A receiver section for an acoustic oil well logging tool comprised of a plurality of receiver sub-units connected longitudinally within a rigid tubular member. Each receiver sub-unit has a series of acoustic wave sensors located for receiving and detecting monopole, dipole, quadrupole and unipole waveforms....http://www.google.de/patents/US5936913?utm_source=gb-gplus-sharePatent US5936913 - Acoustic formation logging system with improved acoustic receiver
