UTEM 4 Borehole - Receiver Description

The UTEM 4 BH receiver is a multi-component EM receiver for use with the UTEM 4 BH down-hole probe. It incorporates an improved pre-emphasis deconvolution (PED) and other new noise processing techniques, yielding a significantly improved noise performance. In addition to EM data processing, the UTEM 4 BH receiver automatically acquires magnetometer, tilt sensor, and monitoring parameters from the down-hole probe. All acquired data are in digital form.

The input signal is a high speed compressed serial code. The UTEM 4 BH receiver performs decompression, decoding, secondary sigma-delta decimation, PED noise processing, gate sampling, stacking, probe orientation, primary field reduction, data logging and user interfacing. Magnetometer, tilt sensor, temperature data, battery voltage, and other status information are automatically acquired as they occur in the data stream and used in orienting the probe.

The UTEM 4 BH receiver also has a integrated depth counter for automatic down hole data labelling. It can be connected to other compatible instruments for clock synchronisation and parameter data transfer. There is an integrated data logger with non-volatile memory and a SCSI interface with both upload and download capability. Data dumping and uploading of geometrical data are done by connecting the UTEM 4 BH receiver to a SCSI compatible drive with removable media (such as a Zip drive.) The geometrical data are stored in the receiver and used in the probe orientation and primary field calculations. A minimum curvature 3D hole trajectory is calculated from the raw dip and azimuth using a proprietary algorithm.

The UTEM 4 BH receiver has extensive real time monitoring capabilities. Raw signal levels, down-hole settings, and live stacked channel data can be monitored. For quality control, the EM channel data can be monitored as multiple bar graphs mimicking analogue meters. The monitoring functions are controlled by rotary switches for easy scanning between channels, components and display modes.