Patent ID: 8451683
Filing Date: 2013-05-28
Classification: G01V

Abstract:
1. A method comprising: (a) analyzing seismic data related to a hydrocarbon reservoir containing rock, wherein the seismic data includes a first set of seismic data obtained at a first time and a second set of seismic data obtained at a second, subsequent time; (b) identifying an interval substantially comprising rock in the hydrocarbon reservoir, wherein the interval has a permeability level associated therewith; (c) calculating 4D seismic attributes for the interval; (d) applying a first set of rock physics relationships to seismic data related to the interval when the permeability level associated therewith is in a first permeability range; (e) applying a second set of rock physics relationships to seismic data related to the interval when the permeability level associated therewith is in a second permeability range, the first and second permeability ranges being non-overlapping; (f) inferring one of a fluid saturation change and a pressure change of the interval based on outputs of one of the first and second sets of rock physics relationships and the calculated 4D seismic attributes for the interval; and (g) outputting to a non-transient medium the inferred one of the fluid saturation change and the pressure change of the interval; wherein the first set of rock physics relationships includes an equation to determine a bulk modulus of fluid in the interval using a harmonic average of bulk moduli of components of the fluid, and the second set of rock physics relationships includes an equation to determine a bulk modulus of fluid in the interval using an arithmetic average of bulk moduli of components of the fluid.