SHIELDING DEVICE FOR IMPROVING DYNAMIC RANGE OF ELECTROMAGNETIC MEASUREMENTS

摘要

The disclosure concerns a device for obtaining electromagnetic measurements in a wellbore. In one implementation, the device includes an electromagnetic source carried by the device and a metamaterial arranged to cover a portion of the device in order to divert electromagnetic waves from the source around the covered portion of the device. In one version, the electromagnetic radiation from the source impinging on the portion of the device covered by the metamaterial, and on the electronics carried by the devices that are covered by the metamaterial is reduced. Depending on the implementation, the electromagnetic source may be an antenna, such as a coil antenna. Also, the antenna coil may be wrapped circumferentially around the tool.