Co2 Flooding Lifting Technology in Oil Well with High Gas-Oil Ratio in Low Permeability Oilfield

Abstract

Abstract Daqingzi oil field is of low permeability, which gets a low fluid production. After implementing CO2 flooding, the carrying fluid can increase obviously. Meanwhile, a series of problems, including high CO2 content, casing pressure increase and high gas-oil ratio, arise, which can influence pump efficiency and lift efficiency. Combined with production performance law and factors to influence lift efficiency in CO2 flooding well, a parameter optimizing design model was established. The CO2 breakthrough and the gas-oil increase were restrained by the methods of fluid pressure control and reasonable lift parameter optimizing. Meanwhile, an anti-gas lifting equip used in the well with high gas-oil ratio was developed, and a gas lift- pump assist- casing control integration technique, which can prevent pump efficiency from influencing by the gas, provide a gas bypass way and utilize gas to pump carrying fluid out, was designed. The field application showed that this technique can meet the needs of regular production of the oil well whose gas-oil ratio is 300m3/t, effectively control the casing pressure under 2MPa, increase the pump efficiency by 12%, low down the casing pressure, as well as improving the production efficiency of the oil well.