Geomagnetic models analysis for directional drilling

UDK: 624.131.34

DOI: 10.24887/0028-2448-2026-2-51-56

Key words: inclinometer, magnetometer, geomagnetic model, directional survey measurements, survey correction

Authors: M.G. Akhundov (Technology Company Schlumberger LLC, RF, Moscow); A.V. Bevzenko (Technology Company Schlumberger LLC, RF, Moscow); E.M. Ganina (Technology Company Schlumberger LLC, RF, Moscow); O.V. Zhdaneev (Almetyevsk State Technological University «Petroleum Higher School», RF, Almetyevsk; Kazan (Volga Region) Federal University, RF, Kazan)

The paper addresses the problem of ensuring the accuracy of directional survey measurements in directional and horizontal drilling, which depends on the use of geomagnetic models for determining wellbore azimuth relative to true north. It is demonstrated that the parameters of mathematical geomagnetic field models directly affect survey uncertainty and the size of wellbore position uncertainty ellipses. A comparative analysis of global geomagnetic models with different resolutions (IGRF, WMM, WMM-HR, HDGM, BGGM) is performed with respect to their applicability to drilling operations. The high definition geomagnetic model (HDGM), previously widely used in the oilfield service industry, is taken as a reference. The study is based on data from 108 wells located in eight regions of the Russian Federation. Quantitative deviations in magnetic field parameters, including total field intensity, inclination, and magnetic declination, are evaluated. Particular attention is given to the influence of the horizontal magnetic field component and latitude on azimuth uncertainty growth. The results show that, after appropriate adjustment of error model parameters in accordance with Industry Steering Committee on Wellbore Survey Accuracy (ISCWSA) requirements, the world magnetic model provides acceptable accuracy, with uncertainty ellipse growth not exceeding 8 % compared to HDGM. The findings confirm the feasibility of using open-access geomagnetic models for directional drilling under limited availability of high-resolution commercial models and highlight the importance of adapting error codes and accounting for regional geomagnetic conditions to maintain reliable wellbore positioning.

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