鄂尔多斯盆地延长组7段3亚段页岩油风险勘探突破与意义  

Breakthrough and significance of risk exploration in the 3rd Sub-member, 7th Member of Yanchang Formation in Ordos Basin

作　　者：付金华[1,2] 牛小兵[1,3] 李明瑞 刘新社[1,4] 李士祥[1,4] 郭芪恒[1,4] 周新平 刘江艳[1,4] Fu Jinhua;Niu Xiaobing;Li Mingrui;Liu Xinshe;Li Shixiang;Guo Qiheng;Zhou Xinping;Liu Jiangyan(National Engineering Laboratory for Exploration and Development of Low-Permeability Oil&Gas Fields,Shaanxi Xi'an 710018,China;PetroChina Changqing Oilfield Company,Shaanxi Xi'an 710018,China;Exploration Division,PetroChina Changqing Oilfield Company,Shaanxi Xi'an 710018,China;Research Institute of Exploration and Development,PetroChina Changqing Oilfield Company,Shaanxi Xi'an 710018,China)

机构地区：[1]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [2]中国石油长庆油田公司,陕西西安710018 [3]中国石油长庆油田公司勘探事业部,陕西西安710018 [4]中国石油长庆油田公司勘探开发研究院,陕西西安710018

出　　处：《石油学报》2022年第6期760-769,787,共11页Acta Petrolei Sinica

基　　金：中国石油天然气集团有限公司前瞻性基础性研究重大科技项目“鄂尔多斯盆地页岩油勘探开发理论与关键技术研究”(2021DJ1806);国家重点基础研究发展计划(973)项目“淡水湖盆细粒沉积与富有机质页岩形成机理”(2014CB239003)资助。

摘　　要：2022年3月,针对鄂尔多斯盆地湖盆中部地区的延长组7段3亚段(长7亚段)的泥页岩层系实施的LY1H风险探井试油获得116.8 t/d的高产油流,试采期平均原油产量达15.8 t/d,实现了页岩油新类型和新层系的重大勘探突破。基于LY1H井钻探成果,系统梳理了长7亚段页岩油成藏地质条件及试油试采特征,分析了页岩油富集高产的主控因素,以期为下一步落实规模储量提供指导。研究表明:长7亚段的砂质岩类具有单层厚度薄、砂体横向延伸短、粒度细、泥质含量高的特征,且受长7亚段高有机质丰度的厚层状泥页岩强生、排烃作用的影响明显,含油饱和度高。长7亚段富有机质泥页岩与其夹持的多套薄层状粉—细砂岩组合具有有利的源-储配置关系,高含油性、微裂缝发育、高气油比均有利于砂质岩夹层内页岩油的富集高产。LY1H井水平段油层表现为强非均质性,为提高页岩油的动用程度,设计了“前端可溶球座细分切割+后端连续油管水力喷砂精准压裂+新型绳结暂堵剂”的一体化组合式差异化压裂改造工艺,采用纳米驱油变黏滑溜水,促进了油水充分置换,缩短了试油周期,并制定了合理的排采制度,有效提高了试油效率。LY1H井的勘探突破证实,鄂尔多斯盆地湖盆中部地区的长7亚段厚层状泥页岩所夹持的薄层状砂质岩类具备页岩油规模富集的地质基础,通过水平井大规模压裂改造工艺可提高其开发效率,是长庆油田下一步增储上产的重要接替领域和勘探重点。In March, 2022, a high-yield oil flow of 116.8 t/d was obtained by formation testing during risk exploration of Well LY1 H in the mud shale strata of 3 rd Sub-member, 7 th Member of Yanchang Formation(Chang 7sub-member) in the central lake basin of the Ordos Basin, and the average crude oil output during the pilot production period was 15.8 t/d, thus making a major breakthrough in exploring new types and strata of shale oil. Based on the exploration results of Well LY1 H, this paper systematically summarizes the geological conditions for hydrocarbon accumulation and the characteristics of formation testing and pilot production of shale oil in Chang 7sub-member, and analyzes the major controlling factors for the enrichment and high yield of shale oil, hoping to guiding the determination of large-scale reserves subsequently. The research shows that the sandy rocks in Chang 7sub-member are characterized with a thin single-layer thickness, short horizontal extension of the sand body, fine particle size and high shale content, and has high oil saturation due to the significant effect of strong generation and hydrocarbon expulsion of the thick-layered mud shale with high organic matter abundance in Chang 7sub-member. There is a favorable source-reservoir configuration relationship in the mud shale rich in organic matters in Chang 7sub-member intercalated with multiple sets of thin-layer silty-fine sandstone. High oil content, micro-fracture development, and high gas-oil ratio are conducive to the enrichment and high yield of shale oil in sandy rock interlayer. The oil layer in the horizontal section of Well LY1 H shows strong heterogeneity. In order to improve the producing degree of shale oil, an integrated combined differential fracturing technique of “front-end soluble ball socket subdivision cutting+back-end coiled tubing hydraulic sand-blasting precise fracturing+new knot-type temporary plugging agent” is designed. Nano variable-viscosity slick water for oil displacement is used to promote the full displacemen

关 键 词：鄂尔多斯盆地 页岩油 延长组7段3亚段 LY1H井 重大突破 

分 类 号：TE122.14[石油与天然气工程—油气勘探]