scholarly journals Heat conduction and thermal convection on thermal front movement during natural gas hydrate thermal stimulation exploitation

2018 ◽  
Vol 73 ◽  
pp. 40 ◽  
Author(s):  
Yongmao Hao ◽  
Xiaozhou Li ◽  
Shuxia Li ◽  
Guangzhong Lü ◽  
Yunye Liu ◽  
...  
Keyword(s):  
Heat Conduction ◽  
Thermal Convection ◽  
Thermal Model ◽  
Hot Water ◽  
Thermal Stimulation ◽  
Analytical Models ◽  
Natural Gas Hydrate ◽  
Thermal Front ◽  
Transfer Mode ◽  
Front Movement

Natural Gas Hydrate (NGH) has attracted increasing attention for its great potential as clean energy in the future. The main heat transfer mode that controls the thermal front movement in the process of NGH exploitation by heat injection was discussed through NGH thermal stimulation experiments, and whether it is reliable that most analytical models only consider the heat conduction but neglect the effect of thermal convection was determined by the comparison results between experiments and Selim’s thermal model. And the following findings were obtained. First, the movement rate of thermal front increases with the rise of hot water injection rate but changes little with the rise of the temperature of the injected hot water, which indicated that thermal convection is the key factor promoting the movement of thermal front. Second, the thermal front movement rates measured in the experiments are about 10 times that by the Selim’s thermal model, the reason for which is that the Selim’s thermal model only takes the heat conduction into account. And third, theoretical calculation shows that heat flux transferred by thermal convection is 15.56 times that by heat conduction. It is concluded that thermal convection is the main heat transfer mode that controls the thermal front movement in the process of NGH thermal stimulation, and its influence should never be neglected in those analytical models.

scholarly journals Analytical solutions of fractal-hydro-thermal model for two-phase flow in thermal stimulation enhanced coalbed methane recovery

2019 ◽  
Vol 23 (3 Part A) ◽  
pp. 1345-1353 ◽  
Author(s):  
Xiaoji Shang ◽  
Jianguo Wang ◽  
Zhizhen Zhang
Keyword(s):  
Heat Conduction ◽  
Coalbed Methane ◽  
Thermal Model ◽  
Two Phase Flow ◽  
Thermal Stimulation ◽  
Phase Flow ◽  
Two Phase ◽  
Methane Recovery ◽  
Enhanced Coalbed Methane Recovery ◽  
Enhanced Coalbed Methane

Thermal stimulation is a useful supplementary mining technique for the enhancement of coalbed methane recovery. This technique couples the temperature change with gas-water two-phase flow in the mining process. Many integer dimension hydro-thermal models have been proposed but cannot well describe this coupling because two-phase flow and heat conduction are usually non-linear, tortuous and fractal. In this study, a fractal-hydro-thermal coupling model is proposed to describe the coupling between heat conduction and two-phase flow behaviors in terms of fractional time and space derivatives. This model is analytically solved through the fractal travelling-wave method for pore pressure and production rate of gas and water. The analytical solutions are compared with the in-situ coalbed methane production rate. Results show that our proposed fractal-hydro-thermal model can describe both heat and mass transfers in thermal stimulation enhanced coalbed methane recovery.

scholarly journals Environmentally Friendly Production of Methane from Natural Gas Hydrate Using Carbon Dioxide

2019 ◽  
Vol 11 (7) ◽  
pp. 1964 ◽  
Author(s):  
Bjørn Kvamme
Keyword(s):  
Free Energy ◽  
Natural Gas ◽  
Gas Hydrate ◽  
Free Water ◽  
Hot Water ◽  
Thermal Stimulation ◽  
Pressure Reduction ◽  
Natural Gas Hydrate ◽  
Transport Barrier ◽  
The World

Huge amounts of natural gas hydrate are trapped in an ice-like structure (hydrate). Most of these hydrates have been formed from biogenic degradation of organic waste in the upper crust and are almost pure methane hydrates. With up to 14 mol% methane, concentrated inside a water phase, this is an attractive energy source. Unlike conventional hydrocarbons, these hydrates are widely distributed around the world, and might in total amount to more than twice the energy in all known sources of conventional fossil fuels. A variety of methods for producing methane from hydrate-filled sediments have been proposed and developed through laboratory scale experiments, pilot scale experiments, and theoretical considerations. Thermal stimulation (steam, hot water) and pressure reduction has by far been the dominating technology platforms during the latest three decades. Thermal stimulation as the primary method is too expensive. There are many challenges related to pressure reduction as a method. Conditions of pressure can be changed to outside the hydrate stability zone, but dissociation energy still needs to be supplied. Pressure release will set up a temperature gradient and heat can be transferred from the surrounding formation, but it has never been proven that the capacity and transport ability will ever be enough to sustain a commercial production rate. On the contrary, some recent pilot tests have been terminated due to freezing down. Other problems include sand production and water production. A more novel approach of injecting CO2 into natural gas hydrate-filled sediments have also been investigated in various laboratories around the world with varying success. In this work, we focus on some frequent misunderstandings related to this concept. The only feasible mechanism for the use of CO2 goes though the formation of a new CO2 hydrate from free water in the pores and the incoming CO2. As demonstrated in this work, the nucleation of a CO2 hydrate film rapidly forms a mass transport barrier that slows down any further growth of the CO2 hydrate. Addition of small amounts of surfactants can break these hydrate films. We also demonstrate that the free energy of the CO2 hydrate is roughly 2 kJ/mol lower than the free energy of the CH4 hydrate. In addition to heat release from the formation of the new CO2 hydrate, the increase in ion content of the remaining water will dissociate CH4 hydrate before the CO2 hydrate due to the difference in free energy.

SS - Gas Hydrate: Gas production from methane hydrate sediment layer by thermal stimulation with hot water injection

2010 ◽  
Author(s):  
Kyuro Sasaki ◽  
Shinzi Ono ◽  
Yuichi Sugai ◽  
Norio Tenma ◽  
Takao Ebinuma ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Methane Hydrate ◽  
Water Injection ◽  
Gas Production ◽  
Hot Water ◽  
Thermal Stimulation ◽  
Sediment Layer

Software Tool for the Study, Analysis and Evaluation of Enhanced Oil Recovery Processes

2014 ◽  
Author(s):  
C. L. Delgadillo-Aya ◽  
M.L.. L. Trujillo-Portillo ◽  
J.M.. M. Palma-Bustamante ◽  
E.. Niz-Velasquez ◽  
C. L. Rodríguez ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Water Injection ◽  
Software Tool ◽  
Steam Injection ◽  
Hot Water ◽  
Assessment Process ◽  
Analytical Models ◽  
Financial Assessment ◽  
Recovery Processes

Abstract Software tools are becoming an important ally in making decisions on the development or implementation of an enhanced oil recovery processes from the technical, financial or risk point of view. This work, can be manually developed in some cases, but becomes more efficient and precise with the help of these tools. In Ecopetrol was developed a tool to make technical and economic evaluation of enhanced oil recovery processes such as air injection, both cyclic and continuous steam injection, and steam assisted gravity drainage (SAGD) and hot water injection. This evaluation is performed using different types of analysis as binary screening, analogies, benchmarking, and prediction using analytical models and financial and risk analysis. All these evaluations are supported by a comprehensive review that has allowed initially find favorable conditions for different recovery methods evaluated, and get a probability of success based on this review. Subsequently, according to the method can be used different prediction methods, given an idea of the process behavior for a given period. Based on the prediction results, it is possible to feed the software to generate a financial assessment process, in line with cash flow previously developed that incorporates all the elements to be considered during the implementation of a project. This allows for greater support to the choice or not the application of a method. Finally the tool to evaluate the levels of risks that outlines the development of the project based on the existing internal methodology in the company, identifying the main and level of criticality and define actions for prevention, mitigation and risk elimination.

scholarly journals Similarity of temperature and concentration field in Poiseuille–Benard channel flow

2019 ◽  
Vol 213 ◽  
pp. 02012
Author(s):  
Jakub Devera ◽  
Tomáš Hyhlík ◽  
Radomír Kalinay
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Concentration Field ◽  
Water Film ◽  
Considerable Effect ◽  
Hot Water ◽  
Transfer Mode ◽  
Commercial Code ◽  
Similar Character

A flow over hot water film in horizontal channel (Poiseuille–Benard flow) is studied experimentally and by means of CFD. Averaged temperature and concentration fields were measured in central transverse plane using RTD and capacitive humidity probe for different Ri = Gr/Re2. A similarity of thermal and concentration field is discussed and the influence of thermal and humidity field by radiative heat transfer is investigated since it has a considerable effect. Same cases are modeled by CFD in commercial code Star-CCM+. Simulated thermal and concentration fields shows similar character as those from measurements when radiative heat transfer mode is considered.

scholarly journals Analytical models of heat conduction in fractured rocks

2014 ◽  
Vol 119 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Á. Ruiz Martínez ◽  
D. Roubinet ◽  
D. M. Tartakovsky
Keyword(s):  
Heat Conduction ◽  
Fractured Rocks ◽  
Analytical Models

Research and Numerical Simulation of Heat Transfer Problems in the Industrial Production

2013 ◽  
Vol 756-759 ◽  
pp. 1679-1683
Author(s):  
Dong Mei Li ◽  
Xin Chun Wang ◽  
Li Nan Shi ◽  
Bo Chao Qu
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Steel Industry ◽  
Heat Transfer Mode ◽  
Radiation Model ◽  
Transfer Mode ◽  
The Difference ◽  
Transfer Problems ◽  
Direct Problems ◽  
The Impact

This article focuses on heat conduction problems in the process of steel industry. Modeling the direct problems of heat transfer, establish heat conduction and thermal radiation model. Model discretization method are used, discussion process from one dimension to two. We give the difference schemes, and the numerical example. Through the results we compare differences between one and two dimensional models, and the impact to the results of the two heat transfer mode.

scholarly journals Modelling Thermal Resistance of Power Modules Having Solder Voids With Finite Elements

1987 ◽  
Vol 12 (4) ◽  
pp. 239-250 ◽  
Author(s):  
R. A. Tatara
Keyword(s):  
Finite Element ◽  
Heat Conduction ◽  
Finite Elements ◽  
Thermal Resistance ◽  
Computer Program ◽  
Thermal Model ◽  
Three Dimensional ◽  
Power Module ◽  
Power Modules ◽  
Sample Case

A general thermal model to calculate the thermal resistance of a power module having rectangular die and layers has been constructed. The model incorporates a finite element computer program to solve for three-dimensional heat conduction. Effects of voids in the solder regions are included. A sample case is analyzed, and a comparison is made to a recent study.

scholarly journals Effect of Bed Deformation on Natural Gas Production from Hydrates

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Mohamed Iqbal Pallipurath
Keyword(s):  
Natural Gas ◽  
Gas Production ◽  
Thermal Stimulation ◽  
Natural Gas Hydrate ◽  
Bed Deformation ◽  
Sediment Bed ◽  
Finite Element Package ◽  
Modelling Studies ◽  
Sediment Deformation ◽  
Stimulation Of

This work is based on modelling studies in an axisymmetric framework. The thermal stimulation of hydrated sediment is taken to occur by a centrally placed heat source. The model includes the hydrate dissociation and its effect on sediment bed deformation and resulting effect on gas production. A finite element package was customized to simulate the gas production from natural gas hydrate by considering the deformation of submarine bed. Three sediment models have been used to simulate gas production. The effect of sediment deformation on gas production by thermal stimulation is studied. Gas production rate is found to increase with an increase in the source temperature. Porosity of the sediment and saturation of the hydrate both have been found to significantly influence the rate of gas production.

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