Numerical simulation of acoustic reflection logging while drilling based on a cylindrical phased array acoustic receiver station

Abstract

With the increase of drilling activities, improving the azimuth measurement capability of acoustic logging while drilling (LWD) tools has been an urgent requirement for the petroleum exploration. In this study, a novel acoustic reflection LWD scheme is developed based on a cylindrical phased array (CPA) acoustic receiver station, which is composed of several arcuate phased array (APA) acoustic receiver stations arranged uniformly along the tool axis. The azimuthal performance of the APA and CPA acoustic receiver stations in acoustic reflection LWD with one or two formation interfaces away from the borehole are studied using the finite-difference time-domain method. The simulation results show that the amplitude distribution of reflected waves received by different azimuthal receiver elements is helpful for determining the azimuth angles of formation interfaces. Compared with the individual-reception mode, the azimuth measurement accuracy of the APA acoustic receiver station is greatly improved when working in the scanning-reception mode. Compared with the APA scanning-reception scheme, the CPA scanning-reception scheme performs better in simultaneously measuring the azimuth angles of two reflectors outside the borehole.