Study On Whole Space Polarization Migration Imaging Technology Of Mine Seismic Exploration

The driving safety in the laneway is frequently controlled by multiple disaster sources,which include fault fracture zone, water-bearing body, goaf, collapse column, and so on.The advanced prediction research is becoming a hotspot. But existing measuring precisionof mine geophysical exploration is hard to meet the practical requirements of geology.Therefore, In order to protect roadway safe and efficient production under complicatedgeological conditions, it is thorough necessary to carry out the subtly advanced predictionof reflected wave method in the whole space.This paper start from the relationship between the real-time polarization analysis ofseismic wave, based on the polarization coefficient difference between surface wave andbody wave, polarization coefficient factor is introduced. In light of the orthogonaldifference between P wave and S wave, principal polarization direction factor is introduced.According to the velocity difference between surface similar wave and converted wave,coherent coefficient factor is introduced. A polarization modulation function is introducedon the basis of computation factors.Based on the coherence stack and diffraction stackmigration, A polarization migration that integrates wave-field separation and migrationimaging is proposed. Considering the characteristics of2-D and3-D space imaging, thepolarization migration programming is completed and PsFilter3.0data processing systemis developed based on the platform of Visual C++.net. Numerical simulation, physicalsimulation and field test are successively carried out in this paper for the sake of verifyingthe effect of polarization migration.In the experiments of advanced prediction numerical simulation with differentorientation single and multiple abnormal interface, the polarization analysis results withintime window lengths of single period of different types reflection wave groups of themaximal offset seismic trace show the orthogonal difference characteristics ofcompressional wave and shear wave main polarization direction and path dirction of wave.Geology abnormal interface imaging effect of different positions, diverse occurrence,various combinations in the front of driving face verify that, the upper and lowersymmetric false appearance of P-P wave and SV-SV wave can be filtered effectively by2Dpolarization migration based on time-frequency analysis method to get time window;2Dpolarization migration, which is got from mutual coherence weighted computing that isbased on the velocity difference of P-SV and SV-P, can availably suppress converted wave and interference wave. From the different migration methods and the contrast experimentsof various observation system of three-layer geological anomaly model with the sametendency, we can find that, compared with traditional pre-stack refraction scanningmigration, Kirchhoff integral migration, and reverse-time migration, the abnormal interfaceof polarization migration has the characteristics of good convergence and high directionresolution, avoiding imaging ill-conditioned problem which is caused by small migrationpore impacted from roadway space, and accurate quantitative evaluation of polarizationmigration can be realized only in linear observation system.In the advanced physical model experiment in the flume, the polarization migrationimaging results of abnormal interface with four different dip indicates that2D polarizationmigration imaging can efficiently judge the position, dip and tendency of anomalous body;In the rock mass model experiment considering the influences of roadway, the convergenceeffects of the anomalous body's spatial contour verify that the spatial resolution of seismicreflection wave method can be obviously improved by3D polarization migration.According to the practical condition in the coal mine,, multi-component seismicsignal with wider frequency band and reliable multiply component is provided by speciallymade detonator source and six-componet sensor for polarization migration. The detectioncontrast experiments of typical mining areas in Shanxi, Henan and Jiangsu indicate thatpolarization migration technology can achieve the advanced prediction effects of highaccuracy and resolution.