Study On Distribution Regularity Of The Magnetic Field Around Casing

In recent years,with the development of encryption of borehole in old oil and gas fields,cluster wells and large displacement wells,distance among wells is reducing when drilling,which increases the risk of well collision and bring many difficulties and huge economic loss for the development of oil and gas fields.The basic studies about electromagnetic wave detection anti-collision technology,recently developed,are made in this thesis.For the electromagnetic wave detection anti-collision technology,the primary problem is the distribution regularity of the magnetic field around the casing under the condition of geomagnetic field.However,the studies about this technology are focus on experiment of the vertical casing less research on inclined casing.Based on research of vertical casing,theoretical analysis,simulation and experiment(vertical and horizontal casing)of different postures are made in this thesis.Based on theory of magnetization,assuming the casing is a hollow cylinder,and the geomagnetic field is uniform,the model of distribution regularity of the magnetic field around casing is built,and corresponding calculating program is written to gain the laws of magnetic intensities.Maxwell is used to simulate,determine the method of establishing uniform magnetic field.Different postures(azimuth and dip angle)and the “end effects” are considered to analysis the distribution regularity of the magnetic field around the casing through simulation.Experiments are carried out of the vertical and horizontal casing to compare the results of theoretical calculation and simulation and experiments.The results of experiments are anastomotic with the results of theoretical calculation and simulation.Which verify the correctness of theoretical calculation and simulation.