应力加载频率及振幅对大庆砂岩衰减特性影响的实验研究  

The Lab studies of influence of stress loading frequencies and amplitudes on Daqing sandstone attenuation characteristics

作　　者：赵闯[1] 施行觉[1] 李成波[1] 杨映希[1] 

机构地区：[1]中国科学技术大学地球和空间科学学院,安徽合肥230026

出　　处：《石油地球物理勘探》2010年第4期534-539,共6页Oil Geophysical Prospecting

基　　金：国家自然科学基金项目(40774096)资助

摘　　要：实验利用CMT5504微机控制万能试验机在不同初应力条件下,对干燥的大庆砂岩衰减(Q-1)特性采用单轴压缩三角波循环加载方式进行研究。在保持应力振幅一定情况下,用应力—应变循环曲线计算了干燥大庆砂岩在0.001～0.01Hz频率范围内的衰减特性;在保持加载频率一定情况下,计算了大庆砂岩衰减和应力振幅之间的关系。发现三角波加载所得的衰减在所取频段内与频率的关系和正弦波加载很相似,同一频率下衰减随应力振幅增大而增大,并且在频率和应力振幅相同的情况下衰减随着初应力水平的增大而减小。结合内时理论和P-M(Preisach-Mayergoyz)模型理论对结果进行了解释。最后利用所得的衰减、频率、振幅和应力水平关系对未知条件下的衰减进行了预测,和实验计算有较好的吻合。In order to study the attenuation properties,a series of uniaxial stress cycling tests performed in triangle waveform loading under different initial stress levels were conducted on dry Daqing sandstones using CMT5504 testing machine.With the stress amplitude fixed,we got the attenuation characteristics in the frequency range of 0.001 to 0.01Hz,then under the fixed frequency,the relationship between attenuation and stress amplitudes was obtained.In comparison with the results of sine waveform loading,it was found that the relationship from triangular waveform loading was similar.Besides this,it's found that the attenuation value was proportional to stress amplitude,but inversely proportional to initial stress level.With the help of Endochronic theory and P-M model theory,we gave a suitable reason for the results.At last,according to the known relationship,we predicted the attenuation under the unknown conditions (such as initial stress level,frequency,strain amplitude),and the prediction results fit the experiment results closely.

关 键 词：衰减 初应力水平 三角波 加载频率 应力振幅 内时理论 P-M模型理论 

分 类 号：O346.2[理学—固体力学]