Fluid Characterization using Nuclear Magnetic Resonance Logging

Abstract

This paper presents a variety of field applications that illustrate recent advances in nuclear magnetic resonance (NMR) logging fluid characterization methods. The main concepts of NMR logging and the principles underlying NMR diffusion measurements, which form the basis for all standalone NMR fluid characterization methods, are briefly reviewed. Field examples of the MRF 2 Magnetic Resonance Fluid characterization method are presented to demonstrate the separation of oil and water signals, saturation measurements, and oil-viscosity determination. The MRF method is also applied in conjunction with new diffusion NMR techniques to infer wettability states in a suite of partially saturated core samples. The application of two-dimensional NMR maps of relaxation times and molecular-diffusion rates to identify fluids and determine their properties in complex multi-fluid environments, including oil-base mud (OBM) filtrate, light oil, and gas is illustrated with field examples from the deepwater Gulf of Mexico and the North Sea.