US 12,421,842 B2
Interference compensated axial magnetometer measurements
Makito Katayama, Cheltenham (GB); and Edward Richards, Cheltenham (GB)
Assigned to Schlumberger Technology Corporation, Sugar Land, TX (US)
Filed by Schlumberger Technology Corporation, Sugar Land, TX (US)
Filed on May 8, 2024, as Appl. No. 18/657,902.
Claims priority of provisional application 63/500,674, filed on May 8, 2023.
Prior Publication US 2024/0376815 A1, Nov. 14, 2024
Int. Cl. E21B 47/0228 (2012.01); E21B 7/06 (2006.01); E21B 44/00 (2006.01); E21B 47/18 (2012.01); G01R 33/00 (2006.01)
CPC E21B 47/0228 (2020.05) [E21B 7/06 (2013.01); E21B 44/005 (2013.01); E21B 47/18 (2013.01); G01R 33/0017 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A downhole tool comprising:
a magnetic field sensor deployed in a downhole tool body in sensory range of magnetic flux emanating from an intermittent source of electromagnetic interference;
a processor configured to:
cause the magnetic field sensor to make magnetic field measurements while the downhole tool is deployed in a wellbore;
compute a first average of the magnetic field measurements over a first time interval in which there is no EM interference;
compute a second average of the magnetic field measurements over a second time interval in which there is EM interference;
compute an interference offset as a difference between the first average and the second average; and
remove the interference offset from magnetic field measurements made during a subsequent period during which there is EM interference to compute compensated magnetic field measurements by computing a moving average of a sum of the magnetic field measurements and the offset.