Laboratory Measurements on Core-scale Sediment and Hydrate Samples to Predict Reservoir Behavior
Timothy J. Kneafsey, Yongkoo Seol, George J. Moridis, Liviu Tomutsa, Barry M. Freifeld, 2009. "Laboratory Measurements on Core-scale Sediment and Hydrate Samples to Predict Reservoir Behavior", Natural Gas Hydrates—Energy Resource Potential and Associated Geologic Hazards, T. Collett, A. Johnson, C. Knapp, R. Boswell
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Measurements on hydrate-bearing laboratory and field samples are needed to provide realistic bounds on parameters used in the numerical modeling of the production of natural gas from hydrate-bearing reservoirs. These parameters include thermal conductivity, permeability, relative permeability-saturation relationships, and capillary-pressure-saturation relationships. We have developed a technique to make hydrate-bearing samples, ranging in scale from core-plug-size to core-size, in the laboratory to facilitate making these measurements. In addition to pressure and temperature measurements, we use x-ray computed-tomography (CT) scanning to provide high-resolution spatial data providing insights on location-specific processes occurring in our samples. Computed tomography allows us to better attribute measured quantities to locations where processes occur and not to the bulk sample. Several methods are available to make gas hydrates in the laboratory, and the method impacts the behavior of the test sample and the parameters measured. We present CT data showing hydrate saturation in samples, and thermal conductivity of laboratory-made samples estimated using the inversion code iTOUGH2 for samples with known and unknown hydrate distributions. Knowledge of the hydrate distribution greatly improves the interpretation and confidence in property measurement.