Seismic-electric Effect-based Hydraulic Fracturing Data Acquisition System

Faced with the increasing gap between domestic crude oil supply and demand,hydraulic fracturing has become a key method to improve oil and gas recovery.Monitoring the development of underground fractures after fracturing is an important basis for judging the effect of hydraulic fracturing.In order to obtain more accurate fracture information and solve the problem that micro-seismic monitoring technology has relatively large errors in fracture monitoring,the mechanism of generating seismoelectric effect caused by seismic source excitation in fluid-bearing pore formations underground is proposed.This paper proposes a joint monitoring method of microseismic and seismoelectricity,And designed and completed the joint data acquisition system.The focus of this study is the single-station dual-channel joint data acquisition instrument,which is suitable for large-scale and multi-channel seismic and crack detection.It also has the advantages of low noise,low distortion,and high rate.It performs micro-seismic signals and seismoelectric signals.Processing can effectively determine fracture distribution information and the distribution range of downhole fluid.The main research contents are as follows:1.Theoretical research on the core theory of seismoelectric effect in joint monitoring technology.Seismoelectric effect is a phenomenon in which seismic waves excite seismic signals when they propagate in fluid-containing porous media.By monitoring the seismic signals,information on rock formations and fluid parameters can be obtained.The numerical simulation of the Pride seismic-electric coupling equations is carried out,and further analysis and derivation of the parameters of the seismic field excited by the Pride theory in the case of unsaturated medium.2.Based on the principle of micro-seismic ground monitoring and seismoelectric monitoring,the joint data monitoring program of microseismic and seismoelectricity is proposed and its principle is explained;according to themonitoring program,the design plan of the joint data acquisition system is determined;Give the overall structural block diagram of the system,set the technical indicators of the data acquisition instrument.3.Based on the overall design of the system,the micro-seismic signal processing channel,seismoelectric signal processing channel,network communication circuit and power management circuit are designed and completed.The micro-seismic signal processing channel includes a pre-processing circuit,a fully differential amplifier,and an analog-to-digital conversion module;the seismic signal processing channel mainly includes a pre-amplifier circuit,a band-pass filter circuit,a buffer isolation circuit,and an analog-to-digital conversion module.4.Completed the design of the analog-to-digital conversion module and the network communication module driver,and expounded its workflow.The display interface of the upper computer virtual oscilloscope is designed.5.Completed system performance analysis and testing.The power supply voltage of each module,the gain of the preamplifier and the passband of the filter circuit are tested.The acquisition function,noise level and power consumption of the Lianhe data acquisition instrument were simulated in the laboratory,and the data download and recovery function of the instrument was tested.Finally,the prototype of the acquisition system was tested in the field,and valid experimental data was collected.