Study on pressure drop models of gas-liquid two-phase pipe flow in gas reservoir

The flow pattern of gas-liquid two-phase is variable,and the flow mechanism is complex.It is necessary to seek a single model to predict pressure drop for any flow conditions.The conventional models of two-phase flow pressure drop widely used in practical engineering are mainly based on the experimental data of circular pipe flow,but their applicable conditions are limited.For the gas-producing wells containing certain formation water,gas-water ratio is usually much higher than that of oil-producing wells.The physical property of water in some aspects has some differences from that of oil,and the velocity slip between gas phase and liquid phase is serious.The flow mechanism of gas-water two-phase fluid was experimentally investigated and the variation of the special parameters of fluid flow was analyzed.On the basis of the current pressure drop model of two-phase flow,a modified pressure loss model(H-B) applicable for gas-producing wells containing formation water was proposed.The application of field data shows that the modified H-B model can improve the predictability and precision of pressure drop in water-producing gas wells.