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我们用雷利原理论述了与声波测井中导波关联的几个问题.使用本文的逼近法,就能计算(1)关于弹性模量或密度模量(即不是常数频率就是常数波数)的相速度的局部微商;(2)群速度;(3)由于弱非均质岩层引起的相速度上的变化;(4)由于轻微不规则井孔引起的变化。我们的公式可用于具有任意相位角,且沿充满了液体的圆柱井孔通过一个强均质地层传播的导波,其对称坐标轴是以该井孔为坐标中心的.使用雷利原理来确定局部微商和群速度,其优点是可以避免某些非准确结果带来的数字误差,一些样点值的计算表明,这些量的计算是非常准确的.使用雷利原理来模拟一个弱非均质地层或非规则井壁,其优点是相当正确的速度扰动能由较少的数字计算估算出来,这一点是尤其重要的,因为该方法在非均质以及许多野外实际情况遇到的井孔不规则的范围里都是有效的,我们还计算了一个具有垂向小裂隙的地层和一个椭圆井孔的相速度上的扰动。
We use Rayleigh principles to discuss several issues associated with guided waves in sonic logs.Using the approximation method of this paper, we can calculate (1) the elastic modulus or density modulus (ie, constant wave number) Phase velocity; (2) group velocity; (3) change in phase velocity due to weak heterogeneous rock formation; and (4) change due to slightly irregular wellbore. Our formula can be applied to waves with arbitrary phase angles and propagating through cylindrical liquid-filled wellbores through a strongly homogeneous formation whose center of symmetry is centered on the wellbore, using the Riley principle The local derivative and group velocity have the advantage of avoiding some numerical errors caused by inaccurate results. The calculation of some sample values shows that the calculation of these quantities is very accurate. Using the Reulez principle to simulate a weak non-homogeneous The advantage of the texture layer or the irregular wall is that rather correct velocity perturbations can be estimated by fewer numerical calculations, which is of particular importance since the method is not well suited to heterogeneous well borehole encountered in many field scenarios The irregular range is valid, and we also calculated the phase velocity perturbation of a formation with a small vertical fracture and an oval well.