Oil and Gas Exploration in Chinese Foreland Fold and Thrust Belts

Abstract

In western-central China, oil and gas exploration in the foreland fold and thrust belts experienced five exploration episodes. Before 1949, the preliminary surface investigation was the first episode of Chinese petroleum exploration. From the 1950s – 1960s, the exploration stepped forward to the initial reorganization episode and the basic advances in techniques episode. From the middle of the 1960s to the middle of the 1980s, the exploration was in recess. Since the middle of the 1980s, the exploration has progressed into a fully operational mode. Because of the complexity of mountains and ranges, seismic data were hard to obtain and seismic images were poor. Also, the complication of structural deformation inserted additional difficulties to seismic data processing and data interpretation. Furthermore, abnormally high pressure underground brought a higher drilling risk. Therefore, the high risk of exploration, the complexity of the topography and the complication of the geological conditions determined that, in the foreland fold and thrust belts, oil and gas exploration is an intricate process. Recent exploration results reveal that foreland basins contain large scale oil and gas reservoirs that have sufficient reserves and a higher production rate per single well. For example, the Kela 2 gas field in the Kuche depression contains an explored natural gas field of 48.1 km2, an explored natural gas reserve of 2,840.29×108 m3, and a reserve abundance of 59×108 m3/km2.