Anchorage, Alaska, September 25, 2025
At the ISCWSA 62nd General Meeting, Gunnar's Clinton Moss and ExxonMobil's Chad Anton presented field results from the world's first commercial deployment of active magnetic ranging-while-drilling on powered drill pipe, in the high-resistivity, salt and oil-based-mud conditions where conventional wireline ranging struggles.
At the Industry Steering Committee on Wellbore Survey Accuracy (ISCWSA) 62nd General Meeting, Wellbore Positioning Technical Section, held September 24–25, 2025 in Anchorage, Alaska, Clinton Moss, Founder & CEO of Gunnar Energy Services, and Chad Anton, Senior Drilling Engineer at ExxonMobil, co-presented “Field Results of Access-Independent Active Magnetic Ranging While Drilling Using Powered Drill Pipe in High Formation Resistivity and Oil-Based Mud Environments.”
The presentation detailed how ranging-while-drilling on powered (wired) drill pipe, enabled by Reelwell's DualLink, carries active and passive magnetic ranging, gyro-while-drilling and continuous interference monitoring downhole, delivering roughly 10× the current injection of conventional wireline AMR with no wireline runs or BHA trips. Critically, it performs in oil-based mud and high-resistivity salt formations that weaken conventional wireline signals. Two successful field deployments followed in 2025, in Australia and the United States.
The U.S. case study showed the method on a well that conventional plug & abandonment could not reach: a stuck packer and parted tubing left no access below ~1,050 ft, with a narrow ~10 ft intercept window beneath the packer, sparse target surveys, high-resistivity salt, oil-based mud and elevated CO₂ pressure. The system located the target at 3,595 ft and followed it for 4,684 ft at 5–10 ft separation, intercepting at the exact planned depth of 8,642 ft MD. Hydraulic communication was confirmed and the well was killed by bullhead; the team then milled the casing window outside-in, re-entered with tubing, and placed a regulator-witnessed cement plug, tagged within 2 ft of prediction.
It was the first successful deployment of active magnetic ranging-while-drilling using powered drill pipe, avoiding 10+ wireline runs and roughly two weeks of rig time, extending range through 10× current injection, and delivering higher accuracy and lower HSE risk than legacy wireline methods. The full presentation is available from ISCWSA.