Geophysical prospecting for petroleum in marine carbonate areas of the lower Yangtze region of southern China

摘要

The lower Yangtze region extends over the Jiangsu Province in eastern China. Most of the region is a huge alluvial plain formed by the delta of the mighty Yangtze River. Beneath the alluvial plain, thick marine carbonates of late Sinian to Middle Triassic age make up a substantial portion of the subsurface sediments of southern China. After deposition of the thick carbonates, this region was subjected to a stage of deformation and extensive erosion. During the Mesozoic and Cenozoic time intervals, clastic deposits formed a continental basin. In the past, most of the petroleum exploration in the region targeted the structures in the continental basins, and some minor oil fields were found. Marine carbonate formations in this region are expected to be more promising for petroleum exploration. Seismic surveys aimed at identifying carbonate structures in this region show that the subsurface structures caused by intense deformation are complex. Structural complexity and extensive erosion have made it difficult to obtain reliable seismic data to resolve the geology of the area. Some new techniques, including wide-line profiling and 3-D seismic acquisition, along with integrated regional profiles, have overcome some of the difficulties in recent years and significant advances have been made.