DMU (MAGNETIC SURVEY & STEERING)
With the wireline steering systems provided by Direct Systems continuous directional cuts have been conducted successfully at depths of up to 2100m, and for cut lengths of up to 65m.
The advantage in Directional Steering is that the high side tool face of the Navi Motor can be precisely known at all times through the cuts and movements on both inclination and Azimuth can be monitored real time which enables dynamic changes to be administered to the settings. Doglegs can easily be calculated and monitored. Required borehole movements can be made in the borehole which reduces downtime for repeat cuts and missing required targets.
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Steering Tool Typical Performance Summary
Instrument Accuracy
Inclination : +/- 0.1o
- Raw Azimuth : +/- 1.0o (Inc >20o, Dip <70o)
- Dynamic Toolface : +/- 5.0o
Operating Features:
- Instrument OD : 1.0"
- Instrument Length : 36" max
- Pressure Case OD : 1 3/4” typ (1 3/8” min available)
- Pressure Rating : 20000 psi
- Parameters Displayed : Inc, Az, TF, Gx,y,z, Bx,y,z, Temp, Battery Voltage
- Survey Data Update Rate : 2 Surveys per second
Sensors
- DMS Triax accelerometer set
- DMS triaxial magnetometers.
Surface Equipment
- Wireline Power supply : Auto-switching 110 / 240 v AC in
- Rig Floor Display : 256 x 128 Transflective LCD with backlight
- : +12v @ 300mA input
- Temperature : 0 - 125°C (150°C available)
- Shock : 1000g, 1/2 sine 1mS
- Vibration : 20g rms 5-500Hz
Extra running gear required for Steer Tools: Wireline winch, Non magnetic rods, wireline entry subs.
Tools are also effective in quickly setting wedges at depth in boreholes as long as the correct mule-shoes are available for the application.