Research On Resistivity Spectrum Logging Experimental System

Complex resistivity spectrum logging(CRS logging)is the innovation and development of the traditional electrical logging method.Based on the current focusing measurement mode of the lateral logging and synthesize kinds of logging method with different frequencies,it is a kind of resistivity spectrum logging method for complex resistivity dispersion measurements.It measures the vector response of formation with a variety of operating frequencies.Electrical parameters,including complex resistivity dispersion information,resistivity and dielectric information can be obtained based on complex resistivity dispersion model.It's more easy for complex resistivity spectrum logging to identify complex reservoirs such as low resistivity reservoirs and water-flooded reservoirs than traditional electrical logs.At present,the complex resistivity spectrum logging prototype had been verified successfully during the "12nd Five-Year Plan" period,and the first-hand complex resistivity spectrum data had been taken to verify the feasibility of the complex resistivity spectrum logging method.In order to study the application of complex resistivity spectrum data and the development and popularization of industrial prototype,it is necessary to study and set up an experimental system of complex resistivity spectrum logging in the laboratory.In this paper,the numerical simulation of the response of the experimental system of the complex resistivity spectrum logging,the development of the hardware and software platform,and the system integration test is systematically studied.The main work is as follows: A 3D finite element model of complex resistivity spectrum logging was established.The electrode array of complex resistivity spectrum logging experimental system was designed.The depth of radial investigation,vertical resolution and the multi-frequency response of the tool in the three-layer media was simulated.The geometric size of the formation model of the experimental system is optimized based on the results of numerical simulation.Amplitude modulation function of the excitation signal with arbitrary frequency is realized based on the analog multiplier.Combined with the mixer receiver technology,the sweep measurement in 1-500 kHz is realized,and hence the reliability of the inversion of the complex resistivity spectrum model is improved from the hardware.At the same time,a new anti-jamming method is proposed.The method is based on SA(Simulated Annealing)fitting,which can better suppress the leakage of spectrum and the influence of random noise on the detection result compared with the common DPSD(Digital Phase-sensitive Detector)method.It provides a test debugging platform for the upgrades of experimental system hardware and software platform and industrial prototype development in the future.In the laboratory,the experimental system of complex resistivity spectrum logging is integrated and the adjustment of focusing balance of multi-frequency of the tool is carried out by using the scale circuit.The response of the tool with the scale circuit load is tested.Finally,we tested the response of the tool connected with the experimental electrode array in the experimental foramtion model.The test results show that the real and imaginary parts of the complex resistivity spectrum logging curve can indicate the characteristics of complex resistivity dispersion distinctly,and the real parts curve has a fine vertical resolution of 0.2 m,consistenting with the numerical simulation results.The SNR of the measurement results of the imaginary parts are improved with the increase of the measurement frequency largely,and it can reflect the complex resistivity dispersion of imaginary parts of the measured medium.After systematic research and test,it shows that the experimental system of complex resistivity spectrum logging is feasible and reliable.