Experimental measurement and clustered equal diameter particle model of permeability with methane hydrate in glass beads

Abstract

Permeability is a key parameter for gas recovery from marine hydrate reservoirs. In this study, two kinds of BZ02 and BZ04 glass beads provided skeleton structure for methane hydrate synthesis in pressure vessel. Based on the observation of Scanning Electron Microscopy (SEM), the glass beads in the pressure vessel were considered to be equal diameter spheres and stacked in the form of orthorhombic. The water effective permeability KW of glass beads with different hydrate saturations (SH) were carried out by steady-state water injection method. Experimental results indicated that the presence of methane hydrate could cause significant decrease of KW, and the gas produced by hydrate dissociation would reduce the resistance of fluid flow in pores. The permeability ratio in the presence and absence of hydrate KrW was exponentially decreasing with the SH. A clustered equal diameter particle (CEDP) model was proposed that methane hydrate was clustered as equal diameter spheres and occupied in the center of pore space. The internal surface area of pore space with and without hydrate was simplified and the KrW-SH relationship was deduced in detail. When the saturation exponent n of BZ02 and BZ04 were recommended to be 10 and 18, respectively, the KrW in the CEDP model was fitted well with the experimental results. This model also revealed that the radius of glass beads and hydrate particles had a stronger effect on the KrW.