In a previous paper, a general theory for gas production during Steam-Assisted Gravity Drainage (SAGD) has been presented1 . The main gases formed during "aquathermolysis" reactions, carbon dioxide and hydrogen sulphide, tend to be produced primarily via the produced water.

The present paper reports a numerical analysis of the theory, and provides the results of a first simulation that describe the gas production history during SAGD. The numerical analysis includes hydrogen sulphide, carbon dioxide, and methane solution gas.

Gases were included in the numerical analysis by using K-values derived from new theory. This theory accounts for the asymptotic behaviour of gases in solution as the critical point of water is approached.

Simulation results corroborate the initial simple analysis, and agree with field observation. Minor differences are discussed.

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