Determination of synthetic hydrate content in sand specimens using dielectrics

Gas hydrates are solid crystalline compounds (clathrates) that encage gas molecules inside the lattices of hydrogen bonded water molecules within a specific temperature-pressure stability zone. It is imperative that reliable detection and quantification modi operandi are developed, as proposed in this research, to identify hydrate-laden strata and determine economic viability of this potential energy yield. This paper presents the experimental analysis of synthetic refrigerant (R-11) hydrates in 20/30 Ottawa sand using dielectric principles to determine specific hydrate content. Hydrate specimens were constructed via moist tamped Ottawa sand, purged with carbon dioxide (CO2), saturated with de-aired water, and mixed with a known amount of R-11 to produce precise hydrate contents. The specimen's bulk dielectric constant was measured using a ThetaProbe by applying the principles of time domain reflectometry (TDR). A distinct relationship between hydrate content and the bulk dielectric constant of sand specimens is determined, as well; volumetric expansion associated with hydrate formation is also portrayed.