Forward Models for Nuclear Magnetic Resonance in Carbonate Rocks

摘要

In the conventional approahc to the interpretation of nuclear magnetic resonance (NMR) measuremetns on water-saturated reservoir rocks, it is assumed that the T_2 distribution and the pore size distribution are directly related. However, both laboratory and log data show that this relationship breaks down in many pore systems, especially carbonates, which consist of micro (intragranular) and macro (intergranular) porosity. This break-down limits our ability to predict permeability and movalbel fluid fractions. Physically, it is due to the diffusion of magnetization between the intra- and intergranular pores.