Study On Fluid Phase Behavior In Vertical Gas Well

Fluid flow in vertical gas well includes pure gas phase of single-phase flow and gas-liquid two phase flow. Therefore, to fully understand the fluid movement rules in well bore of gas well, it needs to deep and detailed study of the theory about single-phase flow and gas-liquid two phase flow.Calculation of pressure distributions and temperature distribution in the well bore is the foundation of the study and guide the gas wells normal, high quality production. Therefore, calculation of pressure and temperature distribution in the well bore based on single flow and gas-liquid two phase flow theory is a very important work. Since in production Later Stage of most gas wells, there will be a certain amount of fluid will produced. Therefore, how to solve the gas well is normal to carrying the liquid to ensure that the gas wells does not appear serious gas well liquid loading is an urgent problems. As the fluid temperature and pressure changes with the depth of gas well, natural gas hydrates will produce under the right temperature and pressure. The generation of natural gas hydrate will have some serious effects on gas well production system. Thus preventing the gas hydrate is another urgent problems, which could ensure that the gas well in a high-quality production.In this paper, based on studying of the gas well single-phase flow and two phase flow related theory we select suitable calculation model of well bore pressure, temperature distribution for the study of gas well and give some instances about calculation and validation. In addition, we also select the model to calculate the critical liquids carrying flow rate for gas wells and fluid pressure and temperature after choke, empirical formula to prediction the conditions of producing gas hydrate, the model to calculate critical flow rate in the choke. Instance about designing the process parameters of the underground throttling is given through these models and formulas, and suggestion setting depth of downhole choke and recommended size of throttle mouth diameter is obtained.