Structure Optimization Design And Working Characteristics Research Of Underground Electromagnetic Transducer

Compared with conventional oil and gas reservoirs,shale reservoirs are characterized by high degree of non-uniformity,low porosity and extremely low permeability,making shale gas exploration and development extremely difficult and extremely risky.General oil and gas development technology is clearly unable to adapt to its effective development.Under the background of the decrease of conventional oil and gas resources production and reserves,the effective reservoir reformation of shale gas reservoirs and the economic exploitation of shale gas are urgent problems to be solved.According to the source of this paper:"The National Science and Technology Major Project-Evaluation and Application Test of the High-Evolution of Marine Phase in the Cen Gong District",and reference to the low frequency oscillation stimulation mechanism of oil wells,at the same time,based on the research of the basic theory of electromagnetics,a design scheme of a frequency sweepable downhole electromagnetic transducer is proposed.The purpose is to improve the shale reservoir and promote the production of shale gas.In order to achieve this program,this paper has done the following research:Firstly,based on the basic theory of electromagnetic fields,the control equation for three-dimensional electromagnetic eddy current field based onT-T₀-?method is obtained.The discrete equations of the magnetic field are established according to the Galerkin finite element method,then the field-circuit coupling mathematical model of the electromagnetic field is obtained by simultaneous the circuit equation and the magnetic field equation.Secondly,the research and analysis of the electromagnetic relationship between the two powered solenoid,optimize the parameters of the physical model of the electromagnetic transducer,determined the optimal value points,and the geometric parameters of the electromagnetic transducer are determined.Under the premise of ensuring the accuracy of calculation,the electromagnetic transducer model is assumed and simplified,and the finite element physical model for solving electromagnetic field,solid mechanics field and temperature field is established in COMSOL Multiphysics software.Thirdly,the simulation results of the working characteristics of the electromagnetic transducer are analyzed,including the geometric solution model of the electromagnetic transducer,the selection of materials,the analysis of the electromagnetic characteristics,the analysis of the motion characteristics of the piston vibrator,the calculation of the loss and the calculation of the temperature.It is the basis for the production of electromagnetic transducers and subsequent experiments.Finally,the prototype of electromagnetic transducer was designed and manufactured to realize the hardware-in-the-loop experiment of the transducer.The operating frequency of the electromagnetic transducer can be continuously adjusted from 0Hz to 40Hz during the experiment.The experiment proves the scientific design of the electromagnetic transducer model,and the results show that the electromagnetic transducer can work stably and reliably.The electromagnetic transducer structure proposed in this paper provides a new way for the improvement of shale reservoir and the stimulation of shale gas production.