基于线性连续速度模型的速度分析与动校正方法
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摘要
提高速度分析和动校正的精度,能够改善叠加成像的效果。沉积岩分布区的垂向非均质性较强,地层速度一般随深度的增加而增加,对于这类地区大炮检距道集采集的地震资料,用常规双曲速度分析和动校正方法处理精度降低、误差变大,必须用非双曲方法处理。在线性连续速度模型(垂向非均质模型)基础上,研究双参数(深度为零时的速度和速度随深度的变化率)、单参数(速度随深度的变化率)速度分析方法和动校正方法。双参数速度分析方法计算量大,且有一定的多解性;在较为准确地已知近地表速度范围的条件下,可采用单参数速度分析方法来减小计算量。理论模型试算和对实际资料的处理结果表明,基于线性连续速度模型的动校正和叠加成像处理效果优于常规双曲方法。图6表1参7
Stacking quality can be improved by enhancing precision of velocity analysis and normal moveout correction. In sedimentary rock area, rock ' s velocity augments with the increase of rock's depth. Therefore, underground media shows strong heterogeneity. Accuracy of conventional hyperbolic velocity analysis and normal moveout correction decreases with the increase of the heterogeneity. Non-hyperbolic method should be adopted to improve their accuracy. Based on heterogeneous model-linear continuous velocity model, velocity analysis of two parameters, velocity analysis of one parameter and normal moveout correction are advanced. The research shows that velocity analysis of two parameters needs large computing time and gives multi-solution. When near-surface velocity is known, velocity analysis of one parameter can be used to decrease multi-solution and computing time.
Stacking quality can be improved by enhancing precision of velocity analysis and normal moveout correction. In sedimentary rock area, rock ' s velocity augments with the increase of rock's depth. Therefore, underground media shows strong heterogeneity. Accuracy of conventional hyperbolic velocity analysis and normal moveout correction decreases with the increase of the heterogeneity. Non-hyperbolic method should be adopted to improve their accuracy. Based on heterogeneous model-linear continuous velocity model, velocity analysis of two parameters, velocity analysis of one parameter and normal moveout correction are advanced. The research shows that velocity analysis of two parameters needs large computing time and gives multi-solution. When near-surface velocity is known, velocity analysis of one parameter can be used to decrease multi-solution and computing time.
引文
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[2] 徐常练,许云,乌达巴拉.速度随炮检距变化(VVO)分析[J].石油地球物理勘探,1998,33(6) :733-740．
[3] Tsvankin I, Thomsen L. Nonhyperbolic reflection moveout in anisotropic media[J]. Geophysics, 1994, 59(8) : 1290-1304．
[4] Alkhalifah T. Velocity analysis using nonhyperbolic moveout in transversely isotropic media[J]. Geophysics, 1997, 62 (6) : 1839-1854．
[5] Wei X C, Dong M Y. Statics estimation of continuous velocity model in loess plateau [A]. Abstract of SEG/SPG Urumqi'96 International Geophysical Conference[C], 1996． 86-90．
[6] 陆基孟.地震勘探原理(上册)[M].东营:石油大学出版社,1993． 48-57．
[7] 牟永光.地震勘探资料数字处理方法[M].北京:石油工业出版社,1986． 121-153．
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