Patent ID: 7893692
Filing Date: 2011-02-22
Classification: G01V,Y02A

Abstract:
1. A method for estimating fluid productivity of a subsurface rock formation from within a wellbore drilled therethrough, comprising: measuring a nuclear magnetic resonance property of the formation at a plurality of lateral depths therein; and using the measured nuclear magnetic resonance property to estimate the productivity, wherein estimating the productivity comprises the steps of: determining porosity, permeability and irreducible water saturation of the formation from the nuclear magnetic resonance (“NMR”) measurements; determining bulk volumes of water, oil and gas and saturations thereof from the NMR measurements; estimating viscosity of oil and gas oil ratio from the NMR measurements; estimating relative permeabilities of oil gas and water; estimating fractional water flow volume from the relative permeabilities; estimating skin factor from the NMR measurements; and estimating the productivity using the skin factor, the viscosity, a formation volume factor, and the relative permeabilities.