Joint Interpretation of Electrical Resistivity and T2 NMR Measurements to Estimate Wettability and Water Saturation

The wettability of rocks can be assessed from interpretation of borehole geophysical measurements, such as electrical resistivity and nuclear magnetic resonance (NMR). These wettability models often require additional inputs (e.g., water saturation, porosity, and pore-geometry-related parameters), which are difficult to obtain independently. Consequently, a multiphysics workflow that integrates resistivity and NMR measurements can reduce the number of input parameters, resulting in a more accurate and robust wettability assessment. The objectives of this paper are to introduce a new workflow for joint interpretation of resistivity and NMR measurements to simultaneously estimate wettability and water saturation, and to verify the reliability of wettability and water-saturation estimates by comparison with experimentally measured contact angles, Amott Indices, and gravimetrically assessed water saturation. Copyright © 2020 Society of Petroleum Engineers