储层孔(裂)隙的物理模拟与超声波实验研究

Physical modeling and Ultrasonic experiment of pore-crack in reservoirs

以超声波实验作为研究手段,用人工物理模型模拟油气储层中的裂缝和孔洞.通过室内超声波实验观测不同缝、洞孔隙度物理模型的地震波特征响应,分析了缝、洞孔隙度的变化对地震波属性参数的影响,重点讨论了裂缝、孔洞孔隙度与纵横波属性的关系.实验分析结果表明:储层缝、洞孔隙度的变化对地震波的纵横波速度、振幅、衰减和主频等参数有着明显的影响,并对各参数的影响程度进行了对比分析.随着缝、洞孔隙度的逐渐增加,地震波的纵横波速度、振幅、衰减和主频等参数都有不同程度的减小,但振幅、衰减、主频的减小程度要比速度高1-3个数量级,这为合理地选择和利用地震波的速度、振幅、衰减和主频等参数来进行地下储层中裂缝、孔洞分布和发育程度的检测和预测提供了可靠的实验依据.

According to physical modeling similarity, different models simulating pore and crack in reservoirs were made. Seismic responses to these artifical physical models of pore\|crack in reservoirs had been observed by ultrasonic experiment using MTS (a rock Mechanics Test System). We analyse the influences of pore\|crack porosity on seismic wave attributes. Summarize according to ultrasonic experiment results: the change of pore\|crack porosity evidently influences the characteristic parameters of seismic wave, such as velocity, amplitude, main frequency and the quality factor etc. even more, we contrast and analyze the degree of influences on each parameters. Along with increase of pore\|crack porosity, the characteristic parameters of seismic wave, such as velocity, amplitude, main frequency and the quality factor of seismic wave etc, gradually decrease. But, the change of each parameter has obvious discrepancy. Decrease of amplitude, main frequency and the quality factor of seismic wave is high one to three quantitative grade than velocity. Therefore, it offers reliable experiment foundation for detecting and predicting crack and pore in reservoirs by the characteristic parameters of seismic wave in reason.