Patent ID: 8502135

Claim:
A method for estimating a saturation for each of a gas, oil and water in a fluid contained in pores of an earth formation, the method comprising: conveying a carrier through a single borehole penetrating the earth formation; irradiating the earth formation with neutrons from a neutron source disposed at the carrier; measuring radiation emitted from the earth formation resulting from the irradiating using at least one detector; calculating or determining a mathematical parameter from radiation measured by the at least one detector; predicting values of the mathematical parameter over a range of values of an earth formation property to establish a first two-phase saturation line relating saturation of the gas to the oil, a second two-phase saturation line relating saturation of the oil to the water, and a third two-phase saturation line relating saturation of the water to the gas, wherein the first, second and third saturation lines define a triangle; and comparing the mathematical parameter to the predicted values of the triangle to estimate the saturation of the gas, oil and water in the earth formation fluid.