Silicone Tubes - Tools for Methane Gas Extraction and Monitoring in the Course of Hydrate Formation and Dissociation

This study assesses the capability and limits of silicone tubes as tools to monitor the methane gas flux and it s distribution in the course of hydrate formation and dissociation. Also, their ability to serve as a suitable in situ gas extraction tool for methane released during hydrate decomposition has been examined. In the framework of the SUGAR Project, we simulate different methods (depressurization, thermal stimulation and distortion of the chemical equilibrium by CO2) for methane gas production from gas hydrates deposits in a LArge scale Reservoir Simulator LARS. Within this setup, thin - walled (0.8 mm) silicon tubes are utilized for in situ gas capture. They function as membranes for the extraction of methane gas, leaving sediment and brine behind. First tests show that, driven by the transmembrane pressure difference, the methane flux through these membranes is about 1 mL per minute per cm² membrane surface at a reservoir pressure of about 20 MPa. The operation of the membranes as a simple capture tool for the released methane from a hydrate deposit is therefore considered as feasible and, due to their robust nature, reliably applicable in remote and rough areas. Furthermore, the silicone tubes have been utilized for the monitoring of spatial and temporal gas distributions. For that, LARS has been equipped with silicone membranes at various locations to quantify free and dissolved gas volumes in the progress of hydrate formation and decomposition. The results show that inhomogeneous gas distributions within the reservoir are detectable and terminable.