Study On Pressure Drop Law Of Gas-Liquid Two-Phase Flow In Horizontal Wells

Because of the unique wellbore structure of horizontal gas wells,the current research on horizontal gas wells is less and more complicated than that of inclined vertical wells.In this paper,experimental and theoretical studies on pressure drop variation of two-phase flow in horizontal gas wells have been carried out,and the following understandings have been obtained:(1)The maximum pressure gradient of deviated section under different wellbore structures is determined.It is indicated from the side that the inclined section is the most difficult section to carry liquid in horizontal wells.It provides a research direction for horizontal well drainage gas production and critical fluid carrying capacity.(2)It is clear that the pressure drop calculation formula and flow pattern discriminant formula for different dip angles of single pipe can not be accurately applied to different sections of horizontal wells.(3)A new method of flow pattern identification and a new method of liquid holdup calculation for vertical and inclined sections of horizontal wells are obtained.(4)By optimizing the pressure drop formulas and parameters of each section of the whole horizontal well,a new set of equations is obtained,which can be better applied to the calculation of the pressure drop of the whole horizontal well.In this paper,a large number of simulation experiments have been carried out on the multi-phase flow experimental platform and the gas well dynamic simulation experimental device in the middle petroleum gas lift test base,and the flow pattern and pressure drop change law in different sections of horizontal wells have been obtained.Through experiments,the commonly used gas-liquid two-phase flow pattern discrimination methods,liquid holdup calculation formula and pressure drop calculation method have been studied and optimized,and the experimental data have been used to carry out the research and optimization.The optimized formula is optimized and a new method for calculating pressure drop of gas-liquid two-phase flow in horizontal gas wells is obtained.It is of great significance for rational production allocation of horizontal wells,prediction of liquid carrying performance,improvement of recovery and efficient development of horizontal gas wells.