超声波数据是预测孔洞型碳酸盐岩储层岩石力学参数的基础资料,而掌握该地层的超声波响应规律是预测结果准确性的关键.本文利用波动理论,以衰减系数为研究对象,展开单孔洞模型的超声波数值模拟研究.结果表明:①随着单孔洞模型的孔隙度增加,超声波衰减系数整体呈递增趋势,其函数规律与孔隙度增长方式有关;②对于圆形、方形孔洞来讲,孔隙度=9%是个重要的临界值,当孔隙度<9%时,可忽略形状对衰减的影响,当孔隙度>9%时,圆形比正方形孔洞的衰减系数变化大;③在椭圆形孔洞模型中,纵横比Ar>1时,孔隙度变化对衰减系数影响较小,Ar<1时,孔隙度变化对衰减系数影响较大;④随着超声波传播方向与椭圆模型中长轴的夹角增大,衰减系数线性递增.%Ultrasonic data is the important information to study the carbonate reservoir pore structure,acoustic response can be used to inversion the pore structure.Base on the acoustic wave theory, the authors study the fracture model, to carry out numerical simulation of ultrasonic wave.The results show that with the increase of fracture porosity, rock acoustic attenuation coefficient overall upward trend, However, the porosity growth in different ways, increasing function of the attenuation coefficient is also different rules;with the joint angle increases, the attenuation coefficient of acoustic rock is the linear law of increase.Attenuation coefficient increases as the crack density increases the power function rule, and pore density and linear attenuation coefficient;using numerical simulation method to avoid human error, saving the cost of experiments.At the same time, it can expand ideas that study cracks, fracture-cave structure of the rock acoustic experimental.
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