Characterization of interlayer distributions in Oilfield X, Pearl River Mouth Basin: a log-seismic integration approach

Oilfield X in the Pearl River Mouth Basin contains significant remaining recoverable reserves. The ZJ2-1 sublayer is the main oil-bearing interval and the primary target for further development. However, current production performance indicates that the types and spatial distribution of interlayers have resulted in a highly heterogeneous distribution of remaining oil within the ZJ2-1 sublayer, which severely constrains precise reservoir development during the mid-to-late stages, such as well placement optimization and stimulation efficiency. In this study, multiple data sources and technical results, including well logs, core data, seismic data, production performance, and laboratory analyses, are integrated. Based on previous research, a well-to-seismic integration approach is applied to systematically investigate the characteristics and distribution of interlayers in the ZJ2-1 sublayer of Oilfield X. The results indicate that three main types of interlayers are developed in the target interval: argillaceous interlayers, calcareous interlayers, and physical-property interlayers. Considering the geological conditions of the study area, different interlayer types are characterized using prestack and poststack geostatistical inversion methods. The spatial distributions of various interlayer types are clearly delineated and show good consistency with production performance data, such as well test results and production decline trends. These results provide a reliable geological basis for improving the recovery of remaining oil and reducing the risks associated with infill drilling and adjustment wells during the late development stage.