复杂地表条件下的变观设计技术
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摘要
在干扰源、障碍物等广泛分布的复杂地表区进行地震采集施工困难,主要表现为固定干扰源及障碍物等引起的空炮或空道形成剖面缺口深度及对目的层有效覆盖次数、地震资料品质的影响。本文讨论了复杂地表条件对地震资料影响程度的定量分析方法,包括干扰的衰减分析方法、给地震数据加载噪声的分析方法、信噪比比值法,并分析了障碍物引起的空炮或空道对地震资料的影响程度。文中认为:①通过定量化分析手段可准确确定外界固定干扰源及障碍物等造成的空炮或空道对地震资料的影响程度,也是进行科学变观设计的基础;②在实际工作中,应根据障碍物的分布情况,以尽可能减少恢复距离、剖面缺口及使恢复后的炮点分布尽量均匀为原则,将纵、横向恢复性变观方法结合起来灵活应用;③当检波点无法布设或检波点被严重干扰、炮点可以选择性布设时,根据炮、检射线路径互换原理,可以采用以炮补道的变观方法。实际应用表明,文中所述方法有效地降低了地震采集难度,保证了资料品质。
The complex surface conditions such as widely distributed interferent sources and obstacles resul-ted in difficulty of seismic acquisition operation, showing up the gap depth on the sections formed by the missing shots or traces resulted from fix interferent sources and obstacles, and the influence on useful folds of targets and quality of seismic data. The paper discussed the quantitative analytic approaches of influence of complex surface conditions on seismic data,including analyzing the attenuation of interference, adding noises to seismic data and S/N ratio value,and analyzed the influence of missing shots or traces from the obstacles on seismic data. The paper considered: (1)accurate definition of the influence of missing shots or traces resulted from outside fix interferent sources and obstacles on seismic data is basis of scientific geometry-variable design;(2)in practical work,according to the distribution of obstacles, it should combine the vertical with horizontal restoration geometry-variable approaches for flexible application by following the principle that makes our effort to reduce restoration distance and gap of section, and makes the restored distribution of shots as uniform as possible; (3)using geometry-variable approach of ' compensating receiver points with shot points' according to reciprocity principle of shot and receiver ray paths when the receiver points are unable to be planted or severely interfered and shot points can be deployed selectively. The practical application showed the approaches presented in the paper effectively reduced the difficulty of seismic acquisition,ensuring the data quality.
The complex surface conditions such as widely distributed interferent sources and obstacles resul-ted in difficulty of seismic acquisition operation, showing up the gap depth on the sections formed by the missing shots or traces resulted from fix interferent sources and obstacles, and the influence on useful folds of targets and quality of seismic data. The paper discussed the quantitative analytic approaches of influence of complex surface conditions on seismic data,including analyzing the attenuation of interference, adding noises to seismic data and S/N ratio value,and analyzed the influence of missing shots or traces from the obstacles on seismic data. The paper considered: (1)accurate definition of the influence of missing shots or traces resulted from outside fix interferent sources and obstacles on seismic data is basis of scientific geometry-variable design;(2)in practical work,according to the distribution of obstacles, it should combine the vertical with horizontal restoration geometry-variable approaches for flexible application by following the principle that makes our effort to reduce restoration distance and gap of section, and makes the restored distribution of shots as uniform as possible; (3)using geometry-variable approach of ' compensating receiver points with shot points' according to reciprocity principle of shot and receiver ray paths when the receiver points are unable to be planted or severely interfered and shot points can be deployed selectively. The practical application showed the approaches presented in the paper effectively reduced the difficulty of seismic acquisition,ensuring the data quality.
引文
[1]杨光大等.乾安城区特殊观测系统设计及应用.石油地球物理勘探,2005,40(4):377～380
[2]刘成斋.黄河入海口地区的地震数据采集方法.石油地球物理勘探,2004,39(1):97～101
[3]石一青等.GMG MESA(绿山)软件在苏北复杂地表及地质条件下地震方法设计中的应用.物探装备,2005,15(3):161～165
[4]任福新等.复杂地表变观方法及效果分析.物探与化探,2006,30(1):55～58
[5]何樵登.地震勘探原理和方法.北京:地质出版社,1986,20～34
[6]马彦良等.三维地震勘探恢复性放炮法变通问题的讨论.中国煤田地质,2004,16(5):45～49
[7]黄显国等.亚肯北山地三维地震采集实例.美国休斯敦:第74届SEG年会论文集,2004
[2]刘成斋.黄河入海口地区的地震数据采集方法.石油地球物理勘探,2004,39(1):97～101
[3]石一青等.GMG MESA(绿山)软件在苏北复杂地表及地质条件下地震方法设计中的应用.物探装备,2005,15(3):161～165
[4]任福新等.复杂地表变观方法及效果分析.物探与化探,2006,30(1):55～58
[5]何樵登.地震勘探原理和方法.北京:地质出版社,1986,20～34
[6]马彦良等.三维地震勘探恢复性放炮法变通问题的讨论.中国煤田地质,2004,16(5):45～49
[7]黄显国等.亚肯北山地三维地震采集实例.美国休斯敦:第74届SEG年会论文集,2004
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