Korean Chem. Eng. Res., Vol. 42, No. 1, February, 2004, pp. 115-120

Electric Heating

†*

133-791 17

* 431-711 1588-14

(2003 10 14! "#, 2003 12 20! $%)

An Experimental Study for Hydrate Dissociation Phenomena and Gas Flowing Analysis by Electric Heating Method in Porous Rocks

Wonmo Sung†, Hoseob Lee and Hojoon Yang*

Department of Geoenvironmental System Eng., Hanyang University, 17, Haengdang-dong, Sungdong-gu, Seoul 133-791, Korea*Technical Department Korea National Oil Company, 1588-14, Gwanyang-dong, Dongan-gu, Anyang, Gyonggi-do 431-711, Korea

(Received 14 October 2003; accepted 20 December 2003)

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Abstract − In this study, an experimental apparatus has been designed and set-up to analyze the dissociating phenomena of

hydrate in porous rock using electric heating method supplied at downhole. The electric heat injecting experiments have been

performed to investigate the heat transfer within the core, the dissociating phenomena of hydrate, and the productivities of dis-

sociated gas and water. These experiments were under constant heat injecting method as well as preheating methods. From the

experimental results, it is seen that dissociation of hydrate is accelerated with heat. The injected heat is consumed for the dis-

sociation and also it is lost together with outflow of the dissociated gas and water. From the investigation of gas producing

behavior for various heat injecting methods, as the injected heat is greater, dissociation is accelerated faster at outlet and hencethe initial gas production becomes higher. Also, it is shown that the initial gas productivity under the constant heating method is

better, however, the heat is low because of smaller amount of the produced gas comparing to the amount of heat injected. In the

experiments of preheating method, it was seen that gas production only initial stage is different with the preheating time, but

the producing behaviors of gas production are similar.

Key words: Hydrate, Formation and Dissociation Experiment, Electric Heating, Gas Production Behavior

1.

. McGuire[1], Bayles [2], Kamath Godbole[3],

Selim [4] !" #$%& Verigin [5]' Yousif [6, 7]

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Fig. 3. Pressure and resistance behaviors during hydrate formation.

Fig. 4. Pressure and resistance behaviors during hydrate dissociation underonly depressurization method without injecting heat.

Fig. 5. Pressure and resistance behaviors during hydrate dissociation undercontinuous heating method.

Fig. 6. Pressure and resistance behaviors during hydrate dissociation underpreheating for 10 min.

Korean Chem. Eng. Res., Vol. 42, No. 1, February, 2004

118

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Fig. 8. Gas production under depressureization method.

Fig. 9. Gas production continuous heating method.

Fig. 10. Gas production under preheating for 40 min.

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Fig. 12. Gas production under preheating for 10 min.

Fig. 13. Comparison of gas recoveries for different heating methods.

Fig. 14. Comparison of water recoveries for different heating methods.

Korean Chem. Eng. Res., Vol. 42, No. 1, February, 2004

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1. McGuire, P. L., “Recovery of Gas from Hydrate Deposits using Conv

tional Technology,” paper SPE/DOE 10832 presented at the Unc

ventional Gas Recovery Symposium, Pittsburgh, PA, May, 373-3

(1982).

2. Bayles, G. A., Sawyer, W. K., Anada, H. R., Reddy, S. and Malo

R. D., “A Steam Cyclic Model for Gas Production from a Hydra

Reservoir,” Chem. Eng. Comm., 47(2), 225-245(1986).

3. Kamath, V. A. and Godbole, S. P., “Evaluation of Hot Brine Stim

lation Technique for Gas Production From Natural Gas Hydrate”

JPT, 39(11), 1379-1388(1987).

4. Selim, M. S. and Sloan, E. D., 1990, “Hydrate Dissociation in Se

iment,” SPERE, May, 245-251(1990).

5. Verigin, N. N., Khabibullin, I. L. and Khalikov, G. V., “Linear Prob-

lem of the Dissociation of the Hydrates of Gas in a Porous Mediu”

Izvest. Akad. Nauk. SSR, Mekhanika Zhidkosti Gaza, 1. 174-177(1980).

6. Yousif, M. H., Li, P. M., Selim, M. S. and Sloan, E. D., “Depressu

ization of Natural Gas Hydrate in Berea Sandstone Cores,” J. Inclu-

sion Phenomena & Molecular Recognition Chem., 8, 71-88(1990).

7. Yousif, M. H., Abass, H., Selim, M. S. and Sloan, E. D., “Expe

mental and Theoretical Investigation of Methane-Gas-Hydrate D

sociation in Porous Media,” SPERE, Feb., 69-76(1991).

8. Sung, W. M., Lee H. S., Kim, S. J. and Kang, H., “Experimen

Investigation of Production behaviors of Methane Hydrate Satura

in Porous Rock,” Energy Sources, 25(8), 845-856(2003).

9. Seo, Y. T., Kang, S. P. and Lee, H., “Experimental Determination

Thermodynamic Modeling of Methane and Nitrogen Hydrates in

Presence of THF, Propylene Oxide, 1,4-Dioxane and Acetone,”Fluid

Phase Equilibria, 189(1-2), 99-110(2001).

Table 1. The comparison of energy efficiencies for different heating methods

Heating Method100 min 500 min 1,000 min

Output (kJ) Energy efficiency Output (kJ) Energy efficiency Output (kJ) Energy efficiency

Continuous heating 25.71 0.49 52.39 0.20 52.39 0.10Preheating for 10 min 9.78 1.85 46.69 8.84 59.70 11.31Preheating for 20 min 16.89 1.60 56.22 5.32 67.81 6.42Preheating for 40 min 56.82 2.69 68.70 3.25 75.65 3.58No heating 9.21 48.38 53.01

42 1 2004 2