南太平洋地区盆地形成演化和油气资源潜力分析

本文从南太平洋地区区域构造演化出发，开展盆地类型划分和石油地质条件分析，了解不同类型盆地的油气成藏特征，并分析油气分布规律和资源潜力，以期对未来油气勘探开发国际合作选区提供借鉴。研究表明:（1）南太平洋地区经历了亨特-鲍恩造山运动、澳大利亚板块与南极洲板块分离、塔斯曼海扩张及珊瑚海扩张、巴布亚新几内亚地区的洋壳俯冲和弧-陆碰撞作用，最终形成了澳大利亚东部南缘和海域及新西兰地区以裂谷盆地为主、澳大利亚东部内陆以克拉通盆地为主的包括晚二叠世-三叠纪前陆盆地、古近纪-新近纪前陆盆地、古近纪-现今弧前盆地和弧后盆地6种盆地类型；（2）澳大利亚内陆南缘和东部海域以及新西兰地区裂谷盆地分布广泛，裂谷盆地油气最为富集，但内陆和海域有所差异，内陆南缘裂谷盆地油气资源丰富且石油与天然气的比值约为2:1，而东部海域裂谷盆地因油气成藏条件差，尚无油气发现；（3）根据盆地的剩余可采储量和远景资源量对南太平洋地区的资源潜力进行分析，认为白垩纪-古近纪裂谷盆地和古近纪-新近纪前陆盆地油气资源潜力最大，并优选出吉普斯兰（Gippsland）、塔拉纳基（Taranaki）和巴布亚（Papua）3个有利盆地。

The evolution of basins and petroleum resource potential in the southern Pacific region

Based on regional tectonic evolution history, basin types in the southern Pacific region are classified and the petroleum geology of the major basin types is studied. The petroleum occurrences and resource potential are finally analysed in an objective to provide support for international cooperation between countries. Our studies show that:(1) The southern Pacific region underwent four stages including Hunter-Bowen orogeny, Antarctic Plate separates form the Australia Plate, the Tasman and Coral seas expending and oceanic crust subduction and arc-land collision occurred in Papua New Guinea, and formed six types of basin that is cratonic basin, rift basin, late permian-triassic foreland basin, paleogene-neogene foreland basin, paleogene-present forearc basin and the back-arc basin. The eastern inland of Australia is mainly the cratonic basin, and the southern margin and sea area of eastern Australia and the New Zealand are mainly the rift basin; (2) The rift margin basin is widely distributed in the south of Australia and the sea area of eastern Australia and the New Zealand. The most concentrated oil and gas accumulation in the rift basin in the study area, but the southern and eastern regions are different, the ratio of oil to gas is about 2:1 in the south margin rift basin. However, there is no hydrocarbon accumulation in the rift basin in the eastern sea because of poor hydrocarbon accumulation conditions; (3) According to the remaining recoverable reserves and prospective resource in basin, analyze the resource potential of sedimentary basins in the eastern of Australia. It is believed that the oil and gas resources in the cretaceous-paleogene rift basin and the paleogene-neogene foreland basin have the greatest potential, and the Gippsland Basin, Taranaki Basin and Papua Basin are optimized as favorable ones for hydrocarbon exploration in the southern Pacific region.