potential. |
| Key words: Ordos Basin Upper Triassic Yanchang Formation Majiatan region source rock forward model |