Patent ID: 7366615

Claim:
A method of determining an indication of a quantity of a first chemical element in a formation traversed by a borehole, the method comprising: a) obtaining an inelastic spectrum yield of said first chemical element; b) obtaining an inelastic spectrum yield and a capture spectrum yield of a second chemical element different from said first chemical element; c) obtaining capture spectrum yields of a plurality of other chemical elements different from said first chemical element and said second chemical element; and d) using said inelastic spectrum yield of said first chemical element, said inelastic spectrum yield and said capture spectrum yield of said second chemical element, and respective measurement sensitivities associated with said inelastic spectrum yield of said first chemical element, said inelastic spectrum yield of said second chemical element and said capture spectrum yield of said second chemical element, finding said quantity of said first chemical element by assigning at least one association factor for said first chemical element and incorporating said first chemical element with said association factor in a closure model which also incorporates said plurality of other chemical elements and association factors therefor to generate a weight fraction for said element.