Calculation of Gas Hydrate Dissociation with Finite‐Element Model

Abstract

In situ gas hydrates have been found abundantly in the Arctic regions of the United States, Canada, and Russia. Gas recovery from such a hydrate reservoir under permafrost conditions is described in the present paper. The technique is based upon a finite‐element transient heat‐conduction model that includes the ability to handle phase change. That model is applied to field data available from the North Slope of Alaska for predicting natural‐gas production. Parametric studies have also been conducted to explore the effects of hydrate zone thickness, wellbore temperature, wellbore radius, porosity, etc., on the gas production rate. Comparisons of temperature distributions throughout the medium, and the propagation of the moving dissociation front with respect to time predicted by the present scheme and a finite‐difference scheme, show good agreement. The data generated in the present study may be useful in deciding on the most optimal technique for gas recovery from hydrates. Additionally, it may provide drilling engineers with valuable information to establish guidelines for safe drilling in the presence of hydrates.