Identifying the Sedimentary Facies Through Analysis of Seismic Facies in Non-Marine Sedimentary Basin: A Case Study From the Offshore Bohai Bay Basin, East China

Identifying favorable sedimentary facies for hydrocarbon accumulation by seismic data is a significant work in the hydrocarbon exploration, especially in the non-marine basin where the sedimentary facies easily shift temporally and spatially. Here, we took the Offshore Bohai Bay Basin (a Cenozoic non-marine rifting basin in east China) as a study case, and investigated the sedimentary facies of several important exploration zones in it through analysis of seismic facies. In this study, characteristics of seismic waveform can be identified and classified by self organizing neural networks analysis technology and PCA; meanwhile, the corresponding geologic features reflected by the seismic waveform were determined based on trace-shape classification within interval of interest. And then, the seismic facies map is obtained. Combining drilling and geologic data, sedimentary facies is obtained through analyzing the seismic facies map. Consequently, based on this result, the favorable reservoirs were identified. In order to increase the precision of the result, the comparison between seismic facies and the analysis on other single attribute (such as amplitude attribute, phase property, frequency attribute) or multi-attributes are considered. This methodology has been widely used in the hydrocarbon exploration of the Offshore Bohai Bay Basin, the sedimentary facies in several exploration projects were studied before drilling, and all the results were confirmed by the following exploration. Besides, the exploration implies that this methodology identifying the sedimentary facies through analysis of seismic facies, and can be referred in the exploration of the similar non-marine rifting basin.