| With the rapid development of the social economy and the increasingly fierce contradiction between energy depletion,the requirements for new energy and new energy extraction technology are becoming higher and higher.As a unconventional energy reservoir transformation technology,hydraulic fracturing is increasingly favored by people.During the hydraulic fracturing process,the pores and fracture network in the underground space will change accordingly,which is often accompanied by the occurrence of microseismic events.In order to locate the direction of pores and fractures,it is necessary to monitor these microseismic events.At present,microseismic monitoring instruments mainly include borehole instruments and ground monitoring seismometers.Ground monitoring seismometers are divided into cable seismometers and node seismometers.In recent years,node seismometers have gradually replaced high cost and difficult to deploy cable seismometers.The node seismometer transmits the collected microseismic data back to the control center through wireless communication,achieving real-time monitoring and processing of microseismic data.In order to solve the problem of excessive dependence on relay status in the master-slave relay network topology,this paper proposes a wireless sensor network topology rotation technology scheme for node seismometers.Based on the existing communication scheme,the hardware communication module of the node seismometer is optimized,and an extension program for multi hop routing discovery protocol and upper computer monitoring software is designed,which can change the topology structure in the event of relay failure,implementing data retrieval through multi hop data transmission.Design a routing discovery protocol and upper computer control program.A routing discovery protocol based on an improved tree is proposed to address the issue of constructing wireless data transmission paths in small wireless sensor networks composed of relay failures and intermediate subnets after topology rotation.The protocol is mainly divided into four stages: clustering,cluster head election,cluster head link formation,and routing maintenance.In the clustering stage,the observation area is divided into 14 fixed clusters;In the cluster head election stage,a fitness function is established for each node in the cluster.After weighted calculation,the node with the highest value of the function is selected as the cluster head.The communication between the node and the cluster head is in the 2.4GHz frequency band;The formation stage of cluster head links is to use a fuzzy comprehensive evaluation method to evaluate each node and calculate the evaluation value of each link.The highest evaluation value and several links covering all cluster head nodes are selected to form a complete communication link,and communication between cluster heads is achieved using the 5.8GHz frequency band;Set an energy threshold for routing maintenance.When the energy of cluster head nodes is too low,the routing discovery process is restarted,and nodes with energy below the threshold do not participate in cluster head competition.Comparing this protocol with other routing protocols in terms of throughput and lifecycle through MATLAB simulation,the simulation results show that the performance of this protocol far exceeds that of other routing protocols.Design an extension program for the upper computer monitoring program combined with a routing discovery protocol,and use the C++-Python interface to call Python programs in C++programs to achieve batch configuration of node seismometers by the upper computer;Call the Python MATLAB interface in Python to call the improved tree routing discovery protocol,and MATLAB outputs the node IP and other information that needs to be modified to the Python program.Implement relay interruption and data recovery function after topology rotation to improve the robustness of the monitoring network.Design a multi frequency hierarchical data communication module.Aiming at the requirement that the routing discovery protocol requires the node seismograph to have two communication frequency bands of 2.4GHz and 5GHz,a 5GHz communication sub board based on the QCA9882 communication chip is designed on the basis of the2.4GHz communication main board currently carried by the node seismograph,which is connected to the communication main board through the PCIe interface;Design a power amplifier circuit based on SE5023 L and a transceiver selection circuit based on SKY85601 to ultimately achieve data transmission in the 5GHz frequency band.After testing,the designed 5GHz communication sub board has a RF output power of 27 d Bm,a reception sensitivity of less than-90 d Bm,a maximum reception level of more than-20 d Bm,an error vector amplitude of less than-28 d B,and a power consumption of less than 6W,all meeting the set index requirements.Conduct field testing of the designed topology rotation scheme.Design a test plan for data transmission networking,evenly distributing 100 nodes in an area of 0.04 km2 with a channel spacing of 20 m.During the test,the measured results of the improved tree routing discovery protocol and the node seismograph built-in multi-hop protocol were compared.The results showed that the improved tree routing discovery protocol improved data reception by about 12%,reduced latency by about 13%,and had better performance;Then compare the number of nodes after network normal operation and AP outage,data reception per unit time,and transmission delay.The results show that after topology rotation,the number of nodes decreases by less than 5%,and throughput decreases by less than 5%.The average network delay is comparable to that before topology rotation,maintaining a stable level,and meeting preset performance indicators.To sum up,this design can meet the temporary data transmission scheme after relay failure during field seismic monitoring,making the data communication network more flexible and robust. |
PDF Full Text Request