Background Pipeline transportation of oil and gas fluids is widely used in the system of recovery, collection and transport of well flowstream in oil industry. In some cases long operating pipes are used (old fund). Accounting that effective and ecologically safe operating of such pipes requires the periodic control system. The electromagnetic methods are widely used as pipe inner diagnostics. So that magnetic permeability determination basing on electromagnetic field measuring is an important scientific and practical problem. It is necessary to calculate the magnetic permeability in spite of specific electric conduction as it is known from the pulse borehole crack and thickness detector operating experience. Realization of this project needs non-grounded spherical contour with the direct current as a source of magnetic field. Electric permeability does not influence the magnetic field of such source, thus, pipe becomes a paramagnetic characterized by magnetic permeability and geometrical parameters. Theoretical basis of such approach is a set of algorithms and calculating formulas, allowing the calculation of magnetic induction vector components (direct problem) and accurate determination of magnetic permability. Aims and Objectives To consider the ability of accurate determination of magnetic permeability and to derive all necessary formulas. Results The work deals with the basic theory of numerical evaluation of the ability to determine the magnetic permeability. There was developed the examples of its practical application using the axial component of magnetic induction vector. This theoretical basis allows to specify the results of interpretation of borehole crack detector, and could be used as a basis for investigation of oil product pipeline facilities.