scholarly journals Mathematical modeling of the equilibrium complete replacement of methane by carbon dioxide in a gas hydrate reservoir at negative temperatures

Author(s):  
Stanislav L. Borodin ◽  
Denis S. Belskikh

Gas hydrates, which contain the largest amount of methane on our planet, are a promising source of natural gas after the depletion of traditional gas fields, the reserves of which are estimated to last about 50 years. Therefore, it is necessary to study the methods for extracting gas from gas hydrates in order to select the best of them and make reasoned technological and engineering decisions in the future. One of these methods is the replacement of methane in its hydrate with carbon dioxide. This work studies the construction of a mathematical model to observe this method. The following process is considered in this article: on one side of a porous reservoir, initially saturated with methane and its hydrate, carbon dioxide is injected; on the opposite side of this reservoir, methane and/or carbon dioxide are extracted. In this case, both the decomposition of methane hydrate and the formation of carbon dioxide hydrate can occur. This problem is stated in a one-dimensional linear formulation for the case of negative temperatures and gaseous carbon dioxide, which means that methane, carbon dioxide, ice, methane, and carbon dioxide hydrates may be present in the reservoir. A mathematical model is built based on the following: the laws of conservation of masses of methane, carbon dioxide, and ice; Darcy’s law for the gas phase motion; equation of state of real gas; energy equation taking into account thermal conductivity, convection, adiabatic cooling, the Joule — Thomson effect, and the release or absorption of latent heat of hydrate formation. The modelling assumes that phase transitions occur in an equilibrium mode and that methane can be completely replaced by carbon dioxide. The results of numerical experiments are presented.

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1482
Author(s):  
Marat K. Khasanov ◽  
Nail G. Musakaev ◽  
Maxim V. Stolpovsky ◽  
Svetlana R. Kildibaeva

The article describes a mathematical model of pumping of heated liquid carbon dioxide into a reservoir of finite extent, the pores of which in the initial state contain methane and methane gas hydrate. This model takes into account the existence in the reservoir of three characteristic regions. We call the first region “near”, the second “intermediate”, and the third “far”. According to the problem statement, the first region contains liquid CO2 and hydrate, the second region is saturated with methane and water, the third contains methane and hydrate. The main features of mathematical models that provide a consistent description of the considered processes are investigated. It was found that at sufficiently high injection pressures and low pressures at the right reservoir boundary, the boundary of carbon dioxide hydrate formation can come up with the boundary of methane gas hydrate decomposition. It is also shown that at sufficiently low values of pressure of injection of carbon dioxide and pressure at the right boundary of the reservoir, the pressure at the boundary of hydrate formation of carbon dioxide drops below the boiling pressure of carbon dioxide. In this case, for a consistent description of the considered processes, it is necessary to correct the mathematical model in order to take into account the boiling of carbon dioxide. Maps of possible solutions have been built, which show in what ranges of parameters one or another mathematical model is consistent.


2020 ◽  
Author(s):  
Michela Giustiniani ◽  
Umberta Tinivella

Few potential distributing areas of gas hydrates have been recognized in literature in Antarctica: the South Shetland continental margin, the Weddell Sea, the Ross Sea continental margin and the Wilkes Land continental margin. The most studied part of Antarctica from gas hydrate point of view is the South Shetland margin, where an important gas hydrate reservoir was well studied with the main purpose to determine the relationship between hydrate stability and environment effects, including climate change. In fact, the climate signals are particularly amplified in transition zones such as the peri-Antarctic regions, suggesting that the monitoring of hydrate system is desirable in order to detect potential hydrate dissociation as predicted by recent modeling offshore Antarctic Peninsula. The main seismic indicator of the gas hydrate presence, the bottom simulating reflector, was recorded in few parts of Antarctica, but in some cases it was associated to opal A/CT transition. The other areas need further studies and measurements in order to confirm or refuse the gas hydrate presence.


2021 ◽  
Vol 230 ◽  
pp. 01007
Author(s):  
Ivan Vargas-Cordero de la Cruz ◽  
Michela Giustiniani ◽  
Umberta Tinivella ◽  
Giulia Alessandrini

In last decades, the Chilean margin has been extensively investigated to better characterize the complex geological setting through the acquisition of geophysical data and, in particular, seismic lines. The analysis of seismic lines allowed identifying the occurrence of gas hydrates and free gas in many places along the margin. Clearly, the gas hydrate reservoir could be a strategic energy reserve for Chile, but, on the other hand, the dissociated of gas hydrate due to climate change could be an issue to face. Moreover, this region is characterized by large and mega-scale earthquakes that may contribute to gas hydrate dissociation and consequent submarine slides triggering. In this context, Chilean margin should be considered a natural laboratory to study the hydrate system evolution.


2008 ◽  
Vol 6 ◽  
pp. 205-209
Author(s):  
V.Sh. Shagapov ◽  
R.R. Urazov

The flow of wet natural gas in the pipeline is considered in the presence of the formation of gas hydrates on the internal walls of the channel. In the description of the phenomenon, such interrelated processes as phase transformations and mass transfer of water into the composition of gas hydrates, heat transfer between the gas stream and the environment, heat conductivity in the ground are taken into account.


2017 ◽  
Vol 12 (2) ◽  
pp. 206-213 ◽  
Author(s):  
O.F. Shepelkevich

The paper deals with the process of injecting liquid carbon dioxide into a hydrate reservoir. It is shown that the process of methane replacement in a hydrate reservoir by injecting liquid carbon dioxide into it can consist of the following steps: piston displacement of free gas from the pores; replacement of methane with liquid carbon dioxide, its dissolution and leaching from the formation; completion of hydrate formation and leaching of the remaining methane gas from the hydrate reservoir. We have presented the distributions of pressure, density, hydrate saturation and temperature at different times.


2016 ◽  
Vol 50 (6) ◽  
pp. 58-68 ◽  
Author(s):  
Narayanaswamy Vedachalam ◽  
Sethuraman Ramesh ◽  
Arunachalam Umapathy ◽  
Gidugu Ananda Ramadass

AbstractNatural gas hydrates are considered to be a strategic unconventional hydrocarbon resource in the Indian energy sector, and thermal stimulation is considered as one of the methods for producing methane from gas hydrate-bearing sediments. This paper discusses the importance of this abundantly available blue economic resource and analyzes the efficiency of methane gas production by circulating hot water in a horizontal well in the fine-grained, clay-rich natural gas hydrate reservoir in the Krishna-Godavari basin of India. Analysis is done using the electrothermal finite element analysis software MagNet-ThermNet and gas hydrate reservoir modeling software TOUGH+HYDRATE with reservoir petrophysical properties as inputs. Energy balance studies indicate that, in the 90% hydrate-saturated reservoir, the theoretical energy conversion ratio is 1:4.9, and for saturations below 20%, the ratio is <1. It is identified that a water flow of 0.2 m3/h at 270°C is required for every 1 m2 of wellhead surface area to dissociate gas hydrates up to a distance of 2.6 m from the well bore within 36 h.


2008 ◽  
Vol 130 (3) ◽  
Author(s):  
M. Uddin ◽  
D. Coombe ◽  
D. Law ◽  
B. Gunter

Numerical modeling of gas hydrates can provide an integrated understanding of the various process mechanisms controlling methane (CH4) production from hydrates and carbon dioxide (CO2) sequestration as a gas hydrate in geologic reservoirs. This work describes a new unified kinetic model which, when coupled with a compositional thermal reservoir simulator, can simulate the dynamics of CH4 and CO2 hydrate formation and decomposition in a geological formation. The kinetic model contains two mass transfer equations: one equation converts gas and water into hydrate and the other equation decomposes hydrate into gas and water. The model structure and parameters were investigated in comparison with a previously published model. The proposed kinetic model was evaluated in two case studies. Case 1 considers a single well within a natural hydrate reservoir for studying the kinetics of CH4 and CO2 hydrate decomposition and formation. A close agreement was achieved between the present numerical simulations and results reported by Hong and Pooladi-Darvish (2003, “A Numerical Study on Gas Production From Formations Containing Gas Hydrates,” Petroleum Society’s Canadian International Petroleum Conference, Calgary, AB, Jun. 10–12, Paper No. 2003-060). Case 2 considers multiple wells within a natural hydrate reservoir for studying the unified kinetic model to demonstrate the feasibility of CO2 sequestration in a natural hydrate reservoir with potential enhancement of CH4 recovery. The model will be applied in future field-scale simulations to predict the dynamics of gas hydrate formation and decomposition processes in actual geological reservoirs.


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