Natural gas production from hydrate decomposition by depressurization

This paper presents a parametric study of natural gas production from the decomposition of methane hydrate in a confined reservoir by a depressurizing well. The one-dimensional linearized model suggested by Makogon is used in the analysis. For different well pressures and reservoir temperatures, distributions of temperature and pressure in the porous layer of methane hydrate and in the gas region are evaluated. The distance of the decomposition front from the well and the natural gas output as functions of time are also computed. Time evolutions of the resulting temperature and pressure profiles in the hydrate reservoir under various conditions are presented. Effects of variations in reservoir porosity and zone permeability are also studied. It is shown that the gas production rate is a sensitive function of well pressure, reservoir temperature and zone permeability. (C) 2001 Elsevier Science Ltd. All rights reserved.