Applications of a New Technique to Acquire Spatially Resolved NMR Petrophysical Data

摘要

NMR pore size distributions derived from measurement of the NMR T2 relaxation are extensively utilized both in the laboratory and in well-logging tools. Typically these measurements are made to quantify the type of fluid in the pore network (clay bound, capillary bound or free fluid). In addition to pore size, the NMR relaxation time T2 is also sensitive to fluid type (oil versus water) and the wettability of the rock. There are a number of applications that can benefit from resolving this information spatially. This work presents a new method for acquiring T2 distributions spatially in a rock sample. Three applications will be investigated to explore the capabilities and usefulness of the new technique. The three applications are: 1) a simple quick method for determining the irreducible water saturation, 2) monitoring fluid redistribution following centrifugation, and 3) investigation of sample heterogeneity.