Study Of High-resolution Multi-channel Seismic Data Interpretation For Neritic Area

High-resolution seismic exploration has been widely used in offshore geological survey.The traditional way of single-channel shallow exploration on resolution has not reached the accuracy, especially for some old oil fields for the second exploration. Marine construction projects, such as offshore drilling platforms, tunnel, bridge, etc., we need to make an accurate quantitative analysis for underground geological structures, including accurate calculation for layer thickness,depth,and precise description discovery for small faults, thin layers. These are the requirements of high- resolution seismic exploration. Described in this paper, multi-channel high-resolution seismic exploration is to use the multiple cover techniques to marine seismic exploration, not only has achieved high-resolution exploration requirements,but has certain economic and environmental benefits.This paper is depended on a district of the South China Sea to study the multi-channel seismic data.First, expliciting the definition of high-resolution, seismic data acquired by high-resolution exploration has more seismic reflection phase axis and obvious characteristics of waves,with very high signal to noise ratio and fidelity to meet the needs of exploration targets. This is also basis for identification of seismic data quality after the acquisition and processing of this multi-channel. Compared to traditional single-channel seismic, multi-channel seismic exploration has obvious advantages. The use of high frequency, high-energy source, multi-channel, trail from the collection methods, so the seismic data itself has a high score rate of the advantages. A variety of methods are used to remove the combination of attenuation in marine seismic data, special the most obvious multiple wave interference.Before the interpretation,seismic data quality assessment must to be done , which is the premise of high-resolution multi-channel seismic interpretation.From the resolution of the band width analysis, the collected multi-channel seismic data effective band is about 0-1000Hz, under the thinnest identifiable seismic stratigraphic thickness of 1 / 4 wavelength to calculate the ideal resolution up to 0.4m, meeting the high resolution requirements. Description of the sea geological background is a essential part of the interpretation process, which can grasp the overall features of the area's geological structure. Study area is located in the northern South China Sea continental margin, which both have marine and continent phase characteristics and therift basin dual structure. With the formation and expansion of the South China Sea, faults are well developed and magmatic act frequently during cenozoic,so the geological structure is very complicated.With the use of large workstation to build database to achieve tidal change,and the shot homing precisely. As the limited drilling data in this study, stack velocity is used to convert seismic velocity and completed layer depth map. by studying geomorphological features,structural evolution of the area, and stratigraphic features of the understanding, using workstations for multi-channel seismic data for the data interpretation, completed the T₀,T₁,T₂¹,T₂²,T₂³,T₂⁴,T₂⁵,T₃,T_g and other nine calibration and fault system layer combination chart. The depth and sediment thickness of the reflecting interface is described in detail to determine the bedrock and its distribution. Through this multi-channel seismic data interpretation, the existence of ancient river,low-speed special geological shield are identified.With single-channel seismic data to analyse components of low speed shield, and eventually revealed the existence of the landslides, avalanches, mud diapirism and other geological disasters. A high-resolution multi-channel seismic exploration of offshore interpretation process is formed finally.