Design Of Data Recovery System For Wireless Seismic Exploration

Seismic exploration technology is one of the important methods for oil and gas exploration.Nodal seismographs(also known as cable-less storage seismographs)have got rid of the shackles of cables and can adapt to complex exploration environments.Therefore,they are widely used in oil and gas exploration operations.However,there is still the problem that the on-site data quality cannot be monitored and it is difficult to ensure the quality and efficiency of exploration.Long-term acquisition stores a large amount of seismic data in the nodes,and it takes a lot of manpower and time to recover data after the acquisition is completed.In order to solve this problem,this subject applied wireless communication technology,researched and developed a wireless seismic exploration data recovery system based on nodal seismographs,and realized on-site recovery and real-time monitoring of seismic data.The main research work of this paper includes the following aspects.(1)Aiming at the problem that the commonly used data transmission method based on FTP protocol is not real-time,the mechanism of file name real-time upload is added,and the data transmission method based on UDP protocol and FTP protocol is proposed.At the same time,using the characteristics of fixed network structure and controllable traffic,the optimized multi node transmission mechanism is adopted to transmit data.The continuous recovery test of a single node shows that when the number of files in the collection node is small,the efficiency of the two data recovery methods is almost the same.With the increase of the number of files stored in the collection node,the recovery efficiency of the original transmission method gradually decreases,while the recovery rate of the method used in this subject is basically stable.When the number of files is 100,the recovery efficiency of the two data recovery methods is nearly three times different.At the same time,the multi node transmission test shows that the optimized multi node transmission mechanism can improve the data transmission rate.(2)In order to solve the problem that the nodes near the center of the relay network are prone to congestion in large-scale exploration,this paper optimizes the congestion control algorithm of the TCP protocol stack of the acquisition node.The standard TCP congestion control algorithm adopted by the acquisition node has poor performance in the wireless network.In this project,the congestion probability prediction model based on ECN is combined with the method of bandwidth estimation to improve the traditional TCP protocol.The packet loss rate of the wireless channel changes because of the complex and changeable exploration environment,so the relationship between TCP error rate and TCP packet length is used to dynamically set the TCP packet length.In the simulation test with serious error packet loss and serious congestion,the throughput is increased by 1 times,and the throughput is increased by 30% in the actual acquisition environment.(3)In view of the demand of controllable and monitorable data recovery,the terminal software is designed based on the application development framework QT.Based on the proposed data transmission scheme,it realizes continuous real-time recovery and single shot data recovery,real-time monitoring of state information and online matching of acquisition parameters.The connection pool and multithread technology are used to realize the multi-node data transmission.The synchronous time period real-time update algorithm and file information queue index mechanism are used to realize the data synchronous processing.Based on the MVC model,the two-dimensional seismic waveform display framework is designed to realize the real-time display of the two-dimensional waveform during the acquisition and monitoring.Based on the above research work,the subject is tested on the hardware platform of nodal seismographs independently developed by the laboratory.The test results show that the wireless seismic exploration system developed by the subject realizes the real-time data transmission on site.In the field environment test of 51 acquisition nodes,the average throughput of real-time continuous recovery is 7.6Mbps,and the overall throughput of the system can be up to 58 Mbps,which is 2.5 times higher than the system without optimization.