回注水适配耐温抗盐弱凝胶调剖体系

A Formation Produced Water Prepared Polymer Gel Profile Control System with Temperature Resistance and Salt Tolerance

赵董艳 杜慧丽 赵永强 张橙 高乃煦 李帅斌 雷小洋

ZHAO Dongyan DU Huili ZHAO Yongqiang ZHANG Cheng GAO Naixi LI Shuaibin LEI Xiaoyang

常规弱凝胶体系的耐温抗盐效果较差，采用高矿化度回注水配制存在成胶强度低、稳定性差的问题。基于耐温抗盐聚合物（TSRP）与酚醛树脂交联剂制得适配于高矿化度回注水的耐温抗盐弱凝胶体系，通过红外光谱、扫描电镜、动态光散射仪分析了弱凝胶体系的耐温机理。结果表明，弱凝胶体系成胶性能受聚合物加量、聚交比和热稳定剂硫脲加量的影响较大。弱凝胶优化后的配方为2 g/L 聚合物、聚交比1∶1、400 mg/L 硫脲。采用矿化度约为38 g/L 的回注水配制弱凝胶，成胶时间为63 h，弱凝胶在90 ℃、7.34 s-1 下的黏度为1760 mPa·s。该凝胶在90 ℃高温老化90 d 后仍保持稳定。聚合物凝胶的高温稳定性与两方面有关。一方面，TSRP分子链上N-乙烯基吡络烷酮的环状基团可提高聚合物分子链的刚性，有效抑制聚合物链的热降解作用；另一方面，TSRP交联后形成刚性网络结构，部分抑制了聚合物链在高矿化度下的卷曲作用，凝胶不易发生脱水收缩。

Conventional polymer gel used for conformance control suffers from unfavorable temperature resistance and salt tolerance. The gel strength and gel stability decrease significantly under high temperature and high salinity conditions. A polymer gel system with temperature-resistance and salt tolerance prepared by formation produced water was developed based on polymer TSRP and phenolic resin crosslinker. The mechanism of thermal stability of the gel system was studied through Fourier transform infrared spectroscopy，scanning electron microscope and dynamic light scattering. The results showed that the gelation kinetics of the gel system was significantly affected by polymer concentration，the mass ratio of polymer to crosslinker，and the dosage of thermal stabilizer. The optimum formula of weak gel was obtained as follows：2 g/L polymer，1∶1 the ratio of polymer and crosslinker and 400 mg/L thioureas. When the weak gel was prepared by formation produced water with a salinity of about 38 g/L，the gel forming time was 63 h，and the viscosity of gel was 1760 mPa·s at 90 ℃ and 7.34 s-1 . The gel system remained stable after aging 90 d at 90 ℃ . The good stability of the gel system at high temperature was related to two aspects. The ring structure of N-vinyl pyrrolidone in the polymer chain of TSRP improved the rigidity of the polymer chain，which effectively inhibited the thermal degradation of polymer chains. Besides，the rigid network structure formed by crosslinked TSRP could partly inhibit the curling of polymer chains at high salinity，which prevented the polymer gel from syneresis.

10.19346/j.cnki.1000-4092.2022.02.015