Patent Document ID: 9939506
Application ID: 14406503
Patent Flag: 1

Claim One:
1. A method of investigating a geological formation traversed by a borehole, comprising: a) obtaining a nuclear magnetic resonance (NMR) tool; b) subjecting a sample of known porosity to a nuclear magnetic resonance (NMR) sequence with a pulse echo spacing using the NMR tool; c) determining a normalized bias B(T 2 ) of said NMR tool as a function of T 2 relaxation times; d) locating the NMR tool in the borehole and detecting signals in response to said NMR sequence at at least one depth in the borehole; e) analyzing a decay of the detected signals with a computer processor, in order to extract a distribution of the T 2 relaxation times; and f) computing and providing, with the computer processor, a value for porosity of the formation at said depth as a function of at least one of said T 2 relaxation times, wherein said computing utilizes a correction factor that modifies the value of the parameter as a function of the T 2 relaxation time for at least the T 2 relaxation times occurring on the order of said pulse echo spacing, wherein said correction factor is a function of said normalized bias.