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

Claim 11:
12. A method of steering a downhole drilling assembly while drilling a borehole beneath the Earth's surface, the downhole drilling assembly comprising: a first proximal end and a second distal end; a rotatable drill bit positioned at the second distal end of the assembly; an at bit inclination and azimuth tool positioned immediately proximate and connected to the rotatable drill bit, wherein the at bit inclination and azimuth tool comprises a first set of three axis inclinometer sensors, a first set of three single axis magnetometer sensors, and a solenoidal alternating current magnetic coil, wherein the first set of three axis inclinometer sensors are configured to gather information related to an angular position of the rotatable drill bit; a bent sub proximally positioned and connected to the at bit inclination and azimuth tool; a downhole motor proximally positioned and coupled to the bent sub for rotating the drill bit; a steering tool proximally positioned to the downhole motor and 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 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 tool;
the processor of the at bit inclination and azimuth tool of the drilling assembly 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 at bit inclination and azimuth 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 at bit inclination and azimuth tool of the drilling assembly determining a corrected azimuth from the corrected values of the magnetic and gravity field vector measurements;
the solenoidal alternating current magnetic coil of the at bit inclination and azimuth 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 including the information related to the angular position of the rotatable drill bit to the steering tool; and
a 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.