GRADIENT INDUCTION LOGGING TOOL HAVING DIRECT FIELD CANCELATION WITH OPTIONAL COMPENSATION

摘要

Direct field cancelation with optional receive antenna compensation is provided in at least some gradient induction logging tool embodiments. Illustrative embodiments include a spatial gradient antenna arrangement having multiple spatially-separated multi-component coil antennas and a multi-component coil antenna having bucking coils that cancel the effects of both the direct field and the gradient of the direct field on the receive signal. Other tool embodiments include a multi-component coil antenna and a spatial gradient antenna arrangement having spatially separated multi-component coil antennas with bucking coils that cancel the effects of both the direct field and the gradient of the direct field on the receive signal. Those embodiments employing a spatial gradient antenna arrangement for receiving may further be configured to provide compensated measurements by combining measurements from rotated orientations of the spatial gradient antenna. Systems and methods employing such tool embodiments may provide increased induction logging tool functionality and enhanced measurement resolution.

主权项

1. A gradient induction logging tool that comprises:
a multi-component coil transmit antenna having a bucking coil for each component of the multi-component coil transmit antenna; and a spatial gradient antenna arrangement having multiple spatially-separated multi-component coil receive antennas, wherein the bucking coils cancel a direct field and cancel a direct field gradient from the multi-component coil transmit antenna at the spatial gradient antenna arrangement.