Non-Magnetic Drill Collars (NMDC) are essential Bottom Hole Assembly (BHA) components used in directional drilling operations to eliminate magnetic interference and ensure accurate downhole measurements.
KTK Energy manufactures NMDCs using self-developed low-carbon stainless steel, engineered to deliver:
- Ultra-low magnetic permeability
- High mechanical strength
- Reliable performance under high temperature and high-pressure conditions
These drill collars are specifically designed to support MWD (Measurement While Drilling), LWD (Logging While Drilling), and gyro survey tools, ensuring precise wellbore positioning and trajectory control.
Technical Specifications
Magnetic Properties
- Relative magnetic permeability: μr ≤ 1.005 – 1.010
- Magnetic field deviation: ≤ ±0.05 μT
Ensures high-accuracy data acquisition for MWD, LWD, and gyro systems.
Material & Chemical Composition
KTK Energy NMDCs are produced using advanced low-carbon stainless steel grades:
- Z1810A (P530 Grade)
- Z2018A (P550 Grade)
- Z2020A (P650 Grade)
- Z1810B (Standard NM Grade)
Key characteristics:
- Optimized Cr-Ni-Mo alloy system
- Enhanced strength and corrosion resistance
- Stable magnetic performance
Corrosion Resistance
- Tested per ASTM A262 (Practice A & E)
- Result: No intergranular corrosion cracking
Ultrasonic Inspection (UT)
- 100% ultrasonic testingaccording to ASTM A388
- Acceptance criteria: API 7-1 compliant
Grain Size
- ASTM grain size: 5 or finer
Thread & Connection Options
- API REG connections
- NC connections
- Double shoulder threads (optional)
- Custom premium connections available
Threads can be processed using cold rolling technology to improve fatigue resistance.
Size Range
- Outer Diameter (OD): 3 1/8” to 11”
- Length: 9150 mm / 9450 mm
- Multiple ID and drift configurations available
Full API and NC size range Custom dimensions supported
Key Features
- Ultra-low magnetic permeabilityfor precise directional measurement
- High-strength alloy steel construction
- API-compliant manufacturing and inspection
- Excellent corrosion resistance
- Cold-rolled threads for extended service life
- Customizable sizes, connections, and configurations
Applications
KTK Energy Non-Magnetic Drill Collars are widely applied in:
- Directional drilling and horizontal drilling
- Extended reach drilling (ERD)
- MWD and LWD tool housing
- Gyro survey operations (north seeking and drop gyro)
- High-temperature and high-pressure wells
How to Select NMDC (Decision Guide)
When selecting non-magnetic drill collars, consider:
- Required OD and ID based on well design
- Compatibility with MWD/LWD or gyro tools
- Connection type (API REG, NC, or premium)
- Downhole temperature and pressure conditions
- Required magnetic performance
KTK Energy provides engineering support for customized NMDC solutions.
FAQ
What are non-magnetic drill collars used for?
They are used to house MWD, LWD, and gyro tools while minimizing magnetic interference in directional drilling.
Why is low magnetic permeability important?
It ensures accurate downhole measurements and prevents signal distortion in survey tools.
Are KTK Energy NMDCs API compliant?
Yes, all products comply with API standards and undergo full inspection and testing.
Can NMDCs be customized?
Yes, KTK Energy offers custom sizes, connections, and thread types based on project requirements.
What drilling operations require NMDC?
NMDCs are essential in directional, horizontal, and high-precision drilling operations using MWD, LWD, or gyro systems.
Summary
Non-Magnetic Drill Collars from KTK Energy are engineered to deliver low magnetic interference, high structural strength, and reliable performance for directional drilling applications. With API-compliant manufacturing, advanced materials, and customizable configurations, NMDCs ensure accurate downhole measurements in global oilfield operations.
Non-Magnetic Drill Collars (NMDC) Supplier & Manufacturer | MWD / LWD / Gyro | KTK Energy
Non-magnetic drill collars (NMDC) from KTK Energy are API-compliant BHA components designed for MWD, LWD, and gyro survey applications, offering ultra-low magnetic permeability and high structural strength for directional drilling from China.
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