Methodology for the Permeability Prediction using Spatial Encoding of the Magnetic Field in Nuclear Magnetic Resonance (NMR)

José Carlos Xavier da Silva, Giovanni Chaves Stael, Silvia Lorena Bejarano Bermudez, Luis Jacobo Aguilera Aguilera, Rodrigo Bagueira de Vasconcellos Azeredo
2021 Revista Brasileira de Geofisica  
We present a new formulation to determine permeability in reservoir core rocks based on the spatial encoding of the magnetic field used in the NMR technique. The variations of the magnetic field generate multiples T 2 spectra in one sample, creating a representative data of porosity distribution. In this study, each T 2 spectrum was called "magnetic cut" and the quantity depends on the length of the samples. The novel methodology was built on the assumption that the permeability in the axial
more » ... ection is a linear combination of two magnetic cuts, which correspond to the maximum and minimum area, calculated from the integration of the porosity distribution in function of the transverse relaxation time. Four groups of wells were analyzed. Three were carbonates from India and Tunisia and one was sandstone from Brazil. The model was adapted to each type of formation and a specific generatrix equation was obtained for each one. The K ON permeability method demonstrated a good correlation to the data obtained by routine-gas analysis. In addition, the K ON model showed a good accuracy even when compared with classic permeability models like Timur-Coates K TC and Schlumberger-Doll Research K SDR . This model could improve the determination of permeability parameters for different lithologies.
doi:10.22564/rbgf.v38i3.2060 fatcat:kzobmbi4yneyvj43xb637jewvu