Research On Magnetic Measurements Positioning Technology In Connected Wells

In the drilling process, directional well drilling requires measuring the direction parameters of the borehole where the drill placed timely and accurately, so as to depict the well track and then guide the drilling work. Among them, the requirement in connection accuracy between operating wells and target wells in modern drilling technology, the traditional well logging instruments can hardly meet the requirements of high-precision and real-time. The article studies a magnetic measurement method in connected wells which based on dynamic magnetic dipole molecule model and Biot-Savart Law, it has important academic value and practical significance in improving the precision and real-time performance of the measurements.The paper summarized the research status, advantages and disadvantages of the rotating magnetic field orientation technology at home and abroad. It designed a location measurement method based on the permanent magnet theory and Biot-Savart Law, conducted systematically study and model simulation on the mechanism of the measurement method, and verified the method by building experiment device. The main tasks and responsibilities of the paper are as follows:Introduce the permanent magnet model from two aspects of molecular circulation and magnetic dipole molecule model, describe the relationship and difference between them, determine the theoretical basis of magnetic ranging system, establish magnetic ranging system mathematical model based on magnetic dipole molecule model and Biot-Savart Law, complete mathematical expression derivation of the distance and angle, verify its dynamic model with Matlab; Design the experiment device of the magnetic ranging system and perform system tests from hardware and software aspects, describe the permanent magnet sub structure and material selection, flux gate and acceleration sensor selection of the system and hardware design such as power module, high precision AD acquisition module, signal conditioning circuit, Manchester encoding and decoding circuit and so on, introduce the software design from the aspects of upper computer, acquisition boards, communication boards, describe the communication protocol between communication boards and acquisition boards; design a band-pass filter based on FIR and IIR methods and compare the advantages and disadvantages of the two filters in order to achieve accurate measurements of magnetic ranging system, eliminating the noise interference introduced by high temperature, high pressure, strong vibration environment. Aim at the FIR filter’s characters of that high precision but large amount of calculation, time-consuming, large memory, hard to meet the embedded system’s real-time requirement, and IIR filter’s characters of simple structure, time-saving, small memory consumption, but the shortcomings of low precision, possible shortcoming of shocks, the paper optimize the design of the two filters respectively, determine an optimal filter scheme by comparison and analysis on the two filters.Experiments show that a magnetic measurement method in connected wells which based on dynamic magnetic dipole molecule model and Biot-Savart Law can improve the accuracy of the data, improve the reliability of the system and further reduce the computation time and hardware requirements. The system is crash-proof when the measurement device is used for connected well orientating, it can meet the requirement of high precision, real-time, high reliability of the system.