| 摘要 |
A transmitter for a sonic wall logging tool contains a piston, the plane of the piston being disposed along the longitudinal axis of the tool. The piston moves, in its entirety, transversely with respect to the tool when an alternating current flows in two coils disposed in magnetic fields created by two mangets. Sonic positive pressure waves are created on one side of the piston, and sonic negative pressure waves are created on the other side of the piston. Shear waves are created in the formation, a positive shear wave being created in the formation on one side of the tool, and a negative shear wave being created in the formation on the other side of the tool.
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