scholarly journals Numerical study of constant-rate gas production from in situ gas hydrate by depressurization

2005 ◽  
Author(s):  
H Hong ◽  
M Pooladi-Darvish
Keyword(s):  
Gas Hydrate ◽  
Numerical Study ◽  
Gas Production ◽  
Constant Rate

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 Evaluation of the Nutrient Composition, In Vitro Fermentation Characteristics, and In Situ Degradability of Amaranthus caudatus, Amaranthus cruentus, and Amaranthus hypochondriacus in Cattle

Animals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Kim Margarette C. Nogoy ◽  
Jia Yu ◽  
Young Gyu Song ◽  
Shida Li ◽  
Jong-Wook Chung ◽  
...  
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
Gas Production ◽  
Nutrient Composition ◽  
Neutral Detergent Fiber ◽  
Amaranthus Cruentus ◽  
Amaranthus Caudatus ◽  
Amaranthus Hypochondriacus

The amaranth plants showed high potential feed value as forage for ruminants. An in-depth study of this plant, particularly in cattle, will help extend its utilization as an alternative protein and fiber feed source in cattle feeding. In this study, the nutrient compositions of three different species of amaranth, Amaranthus caudatus L., Amaranthus cruentus L., and Amaranthus hypochondriacus L.—two varieties for each species, A.ca 74, A.ca 91, A.cu 62, A.cu 66, A. hy 30, and A. hy 48—were evaluated. The in vitro technique was used to evaluate the fermentation characteristics such as total gas production, total volatile fatty acids (VFA) concentration, pH, and ammonia concentration of the rumen fluid. Moreover, the effective degradabilities of dry matter (EDDM) and crude protein (EDCP) of the amaranth forages were determined through in situ bag technique. The amaranth forages: A. caudatus, A. cruentus, and A. hypochondriacus showed better nutritive value than the locally produced forages in Chungcheong province of Korea. The CP of the amaranth ranged from 11.95% to 14.19%, and the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents ranged from 45.53% to 70.88% and 34.17% to 49.83%, respectively. Among the amaranth varieties, A. hypochondriacus 48 showed the most excellent ruminant feed nutrient quality (CP, 14.19%; NDF, 45.53%; and ADF, 34.17%). The effective degradabilities of dry matter (EDDM; 33–56%) and crude protein EDCP (27–59%) of the amaranth were lower compared to other studies, which could be due to the maturity stage at which the forages were harvested. Nonetheless, A. hypochondriacus 48 showed the highest EDDM (56.73%) and EDCP (59.09%). The different amaranth species did not differ greatly in terms of total VFA concentration or molar proportions, total gas production, or ammonia-N concentration. The high nutrient composition, and highly effective degradability of dry matter and crude protein, coupled with the favorable fermentation characteristics, suggest that the amaranth forages showed good to excellent feed quality for cattle.

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
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