Marco Castaldi (Assistant Professor, EEE)
Tuncel Yegulalp (Professor, EEE)
Forrest Zhou (EEE)
Carbon Neutral Methane Production Via Hydrates
The research project here is to investigate and develop a novel concept of generating a point heat source, via in-situ combustion, strategically located in the hydrate deposit which enables methane production where only about 10% of the energy content that is produced from the reservoir is used for the process. This combustion process is capable of utilizing CO2 as a diluent to adjust adiabatic temperatures to the point where methane hydrates decompose, yet CO2 hydrates still can form and replace methane. Feasibility calculations were made for using this point heat source as a temperature-balancing extraction process by which methane gas can be efficiently produced, while sequestering CO2 in a stable environment. Other stimulation methods are also being tested and explored in our 67 liter apparatus capable of sustaining 5000 psi.
Results to Date
As global energy demands increase, there will be a critical need to employ fuels that have minimal environmental impacts. Natural gas hydrates have the potential to meet the global energy needs for the foreseeable future. The project is trying to verify the technical feasibility of a novel method of gas production in hydrate reservoirs. The figure below depicts the point-heat source concept. The method is an in-situ process that creates a point heat source in the hydrate formation. This method not only tremendously reduces the energy input, but also has the potential to sequester as much or more CO2 than would be produced from burning the natural gas produced, thus making this in-situ methane production technique carbon neutral.
The apparatus (left picture) has been built and tested in our lab. The apparatus is a 72 liter, temperature-controlled high-pressure vessel capable of simulating high pressures and low temperatures where hydrates are stable. It holds up to 2000 psi. We are using this experimental apparatus to verify the feasibility of gas hydrates dissociation by down-hole combustion and to understand important characteristics such as temperature and pressure profiles for methane hydrate formation and dissociation in different systems.
Calculations and simulations using FEMLAB™ show the method offers an energy efficient and environmental friendly way to produce natural gas from hydrate reservoirs. Preliminary results indicate that it is possible to have an energy efficiency of near 90% for land based reservoirs for hydrate loadings of 20%. Both energy balance calculation and simulation results shows that the down-hole combustion method is very energy efficiency in that it can reach up to 0.99 for moderate hydrate loadings. Among the heating conditions, constant heat flux has a better efficiency.
Castaldi, M.J., Zhou, Y., and Yegulalp, T. M., (2005)“Down-hole Combustion Method for Gas Production from Methane Hydrates”, Journal of Petroleum Science and Engineering, in press.
Castaldi, M.J., Yegulalp, T.M., and Zhou, Y., (2005) “An Energy Efficient, Environmentally Sound Gas Production Process from Methane Hydrates”International Mining Conference (IMCET), Izmir, Turkey, June 9-12, 2005