Abstract: Ordos Basin is rich in oil-gas resources and now is the largest oil-gas production base in China. With the continuously growing energy demand of the country, Ordos Basin has played the main role in increasing reserves and production. In recent years, based on the innovation in geological theory and breakthrough in key technology, major breakthroughs and significant progress have been made in new fields and new types of oil exploration in Ordos Basin. The paper reviews the four fields of shale oil area, Tianhuan depression-western margin thrust belt, Sanbian areas (Jingbian-Dingbian-Anbian areas), and the lower assemblage of Yanchang Formation, and analyzes their geological conditions, exploration progress, and resource potential. On this basis, the key insights were obtained as below. (1) Shale oil is expected to be the main contributor for the sustainable development of production above 6 000×10⁴t in Changqing oilfield. Ordos Basin develops continental shale oil in the Member 7 and 9 of Mesozoic Yanchang Formation, as well as marine shale oil in Paleozoic Wulalike Formation. Specifically, the interbedded shale oil in the Member 7 of Yanchang Formation has the proven reserves of 40.5×10⁸t, which is the main target for exploration and development; the laminated shale oil has an estimated resource potential of 20×10⁸t, achieving a strategic breakthrough; the breakthrough test for lamellar shale oil is steadily promoted, and its success will have a revolutionary impact. The Member 9 of Yanchang Formation in northern Shaanxi area develops "Lijiapan shale", and the risk exploration of shale oil is progressing smoothly. The exploration in Wulalike Formation in the southern section of the western margin of the basin has a good start, and new strata are exploited in the exploration of Paleozoic marine shale oil. (2) New oil enrichment areas are detected in the complex tectonic zone of Tianhuan depression and western margin thrust belt, forming three replacement areas: Yujialiang, West Huanxian, and North Pingliang, with the resource potential of more than 5×10⁸t. (3) New progress has been made in multi-strata and three-dimensional exploration in Sanbian areas, and the Haotan Integrated Demonstration Zone has been quickly built. The resource potential of Sanbian areas is preliminarily estimated as 5×10⁸t. (4) The lower assemblage of Yanchang Formation shows a good exploration prospect. Multiple favorable areas have been discovered through outstepping exploration in the Member 9 and 10 of Yanchang Formation, with the proven reserves of nearly 3×10⁸t. Overall, Ordos Basin is in the middle stage of exploration and still has great potential for increasing reserves. The new fields and types of oil exploration will provide replacement resources for oil companies to implement the important strategies of high-quality petroleum development.

Key words: Ordos Basin, new field, new type, shale oil, Tianhuan depression, western margin thrust belt, Sanbian areas, lower assemblage of Yanchang Formation

摘要： 鄂尔多斯盆地油气资源富集,是中国目前最大的油气生产基地。随着国家能源需求持续增长,鄂尔多斯盆地成为增储上产的主力。近年来,通过地质理论创新和关键技术攻关,鄂尔多斯盆地在石油勘探新领域、新类型方面取得了重大突破和重要进展。通过梳理页岩油、天环坳陷—西缘冲断带、三边地区(靖边—定边—安边)以及延长组下组合4大领域,分析其地质条件、勘探进展和资源潜力,取得了以下主要认识:①页岩油有望成为长庆油田6 000×10⁴t以上产量可持续发展的主力贡献者。鄂尔多斯盆地发育中生界延长组7段、延长组9段陆相页岩油和古生界乌拉力克海相页岩油,其中,延长组7段夹层型页岩油已落实规模储量40.5×10⁸t,是目前勘探开发的主要对象;纹层型页岩油实现了战略突破,预计资源潜力为20×10⁸t;页理型页岩油的攻关试验正稳步推进,攻关如获突破将会产生革命性影响。陕北地区延长组9段发育"李家畔页岩",页岩油风险勘探进展顺利。盆地西缘南段乌拉力克组的勘探露出苗头,开辟了古生界海相页岩油勘探新层系。②天环坳陷—西缘冲断带复杂构造区落实了新的含油富集区,形成了于家梁、环县西、平凉北3大接替领域,资源潜力超过5×10⁸t。③三边地区多层系立体勘探取得新进展,快速建成了郝滩一体化示范区,初步评价三边地区的资源潜力为3×10⁸t。④延长组下组合展现出较好的勘探前景,延长组9段和延长组10段甩开勘探发现了多个有利区,落实规模储量近3×10⁸t。鄂尔多斯盆地总体处于勘探中期,仍具有较大的增储潜力,石油勘探的新领域、新类型将为油田公司的高质量发展提供接替资源。

关键词: 鄂尔多斯盆地, 新领域, 新类型, 页岩油, 天环坳陷, 西缘冲断带, 三边地区, 延长组下组合