HYDROCARBON EXPLORATION POTENTIAL AND DISTRIBUTION CHARACTERISTICS OF LACUSTRINE CARBONATES IN CHINA

Lacustrine carbonates is widely developed in Meso-Cenozoic continental sedimentary basins in China. That mainly distribute in the Permian, Triassic, Jurassic, Cretaceous and Tertiary in vertical profile. While transverse distribution is different characteristics on the basis of regional tectonic evolution and sedimentary basin distribution. These characteristics are controlled by the many kinds of factors such as tectonic setting, paleoclimate and sedimentary source recharge. The lacustrine carbonates can be hydrocarbon source rock and reservoir rock that has been confirmed by petroleum exploration practice in China, as well as in other countries. So, the research of lacustrine carbonates sedimentation and distribution are important to petroleum exploration.

Comprehensive researches demonstrate that carbonate reservoir of lacustrine facies in China often interlayed with source rock layers and have a better hydrocarbon source conditions. The physical property of reservoir is bad overall except the algal reef reservoir. The enrichment of oil and gas is controlled by the multiple factors including sedimentary facies, fractures development as well as tectonic settings. Since the breakthough in Qaidam Basin 1966, there are collectively 67 oil & gas fields of lacustrine facial reservoir,about 610 million tons of proved oil reservoir discovered in Bohai Bay Basin, Sichuan, and Qaidam BasinBAccording to the statistics, the oil&gas resource in Lacustrine carbonates of China is about 4.5 billion tons which still have a huge exploration potential with only 14% of proven reservoir. Petrochina has carried out the seismic acquisition and arrangement of wells, looking forward to the commercial discoveries.