APPARATUS AND METHOD FOR DETERMINING POSITION OF DRILLING TOOL DURING DRILLIN

摘要

Apparatus and method for determining the position of a drilling tool during drilling The apparatus 11 comprises a magnetic source 13 mounted on a rotating drilling tool 8 and at least three magnetometers located outside the drilled hole 2 ( 12) includes. The sensing data of the rotating magnetic field is transferred from the magnetometers to a control unit (CU) provided with a position calculation algorithm 21. The control unit is also provided with pause data of the magnetometers 25. The control unit compares the received sensing data and determines phase angles from the sensing data. The algorithm uses the phase angles and known positions of the magnetometers when calculating the changed position.