聚合物驱后恢复水驱提高采收率方法平板模型试验研究

EXPERIMENTAL RESEARCH ON THE PLATE MODELS FOR IMPROVING OIL RECOVERY OF RESTORED WATER FLOODING AFTER POLYMER FLOODING

徐婷 李秀生 张学洪 赵福麟 宋汝强

石油大学石油工程学院, 北京昌平 102249 胜利油田股份有限公司胜利采油厂, 山东东营 257506 石油大学石油工程学院, 山东东营 257061 胜利油田股份有限公司孤岛采油厂, 山东东营 257231

通过室内物理模拟试验比较2种聚合物驱后的提高采收率方法,并考虑不同渗透率级差模型对聚合物再利用技术的影响,得到聚合物驱后对地下聚合物溶液再利用技术和效果的认识。研究表明:在聚合物驱-水驱-深部调剖-活性水驱的试验中,聚合物驱后恢复水驱,因水的流度远高于聚合物溶液的流度,会产生严重的指进现象,降低了水的波及系数;同时大量水体又会严重稀释深部调剖剂,使其强度减弱,调剖效果变差。在聚合物驱-水驱-絮凝和固定-深部调剖-活性水驱的试验中,可通过絮凝剂对水驱稀释的聚合物溶液絮凝再利用,形成絮凝体对高渗透层产生封堵,再注入固定剂溶液进入聚合物浓度较高的次高渗透层,通过交联形成交联体起到深部调剖和驱油作用。在3种渗透率级差的平板模型试验中,对絮凝和固定技术进行了对比试验,证实该技术具有一定的有效期,产生的絮凝体和交联体强度较高,为后续深部调剖和活性水驱奠定了良好的基础,同时该技术具有成本低廉、采出程度高、对中低渗透层的伤害程度小及对地下存在聚合物再利用程度高等优点。

Two different treatments for improving oil recovery after polymer flooding have been studied with the laboratory physical modeling.Moreover effects of models with different permeability contrasts have been considered on the technology of polymer reutilization.Then recognition of the polymer reutilization and effects has been acquired after polymer flooding.Research shows that in the treatment of polymer flooding-water flooding-in-depth profile control-active water flooding,severe fingering will be produced for water mobility higher than that of polymer solution when water flooding has been restored after polymer flooding,then the sweep efficiency of water flooding has been greatly decreased.At the same time,water bulk will dilute the in-depth profile control agent to great extent,which erodes the strength of the in-depth profile control agent,making the worse effect of profile control.In the treatment of polymer flooding-water flooding-flocculating and fixing polymer-in-depth profile control-active water flooding,the flocculates in-site polymer diluted by water flooding,which plug high permeability zones with the floc unit.The following injected polymer-fixed agent will penetrate into the secondary high permeability zone,mix with polymer solution of high concentration and produce cross-linking systems which are excellent in in-depth profile control and oil displacement.It has been testified that in plate model experiments of three different permeability contrasts,the polymer-flocculated and polymer-fixed technology is of long valid period,high strength of the floc unit and cross-linking system,the low cost,high oil recovery and utilizing extent of existing polymer in porous media which makes good foundation for succeeding in-depth profile control and active water flooding.

10.3969/j.issn.1000-7393.2003.01.014