Subsurface Fluid Characterization Using Downhole and Core NMR T-1-T-2 Maps Combined with Pore-Scale Imaging Techniques

摘要

Characterization of the subsurface fluid types, porosity, saturations, and wettability are critical for understanding the type and volumes of fluids that will be produced during primary completions and secondary waterflood recovery. The oil reserves within the Green River Formation of the Uinta Basin (Utah, USA) in the Greater Monument Butte Unit (GMBU) have variable fluid volumes, saturations, and wettability. Within a potential pay section of over 2,000 feet are over 20 defined producing sandstone reservoir intervals within the Green River Formation with variable depositional environments, mineralogy, and rock quality. Traditional core analyses for saturations and wettability are time-consuming and expensive because of variable reservoir properties within discontinuous sands and high-paraffinic oil containing asphaltenes and resins. Similarly, the variable wettability complicates standard analyses of NMR (nuclear magnetic resonance) data for fluid type and volume estimations.