压差激活密封剂的制备与应用

Preparation and Application of Pressure Activated Sealant

蒋孟晨 许 林 程现华 李 冬 黄美兰 高 君 闻 扬 王佳明

JIANG Mengchen XU Lin CHENG Xianhua LI Dong HUANG Meilan GAO Jun WEN Yang WANG Jiaming

为满足油气井密封损伤快速、经济、安全修复的要求，以羧基丁腈胶乳、黄原胶、MgCl2和烷基酚聚氧乙烯醚 为原料制备了一种新型压差激活密封剂，通过激光粒度分析仪和超景深三维显微系统分析了密封剂的微观形 貌，通过自制的动态堵漏评价设备考察了密封剂的动态堵漏性能，分析了该密封流体的压差激活封堵机理，并在 海上G2气田进行了现场应用。结果表明，制备的压差激活密封剂是一种多分散相体系，分散相为复合液滴，胶粒 呈规则球状，平均粒径为261.5 μm；在15 MPa内可对丝扣、裂缝等不同微泄漏形成良好封堵，封堵性随温度升高而 增强。构建的力学-化学耦合新模型表明，复合液滴在漏点压差流场内去水化激活中心粒子，活性粒子聚结填充泄 漏孔隙，实现自适应封堵。该压差激活密封剂在海上环空带压井进行了泄漏修复应用，效果良好。

In order to meet the rapid，economical，and safe requirments of seal repair in oil and gas wells，a unique pressure activated sealant（PAS）was prepared with carboxylated acrylonitrile butadiene rubber latex（XNBRL），xanthan gum，MgCl2 and alkylphenol ethoxylates. Morphology characterization of sealant particulate was implemented by laser particle size analyzer and microscopic system with super depth of field. The sealing property was studied using a specially designed dynamic sealing detector， the mechanism of pressure activated seal was analyzed，and the field trial was conducted in G2 offshore gas well. The results showed that the prepared PAS was a kind of polydisperse fluid，wherein the solid particles were regular complex droplets with an average size of 261.5 μm. PAS could effectively plug the leaks，e.g. thread and crack under 15 MPa differential pressure，and the sealing capability reinforced with the increase of temperature. The newly developed mechano-chemical coupling model revealed that the complex droplets could be activated by dehydrition effect caused by the differential pressure of leakages，followed by aggregation and fill of active particulates in leak geometry that led to the self- adaptive sealing property. Field trial was further carried out to validate PAS’s application of tubing leak repair in a certain offshore gas well with a sustained casing pressure.

10.19346/j.cnki.1000-4092.2021.02.005