聚合物驱后进一步提高采收率途径的研究

Study on further EOR after polymer flooding

通过聚合物驱前、后钻取的密闭取心井资料,研究聚合物驱后油层剩余油的分布特征,分析其挖潜机理,探索聚合物驱后进一步提高采收率的途径,并研究其注入时机。研究结果表明,聚驱后剩余油饱和度在40%左右,在纵向上主要分布在沉积单元顶部和发育较差部位,在平面上主要分布在主流线两翼;泡沫复合驱和蒸汽驱是聚合物驱后提高采收率的主要途径和方法;水驱后直接泡沫驱或蒸汽驱和水驱后聚合物驱,然后再泡沫驱或蒸汽驱,虽然两者含水变化不一样,但采收率提高值相差无几。

According to sealed coring well data drilled before and after polymer flooding, remaining oil distribution features after polymer flooding is studied, potential tapping mechanism is analyzed, further EOR methods after polymer flooding is discussed and proper injection time is determined. Research result shows that remaining oil saturation after polymer flooding is about 40%, vertically distributed mainly at sedimentary unit top and poor development part, horizontally distributed mainly at two sides of main flow line; Foam combined flooding and steam flooding are two main methods to enhance recovery factor after polymer flooding; Directly foam flooding or steam flooding after water flooding has little difference from polymer flooding followed by foam flooding or steam flooding after water flooding on recovery factor enhancement, although the water cut changes of the twos cases are different.