ALBERT

Beschreibung: The monograph introduces the reader to the world of inductive well logging - an established method for surveying the electrical conductivity of rocks surrounding a borehole. The emphasis is on developing a theory of inductive logging and on understanding logging tools basic physics, since this theory and understanding furnish valuable insights for inventing practical induction logging techniques. The first chapter of the book presents the basic laws of electromagnetism from a point of view that will facilitate the application of the theory to problems in electromagnetic logging. Many topics that play an important role in the design and interpretation of tools readings are covered. The vertical resolution and radial depth of investigation of different induction tools is systematically considered. Special attention is paid to principles of induction logging with transversal induction coils, to transient method of induction logging in media with cylindrical and horizontal interfaces and to the influence of anisotropy on the electromagnetic field measured in a conducting medium. Multi-coil differential induction probes and induction logging based on measuring the inphase component of the secondary field or the quadrature component difference are also described in detail. The last chapter is devoted to mathematical modeling of the response of induction logging tools in 3D geometries. The theory of inductive logging presented in this volume can be applied to logging after drilling as well as logging while drilling. Introduction. 1. Basic electromagnetic laws and Maxwell's equations. 2. Electromagnetic field of the magnetic dipole in a uniform conducting medium. 3. Methods for the solution of direct problems of induction logging. 4. Electromagnetic field of a vertical magnetic dipole on the axis of a borehole 5. Quasistationary magnetic field of a vertical magnetic dipole in a formation with a finite thickness. 6. The two-coil induction probe on the borehole axis, when the bed has a finite thickness. 7. Multi-coil dioeerential induction probes. 8. Induction logging based on measuring the inphase component of the secondary field or the quadrature component difference of type Q Hz(omega1) - omega1/omega2 Q Hz(omega2). 9. Transient induction logging. 10. Principles of induction logging with transversal induction coils. 11. The influence of anisotropy on the field of the magnetic dipole in a conducting medium. 12. Mathematical modeling of the response of induction logging tools in 3D geometries.