Design Of A Three-dimensional Electromagnetic Resistivity Azimuthal LWD Instrument

?Azimuthal LWD instruments have gradually entered an era of high quality,high standards and high requirements.The aim of the measurements is to explore the formation interface and identify the formation anisotropy.Work environments have also evolved from conventional wells to additional difficult wells.Therefore,the development of a high-quality instrument for LWD in small boreholes is an urgent task.A new azimuth electromagnetic wave resistivity while drilling instrument is designed and developed by reviewing the types and design ideas of Schlumberger,Halliburton,Baker Hughes,Sheng Li Logging Research Institute and CNOOC Oilfield Services,the main work is as follows:Based on basic measurement principles and antenna concepts,we derive signal components for both coplanar and heteroclinic objects,and complete the theoretical derivation of antennas.Thus,the main structure of multi-source distance,multi-spacing,multi-frequency,multi-receiving antenna satisfying "three-dimensional holographic detection" can be obtained.The design program simulates the antenna structure of the instrument and compares it to previous conclusions to verify its correctness.In this paper,we focus on the problem of identifying the formation anisotropy and detecting the formation interface.In this paper,using the full component advantage of "three-dimensional holography",through formula derivation,the useless signals are excluded,and the signals with great effect of detecting the formation interface and identifying anisotropy are found.Moreover,forward simulation validation is performed by creating formation models and control variables.?The problem of instrument structure design in tiny holes and complex environments is addressed.The mechanical structure is based on a 3D holographic antenna architecture.The main miniaturization idea is to use a two-terminal distribution in the electron circuit bin,the space required by the main body of the instrument was axially designed,the external connection part adopts compact modular design.Ansys simulations were used to test the stability and reliability of the instrument’s mechanical structure,which was repaired.In this process,the advantages and disadvantages of the design are summarized,and enlightenment and experience are gained,thus laying a solid foundation for follow-up prototype research and development.