巴布亚盆地主力烃源岩特征及有效性分析

以现代石油地质理论和生排烃理论为基础，利用研究区钻井所获样品的地球化学分析资料，较为系统地研究了巴布亚盆地侏罗系主力烃源岩的特征。研究表明，侏罗系主力烃源岩自下而上可分为迈格布组、巴里科瓦组、科伊-昂基组、依姆布鲁组及远端马利尔组，主要分布于巴布亚盆地中西部地区。烃源岩有机质丰度较高，w（TOC）主要分布于0.5%~2.0%，中、下侏罗统丰度高于上侏罗统；有机质类型以Ⅱ₂-Ⅲ型为主，整体偏生气；烃源岩生油门限为埋深2 500 m，整体处于低成熟-成熟阶段，局部达到高成熟-过成熟阶段。以烃源岩生排烃理论为指导，依据有机质丰度指标中w（TOC）和热解S₁的相关关系，确定了侏罗系有效烃源岩的有机质丰度下限为1.0%；结合侏罗系烃源岩有机质丰度和热演化程度分布特征，预测侏罗系有效烃源岩主要分布于弗莱台地中部地区和巴布亚褶皱带局部地区。 

Characteristics of main source rocks and their effectiveness in Papuan Basin

The main Jurassic source rocks of the Papuan Basin were systematically studied using the geochemical data of well samples and modern petroleum geological theory and hydrocarbon generation theory. The main Jurassic source rocks were divided into four formations, including the Magobu, Barikewa, Koi-Iange and Imburu formations from base to top, and the Maril Formation in the distal part. These source rocks were mainly distributed in the mid-west part of the basin. The Jurassic source rocks have abundant organic matter, with TOC contents mainly distributed between 0.5% and 2.0%. The TOC content of the Mid-Lower Jurassic is higher than that of the Upper Jurassic. The organic matter in the Jurassic mainly belongs to type Ⅱ₂-Ⅲ, mainly generating gas. The mature threshold in the Papuan Basin is 2 500 m. the Jurassic source rocks are in the low maturity to mature stage, with high maturity to over maturity in certain regions. This paper defined the lowest threshold of TOC content of 1.0% for effective Jurassic source rocks based on the relationship between TOC content and S₁ with the guidance of hydrocarbon generation theory. Combined with the distribution of organic matter abundance and maturity of the Jurassic source rocks, the predicted effective Jurassic source rocks are mainly distributed in the central Fly Platform and the restricted area of the Papuan Fold Belt.