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本文采用从法国引进的Metravib热机械分析仪用正弦波加载方式,首次对四种不同孔隙度的饱和砂岩的衰减进行了实验研究,在5～400Hz的频率,-50℃～100℃的温度范围获得衰减的热弛豫规律,由此求得它们的激活能和原子振动频率,其激活能和弛豫时间是处在原子和电子的激活能和弛豫时间之间.可见,在饱和岩石的晶粒间界缺陷处参与扩散的是原子、电子.并得出随孔隙度增大,衰减强度和激活能增大,原子的振动速率加快,弛豫时间缩短.在交变应力作用下,由多种矿物晶体胶结而成的饱和砂岩是一种多晶、多相的固体,由于内部结构复杂,损伤、缺陷广布,弛豫衰减是普遍存在的.饱和砂岩中存在的晶界、相界等许多缺陷,以及缺陷间的相互作用,比如饱和岩石中的饱和液体与岩石骨架之间的作用等等都可以产生弛豫衰减峰,弛豫过程还受晶界上原子扩散所控制.由于饱和岩石中的种种缺陷、相界等等导致上述矿物颗粒或晶界之间的多重弛豫,才使弛豫衰减峰变宽,分布宽度增大.用饱和砂岩中特有的饱和液体及砂岩内部结构的复杂性解释了饱和砂岩的衰减机理,很自然地将其宏观衰减特征与微细观结构紧紧联在一起.衰减及其机理的研究既具有科学意义,对地球物理勘探又具有实用价值.
In this paper, we used the Metravib thermomechanical analyzer introduced from France to simulate the attenuation of saturated sandstone with different porosity for the first time by using the sine wave loading method. At the frequency of 5 ~ 400Hz, the temperature range of -50 ℃ ~ 100 ℃ Get the law of thermal relaxation decay, and thus find their activation energy and atomic vibration frequency, the activation energy and relaxation time is in the atomic and electronic activation energy and relaxation time can be seen in the saturated rock At the grain boundary defects, atoms and electrons are involved in the diffusion, and as the porosity increases, the decay intensity and activation energy increase, the vibration velocity of the atom accelerates, and the relaxation time shortens. Under alternating stress, Saturated sandstone, which is a kind of polycrystalline and heterogeneous solidified by a variety of mineral crystals, is a kind of polycrystal and heterogeneous solid. Because of its complicated internal structure, extensive damage and defects, relaxation attenuation is ubiquitous. The grain boundary, And many other defects, as well as the interaction between defects, such as saturated rock in saturated rock and the interaction between the rock skeleton and so can produce relaxation attenuation peak, the relaxation process is also controlled by atomic diffusion on the grain boundary due to saturation Various defects in the rock, facies boundary, etc. lead to multiple relaxation between the above-mentioned mineral grains or grain boundaries, widening the relaxation attenuation peak and widening the distribution width.Using the saturated liquid and the internal structure of the sandstone The complexity explains the attenuation mechanism of saturated sandstone and naturally links its macroscopic attenuation characteristics closely with the microstructure.The study of attenuation and its mechanism is of scientific significance and practical value for geophysical prospecting.