MELDOR- High-Precision Directional Sensor for MWD Systems
UNIQUE ACCELEROMETER-FREE TECHNOLOGY
Direct Angle Measurement (DAM) and Digital Fluxgate Magnetometer Technology
The MELDOR Directional Sensor is a high-precision downhole measurement module designed for Measurement While Drilling (MWD), Logging While Drilling (LWD), directional drilling, and borehole survey applications.
Unlike conventional directional sensors based solely on MEMS accelerometers and standard magnetic sensors, the MELDOR Directional Sensor combines two proprietary measurement technologies:
- Direct Angle Measurement using a liquid capacitive tilt sensor;
- Digital Vector Magnetometry using a high-precision three-axis digital fluxgate magnetometer.
Together these technologies provide stable and accurate measurements of inclination, azimuth and toolface under severe vibration, shock loading and elevated temperatures.
Key Advantages
✔ Direct Angle Measurement Technology (DAM)
✔ Three-Axis Digital Fluxgate Magnetometer
✔ High-Precision Vector Measurement
✔ Digital Signal Processing
✔ Orthogonality Calibration up to 0.01°
✔ Non-Linearity below 0.1%
✔ High Shock Resistance
✔ Long-Term Stability
✔ Designed for Harsh Downhole Environments
Two Measurement Technologies – One Directional Sensor
Unlike conventional directional modules, the MELDOR Directional Sensor integrates two independently developed measurement technologies specifically optimized for harsh drilling conditions.
The liquid capacitive tilt sensor directly measures inclination angle, while the digital fluxgate magnetometer precisely determines the Earth’s magnetic field vector.
Together they provide accurate directional measurements without relying solely on mathematical estimation techniques.
Direct Angle Measurement (DAM) Technology
Measuring Inclination Directly
Most modern MWD systems determine inclination using MEMS accelerometers.
However, an accelerometer does not measure angle.
It measures acceleration.
The inclination angle is calculated from the measured gravity vector after digital processing.
During drilling the sensor experiences vibration, shock loading, stick-slip, and other dynamic accelerations.
Since gravity and drilling dynamics are both accelerations, sophisticated filtering algorithms are required to estimate the gravity vector.
The MELDOR liquid capacitive tilt sensor follows a fundamentally different approach.
Instead of estimating inclination from acceleration, it directly measures the angular position of the liquid surface relative to gravity.
The sensing liquid naturally attenuates high-frequency vibration before the signal reaches the electronic circuitry.
This enables highly stable inclination measurements in harsh drilling environments.
Benefits
- Direct angle measurement
- Accuracy up to 0.005°
- Mechanical vibration filtering
- No temperature hysteresis
- Less than 0.1% non-linearity
- Excellent long-term stability
- High shock resistance
Digital Vector Magnetometry
High-Precision Three-Axis Digital Fluxgate Magnetometer
Magnetic azimuth accuracy depends not only on sensor sensitivity but also on vector measurement quality.
The MELDOR three-axis digital fluxgate magnetometer has been specifically developed for precision directional measurement in demanding downhole applications.
The entire measurement chain is optimized to provide stable magnetic vector measurements across the operating temperature range.
Digital signal processing, precision calibration, and advanced compensation algorithms minimize systematic errors and improve long-term stability.
Key Advantages
Fully Digital Signal Processing
Digital signal processing minimizes analog errors, improves repeatability and ensures stable measurements.
Precision Orthogonality Calibration
Axis orthogonality is calibrated to 0.01°, significantly reducing vector calculation errors.
Low Measurement Non-Linearity
Measurement non-linearity remains below 0.1% throughout the operating temperature range.
High Vector Accuracy
Designed for precise three-dimensional magnetic field measurement required in directional drilling.
Excellent Temperature Stability
Stable magnetic measurements over a wide temperature range.
Compact Design
Optimized for integration into modern MWD systems.
Low Power Consumption
Suitable for battery-powered downhole tools.
High Reliability
Designed for continuous operation in harsh drilling environments.
Applications
The MELDOR Directional Sensor is designed for:
- Measurement While Drilling (MWD)
- Logging While Drilling (LWD)
- Directional Drilling
- Borehole Survey
- Downhole Navigation
- Geophysical Logging
- High-Temperature Downhole Tools
- Oil & Gas Exploration
- Scientific Downhole Instrumentation
Technical Specifications
| Parameter | Typical Value |
|---|---|
| Inclination Technology | Liquid Capacitive |
| Magnetic Sensor | Three-Axis Digital Fluxgate |
| Inclination Accuracy | Up to 0.005° |
| Orthogonality Calibration | Up to 0.01° |
| Measurement Non-Linearity | <0.1% |
| Azimut Accuracy | Up to 0.01° |
| Long-Term Drift | Negligible |
| Digital Signal Processing | Yes |
| High Shock Resistance | Yes |
| High Temperature Operation | Available upon request |
Frequently Asked Questions
What makes the MELDOR Directional Sensor different?
It combines two proprietary measurement technologies: Direct Angle Measurement using a liquid capacitive tilt sensor and Digital Vector Magnetometry using a three-axis digital fluxgate magnetometer.
Why use a liquid capacitive tilt sensor?
Unlike MEMS accelerometers, which estimate inclination from measured acceleration, the liquid capacitive sensor directly measures inclination angle while naturally attenuating high-frequency vibration.
Why is orthogonality calibration important?
Precise orthogonality between the three magnetic sensing axes directly influences vector measurement accuracy and therefore azimuth accuracy. Calibration to 0.01° minimizes systematic directional errors.
Why is digital signal processing used?
Digital processing improves measurement stability, reduces analog signal degradation, enhances repeatability and enables advanced calibration and compensation techniques.
What applications is the sensor designed for?
MWD, LWD, directional drilling, borehole surveying, downhole navigation and other high-precision drilling applications.
Why MELDOR?
For decades, MELDOR has focused on developing high-precision downhole measurement technologies rather than simply assembling standard sensor components.
Our Directional Sensor integrates proprietary inclination and magnetic measurement technologies to provide stable, repeatable and reliable directional measurements in environments where conventional solutions face significant challenges.
