Design Of Test System For The LWD Neutron And Density Logging Tool

Nuclear technique is applied to well logging,which can acquire nuclear-physics characteristics of formation rock and pore fluid,and analyze geological section of well.The LWD(Logging While Drilling)neutron and density logging tool is an important tool in the field of nuclear logging.It can obtain formation parameters,such as porosity,density and PE value,and play a significant role in oil reserves estimation and formation imaging.It is characterized by a complex control mode,various working modes and large amount of spectrum data.And under the circumstance of high temperature,high pressure and high vibration,the tool can still acquire and store data.In order to realize PC debug and update firmware for the LWD logging tool with instrument development process,developing a matching test system for the tool to support its development and test is necessary.This dissertation designs a test system of the LWD neutron and density logging tool by analyzing the functions of the tool.It is such a system that takes ARM and FPGA as the core,embedded software as the platform,matching host controlling software as the supplementary.The system not only can meet the debugging demands in the process of the development of the LWD neutron and density logging tool,but also can be used in well logging.The dissertation analyzes the design method of the test system and constructs the system structure based on the design objectives and performance requirements of the system.The test device is the core of the communication protocol conversion.The dissertation elaborates the test device's hardware design,software design and FPGA logic design and realizes network communication based on Lw IP,USB communication based on CDC protocol,and bus communication of 1553 and RS485.The test software is an important platform for controlling the drilling instrument.The dissertation using LabWindows/CVI as the development environment of the test software,takes advantage of the TCP function library and the RS-232 function library to design and implement the network communication and serial communication.And it focuses on the introduction of functions of the testing software,such as waveform display,data storage and online update.Lastly,the dissertation gives the experimental results of the single board test and the system debugging of the test system.The laboratory test shows that the system can complete the test with the drilling instrument,and the test results meet the design requirements of the project.