NMR Porosity Partitioning Applied to the Evaluation of Permeability, Irreducible Water Saturation and Electrical Resistivity of Coquinas from the Morro do Chaves Formation

Abstract

The economic viability analysis of a possible petroleum reservoir is based on the knowledge about its petrophysical properties, especially the porosity and its relationship with other properties, such as permeability and resistivity. In carbonate systems, the porosity presents a high degree of heterogeneity, which affects other quantities associated with it. In the present work, data of electrical resistivity, permeability, porosity by nuclear magnetic resonance (total porosity and its partitioning in micro, meso and macroporosity values, and irreducible water saturation) of five samples of Coquinas from the Morro do Chaves Formation (Sergipe-Alagoas Basin) extracted with vertical symmetry. The analysis of these data allowed the correlation between the permoporous pairs and the resistivity, evidencing the effect of the permoporous relations in the electric current flow, and between the percentage distribution of the porous space (micro - percentage values lower than 3.8%, meso - percentage values between 7.9 and 24.8%, and macroporosity, with percentage values higher than 71.5%) with permeability and irreducible water saturation, indicating a strong effect of mesoporosity on the observed values for those parameters. Also, within the analysis process, it was possible to determine the spatial behavior of the analyzed quantities in relation to the outcrop

Keywords

• Coquinas
• Morro do Chaves Formation
• Nuclear Magnetic Resonance