平面聚类静态校正法
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摘要
大地电磁测深法中的静态效应校正一直是国内外电法勘探界人士广泛关注的问题 ,并提出了多种解决方法 ,其中的曲线平移校正法仍是目前的主要手段。然而当曲线平移校正法用于面积性勘探时 ,剖面间的视电阻率经过校正后会产生系统偏差 ,而且两条测线相交处各测线视电阻率可能不一致 ;另一方面 ,此法可能将由实际地质构造变化引起的曲线幅值突变也视为静位移被消除 ,造成有用信息丢失。因此本文提出平面聚类静态校正法 ,该法可在平面先进行汉宁滤波 ,再将测区各测点的视电阻率曲线进行聚类分析 ,自动实现以构造单元分区校正的目的。此法的应用实例与同一地段的地震剖面对比 ,两者有很好的可比性 ,说明此法的有效性。
The corrections of static effect in MT method is always the issue that widely following with interest by the people engaged in electric exploration at home and abroad,who presented a variety of solution methods,among which the parallel curve shift correction method is currently mainly-used method.The apparent resistivity between sections may produce systematic errors after correction and unequal apparent resistivity values may be produced at intersect of two lines when using the parallel curve shift correction method for areal exploration;on the other hand,the sudden variations in curve values resulted from real geologic structural changes may be viewed as static shift and removed by using the method,which resulted in loss of useful information.For this reason,the paper presented static correction method of planer cluster that implements Hanning filtering first on plane,then the cluster analysis is implemented for apparent resistivity curves at each surveying point in exploration area,that can automatically reach the goal of the corrections in separate zones of structural units.The comparison of the applied cases by using the method with seismic sections in same segments showed that both of them are comparable and that means the method is effectiveness.
The corrections of static effect in MT method is always the issue that widely following with interest by the people engaged in electric exploration at home and abroad,who presented a variety of solution methods,among which the parallel curve shift correction method is currently mainly-used method.The apparent resistivity between sections may produce systematic errors after correction and unequal apparent resistivity values may be produced at intersect of two lines when using the parallel curve shift correction method for areal exploration;on the other hand,the sudden variations in curve values resulted from real geologic structural changes may be viewed as static shift and removed by using the method,which resulted in loss of useful information.For this reason,the paper presented static correction method of planer cluster that implements Hanning filtering first on plane,then the cluster analysis is implemented for apparent resistivity curves at each surveying point in exploration area,that can automatically reach the goal of the corrections in separate zones of structural units.The comparison of the applied cases by using the method with seismic sections in same segments showed that both of them are comparable and that means the method is effectiveness.
引文
[1] 陈清礼等.利用地表电阻率校正大地电磁静态偏移.物探与化探,1999,23(4):289～295
[2] 罗志琼.用电磁阵列法压制MT静态效应的研究.地球科学,1990,15(增刊):13～22
[3] JonesA G.Static shift of magnetotelluric data and itsremoval in a sedimentary basic environm ent.Geophysics,1988,49(7):967～978
[4] 魏胜等.全MT张量分解技术及其应用.王家映主编,应用地球物理学进展.武汉:中国地质大学出版社,1996,38～45
[5] GroomR W andBailayR C.Decom position ofm agnetotelluric impedance tensors in the presenc oflocal3D galvanic distortion.J GeophysRes,1989,94:1913～1925
[6] GroomR W andBailayR C.Analytical investigationsof the effects of near- surface three- dimensionalgalvanic scatters onMT tensor decompositions.Geophysics,1991,56:496～51
[2] 罗志琼.用电磁阵列法压制MT静态效应的研究.地球科学,1990,15(增刊):13～22
[3] JonesA G.Static shift of magnetotelluric data and itsremoval in a sedimentary basic environm ent.Geophysics,1988,49(7):967～978
[4] 魏胜等.全MT张量分解技术及其应用.王家映主编,应用地球物理学进展.武汉:中国地质大学出版社,1996,38～45
[5] GroomR W andBailayR C.Decom position ofm agnetotelluric impedance tensors in the presenc oflocal3D galvanic distortion.J GeophysRes,1989,94:1913～1925
[6] GroomR W andBailayR C.Analytical investigationsof the effects of near- surface three- dimensionalgalvanic scatters onMT tensor decompositions.Geophysics,1991,56:496～51
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