Integrated Seismic Processing and Geological Identification of the Late Eocene Reservoir Body in Lufeng Block, Pear River Mouth Basin

Abstract

Abstract The main exploration challenges of the Lufeng Sag, Pear River Mouth Basin (PRMB) area are complex fluvial-deltaic depositional stacking and associated oil-water distributions. The reservoir bodies are buried at approximately 2700 to 3000 m under mud lines, and at these depths the quality of the seismic data is too poor to accurately characterize the reservoirs. The poor seismic quality also results from complex fluvial sedimentation that is overlain by a high-speed limestone layer, as well as deeply buried, thin intervals of interest. In this paper we propose an integrated approach to reprocess the data, increase the imaging quality, and improve the geological understanding of the area. The geology-guided seismic data processing and integrated interpretations, along with seismic inversions, are proved to be a practical solution to improve geologic understanding and help to conduct a drilling campaign for infill wells. The new processed data show improved image quality, including the signal-to-noise ratio and the resolution via noise attenuations, demultiples, and broadband extension processing. Two sedimentation sources are identified with the new data, while the legacy data were vague, and the reservoir layers were interpreted as a single-sourced fluvial-deltaic depositional system. These misleading interpretations do not help us understand the complex oil-water relationship discovered by drilling and failed to locate the sweet spots for future infill wells. However, the new processed data shed light on all the issues and have become a game changer for the area.