Design Of Downhole Main Control Module Of Controlled Source Element Logging Tool

As an important component of energy,oil is essential to the vigorous development of industry.With the increasing of total oil demand and exploitation intensity,the proportion of complex oil and gas reservoirs in total oil and gas reserves is also increasing.As an important branch of nuclear logging,nuclear logging is becoming more and more active in solving the exploration problems of complex oil and gas reservoirs.the formation element log uses the principle of neutron-formation material reaction to obtain the main elements and their mass percentage quantitatively,which can describe the formation material more accurately on the nuclear scale by non-contact measurement,therefore,it plays a key role in logging operations in complex and severe formation environments.This thesis mainly discusses the hardware circuit design and software program design of the main control module of downhole tool system of controllable source element logging tool.Firstly,the research background and significance of the thesis are introduced,and the development status of element logging at home and abroad in recent years is also introduced.Then from the design requirements of the instrument main control module,the overall structure design and workflow planning of the main control module are put forward.Then according to the overall design plan,the design of the main control module is divided into two parts: hardware design and software design.The hardware part focuses on the design and implementation of signal conditioning and acquisition circuit,controller circuit based on DSP and FPGA,communication circuit and auxiliary circuit.The software part focuses on the design of communication program based on EDIB Bus and 485 bus,the design of transmission and acquisition control sequence,the design of energy spectrum and time spectrum forming program and the design of instrument spectrum stabilization program.Finally,the realization of software and hardware functions of the main control module is verified in this thesis from two aspects of single board debugging in laboratory and joint debugging and testing of downhole instrument system.The testing methods in the process of debugging are introduced and the test results are given.The final test results show that the spectrum data deviation obtained by the downhole main control module of the controllable source element logging tool is less than two channels,and the counting error is less than 2%,which meets the design requirements.