Reservoir temperature prediction method for gas well of underground gas storage

Abstract

The invention discloses a reservoir temperature prediction method for a gas well of an underground gas storage, and the method comprises the following steps: S1, calculating the pressure distribution of a near well through a productivity equation of the gas well, and carrying out the prediction of the pressure distribution; s2, determining a pressure gradient according to the pressure distribution of the near well; s3, calculating the specific heat, Joule-Thomson coefficient, comprehensive heat transfer parameter and heat capacity item coefficient of the fluid; and S4, solving a reservoir energy equation by adopting a pressure and temperature decoupling mode, and predicting a reservoir temperature field. According to the method, reservoir temperature prediction is carried out in a temperature and pressure decoupling mode, and the problem of hydrate blockage prejudgment of the gas storage is solved; the gas storage decompresses and absorbs heat in the gas production period, the well bottom flowing temperature is reduced, and well temperature profile and shaft hydrate prejudgment is affected; the injection temperature is low in the gas injection period, a low-temperature area is formed in the reservoir around the well through pressure reduction, and hydrate ice blockage is possibly generated; the adverse factors are used as limiting conditions for injection-production capacity design and reasonable production allocation of the gas storage.

Description

technical field [0001] The invention relates to the field of gas storages, in particular to a reservoir temperature prediction method for gas wells of underground gas storages. Background technique [0002] The underground gas storage is an important facility to ensure the supply of natural gas and maintain the stable operation of the pipeline network. It has the functions of seasonal peak regulation and emergency gas supply. Affected by market demand factors, the daily gas injection and production volume of the gas storage fluctuates greatly and the peak output is high. The injection-production cycle is generally 7 months for gas injection, 4 months for gas production, and 1 month for injection-production conversion. Conventional gas reservoir development generally does not pay much attention to reservoir temperature changes. In engineering, it is usually assumed that the bottomhole temperature is equal to the formation static temperature. The injection-production intensit...

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Problems solved by technology

[0003] During the gas production period, the gas storage depressurizes and absorbs heat, which leads to a decrease in the flow temperature at the bottom of the well, which affects the well temperature profile and the prediction of wellbore hydrates; during the gas injection period, due to the low injection temperature, the depressurization of the reservoir around the well forms a low temperature area, hydrate ice blockage may occur

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