Patent ID: 11965408
Assignee: VECTOR MAGNETICS, LLC
Field: Civil engineering (Other fields)
Classification: CPC E | IPC E

Claim 14:
15. A method of steering a downhole drilling assembly while drilling a borehole beneath the Earth's surface, the downhole drilling assembly comprising: a rotatable drill bit; an at bit inclination and azimuth tool connected to the rotatable drill bit, wherein the at bit inclination and azimuth tool comprises a first set of three axis inclinometer sensors and a first set of three axis magnetometer sensors; a bent sub connected to the at bit inclination and azimuth tool; a downhole motor coupled to the bent sub for rotating the drill bit; a steering tool having a second set of three axis steering tool magnetometer sensors and a second set of three axis steering tool inclinometer sensors connected to a communication device; and a drill string connected to the downhole motor and receiving the steering tool, the method comprising:
a processor of the at bit inclination and azimuth tool of the drilling assembly receiving magnetic and gravity field vector measurements comprising information related to an angular position of the rotatable drill bit from the first set of three axis inclinometer sensors and the first set of three axis magnetometer sensors of the at bit inclination and azimuth and sending the magnetic and gravity field vector measurements comprising the information related to the angular position of the rotatable drill bit to the steering tool;
a processor of the steering tool of the drilling assembly receiving the azimuth and sending the magnetic and gravity field vector measurements from the at bit inclination and azimuth tool and calculating a gravity direction and earth's apparent magnetic field of the at bit inclination and azimuth tool of the drilling assembly within the borehole;
the processor of the steering tool of the drilling assembly removing remanent field contributions and calculating corrected values of the magnetic and gravity field vector measurements;
the processor of the steering tool of the drilling assembly determining a corrected azimuth from the corrected values of the magnetic and gravity field vector measurements;
the processor of the steering tool of the drilling assembly transmitting the corrected azimuth and the corrected values of the magnetic and gravity field vector measurements from the at bit inclination and azimuth tool to the steering tool; and
the processor of the steering tool transmitting the corrected azimuth and the corrected values of the magnetic and gravity field vector measurements from the steering tool to an uphole processor for steering the downhole drilling assembly within the bore.