Evaluation of the Wettability and the Petrophysical Properties in Carbonate Reservoirs by Advanced NMR and MRI Techniques

Abstract

Abstract Carbonate rocks are among the dominant oil reservoir formations. Due to their heterogeneity, their petrophysical properties are difficult to be evaluated. Magnetic Resonance, applied as low-field Nuclear Magnetic Resonance (NMR) or Magnetic Resonance Imaging (MRI), are powerful tools for reservoir characterization. Their basic advantage is the quantitative demarcation of various fluids. In this work we have used MRI methods in order to evaluate the petrophysical properties of carbonate rocks. For this purpose commercial limestone, saturated with deionized water, crude oil and model oil or mixture of water with model oil were used to acquire calculated spin-spin relaxation time (T2) and Diffusion Tensor Imaging (DTI) MRI scans. This leads to the pixel-by-pixel characterization of the rock samples and the quantitative evaluation of the saturation profiles in 3-D space. The proposed MRI techniques offer a new insight in the spatially resolved information of petophysical properties towards better understanding of the fluid-rock matrix interactions.