Magnetic Gradient and Curvature Based Ranging Method

摘要

Methods for determining a distance from a drilling well to a magnetized target well include acquiring magnetic field measurements from the drilling well. The acquired magnetic field measurements are made at a plurality of spaced apart locations in the drilling well. The acquired magnetic field measurements are processed to obtain a ratio including at least one of the following: (i) a ratio of a magnetic field intensity to a first spatial derivative of a magnetic field, (ii) a ratio of a magnetic field intensity to a second spatial derivative of a magnetic field, and (iii) a ratio of a first spatial derivative of a magnetic field to a second spatial derivative of the magnetic field. The ratio (or ratios) is then processed to obtain the distance from the drilling well to the magnetized target well.

主权项

1. A method for determining a distance from a drilling well to a magnetized target well, the method comprising:
(a) deploying a drill string in the drilling well, the drill string including at least one magnetic field sensor in sensory range of magnetic flux emanating from the magnetized target well; (b) making a plurality of spaced apart magnetic field measurements in the drilling well; (c) processing the spaced apart magnetic field measurements to obtain a ratio of a magnetic field intensity to a first spatial derivative of a magnetic field; and (d) processing the ratio computed in (c) to obtain the distance from the drilling well to the magnetized target well.