Nuclear Magnetic Resonance and its applications in low permeability reservoirs

Nuclear Magnetic Resonance well logs have become standard measurements for petrophysical evaluations in the oil industry. In addition to determine porosity and bound and free-water components, NMR logs have been applied to distinguish pore fluids such as gas, condensate and oil in standard reservoirs. Pore size distribution and permeability on the other side are important inputs for evaluating non conventional pays, like the shale-gas reservoirs. Good correlation of NMR pore size distributions, calibrated to the pore size data obtained from PC mercury injection data and NMR permeability calibrated to micro flowmeter measurements, confirm that these measurements can be valid down to 0.1 mD.