山地复杂构造地震成图方法探讨

Seismic mapping of complex structures in mountainous areas

1. 四川石油管理局地调处物探研究中心,四川成都610213;2. 新疆塔里木油田勘探开发研究院,新疆库尔勒841000

1. Geophysical Research Center of Sichuan Petroleum Geological Survey Division, Chengdu 610213, China;2. Research Institute of Exploration and Development of Xinjiang Tarim Oilfield, Korla 841000, China

在山地复杂构造地震成图过程中, 采用不同的方法, 由于其基本原理、剖面类别 (叠加、时间偏移和深度 )和作图参数 (基准面, 静校速度、时深转换速度 )都不同, 其构造形态和圈闭要素就会存在大的差异。文中着重分析了影响山地复杂构造地震成图精度的 3个重要参数 (基准面, 静校速度, 时深转换速度 ), 比较了时间域和空间域成图方法的特点和适用条件, 确认合理的作图基准面应为水平面, 静校速度为目的层的ν^av,时深转换层速度为v^nl。采用Vnlog层位控制法, 进行由偏移时间剖面向深度剖面转换, 是山地复杂构造地震成图的行之有效方法, 它具有操作简单、实用性强和精度高的特点。

Structural configuration and trap factors vary greatly with mapping methods that are different in principle and mapping parameters. This paper discussed the effects of 3 important parameters (datum, static correction velocity, and velocity of time-depth conversion) on the precision of seismic mapping for complex structures in mountainous areas, and compared the time-domain methods with depth-domain ones by their characters and applicability. It was concluded that the proper parameters for seismic mapping of complex structures in mountainous areas are that the datum should be horizontal plane, the static correction velocity the average velocity of the target formation, and the velocity of time-depth conversion be v^nl.The layer-controlled method of Vnlog is an effective method to convert time sections into depth ones in frontland. This method is simple, accurate, and easy to use.