乳液聚合物深部调堵剂的研究及应用

Research and application of emulsion polymer for deep formation plugging and profile control agent

控制调堵剂的黏度和成胶时间,确保封堵油藏深部高渗透层水流通道,控制无效循环,提高中、低渗透层的驱油效率成为了研究热点。乳液聚合物的初始黏度较低,更易随注入水进入高渗透层。但乳液聚合物的性能容易受油藏储层条件的影响。为了改善深部调堵效果,通过筛选性能优秀的功能助剂(缓凝剂、稳定剂),获得了初始黏度低、成胶时间可控、强度及稳定性高的乳液聚合物深部调堵剂。实验研究表明,乳液聚合物深部调堵剂的最佳复合助剂为柠檬酸/硫脲或氨基乙酸/硫脲,调节助剂的添加量可使体系的成胶时间延长至7~15d,终黏高达10000 mPa·s,并在90d内保持稳定。乳液聚合物深部调堵剂具有较好的岩心封堵性能,对水测渗透率为1.512D和2.058D的岩心封堵率在99%以上。三管并联岩心实验结果表明,乳液聚合物深部调堵剂能够有效封堵高渗透层,对中、低渗透层的伤害小,分流率得到明显改善。

Controlling the viscosity and forming time of plugging and profile control agent,ensuring the sealing of the water flow channel in the deep high permeability layer,controlling the ineffective circulation,and improving the oil displacement efficiency in the middle and low permeability layer have become the research focus.The initial viscosity of the emulsion polymer is low,and it is easier to enter the high permeability layer with injected water.However,the properties of emulsion polymer are easily affected by reservoir conditions.In order to improve the effect of deep plugging control,the emulsion polymer for deep formation plugging and profile control agent with low initial viscosity,controllable forming time,high strength and stability was obtained by screening the functional additives(retarder and stabilizer)with excellent performance.The experimental research results showed that the favorable additive of the emulsion polymer for deep formation plugging and profile control agent was citric acid/thiourea,or aminoacetic acid/thiourea.The gelation time of the system could be extended to 7~15 days by adjusting the amount of additives,and the final viscosity could be up to 10000 mPa·s remaining stable properties within 90 days.The emulsion polymer for deep formation plugging and profile control agent has good performance for core plugging,with the core plugging rate of more than 99%for the cores with water permeability of 1.512 D and 2.058 D.The results of 3-tube parallel core experiments showed that the emulsion polymer for deep formation plugging and profile control agent could effectively plug the high permeability layer,had less damage to medium and low permeability layers,and improved the flow separation rate significantly.