Study on the Movement of Hydrate Decomposition Front Under Different Control Mechanisms

Abstract

AbstractThe development of natural gas hydrate reservoirs is mainly affected by the three control mechanisms of decomposition, flow and heat transfer. The movement of the hydrate decomposition front is closely related to the development of hydrate reservoirs, and it has a direct impact on the hydrate reservoir's gas production, pressure, temperature, and other production dynamics. As a result, studying the movement of the decomposition front under various control mechanisms is crucially significant to the development of hydrate reservoirs. Using numerical simulation, this paper establish a one-dimensional hydrate reservoir depressurization model to investigate the decomposition front movement law under single control mechanisms (decomposition control, flow control, and heat transfer control) and coupled control mechanisms (decomposition-heat transfer control, decomposition-flow control, decomposition-heat transfer control, flow-heat transfer control). The results show that under a single control mechanism, when the decomposition control plays a leading role, the decomposition front movement rate remains stable; when heat transfer control or flow control plays a leading role, the movement rate of the decomposition front decreases significantly in the later stage; under the coupled control mechanism, the decomposition mode is stable and non-piston. When decomposition-flow control or decomposition-heat transfer control plays the leading role, the movement rate of the decomposition front remains essentially constant in the later stage, exhibiting linear characteristics; when flow-heat transfer control takes the lead, the movement rate of the decomposition front gradually decreases. Therefore, the movement of the decomposition front is very different under the action of different control mechanisms. This study can provide a reference for the actual production dynamic control of hydrate reservoirs in the future.KeywordsHydrateDecomposition frontControl mechanism