Resolution analysis of shallow marine seismic data acquired using an airgun and an 8-channel streamer cable

摘要

We conducted a high-resolution seismic survey off Yeosu, Korea, using a 30 in3 small airgun as a seismic source and an 8-channel streamer cable with a 5 m group interval as a receiver, to find out the proper acquisition and processing parameters at the study area where shallow sedimentary layers were well deposited. The data were digitally recordedwith a shot interval of 2 s and a sample interval of 0.1 ms using an in-house PC-based acquisition and processing system. The quality of the subsurface image depends on the acquisition parameters such as the sample interval, common midpoint (CMP) interval and CMPfold. To understand the effects of these parameters, we resampled the field data with various sample intervals, CMP intervals and CMP folds and processed the data. The analysis results showthat thin layers of 70–80 cm thickness at a depth of 30–45mfromthe sea bottom can be imaged with good resolution and continuity using acquisition parameters with a sample interval of less than 0.2 ms, a CMPinterval of shorter than 2.5mand a CMPfold of greater than 4. The data quality of the shallow marine seismic survey is greatly enhanced through multichannel data processing flows such as spiking deconvolution, frequency filtering and careful static correction. Our results demonstrate that very highresolution seismic reflection images can be made from8-channel data recoded with high sample rates and processed with appropriate parameters.