澳大利亚大澳湾盆地东部海域勘探潜力

摘要

澳大利亚南缘大澳湾盆地为陆相裂谷与海相被动大陆边缘的叠合盆地，经历了由中晚侏罗世至早白垩世的裂陷期、早白垩世到晚白垩世桑托尼期的过渡期、以及其后的漂移期共三期构造演化。盆地东部海域发育五套烃源岩(岩相主要为白垩系湖相泥岩、三角洲相煤系和海相泥岩)和四套储盖组合，形成了四套成藏组合。 Ceduna坳陷的Ham-merhead群三角洲前缘砂岩储层与前三角洲泥岩可形成自储自盖组合，是有利的勘探区带。%Great Australian Bight Basin is a superimposed basin, which evolved from J2-K1 rifting period, through K1-2 transitional period to K2-Q drifting period. Five sets of source rocks are distinguished in the eastern sea area of basin. These source rocks commonly are Cretaceous lacustrine mudstones, deltaic coal-measures and marine mudstones in lithology. It is shown that four sets of reservoir-cap assemblages and four associated plays develop also in the eastern sea area. The plays are Lower Cretaceous Bronze Whaler Group play and Upper Cretaceous White Pointer Group, Tiger Group and Hammerhead Group plays, in which the Upper Cretaceous Hammerhead play is regarded as the best potential zone for exploration in offshore Ceduna Depression because the Hammerhead delta front sandstone is identified as a good reservoir and the Hammerhead prodeltaic mudstone as a good source rock.