Wireline T1 Logging

Abstract With the recent introduction of NMR Logging While Drilling tools and down-hole NMR Fluid Analyzers, the more fundamental T1 measurement has made its appearance in the oil patch. In both these applications, the preference of T1 over T2 has been its insensitivity to motion, since T1 measurements effectively eliminate the detrimental effects arising from tool motion or fluid flow. Experience has shown that the acquisition and interpretation of T1 logs recorded in the less hostile wireline environment is quite straightforward, mainly due to the absence of tool motion, while yielding several benefits over T2 logs. T1 is a critical fluid NMR parameter and can play a prominent role in fluid typing applications. Also, T1 data sets are more compact and the acquisition is more efficient. Finally, T1 logging offers the potential of substantially increased logging speeds This paper outlines the current T1 logging practice, and substantiates the advantages of T1 logging using real-life data. Examples included demonstrate the value added by wireline T1 measurements into the overall petrophysical understanding of in-situ reservoir fluids.