High-quality hydrocarbon source rock in the Paleogene sequence of the Ping Chau Formation, Hong Kong  

作　　者：YAOSuping HUWenxuan CHENLongsheng ZHUDongya XUEChunyan 

机构地区：[1]DepartmentofEarthSciences,NanjingUniversity,Nanjing210093,China [2]DepartmentofEarthSciences,HongKongUniversity,HongKong,China

出　　处：《Chinese Science Bulletin》2005年第2期145-154,共10页

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.40073017).

摘　　要：Although petroleum exploration is being con- ducted in the Hong Kong region, high-quality hydrocarbon source rocks have never been found in this area. The Ping Chau Formation is only Mesozoic-Cenozoic sedimentary rock exposed in Hong Kong and its surrounding areas. The hydrocarbon source rock of the Ping Chau Formation is very rich in organic matters, which has an average total organic carbon (TOC) of 1.9% and chloroform bitumen “A” range from 0.14% to 0.24%. The total hydrocarbon content varies from 880 to 1800 ppm and the transformation ratio is spe- cific from 5 to 9. The index of pyrolytic hydrogen is up to about 600 mgHC/gTOC. These data demonstrate the char- acteristics of the high-quality hydrocarbon source rock. The lamalginite is the major maceral of the source rock of the Ping Chau Formation, and geochemical characteristics also suggest that the organic materials of the source rock are of type I and type II1, with abundant gammacerane, γ, β-caro- tane and C24 tetracyclic terpane, which indicate that it was formed in the salt water and brackish water sedimentary environment, and the source rock has evolved into a mature phase. The organic inclusions are found within calcite veins in cracks of the source rock, indicating that hydrocarbon has been generated and a secondary migration has happened. The source rock in the Ping Chau Formation is about 200—300 m thick, thus having considerable hydrocarbon potential. The discovery of the high quality hydrocarbon source rock in the Ping Chau Formation will certainly pro- vide insight on hydrocarbon resource exploration in the South China Sea area.Although petroleum exploration is being conducted in the Hong Kong region, high-quality hydrocarbon source rocks have never been found in this area. The Ping Chau Formation is only Mesozoic-Cenozoic sedimentary rock exposed in Hong Kong and its surrounding areas. The hydrocarbon source rock of the Ping Chan Formation is very rich in organic matters, which has an average total organic carbon (TOC) of 1.9% and chloroform bitumen 'A' range from 0.14% to 0.24%. The total hydrocarbon content varies from 880 to 1800 ppm and the transformation ratio is specific from 5 to 9. The index of pyrolytic hydrogen is up to about 600 mgHC/gTOC. These data demonstrate the characteristics of the high-quality hydrocarbon source rock. The lamalginite is the major maceral of the source rock of the Ping Chau Formation, and geochemical characteristics also suggest that the organic materials of the source rock are of type I and type II1, with abundant gammacerane, gamma, beta-carotane and C-24 tetracyclic terpane, which indicate that it was formed in the salt water and brackish water sedimentary environment, and the source rock has evolved into a mature phase. The organic inclusions are found within calcite veins in cracks of the source rock, indicating that hydrocarbon has been generated and a secondary migration has happened. The source rock in the Ping Chan Formation is about 200-300 m thick, thus having considerable hydrocarbon potential. The discovery of the high quality hydrocarbon source rock in the Ping Chan Formation will certainly provide insight on hydrocarbon resource exploration in the South China Sea area.

关 键 词：高质量烃源岩 早第三纪 香港 沉积岩 Ping-Chau岛 地质背景 

分 类 号：P588.2[天文地球—岩石学] P534.611[天文地球—地质学]