Patent ID: 6765380
Filing Date: 2004-07-20
Classification: G01N,G01R,G01V

Abstract:
A method for determining downhole reservoir wettability, comprising:acquiring a first set of nuclear magnetic resonance measurements of formation fluids in earth formations at a selected axial depth along a borehole; inverting the first set of the nuclear magnetic resonance measurements to produce a first distribution of a spin relaxation parameter for a fluid component in the formation fluids; acquiring a second set of nuclear magnetic resonance measurements of a formation fluid sample removed by a formation fluid testing tool at the selected axial depth, the formation fluid sample being kept at a substantially same pressure and a substantially same temperature as those of the formation fluids in the earth formations at the selected axial depth; inverting the second set of nuclear magnetic resonance measurements to produce a second distribution of the spin relaxation parameter for the fluid component in the formation fluid sample; determining the reservoir wettability from a comparison of the first distribution of the spin relaxation parameter and the second distribution of the spin relaxation parameter.