基于水合物分解传热模型的固体自生热解堵剂热量扩散模拟

Thermal diffusion simulation of solid autogenous pyrolysis plugging agent based on hydrate decomposition heat transfer model

关键词:  天然气水合物  数学模型  自生热解堵剂  模拟计算

Key words:  natural gas hydrate  mathematical model  autogenous pyrolysis plugging agent  simulation calculation

摘要:

固体自生热解堵技术是一种适用于解除井筒内水合物堵塞的创新技术。针对自生热解堵剂反应时的放热量扩散及损耗问题,建立了水合物生成相平衡、分解速率及分解传热数学模型。开展了不同含量、不同管径时的热量扩散模拟研究,获得了不同条件下井筒内温度、水体积分数、天然气体积分数、水合物体积分数的分布云图。研究发现:随着自生热解堵剂含量的增加,释放热量的速率加快,向周围传递的热量增加,且热量扩散时呈不规则状；随着井筒内径的增加,解堵时间增加,自生热解堵剂用量也随之增加。本实验开展的模拟计算值与现场实际值的吻合度大于85%,为现场解堵施工提供了理论指导。 

Abstract:

Solid autogenous pyrolysis plugging technology is an innovative technology which is suitable for relieving hydrate plugging in wellbore. A mathematical model of phase equilibrium, decomposition rate and decomposition heat transfer of hydrate was established to solve the problems of heat release diffusion and loss during the reaction of autogenic pyrolysis plugging agent. The study of heat diffusion simulation was carried out at different concentrations and diameters, and the distribution cloud maps of wellbore temperature, water volume fraction, natural gas volume fraction and hydrate volume fraction were obtained under different conditions. The research shows that with the increase of concentration of autogenous pyrolytic plugging agent, the rate of heat release accelerates, the heat transfer to the surrounding area increases, and the heat diffusion is irregular. With the increase of wellbore diameter, the time of pyrolysis plugging increases, and the amount of autogenous pyrolysis plugging agent also increases. In this paper, the fitness of simulated calculation value and actual value is more than 85%, which provides a theoretical guidance for on-site plugging remove operation.