Research On Fine Interpretation Technology Of Comprehensive Geophysical Prospecting In Burnt Rock Area

In the present stage of our country especially in the western area most of the coal burnt rock zone without treatment,it is very difficult to determine the scope of burnt,plus a long time rich water,causing serious economic losses to the construction of wells mining,and burnt rock zone water directly threatens the safety production of coal mine is a major safety hazard,and find out that the spatial distribution of disaster sources plays an important role in coal mine safety production.Based on the theory of transient electromagnetic method and high-precision magnetic measurement technology,the boundary and water abundance of burned area are studied in this paper.From the geophysical model,the characteristics of the magnetic field response characteristic and the transient electromagnetic response characteristic of the coal fire area are analyzed by the calculation and measurement of the geophysical data.Based on the formation and logging data,the geoelectric model of the fire area is established,the boundary anomaly characteristics of the fire area under different geological background are calculated,the determination method and the influencing factors of the boundary of the fire area are analyzed,and the technical support for the boundary detection and quantitative interpretation of the coal fire area in the future is provided.Through comparative analysis and summary of numerical simulation and measured data processing,the following achievements have been achieved.1)According to the geological characteristics of the Zhang Jia Mao coalfield,the model of sphere,step and plate magnetic method is established,and the corresponding law of abnormal curve and abnormal body is obtained.2)According to the geological characteristics of Zhang Jia Mao coalfield,we set up the transient electromagnetic method model of the normal stratum and the burned stratum,and draw the corresponding law between the abnormal curve,the section and the boundary of the abnormal body.The simulation results show that using the magnetic method and the transient electromagnetic method can detect the boundary position of the fire area.3)Analyzes the advantages and disadvantages of different data processing methods,established similar to Zhang Jia Mao interpretation method and index analysis of coal:(1)Using the polar method to make the magnetic anomaly produced by the burned stratum can make the abnormal shape simpler and more convenient to interpret,and at the same time,it can grasp the location of the burned area more clearly.(2)The inversion results of transient electromagnetic method can reflect the position of the fire area for the fire area without water.With the increase of the degree of fire,the boundary of the geological body is more obvious.But it is easy to be affected by the water filling or the thicker low resistance surrounding rock,which leads to the blurring of the boundary of the fire area.(3)For the burned area where there is water,transient electromagnetic method is unable to identify the boundary of the burning area under specific conditions.Two or more exploration methods should be used to determine the location of the burning area.(4)In the Zhang Jia Mao coalfield area,it is suitable to simulate the magnetic dip angle of 72 ~o and the geomagnetic angle of-4.6 ~o.The method of chemical polarity is beneficial to the identification and delineation of fire boundary,and the local precision can be increased by15~50m.This result has a demonstration effect on the same area,and can be applied in the coal mine goaf and the burning rock area.