巴布亚前陆盆地东部构造特征及油气圈闭类型

在调研前人研究成果的基础上,以地震资料最为详实的巴布亚湾海域区块为例,从区域构造演化入手,探讨研究区构造特征及油气圈闭类型,得出以下认识:1盆地主要经历了裂谷前基底期、冈瓦纳同生裂谷—裂后期、珊瑚海同生裂谷—裂后期、达拉伊弧后伸展期和前陆盆地期等演化阶段,沉积地层垂向呈“二元结构”,即前陆构造层叠加在达拉伊弧后及其下的裂谷—裂后期构造层之上,并呈楔状向南西西快速减薄超覆于东部高地之上; 2巴布亚湾海域区块形成了以欧拉褶皱带为前陆冲断带、以莫尔比拗陷为前渊带、以东部高地为前陆隆起和以布莱盆地为隆外拗陷的前陆盆地系统; 3初步分析圈闭类型和油气成藏条件后认为,裂谷—裂后和弧后伸展阶段形成优质海相烃源岩,前陆期形成良好的储盖组合;前陆冲断带发育的成排、成带逆冲背斜为首选钻探目标,前渊带的扇三角洲岩性体、浊积水道和前陆隆起带潜山构造及复合圈闭为潜在目标。

Structure characteristics and hydrocarbon trap types in Papuan Eastern foreland Basin

Based on detailed seismic data, we analyze tectonic structural features and hydrocarbon trap types in Papua bay block according to regional tectonic evolution. The following observations are obtained: A. It has experienced basal stage, Gondwana and coral sea syngenetic rift-rift-extension stage, Dara back-arc extension stage, and foreland stage; there is a “dual structure” vertical sedimentary strata, namely foreland is overlayed on rift formation, which is rapid wedge shaped in the eastern highlands. B. Papua bay block has complete foreland basin system structure: Aure fold thrust belt, Morseby foredeep belt, eastern highlands foreland uplift and Bligh depression. C. Based on trap type and hydrocarbon accumulation condition analysis, high quality marine hydrocarbon source rock was formed during rift-extensional basin, and then good assemblages are formed in the foreland stage; thrust anticlines are the first drilling targets in the thrust nappe belt, lithologic body and turbidite channel of fan delta in foredeep belt as well as sub-mountain and composite trap in forebulge belt are potential targets.