Theoretical Modeling And Application Of Pressure Drop Of CO₂ Drive Fluid Delivery Pipeline

At present,most oilfields in China use water flooding to develop low-permeability oilfields.The oil displacement efficiency of waterfloods is affected by many factors such as the oil-water interfacial tension.It is necessary to develop efficient mining techniques for low-permeability reservoirs in order to make full use of low-permeability oils.Tibetan resources.To guide the optimal design and safe operation of CO₂ flooding ground gathering pipeline,it is of great theoretical and practical value to carry out theoretical modeling of pressure drop of CO₂flooding fluid.After literature investigation and on-site laboratory tests,the black oil model and composition model were used to calculate the parameters of the two-phase flow properties.Crude oil rheology tests were performed to analyze the changes in properties of crude oil,such as viscosity and density.Four types of flow pattern discriminating methods are discussed.For horizontal and down-dip pipes,MB flow type discriminating method is recommended.For up-poured pipes,Barnea flow type discriminating method is recommended.Three liquid holding rate calculation formulae are discussed.For the horizontal tube,the Eaton correlation has a higher accuracy;for the upper tilt tube and the down tube,the BBE correlation has a higher accuracy.Combined with the ups and downs of Changqing Oilfield,the temperature drop model was derived.At the same time,four kinds of combined pressure drop models were selected,and numerical calculations of temperature drop and pressure drop were used to calculate the pressure drop calculation software for the CO₂ flooded fluid conveying pipeline using VBA language.Applying self-developed software,a steady-state simulation of the CO₂ flooding fluid transfer pipeline was performed.The pressure drop,temperature drop,and liquid holdup variation rule of the pipeline under different conditions were analyzed.The heavy hydrocarbon content,gas-liquid ratio,and pipeline were discussed.Influence of inlet pressure on pressure drop in the pipeline.