耐强碱凝胶型深部调剖剂的研制与性能评价

摘要

目前大多数调剖剂在强碱性条件下易发生降解，不能满足三元复合驱深部调剖的要求。根据调剖剂的调剖机理和聚合物的交联机理，在强碱性(pH 为12)条件下，采用聚合物作为主剂，离子和非离子化学剂为交联剂，进行了化学剂种类及质量分数的筛选，应用正交实验对其进行了优化，筛选出了最佳的质量分数配比。对研制的调剖剂进行了性能评价、岩心流动性实验和驱油实验。结果表明，该调剖剂应用于三元复合驱中，对界面张力影响较小，成胶黏度随着碱性的增强而降低，但在 pH=12条件下仍可满足深部调剖的要求，可以通过加入不同质量分数的缓凝剂来调节成胶时间。耐碱性调剖剂封堵性好，适合于深部调剖；该调剖剂应用于三元复合驱驱中调剖时，能够有效地调整产液剖面，更好地发挥三元复合驱提高驱油效率的作用，它能够在三元复合驱的基础上提高采收率4%左右。耐碱调剖剂段塞组合优化结果表明，为使该调剖剂保持较好的性能，可以在调剖前，加入小尺寸的聚合物段塞，以稀释地层中残余的碱。%Currently,most profile control agent would be degraded in strong alkaline conditions,which could not meet the deep profile requirements of ASP flooding.Based on the mechanism of profile agent and the crosslinking mechanism of the polymer,this article screen different chemical agent type and concentration in strong alkaline (pH = 12 ),using ordinary polymer as the main agent,organic and inorganic chemical as the crosslinking agent.The experiment was optimized by orthogonal method and the best concentration ratio was screened out.For the prepared controlprofile agent,the performance evaluation,core liquidity experiment and displacement experiment were carried out.The results showed that the profile agent weakly affected the interfacial tension of the ASP Flooding.The viscosity of gel decreased with the increase of alkalinity.But it still can gelatinize even under the condition of pH=12.So it can meet requirements of deep profile control.The gelation time could be tuned by adjusting the concentration of the delayed coagulant.The alkali-resistant profile agent has good plugging performance which is suitable for deep profile control.When this profile agent was applied in the process of ASP flooding,the liquid producing profile could be effectively adjusted and the oil displacement efficiency of the ASP flooding was improved.On the basis of ASP flooding,oil recovery could be raised by 4%.Alkali-resistant profile agent slug combination experiment results showed that in order to make this kind of profile agentkeep a better gelation performance,a certain amount of pre-polymer slug could be added before profile control so as to dilute the residual alkali in the layer.