APPLICATION OF THIN LAYER LITHOLOGICAL RESERVOIR PREDICTION TECHNOLOGY FOR VARIABLE-DEPTH STEAMER SEISMIC IN PEARL RIVER MOUTH BASIN

Underwater distributary channel sand bodies, a typical kind of braided river delta deposits, characterized by thin thickness and fast lateral variation, are well developed in the southern margin of Huizhou Sag, Pearl River Mouth Basin. At present, the reservoir prediction research based on conventional seismic data is difficult to accurately disclose the sand body distribution pattern, define the lithological boundaries and reservoir thickness. Taking the typical thin-layered lithological reservoir in H oilfield as an example, this paper introduces the advantages of oblique cable broadband seismic survey. Compared to conventional seismic data acquisition, variable-depth steamer broadband seismic data has higher signal-to-noise ratio, fidelity, higher resolution and wider frequency band. Based on the broadband variable-depth steamer seismic, the reservoir prediction research is carried out by using pre-stack inversion technology. The predicted results accurately defined the real position of lithological boundary, and the coincidence degree of sand body thickness prediction with actual drilling is up to 80%. Then the internal structure of the reservoir and the spatial superposition relationship of sand bodies are described, which provides effective guidance for drilling and development of thin-layered lithological reservoirs. Reservoir prediction technology based on broadband seismic data acquired by inclined cable is expected to be popularized in the evaluation of offshore thin lithological traps.