化工进展 ›› 2019, Vol. 38 ›› Issue (06): 2939-2946.DOI: 10.16085/j.issn.1000-6613.2018-1667

• 精细化工 • 上一篇    下一篇

超临界CO2压裂液增黏剂的长管实验评价及增黏机制探讨

黄倩(),付美龙(),赵众从   

  1. 长江大学石油工程学院,湖北 武汉 430100
  • 收稿日期:2018-08-16 出版日期:2019-06-05 发布日期:2019-06-05
  • 通讯作者: 付美龙
  • 作者简介:黄倩(1987—),女,博士研究生。E-mail: <email>912773195@qq.com</email>。
  • 基金资助:
    国家自然科学基金(51604036)

Experimental evaluation and thickening mechanism of long tube in supercritical CO2 fracturing fluid tackifier

Qian HUANG(),Meilong FU(),Zhongcong ZHAO   

  1. School of Petroleum Engineering,Yangtze University, Wuhan 430100, Hubei, China
  • Received:2018-08-16 Online:2019-06-05 Published:2019-06-05
  • Contact: Meilong FU

摘要:

针对超临界CO2压裂中CO2黏度低、携砂困难等问题,开展6种超临界CO2压裂液增黏剂的性能研究。分析增黏剂聚乙酸乙烯酯、聚苯乙烯、氟化丙烯酸酯、聚甲基倍半硅氧烷、聚甲基倍半硅氧烷-乙酸乙烯酯以及氟化丙烯酸酯-苯乙烯的分子结构,测试其增黏效果及热稳定性,评价温度、压力、增黏剂注入量对超临界CO2压裂液黏度的影响,测试不同管径中压裂液的阻力系数,并探讨超临界CO2增黏的机制。实验结果表明,在温度为50℃、压力为12MPa、注入增黏剂质量分数为3%时,氟化丙烯酸酯-苯乙烯对超临界CO2的增黏效果最好,增黏倍数为316.7倍,黏度值为15.202mPa·s;改善增黏剂在CO2中的溶解性可以有效提高超临界CO2压裂液的黏度;具备两亲特性、具有无定形、无规则结构特征以及分子上既存在路易斯酸又有路易斯碱的共聚物能有效提高其在CO2中的溶解性,并形成大分子相互缠绕的空间网络结构,达到增黏的效果。该研究对超临界CO2增黏剂的研制以及超临界CO2压裂施工具有重要的现实意义。

关键词: 超临界二氧化碳, 增黏剂, 聚合物, 分子结构, 黏度, 溶解性

Abstract:

Aiming at the problems of low CO2 viscosity and difficulty in carrying sand in supercritical CO2 fracturing, the performance of six supercritical CO2 fracturing fluid tackifiers was studied. The molecular structure of tackifiers polyvinyl acetate, polystyrene, fluorinated acrylate, polymethylsilsesquioxane, polymethylsilsesquioxane-vinyl acetate, and fluorinated acrylate-styrene is analyzed. The thickening effects and the thermal stability of those tackifiers are tested, the effect of temperature, pressure, and the amount of tackifier injection on the viscosity of the supercritical CO2 fracturing fluid is evaluate, and the drag coefficient of the fracturing fluid in different pipe diameters is tested, at the same time we explore the mechanism of supercritical CO2 viscosity increase. The results of experimental show that fluoroacrylate-styrene has the best thickening effect on supercritical CO2, at a temperature of 50℃, a pressure of 12MPa, and an injection mass percentage of 3%. And its adhesion increase rate is 316.7 times, viscosity value is 15.202mPa·s. To improve the solubility of the tackifier in CO2 can effectively increase the viscosity of the supercritical CO2 fracturing fluid. The supercritical CO2 fracturing fluid possesses amphiphilic characteristics and is characterized by amorphous and irregular structures, which has both Lewis acid and Lewis base copolymers on molecules, that can effectively increase their solubility in CO2 and forms a spatial network structure with large molecules intertwined to achieve the effect of increasing viscosity. This research has important practical significance for the development of supercritical CO2 tackifiers and the application of supercritical CO2 fracturing.

Key words: supercritical carbon dioxide, tackifier, polymer, molecular structure, viscosity, solubility

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