Seismic response analysis and distribution prediction of source rocks in a survey of the South China Sea

Abstract

Identification and prediction of high-quality source rocks is the key to obtaining new resources in the exploration area of Cenozoic basins in offshore China. We investigate the seismic response and area of hydrocarbon source rocks based on seismic data, well curves, lithologic interpretation, and geochemical analysis. The target is the source rock development zone of the W Formation in a survey of the South China Sea. The results show that the seismic response of thick layer source rocks differ from surrounding rocks in the seismic profile (strong reflections with opposite polarity at the top and bottom and messy or chaotic reflections inside). Seismic reflections of interlayer source rocks have the characteristics of low frequency and continuous strong amplitude. The dominant frequency and maximum amplitude decrease as the number of mudstone layers increases. Through seismic petrophysical analysis, we have obtained three sensitive parameters of source rock in this survey: clay content, P-wave impedance, and elastic impedance. We use different classification methods to realize the classification and prediction of hydrocarbon source rocks, among which the Kernel Fisher Discriminant Analysis (KFDA) method is the best. The prediction results are consistent with the geological background, geochemical information, and well curves.