Abstract: As an important crude oil exploration and production area in the western South China Sea, Beibuwan Basin has the advantages of oil enrichment in multiple sags, hydrocarbon accumulation in multiple strata and multiple models. In recent years, breakthroughs have been made in new fields and new types of oil-gas exploration involving shale oil, buried hills, lithologic reservoir, deep hydrocarbon resources, and backup sags/subsags. The paper investigates the regional petroleum geological conditions, so as to make clear the regional hydrocarbon accumulation regularities of the important hydrocarbon-generating sags in Beibuwan Basin, and guide the subsequent fine exploration and development of conventional oil-gas and the new fields and new types of hydrocarbon exploration. The research shows that the multi-stage tectonic movement controlled the tectonic evolution and material filling in Beibuwan Basin. The oil shale and semi-deep lacustrine mudstone of Member 2 of the Paleogene Eocene Liushagang Formation are the most important source rocks in the basin, several sets of source rocks are developed in Member 1 and 3 of Liushagang Formation and Member 2 of Weizhou Formation, and buried-hill reservoir and clastic rock reservoir are also developed, thus forming a multi-source, multi-reservoir and multi-cap pattern. The hydrocarbon accumulation in multiple sags of Beibuwan Basin is controlled by multiple mechanisms, such as near-source primary hydrocarbon accumulation in sag, vertical accumulation in fault belt, fault-uplift belt and steep slope belt, bypass accumulation in slope area, as well as converged accumulation pattern in salient and uplift. Oil and gas are orderly distributed in multi-sags and multi-zones. The oil-gas differential accumulation controls the distribution of internal gas and external oil, deep gas and shallow oil. Moreover, there is a significant difference in the types of oil-gas reservoirs in different zones. Under the guidance of regional petroleum geological conditions and accumulation regularities, the comprehensive analysis of resource potentials, accumulation conditions and exploration and development degree indicate that shale oil, buried-hill, lithologic trap, deep hydrocarbon resources and backup sags/subsags are important new types and new fields for future exploration and development in Beibuwan Basin.

Key words: Beibuwan Basin, new field, new type, accumulation condition, resource potential

摘要： 北部湾盆地是南海西部海域重要的原油勘探区和产区，具备多凹陷含油、多层系成藏、多种油气成藏模式等优势成藏条件，近年来在页岩油、潜山、岩性、深层油气、后备凹陷/洼陷等新领域、新类型油气勘探中取得了突破。为了落实北部湾盆地重要生烃凹陷的区域成藏规律，指导后续常规油气精细勘探开发及新领域、新类型油气勘探，对区域石油地质条件开展了研究，总结了成藏规律。研究结果表明，多期构造运动控制了北部湾盆地的构造演化和物质充填；古近系始新统流沙港组二段油页岩和半深湖亚相泥岩为盆地最重要的烃源岩，此外，在流沙港组三段、流沙港组一段、涠洲组二段也发育多套烃源岩；发育潜山储层和碎屑岩储层，形成了多源、多储、多盖的格局；凹陷区原生近源成藏、凹中断裂带/断隆带/陡坡带垂向成藏、斜坡区过路成藏、凸起/隆起区汇流成藏等多种成藏模式控制了北部湾盆地的多凹陷成藏；油气在多凹多带有序分布，油气的差异聚集控制了内气外油、深气浅油的油气分布特征，不同区带内的油气藏类型差异显著。在区域石油地质条件与成藏规律的指导下，从资源潜力、成藏条件、勘探开发程度综合分析，页岩油、潜山、岩性圈闭、深层油气、后备凹陷/洼陷是北部湾盆地未来勘探开发的重要领域。

关键词: 北部湾盆地, 新领域, 新类型, 成藏条件, 资源潜力