A Counter-Current Heat-Exchange Reactor for the Thermal Stimulation of Hydrate-Bearing Sediments

Abstract

Since huge amounts of CH 4 are bound in natural gas hydrates occurring at active and passive continental margins and in permafrost regions, the production of natural gas from hydrate-bearing sediments has become of more and more interest. Three different methods to destabilize hydrates and release the CH 4 gas are discussed in principle: thermal stimulation, depressurization and chemical stimulation. This study focusses on the thermal stimulation using a counter-current heat-exchange reactor for the in situ combustion of CH 4 . The principle of in situ combustion as a method for thermal stimulation of hydrate bearing sediments has been introduced and discussed earlier [1,2]. In this study we present the first results of several tests performed in a pilot plant scale using a counter-current heat-exchange reactor. The heat of the flameless, catalytic oxidation of CH 4 was used for the decomposition of hydrates in sand within a LArge Reservoir Simulator (LARS). Different catalysts were tested, varying from diverse elements of the platinum group to a universal metal catalyst. The results show differences regarding the conversion rate of CH 4 to CO 2 . The promising results of the latest reactor test, for which LARS was filled with sand and ca. 80% of the pore space was saturated with CH 4 hydrate, are also presented in this study. The data analysis showed that about 15% of the CH 4 gas released from hydrates would have to be used for the successful dissociation of all hydrates in the sediment using thermal stimulation via in situ combustion. OPEN ACCESSEnergies 2013, 6 3003

A cylindrical electrical resistivity tomography array for three-dimensional monitoring of hydrate formation and dissociation

“…Methane hydrate has been formed successfully from methane saturated saline water under simulated in situ conditions while temperature and pressure profiles have been recorded. Production tests, using thermal stimulation or pressure reduction for the dissociation of hydrates were successfully performed (e.g., Schicks et al 2,3 ). However, there was no way to image the spatial distribution of hydrate crystals a) mikep@gfz-potsdam.de during hydrate formation and dissociation, nor could the free methane gas phase released during hydrate dissociation be tracked.…”

A State-Dependent Constitutive Model for Gas Hydrate-Bearing Sediments Considering Cementing Effect

“…Generally speaking, the exploitation of gas hydrates still faces great challenges. At present, the common mining technologies mainly include the depressurization mining method [7], thermal stimulation method [8], CO 2 replacement mining method [9] and a combination of several mining methods [7]. In addition to these mining technologies, there are mainly horizontal wells and vertical wells in a wellbore layout, among which horizontal wells are considered as the most feasible commercial mining method.…”

Comparison and Optimization of Methane Hydrate Production Process Using Different Methods in a Single Vertical Well

“…NGH is a high-density energy source. Under standard condition, one unit volume of gas hydrate can be decomposed to produce 160 to 180 volumes of methane gas [4,7].…”

“…The occurrence of gas hydrate is strongly dependent on the factors including temperature, pressure and constituent components, which result in the formation of NGH in polar and oceanic regions [7][8][9]. In polar regions, NGH exists in the permafrost at both onshore and offshore of the continental shelves.…”

“…It is inevitable to study NGH exploitation as NGH is a kind of high-reserved energy resource, which can help to cope with the growing global energy demand [8,11,12]. Therefore, it will become the research focus all over countries to ensure the efficiency and safety of NGH exploitation, and then the commercial exploitation will be realized in the near future [4,7,9,13].…”