关键词: 第一类水合物藏, 重塑, 传热, 传质, 数值模拟

Abstract:

Class 1 hydrate deposits consist of an upper hydrate layer and a lower two-phase flow layer containing free gas, which are the preferred target for natural gas hydrate exploitation. This paper introduces the characteristics and trial production of the class 1 hydrate reservoirs, and reviews the related experimental and numerical simulation researches. In terms of the experimental research, the remodeling of the class 1 accumulation and the subsequent hydrate decomposition research are summarized. It is found that most of the experimental studies on class 1 hydrate reservoirs have certain limitations in reservoir shaping. The underlying gas of hydrate reservoirs synthesized in many experimental studies is pure gas without porous media, which cannot simulate the mass transfer process of class 1 hydrate reservoirs. Moreover, the gas production rate in different gas production stages is significantly different, and the gas production rate in the initial stage is faster. It is assumed that the model establishment idea that hydrate decomposition occurs on a sharp interface is not applicable to the numerical simulation study of the class 1 hydrate reservoir decomposition because the class 1 hydrate reservoir has multiple decomposition fronts at the same time during the decomposition stage. The future research direction of the class 1 deposits is also proposed. It is suggested to expand the research scale and simulate the stress of hydrate reservoirs in natural marine environment, so as to be closer to the natural hydrate accumulation environment and improve the reference of experimental results.

Key words: class 1 hydrate deposits, remodeling, heat transfer, mass transfer, numerical simulation