MagVAR In-Field Referencing (IFR) improves well placement accuracy in directional drilling by providing a comprehensive 3D geomagnetic reference model for real-time steering.


Measurement while drilling (MWD) employs downhole gravity and magnetic field sensors to determine the inclination and azimuth of the drill bit. Conversion from magnetic azimuth to true azimuth requires knowledge of the direction and strength of the magnetic field in the well bore. MagVAR IFR provides a 3D model of the subsurface geomagnetic field, computed from a combination of marine, airborne and satellite magnetic surveys. Corrections for time-varying disturbance fields have to be applied separately.

MagVAR advanced technology

The strength of the MagVAR IFR method is to account for the entire wavelength spectrum of the geomagnetic field in a single model. This avoids the inaccuracies of earlier methods, where a local magnetic model in plane geometry was added to a global spherical main field model (such as the International Geomagnetic Reference Field), missing the intermediate waveband. MagVAR IFR combines satellite, ship and airborne measurements to seamlessly capture the longest to the shortest wavelengths of the geomagnetic field. Through this comprehensive approach, MagVAR IFR achieves significantly enhanced accuracy of the downhole geomagnetic model.

Product availability

MagVAR IFR solutions are provided as 3D grids, together with a software application enabling the driller to compute the magnetic declination, dip and total field along any chosen well path. This places the driller in control, simplifying well surveying and reducing follow-on costs. Alternatively, MagVAR IFR solutions can also be provided on a per-well basis. MagVAR IFR is available globally from Magnetic Variation Services LLC.

Proven track record

MagVAR technology has been successfully employed in on- and offshore fields of North America, South America, Europe, Africa, Australia and Asia. Validation studies against downhole MWD surveys have confirmed the high accuracy of MagVAR IFR solutions.


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Maus, S., and S. DeVerse, Enhanced Wellbore Placement Accuracy Using Geomagnetic In-Field Referencing and Multi-Station Correction, Unconventional Resources Technology Conference (URTeC) DOI 10.15530/urtec-2015-2173526.
Maus, S., Magnetic Referencing and Survey Accuracy for Horizontal Development in the Permian, AADE Luncheon, Houston, 02/05/2015 link to presentation.
Maus, S., Managing Main & Crustal Magnetic Fields and New Developments in Global Magnetic Modeling, ISCWSA-41, London, 20-Mar-2015 link to presentation.
Podjono, B., N. Beck, A. Buchanan, L. Borri, S. Maus, C. A. Finn, E. W. Worthington and T. White, Improved Geomagnetic Referencing in the Arctic Environment, SPE Arctic and Extreme Environments Conference & Exhibition held in Moscow, Russia, 15–17 October 2013, SPE-166850-PP
Poedjono, B., S. A. Rawlins, C. K. Singam, A. Van Den Tweel, A. Dubinsky, R. Rakhmangulov, and S. Maus, Addressing Wellbore Position Challenges in Ultra-Extended-Reach Drilling in Russia's Far East, SPE Russian Oil & Gas Exploration & Production Technical Conference and Exhibition held in Moscow, Russia, 16–18 October 2012, SPE-160784-PP
Poedjono, B., D. Montenegro, P. Clark, S. Okewunmi, S. Maus, X. Li, Successful Application of Geomagnetic Referencing for Accurate Wellbore Positioning in a Deepwater Project Offshore Brazil, IADC/SPE-150107-PP, Drilling Conference and Exhibition, San Diego, California, USA, 6–8 March 2012.