抗温改性氧化石墨烯基封堵防塌剂的研制及现场应用

Development and Field Application of Temperature-resistant Modified Graphene Oxide-based Plugging and Anti-collapse Agent

氧化石墨烯(GO)可实现泥页岩纳微米孔隙成膜覆盖封堵,为了提高其抗温性能,利用改进的羧基化反应制备了羧基化氧化石墨烯(GO-COOH),对其结构进行了表征,评价了其阻缓压力传递性能、与钻井液体系的配伍性能,并在江苏盐城地区阜宁组泥页岩层段进行了现场应用。研究结果表明,利用本文中的方法成功在氧化石墨烯片层上引入羧基;180℃水热16 h后,GO-COOH的压力传递时间为2120 s,而GO的压力传递时间仅为820 s,这表明GO-COOH具有较强的高温封堵能力。GO-COOH加入聚胺钻井液体系后几乎不影响体系的流变性能,能够改善其抑制性及滤失性能,减少砂床侵入深度,体系50 h压力传递由1 MPa降低至不到0.1 MPa,说明GO-COOH具有良好的配伍性及封堵性能。现场试验井平均井径扩大率仅为8.33%,事故复杂时间平均仅为1.03 d,钻井周期为48.33 d,与施工前相比井径扩大率大幅减小,井下事故复杂时间大幅降低,钻井周期大幅减少,有效缓解了阜宁组井壁失稳问题,产生了较好的经济效益。

Graphene oxide(GO)can realize film-forming covering and plugging of nano-micro pores in shale. In order to improve its temperature resistance,carboxylated graphene oxide(GO-COOH)was prepared by an improved carboxylation reaction,its structure was characterized and its performance of reducing pore pressure transmission and its compatibility with the drilling fluid was evaluated. The carboxylated graphene oxide was applied in the mud shale interval of Funing Formation in Yancheng area,Jiangsu. Infrared and XRD results showed that the method used in this article had successfully introduced carboxyl groups onto the graphene oxide sheet;after keeping the sample at 180 ℃ for 16 hours,the pressure transmission time of GO-COOH was 2120 s,while that of GO was only 820 s,which indicated that GO-COOH had a strong plugging ability at the high temperature. After GO-COOH was added to the polyamine drilling fluid system,it had little influence on the rheological properties of the system,and could improve its inhibition and fluid loss performance,and reduced the depth of sand bed invasion. The pressure transmission of the polyamine system was reduced from 1 MPa to less than 0.1 MPa in 50 hours with GO-COOH added,indicating that GO-COOH had good compatibility and plugging performance. The average hole diameter enlargement rate of field test wells was only 8.33%,the average accident time was only 1.03 d,and the drilling duration was 48.33 d. Compared with the pre-construction,the hole diameter enlargement rate was greatly reduced,and the downhole accident complex time was greatly reduced,and the drilling duration significantly reduced. The addition of GO-COOH had effectively alleviated the problem of borehole wall instability of the Funing Formation and produced good economic benefits.