Research On Noise Acquisition And Processing Technology In Drilling Well Site

In the process of petroleum exploration and development,there are the large amount of drilling equipment,power pipe network and electrical equipment on the drilling site.These electrical equipment will radiate noise when they turn on/off.The electromagnetic noise radiated by these electrical equipment is easy to cause serious noise hazard to the EM-MWD system and other instrument on the drill site.Especially,these drilling well site noises are easily coupled to the receiving antenna of the Electromagnetic-Measurement While Drilling(EM-MWD)system,which will seriously lead to degradation in detection performance.Therefore,knowledge of the noise level and noise characteristics of well site are critical for the optimization of noise identification and processing technology and improving the quality of received data of the MWD telemetry system.This paper aims at the research of noise acquisition and processing technology to acquire the drilling site noise,Which includes three parts.Firstly,this paper analyzes in detail the source,composition and statistical characteristics of noise at the drilling well site for the different well site layouts,drilling conditions and rig types and the relatively scattered distribution of wellsite equipment.Then,the noise statistical models of different noise sources are summarized,which lays a theoretical foundation for the design of Noise Acquisition System of drilling well site.Secondly,this paper designs the hardware circuit of the drilling well site noise acquisition system based on Xilinx's XC6SLX16 low-power FPGA chip,which consists of low noise preamplifier and filter and 16 bit AD7606 analog-digital conversion circuit.In order to realize the logic control of the hardware,the software system was developed based on the Verilog HDL hardware description language,which includes the noise data acquisition program,the upper computer communication program and the noise data storage program.Finally,the drilling site noise data with different drill rigs and in different states were analyzed based on the FFT(to analyze the larger part of the well site noise energy),STFT(to plot the time-varying wellsite noise time spectrum)and Bootstrap(to analyzes the statistical characteristics of the overall drilling well site noise)method.Through the drilling site noise collection experiment,the results show that:(1)The system can work easily for the noise real-time acquisition,signal processing and analysis,display and storage,(2)The compound drilling noise of the well site noise data is about ten to several tens of millivolts,and it is approximately stable Gaussian distribution.The electric drilling rig noise has multiple spectral peaks in the frequency range of 1?400Hz of the power spectrum,which is approximately a Gaussian distribution with steep kurtosis.The noise of trip in has a modulation phenomenon,and there are peaks in the power spectrum at 50 Hz and its odd harmonics,which are approximately mixed Gaussian distributions.(3)The Bootstrap method is a powerful tool for analysis and evaluation drilling site noise with low cost,and can solve the problem that the practical drilling process data cannot be obtained repeatedly.Furthermore,its analysis results can accurately reflect the statistical characteristics of the original data.