速度建模的影响因素与技术对策

Influencing factors and technical strategies for velocity modeling

中国石油勘探开发研究院物探技术研究所, 北京 100083

Research Institute of Petroleum Exploration & Development, CNPC, Beijing 100083, China

叠前深度偏移速度建模是一种基于模型的迭代修正过程。影响速度模型精度的因素,除了速度反演算法之外,还包括复杂近地表条件下的静校正处理和观测系统的不规则性。从地震资料处理解释一体化的研究思路出发,针对不同的地震地质条件,提出了建立精确速度模型的对策。在地震勘探程度较高的地区,首先采用测井约束法建立初始宏观层速度模型,然后利用多域双重迭代法进行优化更新,以达到满足叠前成像精度要求的目的。另外,针对我国西部山地冲断带地区速度建模存在的问题,提出了速度建模的思路和对策,并对该项技术的发展趋势进行了展望。

Velocity model building for prestack depth migration is a model-based iteration process. Besides velocity inversion algorithm, the static correction in complex near-surface condition and irregular geometries may also impact the velocity modeling. Based on integrating seismic processing and interpretation, aimed at different seismic-geological conditions, the strategy of accurate velocity model establishment is proposed. In some high degree exploration areas, the initial macro interval velocity model is firstly established by u-sing the logging-constrained method, and then, the double-iteration method in multi-domains is applied on velocity model updating to meet the accuracy of prestack imaging. In addition, based on some problems in velocity modeling in the foreland basin of west China, the thought and strategy for velocity modeling are proposed and the development tendency of this technique is analyzed.