Study On The Effect Of Pipe Diameter On Flow Pattern And Pressure Drop Of Gas-water Two-phase Flow

Tubes String Optimization is one of the important drainage gas recovery technique of water production gas well,which is widely used.But some models are not sensitive to the pipe size,so it is difficult to choose appropriate size of tubes and can't discharge liquid loading timely,seriously affect the gas well production in section of wellbore pressure calculation.Therefore,this paper adopts the methods of combination of theory,experiment and engineering application and researches the influence of pipe diameter on flow pattern and pressure drop of gas liquid two phases deeply.The main work is as follows:(1)A simulation experiment device of Tubes String Optimization for Water Drainage-Oil Recovery is designed.The experiment of gas-water two-phase upwelling can be carried out in 4 different kinds of diameters of 30mm,40mm,50mm and 65mm in the same conditions.The advanced measurement and control system can be used to monitor the flow of gas,water flow,pressure,differential pressure and other parameters.Thus it provides an important experimental method(2)The literature data calculate the parameters of wellbore fluid physical and flow,determining the parameters range of two phase flow experiment.Combining with the similarity principles,the author designs a simulation experiment scheme about the two phase flow of pipe diameter,gas flow rate and water rising velocity comprehensively.(3)The gas water of two phase orthogonal experiment is carried out,including 9 groups of gas quantity,4 groups of water quantity and 4 groups of the diameter.The author observes the influence of tubing size on the gas-liquid of two-phase flow and makes an analysis.Based on the experimental data,the accuracy of the commonly used flow pattern is evaluated.The Aziz flow pattern has the highest accuracy,which is 95.4%.(4)According to the experimental data,the author counts and evaluates 9 commonly used pressure drop model of gas-liquid of two-phase flow,such as Ansari,Beggs&Brill,Aziz&Govier&Fogarasi on the tube sizes firstly.Secondly,the author makes an evaluation towards pressure drop model on liquid gas ratio,making a preference for tubing pipe pressure drop column calculation model.Calculation results show that,the model of is the Aziz&Govier&Fogarasi is the smallest error in the model involved in the evaluation,the calculated absolute average percentile error is only 5.02%,and the average error is only 0.06%.(5)Railroad Commission's published condensate gas well test data and production wells are collected and arranged.The author testifies the pressure drop model which is recommended in the paper in order to improve the practicality.The research results of this paper will provide an important theoretical basis for Tubes String Optimization on the drainage gas recovery technique of water production,which has an important meaning to the research of gas-water two-phase.