Abstract: The Yingxiongling shale oil reservoir in Qaidam Basin is a global unique thick saline-lacustrine shale oil reservoir developed in plateau mountainous area, and its main oil beds are in Paleogene. Recently, major breakthroughs have been made in oil and gas exploration in the Yingxiongling shale oil reservoir, and industrial oil flow has been obtained in the formation test of 31 layers of 11 prospecting wells. The cumulative oil production of Well Chaiping1 exceeds 10 000 tons in 295 days, showing good exploration potential and development prospect. This paper systematically analyzes the geological setting and main accumulation factors of the Yingxiongling shale oil reservoir, and establishes the enrichment model of shale oil reservoir. The thick plateau mountainous shale oil reservoir is distinctive in terms of the surface and subsurface conditions, so that the existing theories and technologies of shale oil exploration and development at home and abroad cannot be followed completely. Further research progresses are as follows. (1) The key factors for the enrichment of sweet spots in the Yingxiongling shale oil reservoir include the two-stage continuous and efficient hydrocarbon generation of low organic matter abundance shale in saline lacustrine basin, the good reservoir spaces provided by the bedded and laminated calcite dolomite in the thick mixed sedimentary system, the easy stimulation condition due to reservoir with high carbonate mineral and low clay mineral contents, and the high shale oil recovery due to high formation pressure, high gas-oil ratio and good crude oil quality. (2) There are four kinds of enrichment zones with significant different reservoir spaces developed in the Yingxiongling structural belt, i.e., tectonic-stable zone, fault-deformation zone, fault-fracture/fault-karst zone and inter-salt crumple zone, corresponding to four kinds of sweet spot enrichment models, namely stratabound mode, bed-fracture compound control mode, fault control mode and salt control mode. (3) The Yingxiongling shale oil reservoir is located in a unique plateau mountainous environment. The extremely thick deposits of more than kilometers and the rugged landscape of ravines determine the difficulty and diversity of well sites, well patterns and well types. The cold weather, hypoxia and water shortage also greatly increase the difficulty of exploitation. (4) F our well patterns and development modes can be used to achieve efficient production in the Yingxiongling shale oil reservoir, including the zipper-like fracturing mode for stereo horizontal-well network, separate fracturing and commingling production for cluster vertical well or highly inclined well, multi-layer fracturing communication production mode for vertical well or highly inclined well or directional well, and continuous perforation combined with acidification production mode for directional well. The relevant understandings are expected to provide scientific guidance and technical support for the study of shale oil enrichment mode and efficient production mode, and the practice of well pattern and geological-engineering integration in plateau mountainous area.

Key words: mountainous shale oil, enrichment mode, well pattern, development mode, life-cycle management

摘要： 柴达木盆地英雄岭页岩油藏为全球独具特色的巨厚高原山地式咸化湖相页岩油藏，其发育层位主要为古近系，近期已获得油气勘探重大突破，在11口探井31层试油中均获得工业油流，其中，柴平1井在295 d的累积产石油量超过万吨，展现出良好的勘探潜力和开发前景。系统分析英雄岭页岩油藏形成的地质背景与成藏主控因素，建立了页岩油藏的富集模式。巨厚高原山地式页岩油藏具有地面、地下双特殊性，无法完全照搬国内外已有的页岩油勘探开发理论与技术。研究结果表明：①英雄岭页岩油藏"甜点"富集的关键因素包括咸化湖盆低丰度页岩的"两段式"持续高效生烃，巨厚混积体系中的层状、纹层状灰质白云岩提供了良好的储集空间，高碳酸盐矿物含量与低黏土矿物含量有利于储层改造，高地层压力、高气油比以及良好的原油品质有利于页岩油采出；②英雄岭构造带发育构造稳定区、断裂变形区、断裂破碎/断溶区和盐间揉皱区4类储集空间差异显著的富集区，对应发育层控型、层控-缝控复合型、断控型和盐控型4类"甜点"富集模式；③英雄岭页岩油藏地处独特的高原山地环境，超千米的巨厚沉积与沟壑纵横的崎岖地表决定了井场选址、开发布井方式与井型选择的困难性与多样性，高寒、缺氧、缺水又极大地增加了施工难度；④英雄岭页岩油藏可采用4种布井开发模式以实现高效动用，包括立体水平井网—拉链式压裂模式、丛式直井/大斜度井—多层分压合采模式、直井/大斜度井/定向井—多层压裂沟通生产模式和定向井—射孔酸化连作生产模式。相关认识预期可为高原山地区页岩油富集模式与高效动用方式研究、布井模式与地质工程一体化实践提供科学指导和技术支持。

关键词: 山地式页岩油, 富集模式, 布井方式, 开发模式, 全生命周期项目管理