Well logging

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ards the transverse plane present, which is achieved by applying an external magnetic field that is in resonance with the precessing protons, which are polarized. The protons will then continue in their precession process, after rotation, but in a plane that is perpendicular to the aligned protons, which creates a changeable and detectable magnetic field. Dephrasing of the protons may result due to interferences resulting from the polarized magnetic field at the proton’s location. The dephrasing factors can then be quantified, and used to prevent further dephrasing by another time constant (T2).
Focused electrons moving horizontally through the formation: Laterlogs are utilized in low-resistive muds. A focused current is made to flow horizontally by placing two guard electrodes that are located above and below the electrode’s current. The central generating electrode and the guard electrodes are balanced and a sheet of current then penetrates the formation.
High frequency alternating current: these logs are used in oil-based or fresh-water muds. A high frequency current flows through the transmitter when a receiver coil and transmitter coil are placed at the ends of sonde. This creates a magnetic field, which, in turn, generates an alternating current. The generated current alternates depending on formation resistivity and the quantifiable parameters are recorded in the receiver coil.
Rt: is obtained by using Dual Laterlog Borehole correction (both deep and shallow laterlogs). In order to achieve this, Rs, Rm, RLLD, RLLS, Rw, and RSFL should be known. The obtained data must be calculated to substitute the following formulas:
Rw: SP log is used to identify the clan sand lines and shale baseline on the SP log. Temperature is then determined to convert (Rm)Tm to (Rmf)Tf. SSP is then calculated by using the invaded resistivity Rf, and the bed thickness, h. the formula for this conversion is converting Rmf@Tf to Rmfe @ Tf, then Calculate Rwe: Rwe=