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通过Metravib热机械分析仪,用正弦波进行加载,实验时固定静载为100N,正弦波动载荷恒为60 N,将总载荷控制在屈服点以下;在温度为—50～125℃,升温速率为1℃/min,频率为5～1000 Hz的条件下,对泵油饱和长石砂岩、彭山砂岩样品进行单轴循环加载实验,求取泵油饱和长石砂岩和彭山砂岩的衰减、耗散角、模量、波速与温度和频率的关系.以此研究了饱和多孔岩石在弹性范围内的衰减、耗散角、杨氏模量和弹性波波速随温度和频率的变化规律.取得了随频率或温度增高饱和多孔岩石的衰减峰和耗散角峰的峰位向高温或高频方向移动的热激活弛豫规律.以低频共振衰减解释了随频率增高衰减强度增大;用阻尼衰减和以岩石天然孔隙裂缝随疲劳载荷时间的增长,裂缝纵横比增加,解释了随频率增高,衰减峰的峰位向高频方向移动和衰减峰的强度降低的另一实验结果.这些实验结果与低频共振的驻波实验取得了同样的热激活弛豫规律,说明热激活弛豫机制在饱和多孔岩石中具有一定的普适性.本文还获得了杨氏模量和弹性波波速随温度升高而下降,随频率增高而增大,具有频散效应,随温度升高频散效应有减弱的趋势.该研究结果对理论模型研究具有指导意义,对地震资料的解释具有实用意义.
Through the Metravib thermo-mechanical analyzer, a sine wave was applied. The static static load was 100N and the sine wave load constant was 60N. The total load was controlled below the yield point. When the temperature was -50 ~ 125 ℃, the heating rate was Under the condition of 1 ℃ / min and frequency of 5 ~ 1000 Hz, uniaxial cyclic loading experiments were carried out on the samples of oil-saturated feldspar sandstone and Pengshan sandstone, and the decay and consumption of oil-saturated feldspathic sandstone and Pengshan sandstone were obtained Dispersion angle, Young’s modulus and elastic wave velocity with temperature and frequency in the elastic range of the porous rock, the variation law of the temperature and the frequency of the saturated porous rock is obtained. With the increase of frequency or temperature, the heat-activated relaxation of the peak of the attenuation peak and the peak of the dissipation peak shifts to high temperature or high frequency. The attenuation of low frequency resonance explains the increase of the attenuation intensity with increasing frequency. And the experimental results show that with the increasing of the frequency, the peak position of the attenuation peak shifts to the high frequency direction and the strength of the attenuation peak decreases with the increase of the fatigue load time with the natural pore fissures of the rock. The same thermal activation relaxation rule was obtained with the low frequency resonance standing wave experiment, which shows that the thermal activation relaxation mechanism has a certain universality in saturated porous rocks.The Young’s modulus and elastic wave velocity with temperature rise High and falling, increasing with increasing frequency, with the dispersion effect, and the dispersion effect tends to weaken with increasing temperature.The results of this study are instructive for the study of theoretical models and have practical significance for the interpretation of seismic data.