Safe long term storage sealing of CO2 in hydrate

Storage, and value of released natural gas can even compensate for the injection costs. In this Project we focus on a multi-scale strategy in which Quantum mechanics and molecular Dynamics provide information on details of mechanisms as well as thermodynamics and transport properties. One PhD in the Project is dedicated to this scale modeling. So far it is found that there are two primary mechanisms that lead to the exchange. The first of these is a solid state Conversion in which carbon dioxide in contact with hydrate dissociates partly the Outer layers of the hydrate so that methane escapes and hydrate closes again around the carbon dioxide. This is a very slow process. A second and dominating mechanism is that injected carbon dioxide creates a new hydrate from free water in the pores. The released heat from this formation contributes to dissociation of in situ methane hydrate. This process is fast and proportional to liquid water natural self-diffusion. In a second PhD project the nano scale information and data are inserted into a theoretical tool for minimization of free energy under constraints of mass and heat transport. Since this modeling is based on fundamental principles of thermodynamics no assumption on how the system will behave is incorporated and it is possible to study dynamically coupled phase transitions and flow on a pore scale level. During the current reporting period a special focus has been on the role of mineral on water structuring and the corresponding impact on generating nucleation sites for hydrate formation and new unique results have been published and are in progress for further publication and international presentation. A second primary focus has been on investigation of how addition of nitrogen affects the hydrate exchange process. It is demonstrated that CO2 will dominate formation of new hydrate and extract the CO2/N2 mixture for CO2 to level below the possibility of creating new CO2 dominated hydrate. This will reduce the possibility for combined CO2 storage and CH4 production. During 2015 totally new results for Kaolinite/water/methane interactions have been published. One particular face of the Kaolinite will provide very strong water/Kaolinite interactions that only provides for secondary adsorption of CO2 and/or methane in between the two first density maximums of water. A second cutting of the Kaolinite crystal, on the other hand will provide direct adsorption of CO2 before the first density maximum of water. The reservoir simulator has now been extended to include more phase transitions involving hydrate, like hydrate from dissolved CO2 in the water phase. Results from phase field theory (PFT) indicate a strong impact of mineral surfaces also on (as expected) keeping a water liquid like thin film between mineral surfaces (Calcite and Kaolinite) and hydrate. For the nano (phase transitions) to hydrodynamic scale in pores (millimeter level) an extended and totally new version of the PFT is developed, with all new algorithms (spectral solver) and implementation of parallel processing on GPU (graphical processing unit). In the latest year increased focus has been on how CO2 hydrate fills the pores when it forms in cold areas of possible storage reservoirs. The main goal is to find out more about the actual permeability in hydrate sealed regions. Two primary factors control this. The first is a balance between formation of new hydrate from water and CO2 from below and the second is the mineral/hydrate/fluid interactions which leaves fluid space in the pores due to the fact that hydrate can never contact minerals directly. New fundamental studies have been published that documents the feasibility of the concept. During the same time period as this project pilot test projects have been conducted using pressure reduction to release methane from hydrate. Experiences indicate that the need for heat supply from the surroundings exceeds what the surroundings can supply. A planned 6 months test offshore Japan froze down after 24 days. This has resulted in substantial interest in the use of CO2 for combined storage and energy production. Kvamme is called in by China to assist them in their hydrate program. During next stay in Chengdu Kvamme will direct rebuilding of large scale experimental equipment for studies of various production methods, including use of CO2. Reduction of CO2 emissions is a priority in China. Kvamme is working towards a zero emission concept based on production of hydrogen using steam cracking of released CH4 from hydrate and reinjection of the produced CO2 into hydrate formations. The net output from the process is hydrogen for transport or local energy production. Huge amounts of hydrates are located in Tibet and other permafrost regions of China. Kvamme is also headhunted by University of California to unite 3 different hydrate research groups into hydrate energy unit. A dedicated PhD student from university of California is provided for Kvamme.

1) Internasjonal forståelse for mekanismer, stabilitet og økonomisk fordel av å lagre CO2 i hydrater. 2) Internasjonale nettverk innen CO2 lagring i hydrat 3) Oppmerksomhet rundt publikasjoner fra prosjektet og interesse for kommersialisering 4) Invitert inn i en rekke internasjonale prosjektsøknader i USA og Europa 5) Spin-off til H2 og videre internasjonale muligheter 6) Hentet inn av Kina til å hjelpe dem med hydrat programmet 7) Hentet inn til å samle 3 hydratmiljø ved University of California for CO2 lagring i hydrat. Dedikert PhD student gitt til Kvamme. 8) Publikasjoner som belyser svært mange sentrale mekanismer knyttet til hydrater i porøse medier som ikke har vært forstått tidligere 9) Norsk boreteknologi effektivt markedsført sammen med konseptet. 10) Muligheter for kommersialisering av et null-utslipps konsept for produksjon av hydrogen energi. 11) Populærvitenskapelig formidling i ulike generelle forum knyttet til reduksjon av CO2 utslipp og H2 energi

The existence of trapped natural gas hydrate resources have proven sealing integrety since hydrates would otherwise have dissociated by contact with groundwater through contact in fractures and faults. Storing carbon dioxide in natural gas hydrate reservo irs therefore implies the double sealing of verified clay or cap-rock on top and a solid phase trap (hydrate) for the cabon dioxide molecules. The concept have been proven experimentally and theoretically during the last two decades. A succesful field tes t in Alaska proved that injection of a mixture of carbon dioxide and nitrogen into a hydrate formation released in situ methane from hydrate during conversion of the injected carbon dioxide into mixed hydrate of carbon dioxide, methane and nitrogen. Even the very limited mapping of natural gas hydrates offshore Norway shows substantial quantities that can be used for hydrate storage of carbon dioxide. The released methane can be sampled and used in a combined carbon dioxide storage and methane production conceot, or the methane can be left to accumulate for later production. In either case the released methane is a value that will compensate for storage costs. A positive side effect is that the produce carbon dioxide hydrate (with some remains of methane) will be more stable than the original hydrate and thus less sensitive to possile future temperature increase and corresponding risks for rapid and catastrophic dissociation. Norwegian industry, with STATOIL as a locomotive, shows an increased interest in hydrate and projects like this can contribute to an increased interest in safe long terms storage and methane production from hydrate. Storing carbon dioxide in resrvoirs with regions where temperature and pressure makes hydrate possiblecan lead to addit ional sealing and can potentially repair leakage of carbon dioxide through fractures and holes. Hydrates in porous media are not thermodynamically stable and there are limits of acceptable dissociation rates.