Discovery of Asphalt in the Upper Permian Reef Limestone in Liuqiao, Guangxi

The studied region, located between Dongmen and Liuqiao at Fusui in Guangxi, mainly consists of Upper Permian and Lower Triassic strata. The Upper Permian is divided into three units; they include the Heshan Formation, Upper Permian reef limestones, and Dalong Formation. The Lower Triassic mudstone and limestone are known as the Luolou Formation. The Dalong Formation consists predominantly of radiolarian cherts and mudstones, and contains abundant late Changhsingian fossils, including radiolarians, foraminifera, ostracods, fungus spores, brachiopods, ammonoids and bivalves. These sedimentary and lithological features of the Dalong Formation are indicative of good source rocks. The reef limestones are characterized by plentiful fractures and pore spaces, showing a nature of good reservoirs. The fractures and pores are generally filled by asphalt in Dongpan, Balong and Baliao sections at Liuqiao in southwestern Guangxi. On these points, the Upper Permian reef limestones in Liuqiao area would be of significance for the future exploration of oil and natural gas.