Study And Application On Processing Technology For Quasi-3D Seismic Data Of Gas Hydrate

Quasi-3D seismic technology was applied to the exploration of gas hydrate in the northern South China Sea, with which we can obtain 3D seismic data and detect the location and spatial distribution of gas hydrate. However, influenced by some factors, such as irregular geometry, dramatic changes of cross-line folds and spatial aliasing problems, it had not achieved desired results, which restricted the development of gas hydrate to a great extent. So it is essential to study processing technology of quasi-3D seismic data.Based on analyzing the current research situation of processing technology of quasi-3D seismic data at home and abroad, this paper study about pre-stack denoise、inverse convolution、quasi-3D migration imaging of gas hydrate,and this paper proposed Macro-Velocity,and then applied the Bi-angle migration software processing system to quasi-3D migration of gas hydrate according to quasi-3D seismic data of the northern South China Sea,effectively suppress noise,improved resolution,imaging clear,gas hydrate seismic reflection characteristics. Therefore find a processing technology for Quasi -3D seismic data of gas hydrate, and it have provided an important technical support for the drilling of gas hydrate in the northern South China Sea.This paper based on project "863", " key technology for gas hydrate first drilling target in the northern South China Sea ", a rapid response task (item No. 2005 AA611050) and "Gas hydrate Orebody high frequency of three-dimensional seismic and seabed United detection technology".Five steps is adopted mainly in the process of quasi-3D processing technology: Firstly, quasi-3D geometry was defined and bin size was determined by theoretical calculations and stack and migration tests; Secondly, pre-stack denoise to quasi-3D seismic data ;Thirdly, inverse convolution ; Fourthly, analyzing velocity ; Fifthly, the quasi-3D seismic pre-stack time migration was completed by the actualizing of the following key technologies, such as Macro-Velocity model and Bi-angle migration software processing system. Compared with Kirchhoff pre-stack time migration the Bi-angle pre-stack time migration sections have improved significantl.At the last part of the works, a seismic direct detection model of gas hydrate in study area is established according to interpretation and research on 3D seismic data, which proved the practical value of this study.