Design Of Electromagnetic Signal Acquisition And Transmission System For Dection The Adjacent Well's Distance

"Complex structure well" is the twenty-first century cutting-edge technology of the international oil industry,from the adjacent wells while drilling is one of the key technology to detect fine control "complex structures well" wellbore trajectory.Based on the principle of rotating magnetic field ranging,well trajectory and horizontal to vertical wells for CBM communication is controlled to the target application,developed from the adjacent wells while drilling electromagnetic detection system.Adjacent wells from the MWD technology is the use of electromagnetic induction,used magnetic source is mounted behind the drill bit short section as a magnetic field generator located adjacent wells three-axis magnetic field sensor as a receiver to calculate the distance between the wells and position,for guiding the direction of the drilling bit.In this paper,the system is divided into data acquisition circuit,data transmission module and PC software to receive three parts.Low-frequency magnetic field signal characteristic for the weak,developed a low-noise,narrow band-pass,high-precision data acquisition circuit;the improved DFT peak method,automatic tracking lock downhole triaxial magnetic field signals,filter out the clutter and noise of other frequencies,accurate extract the amplitude of the signal;data transmission module adopts anti-interference ability,transmission distance,complete with reliable data transfer speed of Manchester code transmission protocol of long-distance transmission.PC reception software uses visual development tool for C ++ Builder design is completed.Outdoor tests and field tests show that the developed adjacent wells from the detection system,the detection distance can reach 50 meters,to meet the actual needs of the gas layer mining vertical and horizontal wells in communication.