聚合物驱后油藏提高采收率技术研究

The Study on Enhanced Oil Recovery Technology in Reservoirs after Polymer Flooding

根据室内实验和现场试验效果分析了聚合物驱后油藏进一步提高原油采收率的技术潜力。室内驱油实验表明,聚合物+表面活性剂二元复合驱提高采收率为17.6%～20.1%,提高采收率幅度高于单一表面活性剂驱(3%左右)和单一聚合物驱(11%～15%),高于表面活性剂驱和聚合物驱二者之和,优于同等经济条件下聚合物驱的效果。孤岛中一区Ng3-6和孤东六区聚合物注入完成后接着实施二元复合驱,综合含水进一步下降,日产油量明显增加。聚合物溶液中加入粘弹性颗粒PPG(Preformed Particle Gel)后,体系从偏粘性转变为偏弹性,具有较强的剖面调整能力。2009年2月在聚合物驱转后续水驱多年的孤岛中一区Ng3单元实施聚合物+PPG驱,注入压力上升了1.4MPa,油层纵向非均质性明显改善,纵向各层吸水趋于均匀。

Enhanced oil recovery technology is studied in reservoirs after polymer flooding by laboratory experimentation and field test. The enhanced oil recovery is 17.6%-20.1% by surfactant/polymer flooding in laboratory, more than that of polymer flooding(11%-15%) or surfactant flooding(about 3%), more than the sum of polymer flooding and surfactant flooding, more than the economic equivalent polymer flooding. The oil production increased farther and the water cut decreased farther in zone Ng3-6 of Zhong-1 unit of Gudao oilfield and the sixth unit of Gudong oilfield after surfactant/polymer flooding once polymer injection finished. The viscosity and the elastic modulus increased and the relative azimuth decreased when PPG(Preformed Particle Gel)added into the polymer solution. The PPG/polymer system trend to elastic and could modify the injection profile evidently. The PPG/polymer flooding was put into practice in zone Ng3 of Zhong-1 unit of Gudao oilfield in Feb, 2009. By the end of May, the injection pressure went 1.4 MPa up and the vertical water intake turned to uniform.