Nuclear Magnetic Resonance Relaxation Permeability Response in Oil Production Conditions
Smith, Charles H.1; Espina, Cristian; Hamilton, Layne; and Quintavalla, Claudio
The empirical application of nuclear magnetic resonance (NMR) relaxation, or T2, response has been documented in many different formations. The comparison of permeability calculated using only textural information provided by these T2 measurements has been remarkably successful at emulating the data from cores and from production rates after completion. The Bray-Smith permeability equation used in these studies removes the necessity of external input from cores or other lab studies to arrive at these useful answers. Most of these studies were concluded in dry gas reservoirs. With the increased emphasis on oil production as a result of commodity prices, the focus of much of the industry exploration has shifted to this heavier and more viscous fluid. The NMR relaxation responses are more complex with the introduction of additional fluids. In many of these reservoirs, three fluids are present: gas, water, and oil of varying thickness and viscosity. Any device that could provide a reasonably accurate permeability response in these conditions would be valuable in determining the economic value of any well or reservoir. This paper makes a comparison of these relaxation (T2) events in oil conditions from fields in Argentina using this Bray-Smith solution for permeability. The expected rate from the derived permeability is compared to the actual production. The more complex fluid conditions are reasonably well approximated by this technique.
AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013