Preliminary relative permeability estimates of methane hydrate-bearing sand

• Main Authors: Seol, Yongkoo, Kneafsey, Timothy J., Tomutsa, Liviu, Moridis, George J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: eScholarship, University of California 2006
• Subjects: Earth Sciences; gas hydrate relative permeability; Methane hydrate
• Online Access: http://www.escholarship.org/uc/item/50b9n4c0

The relative permeability to fluids in hydrate-bearing sediments is an important parameter for predicting natural gas production from gas hydrate reservoirs. We estimated the relative permeability parameters (van Genuchten alpha and m) in a hydrate-bearing sand by means of inverse modeling, which involved matching water saturation predictions with observations from a controlled waterflood experiment. We used x-ray computed tomography (CT) scanning to determine both the porosity and the hydrate and aqueous phase saturation distributions in the samples. X-ray CT images showed that hydrate and aqueous phase saturations are non-uniform, and that water flow focuses in regions of lower hydrate saturation. The relative permeability parameters were estimated at two locations in each sample. Differences between the estimated parameter sets at the two locations were attributed to heterogeneity in the hydrate saturation. Better estimates of the relative permeability parameters require further refinement of the experimental design, and better description of heterogeneity in the numerical inversions.