Quantitative in situ enhanced oil recovery monitoring using nuclear magnetic resonance

Jonathan Mitchell, John Staniland, Romain Chassagne, Edmund J. Fordham

    Research output: Contribution to journalArticle

    32 Citations (Scopus)

    Abstract

    Quantitative in situ monitoring of oil recovery from sedimentary rock is demonstrated for the first time using advanced two-dimensional (2D) nuclear magnetic resonance (NMR) correlation measurements on a low field spectrometer. The laboratory-scale NMR system was chosen to provide a common physics of measurement with NMR well-logging tools. The NMR protocols are used to monitor recovery of a heavy Middle East crude oil from high permeability sandstone plugs using a brine (water) flood followed by chemical enhanced oil recovery agents: polymer and alkaline-surfactant-polymer solutions. 2D correlations between relaxation time (T (1), T (2)) and apparent self-diffusion coefficient D (app) are used to obtain simultaneously a volumetric determination of the oil and aqueous fluid-phase saturations present in the porous material. The T (1) - T (2) and D (app) - T (2) correlations are bulk measurements of the entire rock core-plug; excellent agreement is shown between the measures of remaining oil (from NMR) and recovered oil (from gravimetric assay of the effluent). Furthermore, we introduce the capability to measure spatially resolved T (2) distributions on a low field spectrometer using a rapid frequency-encoded y - T (2) map. A non-uniform distribution of remaining oil is observed due to viscous instabilities in the flowing liquids; the final oil saturation ranges from to 20 % along the direction of flow. These results highlight the quantitative nature of the NMR data obtainable in low field NMR core analysis and also the importance of spatially resolved measurements when studying short core-plugs.

    Original languageEnglish
    Pages (from-to)683-706
    Number of pages24
    JournalTransport in Porous Media
    Volume94
    Issue number3
    DOIs
    Publication statusPublished - Sep 2012

    Keywords

    • Nuclear magnetic resonance
    • Core analysis
    • Enhanced oil recovery
    • Spatially resolved T-2
    • Diffusion-editing
    • LATTICE-RELAXATION MEASUREMENTS
    • PORE-SIZE DISTRIBUTIONS
    • SATURATED POROUS SOLIDS
    • DIFFUSION MEASUREMENTS
    • INTEGRAL-EQUATIONS
    • FLOW PROPAGATORS
    • FIELD GRADIENT
    • 2-PHASE FLOW
    • ROCK CORES
    • 1ST KIND

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