Hydrate reformation, caused by the Joule-Thomson effect (JTE) during depressurization, poses a major obstacle to efficient gas production. This study examines the impact of the JTE on hydrate reformation near the wellbore during depressurization, focusing on the influences of gas-to-water ratio, depressurization range, and permeability. The results indicate that JTE significantly contributes to a gradual temperature decrease, leading to hydrate reformation. Reformed hydrates, potentially saturating up to 80%, initially appear near the wellbore then move away due to intense depressurization that eroded their inner surface, creating a moving low-permeability barrier that obstructs fluid flow and reduces gas-water production rates. Formations with higher permeability and gas saturation experience intensified JTE, leading to faster temperature drops, shorter hydrate reformation times, and quicker expansion of secondary hydrate bands. The study also evaluates the effectiveness of wellbore heating to mitigate hydrate reformation. Wellbore heating is found to be more effective in low-permeability formations, but only within a 0.5 m radius near the wellbore in high-permeability formations. This research suggests narrower depressurization ranges to prevent hydrate reformation and indicates the limited impact of wellbore heating on enhancing gas production. The findings have significant implications for preventing hydrate reformation near the wellbore and improving hydrate production efficiency.

中文翻译：

---

研究焦耳-汤姆逊冷却对井筒附近水合物重整的影响

减压过程中焦耳-汤姆逊效应 (JTE) 引起的水合物重整是高效天然气生产的主要障碍。本研究考察了 JTE 在降压过程中对井筒附近水合物重整的影响，重点关注气水比、降压范围和渗透率的影响。结果表明，JTE 显着促进温度逐渐降低，从而导致水合物重整。重整水合物的饱和度可能高达 80%，最初出现在井筒附近，然后由于强烈的减压作用而移走，侵蚀了其内表面，形成了移动的低渗透屏障，阻碍了流体流动并降低了气水生产率。具有较高渗透率和含气饱和度的地层经历了 JTE 强化，导致温度下降更快、水合物重整时间更短、二次水合物带扩展更快。该研究还评估了井筒加热减轻水合物重整的有效性。研究发现，井眼加热在低渗透地层中更为有效，但仅限于高渗透地层中井眼附近 0.5 m 半径范围内。这项研究建议缩小降压范围以防止水合物重整，并表明井筒加热对提高天然气产量的影响有限。这些发现对于防止井筒附近的水合物重整和提高水合物生产效率具有重要意义。