Monel

Description

3. Application in HDD Pilot Drilling

In HDD (Horizontal Directional Drilling), accurate Azimuth (directional) control is paramount for hitting the target.

• Typical HDD Use: Due to the relatively short length of many HDD bores compared to conventional oil and gas wells, high-strength NMM are used immediately above the directional steering head (like a bent sub or motor) to house the magnetic sensor of the MWD system.
• Monel Use: The user specifically mentioned Monel. Monel, while more expensive and possessing lower mechanical strength than specialty steel NMM, is favoured in HDD for specific reasons:
  • High Precision Surveys: Its exceptionally low magnetic permeability ensures the most stable and accurate magnetic readings possible.
  • Corrosion/Environment: Monel provides high resistance to stress corrosion cracking, especially in certain drilling fluids.