An investigation of electromagnetic anti-collision real-time measurement for drilling cluster wells

• A new antisymmetry electromagnets rotating magnetic ranging method is proposed.
• A collision avoidance estimation is established based on magnetic difference signals.
• The influence of several factors on magnetic difference signals are analyzed.

Measuring borehole distance while drilling, an essential process that guides the drill, effectively avoids collisions with existing wells. This paper proposes a rotating magnetic ranging method based on two symmetrical electromagnets with opposite magnetic moments. An electromagnetic collision avoidance calculation model is established, and the influence of inclination of target well and borehole distance on magnetic difference signal is analyzed. The results demonstrate that the severity of oscillation of magnetic difference curve reflects the existence of casing in the target well. By analyzing the variation trend of the curve, it is possible to determine whether the drill is approaching or departing from the target well. Distortion in magnetic difference curve indicates the possibility of collision, and the peak–peak value of the curve effectively reflects the approximate borehole distance. The complete research validates the effectiveness and accuracy of the rotating magnetic method based on two symmetrical electromagnets with opposite magnetic moments, providing theoretical support for the development of the electromagnetic collision avoidance system.