Carol Finn Jeffrey J. Love E. William Worthington Fraser Lawson Stefan Maus Shola Okewunmi Benny Poedjono Andrew Buchanan 2013 To pinpoint the location and direction of a wellborne, directional driller rely on measurements from accelerometers, magnetometer and gyroscopes. In the past, high-accuracy guidance methods required a halt in drilling to obtain directional measurements. Advances in geomagnetic referencing now allow companies to use real-time data acquired during drilling to accurately potion horizontal wells, decrease well spacing and drill multiple wells from limited surface locations. application/pdf en Schlumberger Geomagnetic referencing--the real-time compass for directional drillers article