Method and apparatus for measuring formation compression and shear wave velocity

摘要

Method and apparatus for measuring formation compressional and shear wave velocities characterized by a downhole tool having an attenuation chamber between a transmitter and a receiver and a plurality of receivers spaced from the transducer so as to discriminate through the amplitude of the reflected compressional wave the critical angles for the respective formation compressional and shear wave velocities, thereby determining the formation compressional and shear wave velocities. Also disclosed are preferred embodiments in which the plurality of connectors connected between the receivers are also connected with a recorder for recording gated time interval signals. A discriminator and gate are provided for discriminating the largest amplitude of received acoustic energy signals received during the gating period. In a preferred embodiment, a microprocessor is also employed to calculate the density from the compressional velocity and the normal incidence reflection coefficient and arrange for displaying the compressional wave velocity, the shear wave velocity and the density as a function of depth.