全球5个深水盆地带油气地质特征

Characteristics of petroleum geology of global five deep-water basin belts

深水油气是当今世界勘探的三大热点之一。基于板块构造理论,全球海洋深水油气盆地沿“三竖两横”5个巨型带分布,“三竖”是近南北走向的大西洋陆缘深水盆地带、东非陆缘深水盆地带、西太平洋陆缘深水盆地带;“两横”是近东西走向的新特提斯构造域陆缘深水盆地带与环北冰洋陆缘深水盆地带。在以上5个盆地带均有巨型—大型油气区发现,共15个。研究发现,巨型—大型油气区形成受三大因素控制。首要因素是发育世界级烃源岩,包括大型湖相、海陆过渡相和海相3类烃源岩,其中湖相烃源岩主要发育于南大西洋陆缘盆地,海相烃源岩分布在北大西洋陆缘盆地、东非陆缘盆地等海湾环境,海陆过渡相烃源岩主要分布在西太平洋陆缘盆地和新特提斯构造域陆缘盆地大型煤系河流三角洲。第二个因素是发育世界级优质储层,包括碎屑岩和碳酸盐岩两类:碎屑岩储层主要是受大型河流—三角洲控制发育的浊积扇,碳酸盐岩主要与介壳灰岩等有关。第三个因素是世界级圈闭群发育,包括盐构造圈闭、重力滑脱构造圈闭、巨型逆冲退覆构造圈闭、大型浊积体岩性圈闭等。全球海洋深水盆地勘探具有不平衡、不充分特征,存在战略拓展、战略突破、战略发现和战略准备4个战略领域。战略拓展方向包括已证实巨型—大型油气区已证实的富油气成藏组合,是目前获取储量的主要领域,是投资风险小、见效快的投资方向。战略突破方向主要包括已证实巨型—大型油气区的新成藏组合,是烃源岩条件已证实的领域,实现商业性发现的风险小。战略发现方向是已有油气显示或潜在商业发现的潜在油气区,存在规模性发现的潜力。战略准备方向是目前还没有发现、但存在大发现可能的区域。总体看,全球深水油气勘探潜力巨大。

Deepwater field is one of the three global hot spots for oil and gas exploration.Based on the theory of plate tectonics,the distribution of global deep-water basins is characterized by“three in longitudes and two in latitudes”.“Three in longitudes”are three nearly N-S direction deep-water basin belts in the Atlantic continental margin,the East Africa continental margin and western Pacific continental margin.“Two in latitudes”are E-W direction deep-water basin belts in the Neotethyan tectonic domain continental margin and the circumArctic Ocean continental margin.Totally 15 giant-large sized oil and gas discoveries have been proved in five basin belts.The study shows that the formation of giant-large sized oil and gas regions is controlled by three factors.The primary factor is the development of worldclass source rocks of large-area lacustrine facies,marine and continental transitional facies,and marine facies.The lacustrine source rocks are mainly deposited in South Atlantic continental marginal basins;The marine source rocks are distributed in North Atlantic and East African continental marginal basins;While the transitional source rocks are mainly distributed in western Pacific continental margin and Neotethyan tectonic domain continental margin of large coal measure river delta facies.The second factor is the development of world-class high-quality reservoirs,including two types of clastic rock and carbonate rock.The clastic reservoirs are mainly turbidite fan controlled by large riverdelta,while carbonate reservoirs are related to shell limestone.The third factor is the development of world-class trap groups,such as salt structural trap,gravity detachment structural trap,giant thrust nappe structural trap,and large turbidite lithologic trap,etc.The global oil and gas exploration in deep-water basins is unbalanced and inadequate,and there are four strategic fields in the future,i.e.,strategic expansion,strategic breakthrough,strategic discovery and strategic preparation.The exploration orientation for strategic expansion includes the proven hydrocarbon rich plays in the proven giant-large oil and gas regions,which is the main field to obtain reserves with low investment risk and quick results at present.The exploration orientation for strategic breakthrough mainly includes new confirmed plays in the proven giant-large oil and gas region with proven source rock conditions,which has a low risk to achieve commercial discovery.The exploration orientation for strategic discovery is the potential oil and gas area with oil and gas shows or potential commercial discovery,which has the potential of largescale discovery.The exploration orientation for strategic preparation is the area that has no but the possibility to find major discoveries.On the whole,the global oil and gas exploration in deep-water basins has a huge potential.