Design And Implementation Of High-Speed Bus Of Downhole Well Logging Instrument Based On RS485

As a kind of valuable and non-renewable resource, oil plays an irreplaceable role in human society. With the continuous improvement of industrial level around the world, the demand for oil is increasing dramatically. The limited oil resource is becoming increasingly valuable. So how to grasp the distribution of oil resources more accurately and to drill for oil more efficiently is becoming more and more important.In the field of oil well logging, well logging technology continues to advance and the data transfer rate of multi-core cable logging system is able to reach more than 1Mbps. With the rapid development of imaging logging and combination logging, data volume of well logging instruments has been greatly increased. The down-hole well logging instrument bus is faced with great challenge. Especially in the high temperature logging environment, the well logging instrument bus can’t meet the demand of well logging instruments’data transmission. Therefore, the research of down-hole well logging instrument bus is of great significance. This thesis designs and implements a new kind of down-hole well logging instrument bus to solve the bottleneck problem of down-hole well logging data transmission under high temperature.The main research contents are as follows:1. According to the characteristics of the well logging network under high temperature, this thesis puts forward an overall solution of the high-speed down-hole well logging instrument bus system. Referenced with the OSI model, the protocol of high-speed bus is divided into three layers:the physical layer, the data link layer and the application layer. At the same time, the definition and function of each layer are given respectively with the key of the physical layer and data link layer.2. Based on the characteristics of data services about well logging, the high-speed bus system is designed to have two channels. One is the low-speed channel which is mainly responsible for the transmission of well logging command and data which the well logging instrument with small data collects. The other is the high-speed channel which is mainly responsible for the transmission of data which the well logging instrument with large data collects.3. This thesis designs and implements the high-speed bus controller for the high temperature logging environment. Low-speed channel controller is implemented by DSP chip of TMS320 F28335 and high-speed channel controller is implemented by FPGA chips of A3P060 and A3P250. This thesis highlights the design and implementation of high-speed channel controller, including physical coding, data link layer process, arbitration mechanism and the design of microprocessor interface, etc.4. This thesis tests the performance of high-speed bus system by the test platform which is constructed by the simulated well logging instruments and remote transmission instrument.A large number of experimental tests show that the design of down-hole instrument high-speed bus system with dual channels solves the bottleneck problem of down-hole well logging data transmission under high temperature. The research methods and results of this thesis have a certain reference value on the optimization design of logging network system.