检波器野外组合因素对地震资料品质的影响分析

Impact analysis of geophone array factors on seismic data quality

(中国石油化工集团公司胜利石油管理局地球物理勘探开发公司,山东东营257100)

Geophysical Corporation,Shengli Oil Administration Bureau,SINOPEC,Dongying 257100,China

波器组合是地震资料野外采集阶段衰减噪声最重要的手段之一。决定组合衰减噪声效果的因素有组合因素(组合基距,组内距,检波器数量,组合高差,组合形式等)以及施工地区的地质条件、噪声的类型与强度等。从验证不同组合因素对地震资料的影响出发,通过计算组合的方向特性曲线及野外试验,量化分析了组合因素对地震资料的影响,提出一种组合基距在Inline方向设置为一个道距,在Crossline方向设置为一个最大干扰波波长的组合方案,以有效衰减来自各个方向的规则干扰波。计算表明,在组合基距确定的前提下,缩小组内距、增加检波器数量有利于提高资料的信噪比，但当检波器数量增加到某个临界点后,继续缩小组内距、增加检波器个数则不能显著提高组合的压噪能力。实践证明,在地表复杂、地层吸收严重、次生干扰发育的地区,组内高差允许值应适当放宽,这有利于提高地震资料的信噪比。分析认为,Inline方向大致等于一个道距,Crossline方向大致等于一个最大干扰波波长的矩形组合是具有良好方向特性，又便于野外施工的检波器最佳组合方式之一。

Geophone array is one of the most important measurements to attenuate noise in field acquisition.The factors determining array attenuating noise includes array elements (array length,geophone spacing,geophone amount,elevation difference within array,geophone layout pattern,etc),geologic conditions as well as the type and intensity of noise.Starting from verifying the impact of different factors on seismic data,by computing direction characteristics curve of array and field testing,the impact was quantitatively analyzed,and an array scheme was proposed.According to the scheme,the array should be designed as: array length in Inline direction is about a geophone group interval,and in Crossline direction is about a maximum apparent wavelength.With this array,the regular wave from all directions would be effectively attenuated.Computation results show that shortening geophone spacing and increasing geophones are beneficial to improving the S/N of data if array length is fixed.However,when the number of geophones increases to a critical value,continuously shortening geophone spacing and increasing geophone amount cannot effectively improve the noise attenuation ability of array.Application shows that at the area with complex surface conditions,serious layer absorption effect and serous secondary interference,the allowed elevation difference within array should be properly increased,which is beneficial to improve the S/N of seismic data.Analysis results indicates that the above designed rectangle array is one of the best array patterns with good direction characteristic and convenient for field acquisition.