焖井时间对CO2吞吐开发低渗油藏影响机理研究

CO_2吞吐开发低渗透油藏具有投资少、见效快、见效时间长等优点,在开发复杂低渗断块油藏方面,其效果可与压裂法相媲美。影响CO_2吞吐采油效果的因素复杂,焖井时间就是其中一个重要参数。为此,针对室内实验存在最佳焖井时间这一现象,从CO_2移动前缘和开井生产时压力波传播前缘的相对位置关系分析了室内存在最佳焖井时间的原因;即CO_2移动前缘和开井生产时压力波传播前缘的相对位置不同,导致最终采收率及周期换油率不同,从而确定了最佳焖井时间。最佳焖井时间的确定对于提高低渗油藏开发效果具有重要作用。

Mechanism study on soak time for the efficiency of CO2 huff and puff in developing low permeability reservoirs

CO2 huff and puff has many advantages in developing low permeability reservoirs,such as small investment and quick return. Particularly ,it has the same efficiency with hydraulic fracturing in developing complex low permeability fault block reservoirs. However, there are many factors influencing the efficiency of CO2 huff and puff in developing low permeability reservoirs.Soak time is one of these important parameters.According to the phenomenion that there exists optimal soak time in the experiment,this paper studies the cause of optimal soak time from the relative position of CO2 mobile front and pressure drop front,that is due to the difference of their relative positions, recovery efficiency and oil-draining rate are different,eventually produces the optimal soak time.The determination of optimal soak time plays an important role in improving the development of low permeability reservoirs.