1-D Modeling of Hydrate Decomposition in Porous Media

Authors: F. Esmaeilzadeh, M. E. Zeighami, J. Fathi

Abstract:

This paper describes a one-dimensional numerical model for natural gas production from the dissociation of methane hydrate in hydrate-capped gas reservoir under depressurization and thermal stimulation. Some of the hydrate reservoirs discovered are overlying a free-gas layer, known as hydrate-capped gas reservoirs. These reservoirs are thought to be easiest and probably the first type of hydrate reservoirs to be produced. The mathematical equations that can be described this type of reservoir include mass balance, heat balance and kinetics of hydrate decomposition. These non-linear partial differential equations are solved using finite-difference fully implicit scheme. In the model, the effect of convection and conduction heat transfer, variation change of formation porosity, the effect of using different equations of state such as PR and ER and steam or hot water injection are considered. In addition distributions of pressure, temperature, saturation of gas, hydrate and water in the reservoir are evaluated. It is shown that the gas production rate is a sensitive function of well pressure.

Keywords: Hydrate reservoir, numerical modeling, depressurization, thermal stimulation, gas generation.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1330993

References:

[1] Collett, T. S. and Kuskra, V. A.: Hydrates Contain Vast Store of World Gas Resources. Oil and Gas J., (11May 1998)96, NO. 19, 90-95.
[2] Kvenvolden, K.A.: A Primer on the Geological Occurrence of Gas Hydrate, Henriet, J.P and Mienert, J. (eds.) Gas Hydrates: Relevance to World Margin Stability and Climate Change. Geological Society, London, Special Publications, pp. 1379-30, 1998.
[3] Sun, X. Nanchary, N. and Mohanty K. K.: 1-D Modeling of Hydrate Depressurization in Porous Media. Transp Porous Med (2005) 58:315- 338.
[4] Gerami, S., and Pooladi-Darvish, M.: Predicting Gas Generation by Depressurization of Hydrates where the Sharp-Interface Assumption is Not Valid, Accepted (January 2006) for publication in Journal of Petroleum Science and Engineering.
[5] Kamath, V.A, and Holder, G.D.: Dissociation Heat Transfer Characteristics of Methane Hydrates, AIChE J., 33, pp. 347-350, 1987.
[6] Hong, H., Pooladi-Darvish, M., and Bishnoi, P.R.:Analytical Modeling of Gas Production from Hydrates in Porous Media, J. Can. Pet. Tech., vol. 42, No. 11, pp. 45-56, November 2003.
[7] Uddin, M., Coombe, D. A., Law, D. A., Gunter, W. D.: Numerical Studies of Gas-Hydrate Formation and Decomposition in a Geological Reservoir. SPE100460.
[8] Kim, H.C., Bishnoi, P.R., Heidemann, R.A., and Rizvi, S.S.H.: Kinetics of Methane Hydrate Decomposition, Chem. Eng. Sci., vol. 42, pp. 1645- 1653, 1987.
[9] Sloan, E.D.: Clathrate Hydrates of Natural Gases, 2nd ed., Marcel Dekker, pp. 513-537, 1998.
[10] Selim, M.S., and Sloan, E.D.: "Hydrate Dissociation in Sediment," SPE Reservoir Engineering, vol. 5, No. 2, pp. 245-251, 1990.