Optimization Of Process Parameters Of CO₂ Flooding Fluid Collection And Transportation In Jiyuan Chang 8 Reservoir

The CO₂ flooding test area in the Huang 3 well area of Jiyuan Oilfield is the location of the“National CO₂ Flooding and Storage”demonstration project.With the deepening of the CO₂flooding test,the CO₂ content in the associated gas and produced fluid will increase significantly.The crude oil gathering and transportation system in the test area has an impact.Through the rheological test of crude oil,it was found that the parameters such as viscosity,waxing point and abnormal point of crude oil extracted by CO₂ increased,and the content of heavy components such as colloid and asphaltene increased.The main reason is that some of the light components in the crude oil are extracted and released by CO₂,so that the content of heavy components is relatively increased,resulting in deterioration of rheology of the crude oil.In the study of heat and mass transfer law of CO₂-containing fluid,the system compares the effects of liquid volume,gas volume,gas-liquid ratio,tube length,pipe diameter,starting temperature and starting pressure on the temperature drop of the pipeline.It is found that the liquid amount is the main factor affecting the temperature drop,followed by the length of the pipeline,and again volume,the starting point temperature and diameter of the gas.The effect of the wellhead pressure on the temperature drop of the pipeline can be neglected;the actual pipeline pressure and temperature are less than the critical temperature and pressure of CO₂.Therefore,the gas and liquid are in a gas-liquid equilibrium state in the actual pipeline.Using MATLAB software to program Dukler II,BB,MB three pressure drop models and compare with multi-phase flow OLGA software,combined with the actual conditions of the Huang 3 well area pipeline and production,for the horizontal and updip pipeline pressure drop,recommend the BBMD combination model;For downdip pipes,the MB model is recommended.Based on the above research,PIPEPHASE software was used to establish the model of the gathering pipeline network in the Huang 3 well area.The calculated data shows that under the existing conditions,the temperature system can meet the gathering requirements,but the pressure system needs further improvement.It is recommended to add three additional boost points in the gathering system to meet the requirements of the station pressure not less than 0.3MPa.