重复性噪声对实施四维地震监测的影响

Effects of repeatability noises on 4-D seismic monitoring

在四维地震油藏监测过程中 ,油藏开采引起的储层弹性特性变化的大小以及重复采集地震资料的重复性噪声水平的高低 ,是决定四维地震能否顺利实施的关键。经验表明 ,只有当流体驱替所引起的声阻抗变化大于4 %时 ,才有望在地震资料中观测到地震差异。然而 ,对于重复性噪声的定量研究相对较少。用正演模拟方法对地震资料重复性噪声水平及其对四维地震监测的影响进行了分析。研究发现 ,在油藏条件满足地震监测要求的前提下 ,重复性噪声水平的高低是影响四维地震监测的决定因素。因此 。

In the process of 4 D seismic reservoir monitoring, the variations of elastic characterization of reservoir rocks caused by reservoir development and the strength of repeatability noises are two key elements to effect 4 D seismic exploration. Practice have showed that 4 D seismic can be successfully performed only when the change of acoustic impedance caused by fluid substitution is more than 4%。The quantitative analysis on repeatability noises has not been reported widely. The strength of repeatability noises and their effects on 4 D seismic monitoring were analyzed by forward modeling. Results show that the repeatability noises are the key factors affecting 4 D seismic monitoring when reservoir variation meets the demands of 4 D seismic monitoring. Improvement of repeatability of 4 D seismic data is the key to success of 4 D seismic exploration.