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应用实轴积分方法研究了实现由充液井孔中的相控线阵声波辐射器向井外地层中扫描辐射声场的方法. 研究表明,通过改变井孔中的相控线阵声波辐射器的阵元个数、相邻阵元间激励信号的延迟时间等参数可以控制辐射声束的角宽和入射于井壁的入射角. 当辐射器产生的声束以小于第一临界角的偏转角入射到井壁上后,在井外地层中产生的纵波的偏转角近似满足平面波入射于平面界面时的折射定律. 当井孔中的相控线阵的辐射声束角宽较小,且声束偏转角小于第一临界角时,可以假设将相控线阵置于无井孔的均匀固体中,利用固体中相控线阵的指向性函数直接计算井外声场的空间分布. 向井外地层中扫描辐射声场技术可以用于提高反射声波测井和井间声波勘探的空间分辨和信噪比.
The method of real axis integration is used to study the method of scanning the radiation field from the phased array acoustic wave emitter in the wellbore to the formation. The study shows that by changing the array of phased array acoustic wave radiators The number of elements and the delay time of the excitation signal between adjacent elements can control the angle width of the radiation beam and the angle of incidence incident on the wall.When the sound beam generated by the radiator is incident at the deflection angle smaller than the first critical angle The deflection angle of the longitudinal wave generated in the formation outside the well wall approximates the law of refraction when the plane wave is incident on the plane interface to the borehole wall.When the beam width of the radiation beam of the phased array in the wellbore is small, When the deflection angle is less than the first critical angle, it can be assumed that the phased array is placed in a uniform solid without holes, and the spatial distribution of the sound field outside the well is directly calculated using the directivity function of the phased array in the solid. Scanning radiation acoustic field techniques can be used to improve the spatial resolution and signal-to-noise ratio of reflected acoustic logging and crosswell sounding.