ABSTRACT: Gas exploration and development opportunities around the Hainan Island
Zhang, Guohua and Mingqiang Zhang , China National Offshore Oil Corporation, Beijing, China
Yinggehai (YGH) and Qiongdongnan (QDN) basins are on the west and southeast of the Hainan island. Both are Tertiary basins, characterized by rapid subsidence, high geothermal gradient and overpressure encountered in the central part of basin or deeper depressions. The thick Oligocene and Miocene mudstone deposits of swamp and marine facies rich in type III kerogen are the main gas-prone source rocks, and form the QDN Oligocene and YGH Miocene petroleum systems. The laboratory data from wells in YGH and QDN basins shows that the late rapid subsidence and abnormally high geopressure produced relatively slowdown and enlarged gas generation window. The diapir activities gave active and high-speed vertical gas migration pathway. Three kinds of trapsoa basement drape anticline, dirpiric anticline and stratigraphic trap, are proved to be favorable prospects by drilling. A number of large scale traps with closure areas of up to over 50 - 300 sq km have been identified within the basins provide big potential for gas exploration.
Four gas fields and several gas-bearing traps have been found in the basins and one of them had put into production in 1996 with annual production of over 3.4 bcm. It believes that there is big demand for natural gas due to rapid development of economy and shortfall of energy resource around the southeast coast cities of China.
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia