Geoscientists are inclined use pore pressure (PP) plots expressed in PSI versus depth (P-D) because it is beneficial for prospect and play-concept compartmentalization and seal integrity appraisals. On the other hand, drillers and engineers use mud weight equivalents (MWE) in pounds per gallon versus depth (PPG-D) prepare their well prognosis and carry out their drilling program. The conversion method for calculating PPG from the actual measurements in PSI is usually computationally distorted, especially in a geopressured system. PP in permeable beds shows a positive gradient slope on the P-D plot but it generally has a negative slope on the PPG-D plot. This has been attributed incorrectly several geopressure phenomena, such as regression, centroid, etc. This article demonstrates how a new geologically based geopressure conversion modeling (GMC) compensates for erroneous values derived from using a universal (0.052) standard conversion factor (SCF). Moreover, this model simulates realistic geopressure compartmentalization and seal effectiveness in concordance with the actual measured values on the P-D plots and the drilling records. SCF is derived as follows: \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[\begin{array}{ll}\mathrm{From lb/gal to {\ldots}}&\mathrm{12in^{3}/231 in^{3} = 0.052}\\\mathrm{and vice versa}&\\\mathrm{from to lb/gal {\ldots}}&\mathrm{1/0.052 = 19.2}\end{array}\] \end{document} The mathematically driven SCF, which is embedded in most pore pressure prediction software, converts from psi/ft PPG MWE in all calculations without integrating lithology, compartmentalization, pressure differential between seals and reservoirs, structural setting, and hydrocarbon presence. Conversely, GMC, which has been applied successfully in several wells on the shelf and deepwater, produces a comprehensive representation of the equivalent mud weight (EMW) needed exert pore pressure in wet and pay sands. Moreover, it emphasizes the status of the subsurface compartmentalization as would be derived from a D-P plot and the drilling resume. This article will use two cases clarify the GMC concept—one in wet sand and one in pay sand. …