Theoretical Investigation Of Upward Gas-liquid Two-Phase Flow In Annuli And Applications In The Process Of Production In Oilfield

The theory of gas-liquid two-phase flow in annuli is the significant fundamental theory for choosing artificial lift means and analyzing the production performance of wells. For long time, by using hydraulic equivalent diameter, the theory of gas-liquid two-phase flow in vertical circular tube has been taken advantage of to solve problems in vertical annuli. However, the accuracy of this calculation is often limited.Based on the research outcomes in related areas at home and abroad, the flow mechanism of the gas-liquid flow in vertical annuli is researched by using fluid mechanics theory. The division method, alternation characteristic and transformation model of flow patterns are studied. Conditions of bubbly flow being and the relationship between the flow pattern transformation and the structure parameters of annuli are analyzed specially. The model of liquid holdup, friction pressure gradient, gravity pressure gradient and the total pressure gradient in five flow pattern are derived. Variation of liquid holdup, friction pressure gradient, gravity pressure gradient and the total pressure gradient with gas and liquid superficial velocity at different flow pattern are analyzed specially. With Caetano experimental data, the flow pattern transformation model and pressure drop calculation model of different flow pattern be evaluated. Using Matlab software write calculation program. With five series of production parameter of two pumping oil, calculation precision of proposed model and Beggs-Brill model against practical data is compared and the proposed model is evaluated and verified.