乳化性能差异对中低渗岩心驱油效果的影响

Influence of emulsification performance difference on oil displacement efficiency of medium-low permeability cores

乳化是表面活性剂的重要作用之一,对表面活性剂应用于三次采油的驱油效果具有重要影响。文中通过一系列室内实验,对比分析了2种乳化性能不同的表面活性剂在不同渗透率条件下,应用于单一表面活性剂驱和聚/表二元驱的驱油效果。实验结果表明,对于2种强化采油方式,在不同渗透率条件下,乳化效果好的表面活性剂提高采收率的效果更加明显。相对于单一表面活性剂驱,二元复合驱中乳化作用提高采收率的效果变弱。当渗透率较高时,良好的乳化性能可明显提高采收率,同时对注入压力的影响较小;当渗透率较低时,乳化作用的改善对提高采收率效果的影响不明显,并会引起注入压力的急剧升高。相对于中高渗地层而言,低渗地层化学驱更适于选用乳化性能较差或一般的表面活性剂。

Emulsification is one of the most important properties of surfactant, which has a remarkable iniluenee on displaeemenl charaeleristies used in tertiary oil reeuvery for surfaetant. A series of laboratory experiments have been perfurmed to analyze the effect of the displacement characteristics of two surfactants wilh tlifferent emulsificatiou performances at the conditions of different permeahilily used for single suffactant flooding and pulymer/suffaetant binary system flooding. Results indicate that the suffactant with good emulsification effect shows obvious effect of enhaneed oil recovery at the conditions of different permeabilily for two euhaneed reeoveo＇ methods. Compared wilh single suffaetant flooding, the effeet of emulsification in polymer/surfactanl binary system flooding has been weakened. Emulsification can obviously enhance oil recovery rate at high permeahility, with little influence on injection pressure. At low permeability, emulsigcation can slightly impruve oil recovery, which can cause a sharp rising of injection pressure. With respect to medium-low permeability reservoirs, chemistry flooding should select the surfactants with poor and common emnlsifieatiuns in low penneahility reservoir.