scholarly journals Influence of the Particle Size of Sandy Sediments on Heat and Mass Transfer Characteristics during Methane Hydrate Dissociation by Thermal Stimulation

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4227 ◽  
Author(s):  
Yi Wang ◽  
Lei Zhan ◽  
Jing-Chun Feng ◽  
Xiao-Sen Li

Natural gas hydrate could be regarded as an alternative energy source in the future. Therefore, the investigation of the gas production from hydrate reservoirs is attracting extensive attention. In this work, a novel set-up was built to investigate sand production and sediment deformation during hydrate dissociation by heat stimulation. The influence of the particle sizes on the hydrate dissociation and sediment deformation was first investigated experimentally. The experimental results indicated that the rate of hydrate decomposition by heat stimulation was in proportion to the particle size of the sediment. The heat transfer rate and the energy efficiency decreased with the decrease of the particle size of the sediment. This was because higher permeability might lead to a larger sweep area of the fluid flow, which was beneficial for the supply of heat for hydrate dissociation. The sand production was found during hydrate dissociation by heat stimulation. The particle migration was due to the hydrodynamics of the water injection. The sand sediment expanded under the drive force from water injection and hydrate dissociation. Additionally, the smaller permeability led to the larger pressure difference leading to the larger sediment deformation. Because the sediment became loose after hydrate dissociation, small particle migration due to the hydrodynamics of the water injection could happen during the experiments. However, the sand production in the sediment with the larger particle size was more difficult, because the larger particles were harder to move due to the hydrodynamics, and the larger particles were harder to move across the holes on the production well with a diameter of 1 mm. Therefore, the sediment deformation during hydrate dissociation by heat stimulation should not be ignored.

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 548
Author(s):  
Lijia Li ◽  
Xiaosen Li ◽  
Yi Wang ◽  
Chaozhong Qin ◽  
Bo Li ◽  
...  

Natural gas hydrate (NGH) has been widely focused on having great potential for alternative energy. Numerous studies on gas production from hydrate-bearing sediments have been conducted in both laboratory and field. Since the strength of hydrate-bearing sediments depends on the saturation of NGH, the decomposition of NGH may cause the failure of sediments, then leading to reservoir deformation and other geological hazards. Plenty of research has shown that the reservoir deformation caused by hydrate decomposition is considerable. In order to investigate this, the influence of sediment deformation on the production of NGH, a fully coupled thermo-hydro-chemo-mechanical (THMC) model is established in this study. The interaction effects between reservoir deformation and hydrate dissociation are discussed by comparing the simulation results of the mechanical coupling and uncoupled models on the laboratory scale. Results show that obvious differences in behaviors between gas and water production are observed among these two models. Compared to the mechanical uncoupled model, the mechanical coupling model shows a significant compaction process when given a load equal to the initial pore pressure, which leads to a remarkable decrease of effective porosity and reservoir permeability, then delays the pore pressure drop rate and reduces the maximum gas production rate. It takes a longer time for gas production in the mechanical coupling model. Since the reservoir temperature is impacted by the comprehensive effects of the heat transfer from the boundary and the heat consumption of hydrate decomposition, the reduced maximum gas production rate and extended gas production process for the mechanical coupling model lead to the minimum reservoir temperature in the mechanical coupling model larger than that of the mechanical uncoupled model. The reduction of the effective porosity for the mechanical coupling model causes a larger cumulative water production. The results of this paper indicate that the reservoir deformation in the gas production process should be taken into account by laboratory and numerical methods to accurately predict the behaviors of gas production on the field scale.


2015 ◽  
Vol 733 ◽  
pp. 55-58
Author(s):  
Pei Long Wang ◽  
Guang Sheng Cao ◽  
Guo Jing Miao ◽  
Hong Fei Cui

Due to the particularity of its percolation of low permeability reservoirs, water injection is very difficult and damage to the reservoir, especially the impurities in injection Wells, at the same time affect the injection efficiency, it will ultimately affect the recovery of the reservoir and the oilfield production. So it is necessary to carry out the ingredients and the causes of impurities in injection wells, clearing the Source for different kinds of impurity to provide the basis for reduce the impurity content in injection wells. In this paper, the author analyzed impurities particle size, composition and content in oilfield injection water In Longhop Oilfield through the indoor experiment, and with the comparison between the ion content and composition of the filtered water samples, analyzing the cause of the impurity within the wellbore. Experimental results show that in oil field water injection well, impurities particle size are mainly distributed between 2.6 and 5.4 um, impurity content mainly changes between 0.003746% and 0.017189%, the main ingredients of impurities is Fe2O3 and acid insoluble substances (SiO2). Fe2O3 mainly comes from the injection water; acid insoluble substances mainly come from the formation sand production.


2021 ◽  
Vol 9 ◽  
Author(s):  
Xuke Ruan ◽  
Chun-Gang Xu ◽  
Ke-Feng Yan ◽  
Xiao-Sen Li

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.


Author(s):  
Ah-Ram Kim ◽  
Gye-Chun Cho ◽  
Joo-Yong Lee ◽  
Se-Joon Kim

Methane hydrate has been received large attention as a new energy source instead of oil and fossil fuel. However, there is high potential for geomechanical stability problems such as marine landslides, seafloor subsidence, and large volume contraction in the hydrate-bearing sediment during gas production induced by depressurization. In this study, a thermal-hydraulic-mechanical coupled numerical analysis is conducted to simulate methane gas production from the hydrate deposits in the Ulleung basin, East Sea, Korea. The field-scale axisymmetric model incorporates the physical processes of hydrate dissociation, pore fluid flow, thermal changes (i.e., latent heat, conduction and advection), and geomechanical behaviors of the hydrate-bearing sediment. During depressurization, deformation of sediments around the production well is generated by the effective stress transformed from the pore pressure difference in the depressurized region. This tendency becomes more pronounced due to the stiffness decrease of hydrate-bearing sediments which is caused by hydrate dissociation.


2010 ◽  
Author(s):  
Kyuro Sasaki ◽  
Shinzi Ono ◽  
Yuichi Sugai ◽  
Norio Tenma ◽  
Takao Ebinuma ◽  
...  

2021 ◽  
Author(s):  
Ermeng Zhao ◽  
Jian Hou ◽  
Yunkai Ji ◽  
Lu Liu ◽  
Yongge Liu ◽  
...  

Abstract Natural gas hydrate is widely distributed in the permafrost and marine deposits, and is regarded as an energy resource with great potential. The low-frequency electric heating assisted depressurization (LF-EHAD) has been proven to be an efficient method for exploiting hydrate sediments, which involves complex multi-physics processes, i.e. current conduction, multiphase flow, chemical reaction and heat transfer. The physical properties vary greatly in different hydrate sediments, which may profoundly affect the hydrate decomposition in the LF-EHAD process. In order to evaluate the influence of hydrate-bearing sediment properties on the gas production behavior and energy utilization efficiency of the LF-EHAD method, a geological model was first established based on the data of hydrate sediments in the Shenhu Area. Then, the influence of permeability, porosity, thermal conductivity, specific heat capacity, hydrate saturation and hydrate-bearing layer (HBL) thickness on gas production behavior is comprehensively analyzed by numerical simulation method. Finally, the energy efficiency ratio under different sediment properties is compared. Results indicate that higher gas production is obtained in the high-permeability hydrate sediments during depressurization. However, after the electric heating is implemented, the gas production first increases and then tends to be insensitive as the permeability decreases. With the increasing of porosity, the gas production during depressurization decreases due to the low effective permeability; while in the electric heating stage, this effect is reversed. High thermal conductivity is beneficial to enhance the heat conduction, thus promoting the hydrate decomposition. During depressurization, the gas production is enhanced with the increase of specific heat capacity. However, more heat is consumed to increase the reservoir temperature during electric heating, thereby reducing the gas production. High hydrate saturation is not conducive to depressurization because of the low effective permeability. After electric heating, the gas production increases significantly. High HBL thickness results in a higher gas production during depressurization, while in the electric heating stage, the gas production first increases and then remains unchanged with the increase of thickness, due to the limited heat supply. The comparison results of energy efficiency suggest that electric heating is more advantageous for hydrate sediments with low permeability, high porosity, high thermal conductivity, low specific heat capacity, high hydrate saturation and high HBL thickness. The findings in this work can provide a useful reference for evaluating the application of the LF-EHAD method in gas hydrate sediments.


2021 ◽  
Vol 73 (09) ◽  
pp. 58-59
Author(s):  
Chris Carpenter

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 30407, “Case Study of Nanopolysilicon Materials’ Depressurization and Injection-Increasing Technology in Offshore Bohai Bay Oil Field KL21-1,” by Qing Feng, Nan Xiao Li, and Jun Zi Huang, China Oilfield Services, et al., prepared for the 2020 Offshore Technology Conference Asia, originally scheduled to be held in Kuala Lumpur, 2–6 November. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. Nanotechnology offers creative approaches to solve problems of oil and gas production that also provide potential for pressure-decreasing application in oil fields. However, at the time of writing, successful pressure-decreasing nanotechnology has rarely been reported. The complete paper reports nanopolysilicon as a new depressurization and injection-increasing agent. The stability of nanopolysilicon was studied in the presence of various ions, including sodium (Na+), calcium (Ca2+), and magnesium (Mg2+). The study found that the addition of nanomaterials can improve porosity and permeability of porous media. Introduction More than 600 water-injection wells exist in Bohai Bay, China. Offshore Field KL21-1, developed by water-flooding, is confronted with the following challenges: - Rapid increase and reduction of water-injection pressure - Weak water-injection capacity of reservoir - Decline of oil production - Poor reservoir properties - Serious hydration and expansion effects of clay minerals To overcome injection difficulties in offshore fields, conventional acidizing measures usually are taken. But, after multiple cycles of acidification, the amount of soluble substances in the rock gradually decreases and injection performance is shortened. Through injection-performance experiments, it can be determined that the biological nanopolysilicon colloid has positive effects on pressure reduction and injection increase. Fluid-seepage-resistance decreases, the injection rate increases by 40%, and injection pressure decreases by 10%. Features of Biological Nanopolysilicon Systems The biological nanopolysilicon-injection system was composed of a bioemulsifier (CDL32), a biological dispersant (DS2), and a nanopolysilicon hydrophobic system (NP12). The bacterial strain of CDL32 was used to obtain the culture colloid of biological emulsifier at 37°C for 5 days. DS2 was made from biological emulsifier CDL32 and some industrial raw materials described in Table 1 of the complete paper. Nanopolysilicon hydrophobic system NP12 was composed of silicon dioxide particles. The hydrophobic nanopolysilicons selected in this project featured particle sizes of less than 100 nm. In the original samples, a floc of nanopolysilicon was fluffy and uniform. But, when wet, nanopolysilicon will self-aggregate and its particle size increases greatly. At the same time, nanopolysilicon features significant agglomeration in water. Because of its high interface energy, nanopolysilicon is easily agglomerated, as shown in Fig. 1.


2016 ◽  
Vol 30 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Shin-ichi Tagawa ◽  
Lucia Holtshausen ◽  
Tim A McAllister ◽  
Wen Zhu Yang ◽  
Karen Ann Beauchemin

2021 ◽  
Vol 16 (2) ◽  
pp. 320-330
Author(s):  
Fitriyah Wulan Dini ◽  
Helmiyati Helmiyati ◽  
Yuni K. Krisnandi

This work demonstrated the use of green material catalysts, produced from Sengon sawdust waste, to obtain nanocellulose biopolymers. The green material catalysts were utilized as catalysts support of TiO2−ZrO2 binary oxide in the form of nanocomposite materials with superior synergistic properties. The isolation of nanocellulose was achieved using a hydrolysis method with a yield of 63.40%. The TiO2 and ZrO2 nanoparticles have average particle sizes of around 25 and 15 nm, respectively, and the binary oxides of TiO2–ZrO2 pretained an average particle size of 30 nm were used. Furthermore, the nanocellulose combined with the TiO2−ZrO2 binary oxide had formed a cellulose/TiO2−ZrO2 nanocomposite with an average particle size of 30 nm. This indicates that the supporting nanocellulose can stabilize the nanoparticles and avoid aggregation. Moreover, the nanocomposites can be used as a catalyst for the conversion of glucose to 5-ethoxymethylfurfural (5-EMF). The catalytic activity increased with the nanoparticle effect obtained ZrO2, TiO2, TiO2-ZrO2, and cellulose and TiO2-ZrO2 nanocomposite, in 15.50%, 20.20%, 35.20%, and 45.50% yields, respectively. The best yield of 5-EMF was 45.50%, with reaction conditions of 1:1 TiO2–ZrO2 ratio, 4 h reaction time, and 160 °C reaction temperature. The use of nanocellulose biopolymer generated from Sengon sawdust waste in Indonesia provides a promising catalyst support material as an alternative green catalyst. In addition, the glucose carbohydrates can be converted to biofuel feedstocks in the development of a renewable alternative energy. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 


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