An Experimental Investigation on the Kinetics of Integrated Methane Recovery and CO2 Sequestration by Injection of Flue Gas into Permafrost Methane Hydrate Reservoirs (original) (raw)
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Flue gas injection into gas hydrate reservoirs for methane recovery and carbon dioxide sequestration
Energy Conversion and Management, 2017
Flue gas injection into methane hydrate-bearing sediments was experimentally investigated to explore the potential both for methane recovery from gas hydrate reservoirs and for direct capture and sequestration of carbon dioxide from flue gas as carbon dioxide hydrate. A simulated flue gas from coal-fired power plants composed of 14.6 mole% carbon dioxide and 85.4 mole% nitrogen was injected into a silica sand pack containing different saturations of
Day 4 Fri, March 23, 2018, 2018
Because CO2 hydrate is stable at pressures lower than those required to stabilize hydrates of CH4 when compared at the same temperature the injection of CO2 into gas hydrate reservoirs was proposed a while ago as a method to recover methane. The added advantage of such a technology is the simultaneous sequestering/storage of CO2 captured from fossil fuel power plants or other significant point sources of CO2. Recent reviews on the subject have provided an account of the laboratory and theoretical work on this topic. The reviews highlighted the need to further elucidate the dynamics of the exchange process and provide information needed for the design of industrial scale facilities. In this work, the kinetics of the CO2/CH4 exchange process are investigated in a 5.3 L laboratory crystallizer (reservoir) equipped with ahorizontal injection tube with 24 exits into the packed bed of silica sand particles. Preliminary experiments conducted using this apparatus and also with a high pressu...
2007
Although recent estimates (MILKOV et al., 2003) put the global accumulations of natural gas hydrate at 3,000 to 5,000 trillion cubic meters (TCM), compared against 440 TCM estimated (COLLETT, 2004) for conventional natural gas accumulations, how much gas could be produced from these vast natural gas hydrate deposits remains speculative. What is needed to convert these gas-hydrate accumulations to recoverable reserves are technological innovations, sparked through sustained scientific research and development. As with other unconventional energy resources, the challenge is to first understand the resource, its coupled thermodynamic and transport properties, and then address production challenges. Carbon dioxide sequestration coupled with hydrocarbon resource recovery is often economically attractive. Use of CO 2 for enhanced recovery of oil, conventional natural gas, and coal-bed methane are in various stages of common practice. In this report, we discuss a new technique utilizing CO 2 for enhanced recovery of natural gas hydrate. We have focused our attention on the Alaska North Slope where approximately 640 Tcf of natural gas reserves in the form of gas hydrate have been identified. Alaska is also unique in that potential future CO 2 sources are nearby, and petroleum infrastructure exists or is being planned that could bring the produced gas to market or for use locally.
Thermally Assisted Dissociation of Methane Hydrates and the Impact of CO2 Injection
The largest amount of methane gas is trapped in lessconventional natural gas resources, such as methane hydrates. It is estimated that these reserves of methane gas, in the form of hydrates, are larger than all of the conventional resources of methane gas combined. [U.S. Energy Information Administration (EIA), Independent Statistics and Analysis, Potential of Gas Hydrates Is Great, but Practical Development Is Far of, http://www.eia.gov/todayinenergy/detail.cfm?id=8690\]. Methane extraction from hydrates can be coupled with carbon dioxide sequestration to make this process carbon-neutral. A large-scale laboratory reactor is used to simulate the conditions existing in permafrost hydrate sediments to study the hydrate formation and dissociation processes. The dissociation process occurs via a cartridge heat source (to simulate the down-hole combustion) and carbon dioxide injection, to study the CO2 sequestration behavior. The hydrate sediment studied was formed with 50% saturation of hydrate by pore volume and the dissociation of this sediment was done using different combinations of high and low heating rates (100 W and 20 W) and high and low CO2 injection rates (1000 and 155 mL/min). Two baseline tests were conducted without any addition of heat at CO2 injection rates of 155 and 1000 mL/min, for comparison. The results indicate that, at a constant heating rate, the number of moles of methane recovered decreases with an increasing flow rate of CO2 injection, whereas the number of moles of CO2 sequestered increases as the CO2 injection flow rate increases. At 50% initial hydrate saturation (SH) and a heating rate of 100 W, the number of moles of methane recovered decreased from 96 to 58 when the CO2 injection rate was increased from 155 mL/ min to 1000 mL/min, respectively. Whereas, at 50% initial saturation and a heating rate of 100 W, the number of moles of CO2 sequestered increased from 13 to 40 when the CO2 injection rates were increased from 155 mL/min to 1000 mL/min. The recovery efficiency improved from 18% to 22% to 60% when the heating rate was increased from 0 to 20 W to 100 W, respectively, at 1000 mL/min CO2 injection.
Numerical simulations for enhanced methane recovery from gas hydrate accumulations by utilizing CO2 sequestration Prathyusha Sridhara In 2013, the International Energy Outlook (EIA, 2013) projected that global energy demand will grow by 56% between 2010 and 2040. Despite strong growth in renewable energy supplies, much of this growth is expected to be met by fossil fuels. Concerns ranging from greenhouse gas emissions and energy security are spawning new interests for other sources of energy including renewable and unconventional fossil fuel such as shale gas and oil as well as gas hydrates. The production methods as well as long-term reservoir behavior of gas hydrate deposits have been under extensive investigation. Reservoir simulators can be used to predict the production potentials of hydrate formations and to determine which technique results in enhanced gas recovery. In this work, a new simulation tool, Mix3HydrateResSim (Mix3HRS), which accounts for complex thermodynamics of multi-component hydrate phase comprised of varying hydrate solid crystal structure, is used to perform the CO2-assisted production technique simulations from CH4 hydrate accumulations. The simulator is one among very few reservoir simulators which can simulate the process of CH4 substitution by CO2 (and N2) in the hydrate lattice. Natural gas hydrate deposits around the globe are categorized into three different classes based on the characteristics of the geological sediments present in contact with the hydrate bearing deposits. Amongst these, the Class 2 hydrate accumulations predominantly confirmed in the permafrost and along seashore, are characterized by a mobile aqueous phase underneath a hydrate bearing sediment. The exploitation of such gas hydrate deposits results in release of large amounts of water due to the presence of permeable water-saturated sediments encompassing the hydrate deposits, thus lowering the produced gas rates. In this study, a suite of numerical simulation scenarios with varied complexity are considered which aimed at understanding the underlying changes in physical, thermodynamic and transport properties with change in pressure and temperature due to the presence of the simple CO2-hydrate and mixed hydrates (mainly CH4-CO2 hydrate and CH4-CO2-N2 hydrate) in the porous geologic media. These simulations on CO2/ CH4-CO2 hydrate reservoirs provided a basic insight to formulate and interpret a novel technological approach. iii Dedicated to my parents iv Acknowledgement First and foremost, I'd like to express my deepest gratitude to Sri Ganapathi Sachchidananda Swamiji for His divine blessings and insightful messages. "Patience and perseverance are crucial for success"-this has been one of the most influential sayings of His on me and helped me to become goal-oriented. I'd like to express my deepest gratitude to my research advisor, Dr. Brian Anderson for his constant support, remarkable guidance and encouragement. He has set himself as an example and shown me what a good scientist (and person) should be. I am also immensely indebted to Dr. Evgeniy Myshakin for his motivation and comprehensive advices throughout the research work. Their suggestions helped me to learn a great deal about scientific research and life in general. I'd like to thank Department of Chemical Engineering at WVU and also everyone in my dissertation committee members for their valuable suggestions and for providing unending inspiration. I am immensely grateful to West Virginia University for providing me an opportunity to pursue my doctoral studies here in Morgantown. It also gave me a chance to explore the "wild and wonderful", and I take immense pleasure and pride in referring it as my second home and being a Mountaineer, I learnt from the people around here, that being kind and generous is an important virtue one should abide.
Energy & Fuels, 2018
Class 2 hydrate accumulations are characterized by the presence of an aquifer underneath hydrate bearing sediment. Gas extraction from of these hydrate deposits is accompanied with release of large volumes of water that decreases gas production rates, imposes additional load on the lifting system, and, as a result, degrades economical attractiveness of possible exploitation sites. This work studies enhanced methane production from Class 2 hydrate accumulations using the CO 2-assisted technique where the aquifer serves as a target zone for CO 2 injection. The heat release associated with the CO 2 hydrate formation and reduction of the aquifer's permeability benefit the subsequent decomposition of the overlying methane hydrate. The new production technique includes three stages utilizing one vertical well, which serves as an injector during the first stage and as a producer in the third stage. First, the CO 2 is injected into the underlying aquifer, then the well is shut down and injected CO 2 is converted into hydrate during the second stage. In the third stage, decomposition of CH 4 hydrate is induced by the depressurization method to estimate gas production potential over 15 years. The results reveal that methane production is increased together with simultaneous reduction of concomitant water production comparing to production from the Class 2 reservoir using only conventional depressurization.
Journal of Petroleum Science and Engineering, 2011
In the second paper of this series, we evaluate two additional well designs for production from permafrostassociated (PA) hydrate deposits. Both designs are within the capabilities of conventional technology. We determine that large volumes of gas can be produced at high rates (several MMSCFD) for long times using either well design. The production approach involves initial fluid withdrawal from the water zone underneath the hydrate-bearing layer (HBL). The production process follows a cyclical pattern, with each cycle composed of two stages: a long stage (months to years) of increasing gas production and decreasing water production, and a short stage (days to weeks) that involves destruction of the secondary hydrate (mainly though warm water injection) that evolves during the first stage, and is followed by a reduction in the fluid withdrawal rate. A well configuration with completion throughout the HBL leads to high production rates, but also the creation of a secondary hydrate barrier around the well that needs to be destroyed regularly by water injection. However, a configuration that initially involves heating of the outer surface of the wellbore and later continuous injection of warm water at low rates (Case C) appears to deliver optimum performance over the period it takes for the exhaustion the hydrate deposit. Using Case C as the standard, we determine that gas production from PA hydrate deposits increases with the fluid withdrawal rate, the initial hydrate saturation and temperature, and with the formation permeability.
Simulating Thermal Interaction of Gas Production Wells with Relict Gas Hydrate-Bearing Permafrost
Geosciences, 2022
The thermal interaction of a gas production well with ice-rich permafrost that bears relict gas hydrates is simulated in Ansys Fluent using the enthalpy formulation of the Stefan problem. The model admits phase changes of pore ice and hydrate (ice melting and gas hydrate dissociation) upon permafrost thawing. The solution is derived from the energy conservation within the modeling domain by solving a quasilinear thermal conductivity equation. The calculations are determined for a well completion with three casing strings and the heat insulation of a gas lifting pipe down to a depth of 55 m. The thermal parameters of permafrost are selected according to laboratory and field measurements from the Bovanenkovo gas-condensate field in the Yamal Peninsula. The modeling results refer to the Bovanenkovo field area and include the size of the thawing zone around wells, with regard to free methane release as a result of gas hydrate dissociation in degrading permafrost. The radius of thawing a...