Research On Analog Circuit System For Excitation And Reception Of Seismic Signals While Drilling

The rapid development of various industries is full of demand for resources,and clean energy cannot be widely popularized due to cost and other reasons,making oil and gas and other fossil resources still the mainstay of energy use.The exploration of oil fields has also become a hot spot in the exploitation of resources in today's era.Compared with traditional oilfield exploration methods,seismic-while-drilling electrical logging has many advantages.The new oilfield detection technology is based on the theory of seismoelectric effect,which is the coupling and conversion of energy in mechanical and electromagnetic waves in underground media.Therefore,the main difficulty in considering the implementation of this method is the generation of mechanical waves and the reception of electromagnetic waves.The analysis of formation parameters requires the measurement of the propagation speed of mechanical waves in the formation.The research content designed in this paper is divided into two parts for discussion,which are the generation of mechanical waves and the reception of electromagnetic waves.Here,they are divided into an excitation system and a reception system.The excitation system is used to generate sound waves of a certain energy and is used to act on saturated fluids.To obtain electromagnetic waves through the coupling of porous media,the excitation waveform and power need to be considered.The device used to generate sound waves is an ultrasonic transducer.Its center frequency limits the characteristics of the excitation waveform to high-voltage or narrow-band signals with concentrated frequencies,so different excitation waveforms are considered separately.The coupling effect of the seismoelectric effect is low.Therefore,in the excitation system,a Gaussian signal modulated by a sine wave is proposed to drive,and a D-type power amplifier is used to drive the power amplifier.In terms of the receiving system,eight-channel acquisition circuits are installed at equal intervals into the framework used for waterproofing.In this way,the transmission rate of sound waves can be calculated by calculating the time interval of seismological signals collected from each channel,and then the formation parameters can be calculated.We need to consider weak signal acquisition,signal transmission and experimental conditions in the design.The seismic signal is weak,and the measurement effect is seriously affected by noise.Therefore,the gain and noise requirements of the acquisition circuit board are extremely high.In normal operation,the circuit board needs to be integrated into the skeleton,so limited size issues need to be considered in the design of the circuit.In addition,chip selection,noise optimization and PCB layout have been investigated,and the acquisition board function is for seismic signal amplification,Filtered and quantized into digital signals for transmission,the receiving system receives the synchronization signal of the excitation system,the digital part collects the processed seismic signals and transmits them to the one-way adapter board through SPI protocol,and then transmits to the upper computer using RS485 interface.Finally,the system was tested and operated in the built experimental environment.Both the excitation system and the receiving system can be operated stably,and the seismoelectric signals were measured.Through the subsequent data processing process,the sound wave velocity can be calculated to achieve the project's expected effect.