scholarly journals Dynamic 3D imaging of gas hydrate kinetics using synchrotron computed tomography

2020 ◽  
Vol 205 ◽  
pp. 11004
Author(s):  
Zaher Jarrar ◽  
Riyadh Al-Raoush ◽  
Khalid Alshibli ◽  
Jongwon Jung
Keyword(s):  
Surface Area ◽  
Gas Hydrates ◽  
Energy Demand ◽  
Three Dimensional ◽  
Hydrate Formation ◽  
Gas Production ◽  
Dissociation Kinetics ◽  
Hydrate Dissociation ◽  
Hydrate Saturation ◽  
3D Volume

The availability of natural gas hydrates and the continuing increase in energy demand, motivated researchers to consider gas hydrates as a future source of energy. Fundamental understanding of hydrate dissociation kinetics is essential to improve techniques of gas production from natural hydrates reservoirs. During hydrate dissociation, bonds between water (host molecules) and gas (guest molecules) break and free gas is released. This paper investigates the evolution of hydrate surface area, pore habit, and tortuosity using in-situ imaging of Xenon (Xe) hydrate formation and dissociation in porous media with dynamic three-dimensional synchrotron microcomputed tomography (SMT). Xe hydrate was formed inside a high- pressure, low-temperature cell and then dissociated by thermal stimulation. During formation and dissociation, full 3D SMT scans were acquired continuously and reconstructed into 3D volume images. Each scan took only 45 seconds to complete, and a total of 60 scans were acquired. Hydrate volume and surface area evolution were directly measured from the SMT scans. At low hydrate saturation, the predominant pore habit was surface coating, while the predominant pore habit at high hydrate saturation was pore filling. A second-degree polynomial can be used to predict variation of tortuosity with hydrate saturation with an R2 value of 0.997.

scholarly journals Experimental and Modeling Study of Kinetics for Hydrate Decomposition Induced by Depressurization in a Porous Medium

2021 ◽  
Vol 9 ◽  
Author(s):  
Xuke Ruan ◽  
Chun-Gang Xu ◽  
Ke-Feng Yan ◽  
Xiao-Sen Li
Keyword(s):  
Porous Media ◽  
Surface Area ◽  
Strong Dependence ◽  
Gas Production ◽  
Numerical Code ◽  
Dissociation Kinetics ◽  
Hydrate Dissociation ◽  
Hydrate Decomposition ◽  
Hydrate Saturation ◽  
Kinetics Of

The hydrate decomposition kinetics is a key factor for the gas production from hydrate-saturated porous media. Meanwhile, it is also related to other factors. Among them, the permeability and hydrate dissociation surface area on hydrate dissociation kinetics have been studied experimentally and numerically in this work. First, the permeability to water was experimentally determined at different hydrate saturations (0%, 10%, 17%, 21%, 34%, 40.5%, and 48.75%) in hydrate-bearing porous media. By the comparison of permeability results from the experimental measurements and theoretical calculations with the empirical permeability models, it was found that, for the lower hydrate saturations (less than 40%), the experimental results of water permeability are closer to the predicted values of the grain-coating permeability model, whereas, for the hydrate saturation above 40%, the tendencies of hydrate accumulation in porous media are quite consistent with the pore-filling hydrate habits. A developed two-dimensional core-scale numerical code, which incorporates the models for permeability and hydrate dissociation surface area along with the hydrate accumulation habits in porous media, was used to investigate the kinetics of hydrate dissociation by depressurization, and a “shrinking-core” hydrate dissociation driven by the radial heat transfer was found in the numerical simulations of hydrate dissociation induced by depressurization in core-scale porous media. The numerical results indicate that the gas production from hydrates in porous media has a strong dependence on the permeability and hydrate dissociation surface area. Meanwhile, the simulation shows that the controlling factor for the dissociation kinetics of hydrate switches from permeability to hydrate dissociation surface area depending on the hydrate saturation and hydrate accumulation habits in porous media.

Experimental Study on Gas Production from Methane Hydrate Bearing Sand by Depressurization

2013 ◽  
Vol 310 ◽  
pp. 28-32
Author(s):  
Jian Ye Sun ◽  
Yu Guang Ye ◽  
Chang Ling Liu ◽  
Jian Zhang
Keyword(s):  
Experimental Study ◽  
Methane Hydrate ◽  
Hydrate Formation ◽  
Gas Production ◽  
Decomposition Kinetics ◽  
Dissociation Process ◽  
Hydrate Dissociation ◽  
Gas Hydrate Formation ◽  
Experimental Apparatus ◽  
Hydrate Saturation

The simulate experiments of gas production from methane hydrates reservoirs was proceeded with an experimental apparatus. Especially, TDR technique was applied to represent the change of hydrate saturation in real time during gas hydrate formation and dissociation. In this paper, we discussed and explained material transformation during hydrate formation and dissociation. The hydrates form and grow on the top of the sediments where the sediments and gas connect firstly. During hydrates dissociation by depressurization, the temperatures and hydrate saturation presented variously in different locations of sediments, which shows that hydrates dissociate earlier on the surface and outer layer of the sediments than those of in inner. The regulation of hydrates dissociation is consistent with the law of decomposition kinetics. Furthermore, we investigated the depressurizing range influence on hydrate dissociation process.

scholarly journals Method for Determining the Mass Flow for Pressure Measurements of Gas Hydrates Formation in the Well

2021 ◽  
pp. 195-205
Author(s):  
Natalya N. Borisova ◽  
Igor I. Rozhin
Keyword(s):  
Mass Flow ◽  
Gas Hydrates ◽  
Hydrate Formation ◽  
Gas Production ◽  
Pressure Measurements ◽  
Time Dependency ◽  
Flow Area ◽  
Additional Information ◽  
Bottom Hole ◽  
The Republic

The work focuses on the inverse problem of determining differential equation coefficients for additional information on the behavior of solution. Furthermore, the algorithm for determining parameters of systems of ordinary differential equations on the basis of stomatal pressure measurements is generalized for the model of hydrate formation when the internal well section of changes with time and also has to be determined during the solution of the general problem. The computational experiment has been conducted for wells of Otradninsky gas condensate deposits of the Republic Sakha (Yakutia), the exploitation of which indicates that the complications are most likely caused by formation of gas hydrates both in the bottom-hole and in the well and its plumes. It has been established that the most important influence on the dynamics of hydrate plugs formation in wells is the gas production mode, its equation of state, reservoir and geocryological conditions. Time dependency of mass flow has been determined, which knowledge will make it possible to control the change of flow area of the entire well and, if necessary, to prevent and remove formation of natural gas hydrates

Considerations in Gas Pipeline Commissioning to Prevent Hydrate Formation

2002 ◽  
Author(s):  
Boyun Guo ◽  
Ali Ghalambor ◽  
Chengcai Xue
Keyword(s):  
Water Content ◽  
Gas Hydrates ◽  
Research Work ◽  
Hydrate Formation ◽  
Gas Production ◽  
Gas Pipeline ◽  
Normal Operation ◽  
Free Fluid ◽  
Systematic Method ◽  
Operation Conditions

Formation of gas hydrates in gas production pipelines is one of the major problems in deepwater development. Most of the research work has focused on the problem during normal operation conditions. However, this problem can arise during pipeline commissioning and get worse after commissioning, even though export gas is dry enough to be considered as a hydrate-free fluid under normal operation conditions. This is because the water content that was left in the pipeline during commissioning can initiate formation of gas hydrates when export gas is introduced into the pipeline. The water content depends on the commissioning procedure and fluids used during the commissioning. This paper presents a systematic method to optimize the commissioning procedure. An application example is also presented.

Soaking effects on CH4-CO2 replacement efficiency in gas hydrates

2020 ◽  
Author(s):  
Jongwon Jung ◽  
Jaeeun Ryou ◽  
Joo Yong Lee ◽  
Riyadh I AI-Raoush ◽  
Khalid Alshibli ◽  
...  
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Production Efficiency ◽  
Gas Permeability ◽  
Gas Production ◽  
Production Methods ◽  
Injection Method ◽  
Development Organization ◽  
Replacement Method ◽  
Hydrate Saturation

<p>Gas hydrates are potential energy resources which can be formed at low temperature and high pressure. The number of recoverable gas hydrates are limited due to the specific temperature, pressure conditions and technical limitations of gas production. Various production methods have been studied around the world to overcome these technical limitations. Gas production methods from gas hydrates are divided into methods of dissociating gas hydrates and non-dissociating gas hydrates. The dissociation methods including depressurization method, thermal injection method, and chemical inhibitor injection method can decrease in effective stress of the ground due to phase conversion. On the other hand, CH<sub>4</sub>-CO<sub>2 </sub>replacement method is geomechanically stable because it does not dissociate gas hydrates. Also, CH<sub>4</sub>-CO<sub>2 </sub>replacement method has the advantage of sequestering carbon dioxide while producing methane. However, CH<sub>4</sub>-CO<sub>2</sub> replacement method has the disadvantage such as low production efficiency and understanding kinetics of gas production. In this study, soaking, gas permeability of gas hydrate layer and hydrate saturation are considered in order to promote the production efficiency of CH<sub>4</sub>-CO<sub>2</sub> replacement method. Results show that production efficiency increases with the number of soaking process, the higher gas permeability and hydrate saturation. According to the experimental results in this study, the production efficiency can be increased by considering the soaking time, procedure and selecting the proper gas hydrates site.</p><p>Acknowledgement</p><p>This work is supported by the Korea Agency for Infrastructure Technology Advancement(KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant 20CTAP-C152100-02). Also, it is supported by partial funding from NPRP grant # NPRP8-594-2-244 from the Qatar national research fund (a member of Qatar Foundation) and  the Ministry of Trade, Industry, and Energy (MOTIE) through the Project “Gas Hydrate Exploration and Production Study (20-1143)” under the management of the Gas Hydrate Research and Development Organization (GHDO) of Korea and the Korea Institute of Geoscience and Mineral Resources (KIGAM).</p>

An Investigation Into the Occurrence of Hydrate-Bearing Sediments Offshore the East Coast of Trinidad and Tobago

SPE Journal ◽  
2016 ◽  
Vol 21 (05) ◽  
pp. 1782-1792
Author(s):  
Maxian B. Seales ◽  
Jill Marcelle-De Silva ◽  
Turgay Ertekin ◽  
John Yilin Wang
Keyword(s):  
Natural Gas ◽  
Crude Oil ◽  
Trinidad And Tobago ◽  
Gas Hydrates ◽  
Energy Demand ◽  
East Coast ◽  
Gas Production ◽  
Energy Potential ◽  
Production Ratio ◽  
Natural Gas Hydrates

Summary It is anticipated that increasing pressure for cleaner burning fuels and lower carbon dioxide (CO2) emissions will cause a shift in global energy demand from oil to natural gas. In the near future, natural gas is expected to replace crude oil as the fuel of choice for energy production and transportation. In Trinidad and Tobago, natural-gas production has already surpassed crude-oil production. Natural gas accounts for 80% of the country's energy export, but the reserves-to-production ratio is only 7 years (year 2022). Consequently, the Ministry of Energy has taken steps to supplement the natural-gas resource base by supporting initiatives that can potentially bolster the nation's proven gas reserves. Such initiatives include invitations to tender on deepwater blocks offshore Trinidad and Tobago's gas-rich east coast. Even though initiatives are under way to boost conventional natural-gas reserves, effort was not placed on identifying and/or characterizing unconventional gas resources such as natural-gas hydrates. Furthermore, the potential hazards of submarine gas hydrates on deepwater exploration and production (E&P) activities on Trinidad and Tobago's east coast were not assessed. The results presented in this manuscript provide oil-and-gas operators with a means of proactively managing the risk associated with natural-gas hydrates. More importantly, this study acts as a necessary precursor to future studies in characterizing and, later, harnessing the energy potential of Trinidad-and-Tobago's natural-gas-hydrate deposits.

Numerical Studies of Gas Hydrate Formation and Decomposition in a Geological Reservoir

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
M. Uddin ◽  
D. Coombe ◽  
D. Law ◽  
B. Gunter
Keyword(s):  
Kinetic Model ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Co2 Sequestration ◽  
Numerical Study ◽  
Hydrate Formation ◽  
Gas Production ◽  
Ch4 Production ◽  
Hydrate Reservoir ◽  
Gas Hydrate Formation

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.

scholarly journals Simulation of Hydrate Phase Boundary for Natural Gas Mixture with High CO2Content through Simulation

2019 ◽  
Vol 9 (2) ◽  
pp. 4030-4034
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Oil And Gas ◽  
Hydrate Formation ◽  
Gas Production ◽  
Gas Mixture ◽  
Oil And Gas Production ◽  
Equation Of States ◽  
Gas Molecules ◽  
Simulation Results

Gas hydrates are solid crystalline structures in which water molecules trap small guest gas molecules and encage them through hydrogen bonding. Gas hydrates are known to be problematic in flow assurance applications as they can form plug inside the pipelines during oil and gas production, transportation and processing. In order to inhibit hydrate formation thermodynamically, various chemicals including some alcohols e.g. methanol (MeOH), mono- ethylene glycol (MEG) are used as thermodynamic hydrate inhibitors (THIs). In this paper, a simulation study is performed using PVTsim software wherein it predicts the hydrate formation for pure CO2 solution mixture and CO2 -MEG solution mixture systems using different equation of states. These equations of states include Soave-Redlich-Kwong (SRK), SRK-Peneloux, Peng- Robinson (PR) and Peng-Robinson Peneloux. The simulation results obtained using these equation of states were validated with the experimental data and PRPenelouxEoS was found to be in better agreement. The hydrate formation regions are determined in between the pressure range of 10 to 110 bara for natural gas mixture containing high percentage of CO2 in it. The inhibitors are used in 5, 10 and 20 wt% concentrations. The hydrate inhibition efficiency increased with the increase in concentration. Simulation results showed that methanol performed better in comparison to the other inhibitors at all concentrations.

Optimization Strategies of Production Parameters to Prevent Hydrate Reformation in Marine Gas Hydrate Production System

2021 ◽  
Author(s):  
Zheng Liu ◽  
Baojiang Sun ◽  
Zhiyuan Wang ◽  
Jianbo Zhang
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Production System ◽  
Hydrate Formation ◽  
Gas Production ◽  
Design Parameters ◽  
Formation Condition ◽  
Transient Temperature ◽  
Marine Gas Hydrate

Abstract In recent decades, the development of natural gas hydrates has become a research hotspot of scholars all over the world. However, the decomposed gas and water in marine gas hydrate production system may regenerate gas hydrates due to the low-temperature and high-pressure environment in seafloor. In this study, a transient temperature and pressure calculating model was established to predict the risk of hydrate reformation in production pipelines during offshore natural gas hydrate development. Using the proposed model, the region of hydrate reformation in gas hydrate production wells were predicted quantitatively. Meanwhile, the hydrate reformation management strategies through optimization of production design parameters in combination with hydrate inhibitor injection were proposed and discussed in detail. The results indicate that the risk of hydrate reformation is the highest in the drainage pipeline (DP); however, the flow in gas-water mixed transportation and gas production pipelines (MTP and GPP) basically does not satisfy the hydrate formation condition. In the process of production well design, adding additional the EH and ESP can fully eliminate the hydrate reformation risk in the DP without using the hydrate inhibitor.

scholarly journals Gas hydrate in-situ formation and dissociation in clayey-silt sediments: An investigation by low-field NMR

2020 ◽  
pp. 014459872097415
Author(s):  
Xiaoxiao Sun ◽  
Xuwen Qin ◽  
Hongfeng Lu ◽  
Jingli Wang ◽  
Jianchun Xu ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Hydrate Formation ◽  
Dissociation Process ◽  
Hydrate Dissociation ◽  
Hydrate Reservoir ◽  
Low Field ◽  
Gas Hydrate Formation ◽  
Clayey Silt ◽  
Hydrate Saturation ◽  
Low Field Nmr

The hydrate reservoir in the Shenhu Area of the South China Sea is a typical clayey-silt porous media with high clay mineral content and poor cementation, in which gas hydrate formation and dissociation characteristics are unclear. In this study, the CO2 hydrate saturation, growth rate, and permeability were studied in sandstone, artificial samples, and clayey-silt sediments using a custom-built measurement apparatus based on the low-field NMR technique. Results show that the T2 spectra amplitudes decrease with the hydrate formation and increase with the dissociation process. For the artificial samples and Shenhu sediments, the CO2 hydrate occupies larger pores first and the homogeneity of the sandstone pores becomes poor. Meanwhile, compared with the clayey-silt sediments, CO2 hydrate is easier to form and with higher hydrate saturation for the sandstone and artificial samples. In hydrate dissociation process, there exists a protection mechanism, i.e. the dissociation near the center of hydrates grain is suppressed when gas pressure drops suddenly and quickly. For permeability of those samples, it decreased with hydrate forms, and increases with hydrate dissociation. Meanwhile, with the same hydrate saturation, permeability is higher in hydrate formation than in dissociation.

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