Petroleum Geology of New Frontiers in China
Petroleum exploration in China’s new frontiers has led to significant discoveries, implying a promising exploration potential in the coming years.
Deep water areas in the northern continental slope of South China Sea possess favorable geological conditions for the formation of major or even giant fields. Abundant hydrocarbon source rocks include dark shale and mudstone in the Tertiary with a high thermal maturity. Main reservoir rocks include marine sandstone, deep-water turbidite sand body and bank reef limestone. Structural and structural-lithological and structural-stratigraphical traps are present in these areas. Faults, sand body, and uncomformity surface provide favorable pathways for oil and gas migration.
The Qinghai-Tibet Plateau is one of the biggest new frontiers of petroleum exploration in China. It contains tens of sedimentary basins. Some basins possess good petroleum geological conditions with relative high resource potentials. The Qiangtang basin, the largest basin in the Plateau, has thick Paleozoic and Mesozoic marine strata with good source rocks and reservoirs. Cenozoic lacustrine basins, such as the Kekexili and Lunpola, have thick Paleogene mudstone and shale rocks which are characterized by good potentials of hydrocarbon generation with some oil seepage.
The South Yellow Sea basin is the only offshore basin which has not recorded any signficant discovery in China. As part of the Yangtze platform, the basin with a relatively stable tectonic setting was filled with thick sediments including Precambrian, Paleozoic, Mesozoic and Cenozoic, which are widely distributed. There are three principle source rock intervals: Lower Paleozoic, Upper Paleozoic and Mesozoic. The main reservoirs include dolomite, limestone and sandstone. Structural styles are very complex, but there are still lots of good traps in stable areas.
The East Qinglin-Dabie orogenic belt constitutes the borders between two platforms of North China and Yangtze. Peripheral areas of the orogenic belt have experienced complicated tectonic evolutions in the geological history from Sinian to Tertiary. As a result, many prototype basins with thick Paleozoic marine strata occur in these areas. The recent regional geological investigations in these areas by Chinese geologists have shown that these marine strata possess good source-reservoir-caprock assemblages and significant discoveries are likely to be made in these strata in the near future.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009