Magnetized-Casing Passive Ranging, SAGD Well Pair

• →SAGD pairs need continuous separation control along the full length of the lateral.
• →Passive ranging needs the target casing to carry a strong, uniform magnetic signature.
• →Magnetized casing shifts measured MWD azimuth by ~45°, so azimuth has to be reconstructed.
• →The imparted field had to be strong enough to return a result at ~30 ft separation, near the limit of usable signal for unmagnetized casing.

Gunnar engineered and designed the magnetization pattern, applied to the casing on a custom-fabricated magnetization table. The casing was magnetized 400 km from site, transported to location and run in the wellbore. Roughly a week later the signal was collected while drilling past the constellation of poles, with Top Gun 2.0 processing the ranging solutions and reconstructing an azimuth perturbed ~45° by the magnetized casing.