| 摘要 |
Nuclear magnetic resonance measurements of a porous medium using multiple wa it times are used for determining the longitudinal relaxation time T1 time of o il in a hydrocarbon reservoir. The T1 values of water in the formation are represented by a distribution. In a dual wait time implementation of the method, data are acquired with a short wait time TWS chosen such that the wetting fluid phase (e.g., brine) is completely relaxed but the hydrocarbon phase is partially relaxed, giving a sequence ECHOA and with a long wait tim e TWL giving an echo sequence ECHOB. Using known methods, the T2 for the oil a nd water may be determined. The individual echo trains are summed and the T1 values determined form the summed echo trains and the determined values of T 2. The summation greatly improves the SNR. An equivalent method determines the T1 values by summation of a first echo train that is the sum of the individual echo trains and the summation of a second echo train that is the difference of the individual echo trains. The various summed values may also be used as fo r quality control of the data.
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