检波器组内高差对高频信息压制的理论分析
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摘要
在地震勘探野外采集中,目前普遍采用地表低速带的速度V0乘以目的层反射波主频的1/4视周期来计算检波器组内高差允许值,即使在沙漠及山地的地震资料采集中也是如此。本文通过理论计算与模型试验证明:在主频不是很高而次生干扰波非常发育的一些工区,采用降速带的速度V1乘以最浅目的层反射波主频的1/2视周期计算组内高差,就可以得到信噪比较高的用于构造解释的低频剖面;相反,如果在这类地区拘泥于原先关于组内高差的规定,就会因为强烈的次生干扰波没有得到有效压制而导致地震剖面的信噪比大大降低,进而使得企图通过减小组内高差、保护高频信息、提高分辨率的初衷也无法实现。
Currently,in seismic data field acquisition,we generally adopt the velocity of near-surface lower velocity layer V0 multiplying one fourth apparent cycle of dominant reflection frequency on the targets to compute the permissible value of elevation difference in a geophone array, even in deserts and on mountains. The paper demonstrated by theoretical computation and model tests that in areas developed strong secondary interferent waves and where the dominant frequency is not very high, we carry out construction by using velocity of subwe-athered zone V1 multiplying half-apparent cycle of dominant reflection frequency on the shallowest target to compute elevation difference in an array, which can get lower-frequency's section with higher S/N ratio that used for structural interpretation; on the contrary,if following the original rule of elevation difference in an array in this kind of areas , the S/N ratio on the seismic section may greatly be reduced by without effectively suppressing strong secondary interferent waves and original intension that attempts to reduce elevation difference in an array, protect high-frequency data and improve resolution can not be fulfilled.
Currently,in seismic data field acquisition,we generally adopt the velocity of near-surface lower velocity layer V0 multiplying one fourth apparent cycle of dominant reflection frequency on the targets to compute the permissible value of elevation difference in a geophone array, even in deserts and on mountains. The paper demonstrated by theoretical computation and model tests that in areas developed strong secondary interferent waves and where the dominant frequency is not very high, we carry out construction by using velocity of subwe-athered zone V1 multiplying half-apparent cycle of dominant reflection frequency on the shallowest target to compute elevation difference in an array, which can get lower-frequency's section with higher S/N ratio that used for structural interpretation; on the contrary,if following the original rule of elevation difference in an array in this kind of areas , the S/N ratio on the seismic section may greatly be reduced by without effectively suppressing strong secondary interferent waves and original intension that attempts to reduce elevation difference in an array, protect high-frequency data and improve resolution can not be fulfilled.
引文
[1]陆基孟.地震勘探原理.北京:石油工业出版社,1982
[2]吴长祥,李忠平,丁士平.塔里木盆地卡3区块二维地震采集技术研究.石油物探,2005,44(2):179～182
[3]齐中山,杜耀斌,马亚松,李会宪,王国盛.塔里木盆地塔中地区地震资料采集方法探讨.河南石油,2005,19(1):22～24
[4]杨贵明,钱荣钧,严峰.塔里木盆地大沙漠静校正方法.石油地球物理勘探,1994,29(增刊1):110～124,128
[2]吴长祥,李忠平,丁士平.塔里木盆地卡3区块二维地震采集技术研究.石油物探,2005,44(2):179～182
[3]齐中山,杜耀斌,马亚松,李会宪,王国盛.塔里木盆地塔中地区地震资料采集方法探讨.河南石油,2005,19(1):22～24
[4]杨贵明,钱荣钧,严峰.塔里木盆地大沙漠静校正方法.石油地球物理勘探,1994,29(增刊1):110～124,128
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