Design And Implementation Of Anti-jamming Communication System For Sidewall Coring Tool

The development of the modern industrial society demands more and more oil.As an indispensable resource on the earth,oil extraction efficiency has attracted more and more attention.In the process of petroleum exploration,core sampling is used as a means to obtain the physical characteristics of underground rock formations and to infer the status of oil and gas.The key technology is core wall core technology.The core wall coring transmission system uses a specific communication method to interact the surface command data and the downhole core sampling data according to a certain signal format.Only when the downhole oil and gas situation is accurately understood by the relevant experts can the oil field be exploited in the most reasonable way,so the downhole oil field can be fully utilized to improve the efficiency of crude oil development.The anti-jamming communication system for shaft wall coring in this thesis is a numerical control shaft coring transmission system with strong anti-interference developed for strong interference downhole.The system is based on multi-carrier wideband modulation OFDM technology,which realizes cable data transmission with strong anti-interference.This thesis conducted the following research:1.Analysis of the anti-jamming communication system of the core wall.Due to the special environment when the system works,this thesis analyzes the severity of the system environment to provide a basis for system design.These include working environment temperature limitations,communication bandwidth limitations,downhole remote transmission module circuit board size limitations,and data transmission noise and interference.In order to analyze the system noise,this thesis designs the acquisition system to realize the acquisition of noise interference.The analysis shows that the main components of the system interference are: out-of-band periodic interference,in-band periodic interference,and Gaussian white noise.2.Design of anti-jamming communication system for shaft wall coring.Due to the size of the underground framework and temperature limitations,in order to meet the project requirements,the high temperature DSP chip TMS320F28335 was selected as the underground hardware implementation platform,and the DSP chip TMS320C6415 was selected as the ground hardware implementation platform.According to the analysis results of the system,the communication protocol of the anti-jamming communication system for the shaft wall coring is designed.The adaptive denoising algorithm and bit allocation algorithm are studied and simulated.For narrow-band interference,multicarrier modulation OFDM technology is used to adapt to interference in different frequency bands.An adaptive noise cancellation algorithm is used in the time domain to suppress periodic noise interference.3.System software design and testing.Realizing the system design in software mainly includes the software design of underground and surface software,the hardware driver layer software design and the software implementation of each module in OFDM modem.And on the software,module test of OFDM synchronization,channel estimation and RS coding and decoding is carried out.