Research on Precise Positioning Technology of Staged Fracturing Sleeve Based on Geomagnetic Anomaly Marking

In order to break through the limitation of the number of positioning stages of the traditional ball-throwing staged fracturing sliding sleeve. Based on the theory of static magnetic field and electromagnetic induction, this paper proposes a precise positioning technology of staged fracturing sleeve based on geomagnetic anomaly marking. This technology sets a high-permeability Permalloy ring group inside the casing according to a certain coding laws as a geomagnetic anomaly tag, collects the magnetic gradient change of the casing diameter through the designed geomagnetic anomaly signal acquisition system, and performs the processing of amplitude limiting amplification, filtering, Analog -to- Digital conversion, zero crossing comparison, and decoding on the collected signals, and finally recognizes the tag positioning data, so as to realize the precise positioning of fracturing sliding sleeve. The reliability of the method is verified by analyzing the magnetic field simulation and building an experimental bench for experimental verification. This technology has the advantages of natural, passive, stable and reliable, and can be widely applied to the precise positioning of fracturing sliding sleeve.