| When the production of gas well is stable,the main flow pattern in the wellbore is annular flow,the liquid is carried out in the form of liquid drop and liquid film,almost 60%liquid was carried out in the form of liquid film.Therefore,the paper focuses on the formation mechanism of liquid film and the calculation method of pressure drop model.The following is the conclusion of this paper:(1)A set of liquid film liquid carrying experimental device for gas well is developed.The proportional relationship between the liquid film and the liquid drop carrying in the annular flow was analyzed and the regeneration process of liquid membrane was observed.Providing a method for the below study.(2)Liquid film experiment phenomenon showed that when the volume of gas is constant,with the increase of liquid volume,the interfacial morphology of liquid film gradually appeared laminar ripple,waviness and fine flake scale ripple.When the liquid volume is certain,the interfacial morphology of liquid film presents layered ripples and ripples until liquid film disappears.(3)The analysis of liquid film flow demonstrated that with the increase of the liquid,although there is a change in the gas and pressure,the linear increase trend of liquid film flow is still obvious.On the contrary,with the increase of gas volume or pressure,the change of liquid makes the liquid film flow rate change is not obvious.(4)The volume fraction of liquid film presents that the experimental results show that the volume fraction of liquid film increases with the increase of gas,and increases then decreases with the increase of liquid volume,decreases with the increase of pressure.(5)From the regeneration rate of liquid film experiment,through the experiment,the changing law of the liquid film regeneration rate is analyzed.The influence of the air volume and pressure on the liquid film reproduction speed is small,but the liquid film production rate increases when the liquid volume increases.(6)Based on the force analysis of liquid film,the thickness equation of liquid film is derived.The experimental data show that the average relative error of the new model is-7.795%.(7)According to the law of droplet liquid film conversion,the model of pressure drop of annular flow is derived from the thickness of liquid film.Compared with field production data,the average relative error is 5%when the gas flow rate is large.The paper makes a quantitative research about annular liquid film and pressure drop,which provides a theoretical support and method for calculating the bottom hole flow pressure.It is significant to the study of two-phase flow. |
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