ADVANCES OF GEOPHYSICAL-PROSPECTING FOR PETROLEUM IN MARINE CARBONATE AREAS OF THE UPPER YANGTZE REGION, SOUTHERN CHINA

In the marine carbonate area of the upper Yangtze region, southern China, including parts of Guizhou and Sichuan Provinces, complex subsurface structures and undulating surface terrain exist because of multiple tectonic events. Various geophysical prospecting methods have been conducted in local areas in an attempt to map these structures. In the Guizhou Plateau, a carbonate-exposed area, crooked seismic lines were acquired using vibrators as the main source, supplemented with dynamite. In Sichuan Province, a mountainous area, regional seismic profiles, wide-line profiling, and 3-D seismic surveys were conducted. These were accomplished with portable air drills and human transport. Data processing techniques were designed to improve data quality in the presence of noise and to image complex structures. In central Sichuan Province, high-resolution and converted-wave seismic surveys were carried out for imaging complex structures and for collecting lithologic parameters. These methods have enabled us to get effective information from complex structural, mountainous, and carbonate-exposed hilly areas in the upper Yangtze region of southern China. These collective efforts have produced a database appropriate for sedimentology, tectonic, and prospective area evaluation studies.