频散作用对储层砂岩速度实验结果的影响分析

Effect of dispersion on the experimental results of sandstone velocity in reservoirs.

在不同围限压力下,利用超声波脉冲透射法对一套物性参数变化较大的储层砂岩弹性波速度进行了实验测量。基于Biot流与喷射流机制的理论模型对实验结果进行了定量解释,给出了这2种速度频散机制对实验结果的影响,并分析了将实验高频速度应用于现场地震低频的可能性。根据研究结果指出,喷射流频散作用对速度的影响明显,对于以喷射流作用为主导频散机制的实验结果不能直接用于现场的地震频段;如果Biot流作用是主导频散机制,对实验速度结果影响不明显,可将实验结果直接用于地震频段。

Under the different confining pressure, a suit of elastic velocities reservoir sandstones with widely varying petro-physical properties was measured using ultrasonic pulse transmission technique. The experimental results were interpreted based on the theoretical model of Biot flow and squirt flow, and the effects of two dispersion mechanism on experimental results are also given to analyze the possibility of applying the laboratory results to in-situ seismic exploration. Some important conclusions were draw that squirt fluid seriously influence the experimental results of velocity, and laboratory velocity results at ultrasonic frequency can not be applied to low-frequency of seismic exploration directly if the squirt fluid is the dominant dispersion mechanism; if the dominant dispersion is Biot flow that do not affect the velocity results apparently, the laboratory velocity results can apply to the low-frequency of seismic exploratioa