Tutorial: A Survey of Directional Drilling Sensor Module Calibration Techniques



Directional drilling has become a de facto practice for the oil and gas industries. However, the many advantages brought by this technique come at a cost: the technical challenges related to the underground 3D navigation of the drill string.

Directional drilling navigation is done exclusively without the aid of GNSS, a major feat in assuring the borehole stays on the assigned trajectory. Wondering outside the concession’s borders or unintentionally colliding with other boreholes are some of the risks that complement missing the gas or oil reservoir.

In addition to these constraints, the directional drilling sensor modules, or directional modules in short, operate under high vibration, shock and high temperatures.

The constraints imposed by the risks and harsh operating environment impose very stringent performance requirements for the directional modules, calling for their calibration.

The tutorial provides a survey of the methods used in the calibration of directional modules, from the traditional to the state of the art, and provides plenty of key technical points.


The main objectives of this tutorial are:

  1. Provide take-away nuggets that attendees can use in their projects or research programs. Directional module R&D scientists and engineers can glean ideas on how to better design for testability, production and test engineers will get tips on productivity enhancement, software engineers will learn techniques associated with nonlinear equation solving.
  2. Build a bridge between academia and industry. The tutorial will illustrate how abstract concepts and practical considerations mesh up in real-life application. Stir the interest of student attendees and, perhaps, help them make career choices whether in directional drilling sensor development or test engineering.
  3. Stimulate discussions among the attendees and with the instructor on industry best practices.


The tutorial will be presented as a lecture and be supported with a Power Point presentation. The lecture and discussions will fit in the 90-minute time slot.

The outline is shown below:

  1. Part I – Introduction
    1. Directional Drilling Primer
    2. Types of Directional Module Sensors
    3. Azimuth
    4. Inclination
    5. Dip Angle
    6. Tool Face – Gravitational
    7. Tool Face – Magnetic
    8. Sensor Errors
  2. Part II – Classes of Calibration
    1. Reference-Based Calibration Methods
    2. Reference-Free Calibration Methods
  3. Part III – Current State of the Art Techniques
    1. “Kneading the Field”
    2. Scale Factors and Biases
    3. Misalignments
    4. Alignment Between Accelerometers and Magnetometers
    5. Pros and Cons Summary
  4. Part IV – New Calibration Techniques
    1. Other Total Field Calibration Techniques
    2. Sensor Frame to Body Frame Alignment
    3. Accelerometer to Magnetometer Frames Alignment
    4. Pros and Cons Summary
  5. Part V – Questions and Answers


Speaker Bio

Marius Gheorghe has earned a degree in electrical engineering from the Polytechnic Institute of Bucharest, Romania in 1986.

A great deal of his professional career was dedicated to designing test equipment used in a variety of applications ranging from the semiconductor industry to military jet aircraft, nuclear submarines and space programs. Prior to joining Ideal Aerosmith Inc., where he holds the position of Engineering Manager, he has worked for over 14 years with a world leader in ATE manufacturing in Ontario, Canada. His portfolio includes substantial hardware and software design, award-winning ATE and technical leadership. In addition to his industry experience, he has authored papers on inertial sensor calibration techniques, has taught at the Polytechnic Institute of Bucharest and the Advanced Computer Training for Engineers, Toronto, and is a contributor to IEEE standards on inertial sensors and systems.

Mr. Gheorghe is a senior member of IEEE and licensed as Professional Engineer in Ontario, Canada. He has been awarded the Distinguished Committee Service Award for his contribution to the development of the IPC/WHMA-A- 620A standard in 2007 and his Horizon 1500 wiring analyzer design was awarded The Best in Test by Test and Measurement World in 1996.