Investigation and analysis of focusing ability and instrument structures of micro-cylindrically focused logging

Micro-cylindrically focused logging (MCFL) method can measure the resistivity of shallow formations at different depths. In this paper, the principle of MCFL is analyzed and the three-dimensional modeling and simulation of the instrument is realized by finite element method (FEM) and COMSOL multiphysics. Moreover, the focusing ability is verified by comparison with the unfocused state. The detection performance of the instrument and the influence of electrode structures are discussed, which are of great significance to guide the production and optimize the instrument. Numerical results show that the instrument has excellent focusing ability, and can change the detection performance by adjusting the electrode structures to meet different engineering requirements.