Study of the formation mechanism of annular flow liquid film and the flow pattern conversion

In recent years, the exploration and development of oil and gas resources in China have been successively transferred to sea, ocean, Seabeach and desert and many large-sized oil and gas fields have been discovered there in succession. Among the ways of oil and gas transmission, the miscible transmission technique is enabled to reduce the cost of oil field development by about 10% to approximately 40%. But the conversion among the flow patterns of miscible transmission is a problem awaiting solution yet due to complex flow state of miscible transmission. For this reason, based on the mathematical model of annular flow, the formation mechanism of annular flow liquid film and the reason for its stable existence are analyzed theoretically, obtaining the necessary conditions for stable existence of annular flow structure and criterion formula, and the effect of the inclination angle on the liquid film in annular flow pattern is analyzed also, which has an important leading significance for correctly understanding the characteristics of annular flow pattern and flow law, and offers a reliable basis for further studying the calculation of annular flow.