依据二维叠偏剖面编制构造图的空校原理

Principle of spatial correction for structure mapping on 2-D migration section

辽河油田勘探开发研究院计算所,辽宁盘锦124010

Computation Institute, Research Institute of Exploration and Development, Liaohe Oilfield, Panjin 124010, China

以连续介质为主, 以单斜构造为模型, 结合具体的测算结果, 论证了在空间域中, 反射点三维空间偏移量的二维分量与二维偏移量是相等的。在时间域中, 在非倾向方向上存在二维偏移量偏大, 倾角偏缓, 二维深度偏浅等偏差, 与空间域的结论相矛盾。通过论证分析表明, 现有的方法与公式只适用于倾向方向, 不适用于非倾向方向。在没有二维偏移偏差的条件下, 根据二步法空校原理及其关系, 建立起新的改进算法, 不但改正了偏差, 也证明了在时间域中, 反射点的三维偏移量的二维分量与二维偏移量是相等的, 为成图方法明确了理论依据和检验标准。

This paper proved that the 2-D component of a 3-D migration offset at a reflection point is equal to the amount of 2-D offset, in case of continuous medium and monoclinal structure. There are deviations in direction of non inclination in time domain, such as bigger 2-D migration offset, gentler inclination, shallower depth, etc. Therefore, contradiction exists between results from time domain and space domain. Analysis shows that existing methods are applicable only in inclination direction. A new algorithm was developed according to principle of spatial correction in two pass, provided that 2-D migration offset is zero. Tests with real data show that the method yields no deviation. Thus it confirms that the 2-D component of a 3-D migration offset at a reflection point is equal to the amount of 2-D offset. The result can be used as evidence of correct mapping.