| Since the combustible ice is an important clean energy source for the future,its exploration and development has become a new trend in Chinese marine resources acquisition.Marine seismic exploration is an important means to obtain the geological information of combustible ice mining areas,but the international mainstream marine seismic exploration systems mostly use multi-streamer avenue spacing structure,which cannot meet the 3D high-resolution imaging requirements before commercial mining of combustible ice in the Shenhu area of the South Sea.To this end,this paper puts forward the overall proposal of the right-angle comb-shaped 3D high-resolution seismic exploration system of single leading segment-multiple working segments,and carry out a series of research work focusing on the two key technologies as long-distance high-speed data transmission and high-synchronization precision sampling of seismic signals,and develop a 4-line array 8-node 192-channel small 3D high-resolution marine seismic exploration system.The main work of the thesis is as follows:1.Comparing the advantages and disadvantages of the topological structure of commonly used seismic exploration systems,and by aiming at the needs of 3D high-resolution imaging in combustible ice mining areas,proposing the topological structure and scheme of the right-angle comb-shaped 3D high-resolution seismic exploration system of single leading segment-multiple working segments.The advantages and disadvantages of this scheme are analyzed and its key technologies are pointed out.2.Aiming at the structural characteristics of the single leading segment-multiple working segments right-angle comb seismic exploration system and the long-distance high-speed data transmission requirements,a low-speed-high-speed hybrid pipelined data transmission method was proposed,and a single-dual stepwise data level was constructed.The combined pipeline transmission model realizes the long-distance transmission of data between single-cable nodes in the working section of the exploration system through a low-speed single-stage method,and realizes the high-speed and reliable transmission of multi-cable data through a high-speed double-stage method in the bridge section.Based on the twisted pair balanced data transmission mode of pre emphasis drive and adaptive equalization,a transmission experimental system between nodes is built.Under the condition of a 300m transmission distance and a transmission 16.384Mbps rate,a transmission error rate of 7.06×10-12 between acquisition nodes has been achieved.Under the condition of100m distance and 65.536Mbps transmission,a transmission error rate of 2.47×10-12between forwarding nodes is realized.3.In response to the need for high-synchronization precision sampling of seismic signals from a large number of distributed acquisition channels,a high-synchronization precision sampling method with non-phase-locked loop local clock asynchronous drive is proposed,and a non-phase-locked loop local clock asynchronous drive high synchronization based on master-slave synchronization is established.The effects of clock stability,transmission delay and phase jitter on the synchronous sampling error are analyzed,designs a high-precision calibration method for synchronous sampling error with progressive compensation of transmission delay,and builds a synchronous sampling experimental system.The result shows that the synchronous sampling accuracy is better than 10ns.4.Developed a 4-line array 8-node 192-channel small three-dimensional high-resolution marine seismic exploration system.Using the method of synchronously generating pseudo-random sequences within each digital packet,the 8-node data transmission error rate was tested and reached 4.81×10-12 transmission error rate;192-channel synchronous sampling error was tested,and synchronous sampling accuracy better than 20ns was achieved. |
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