低渗透油藏水凝胶调驱剂的制备及封堵性能评价

Preparation and Plugging Performance of Hydrogel Profile Control Agent for Low Permeability Reservoir

吴天江 鄢长灏 赵海峰 高雨

WU Tianjiang YAN Changhao ZHAO Haifeng GAO Yu

为了提升低渗透油藏调驱剂的注入性和封堵性，开发了一种水凝胶体系，以成胶强度为指标优选了水凝胶 配方及制备条件，并评价了其封堵性能和调驱性能。优化的水凝胶配方如下：丙烯酸用量为20 g/L、丙烯酰胺用 量为5 g/L、过硫酸铵用量为0.07 g/L、改性淀粉用量为5 g/L、交联剂N，N-亚甲基双丙烯酰胺用量为0.08 g/L，最 佳合成条件为中和度75%、反应温度9 ℃，所生成水凝胶的成胶强度为35～37 Pa·s。通过机械剪切、烘干得到微 米级粒径的水凝胶调驱剂。封堵实验表明，质量浓度为0.1～0.7 g/L 的水凝胶调驱剂对渗透率为1600×10-3～ 1900×10-3 μm2的填砂管的封堵率在92%以上，随着水凝胶质量浓度的增大，阻力系数增大，注入压力爬升较快， 但残余阻力系数和封堵率变化较小。水凝胶作为驱油剂使用建议采用低浓度注入，在水驱基础上可提高采收率 10%左右。低浓度微颗粒水凝胶调驱剂可有效解决低渗透油藏调驱注入性和封堵性的矛盾。综合考虑注入性、 封堵性和驱油性能，推荐水凝胶水溶液现场应用的质量浓度为0.1～0.3 g/L。

In order to improve the injecting and plugging properties of low permeability reservoirs，a hydrogel system was developed，the formulation and preparation conditions of the hydrogel were optimized based on the gel strength，and the plugging and flooding performance were evaluated. The optimized hydrogel formula was as follows，the dosage of acrylic acid，acrylamide，ammonium persulfate，modified starch and N，N- methylene bis acrylamide was 20 g/L，5 g/L，0.07 g/L，5 g/L，0.08 g/L， respectively，and the best synthesis condition was that neutralization degree was 75%，initiation temperature was 9 ℃ .The gel strength of the obtained hydrogel was 35—37 Pa · s. Hydrogel profile control agent with micrometer size was obtained by mechanical shearing and drying. The plugging experiment showed that the plugging rate of hydrogel with the mass concentration of 0.1—0.7 g/L to the sand-filled pipe with the permeability of 1600×10-3—1900×10-3 μm2 was more than 92%. With the increase of the mass concentration of hydrogel，the drag coefficient increased，and the injection pressure increased rapidly，but the residual resistance coefficient and plugging rate changed little. It was recommended to use low concentration injection of hydrogel as oil displacement agent，which could improve oil recovery by about 10% on the basis of water flooding. Low concentration micro particle hydrogel could effectively solve the contradiction between injectivity and plugging of profile control in low permeability reservoirs. Considering the injection and plugging and flooding properties，the recommended mass concentration of hydrogel was 0.1—0.3 g/L.

10.19346/j.cnki.1000-4092.2023.01.009