MagCUBE™

MagCUBE™ builds an IFR (in-field referencing) model for an improved wellbore positioning in horizontal and directional drilling. We build an IFR model with some differential considerations. First, use the geologic (basement) constraint. Second, use variable declinations and variable inclinations in converting a scalar field into a vector field. Third, use high-resolution magnetic data. Coupled with our global aeromagnetic data acquisition capabilities, operators and drillers now have accurate and easily accessible IFR models. MagCUBE™ has been successful in improving positioniing accuracy and reducing costs in horizontal and directional drilling projects globally.

Horizontal and directional drilling maximizes the extraction of oil and gas while minimizing the cost. Horizontal and directional wells are constantly drilled longer and spaced closer while geological targets even become smaller. The positional uncertainty increases with distance drilled. It is critical to reduce positional uncertainty or to improve surveying and positioning accuracy in horizontal and directional drilling.

The Measurement While Drilling (MWD) describes directional surveying and drilling-related measurements. A cost-effective survey in MWD is to measure the distance and two angles: the dip measured by a triaxial accelerometer and the azimuth by a triaxial magnetometer. Magnetic survey relies on the principle of measuring the direction of the wellbore relative to the direction of the local geomagnetic field. Its accuracy is thus limited by the accuracy with which the Earth’s local magnetic field is known at the drilling site and time.

Surface magnetic data is essential because the magnetic azimuth of the bottom hole assembly (BHA) is inferred from the vector component measurements of the MWD survey tool. To convert the magnetic azimuth into a true azimuth, one needs the local declination angle provided by a geomagnetic reference model that includes the local crustal magnetic field variations. The more accurate the reference model, the more accurate the true azimuth of the BHA, i.e., the wellbore positioning.