安页2-3HF井强封堵油基钻井液技术研究与应用

Research and application of strong plugging oil-based drilling fluid technology for Anye 2-3HF well

针对正安区块页岩气开发过程中龙马溪组井壁失稳频发、掉块严重、卡钻频繁等问题,通过对龙马溪组地层岩性特征研究及井壁失稳机制分析,确定了强化封堵性是研发和改进正安区块油基钻井液技术的关键点。通过关键处理剂中乳化剂和封堵剂的研究,形成了强封堵油基钻井液体系配方,并对其进行性能评价。结果表明:该钻井液具有良好的即时和长效封堵性能,能够有效抑制岩屑的水化分散和膨胀缩径,具有良好的抗岩屑污染能力,岩屑量在20%以内可保持整体性能基本稳定,综合性能远远优于常规油基钻井液,满足正安区块井壁稳定需求。同时,将强封堵油基钻井液在安页2-3HF井现场试用,与已钻邻井相比,三开井段未出现井壁失稳情况,提升了钻井效率,为该区块钻井液优化改进提供了一定的参考。

Aiming at the frequent occurrence of well wall instability in Longmaxi formation during the development of Zheng’an shale gas,the seriousness of block dropping,and the frequent causing of stuck drilling accidents,etc.,through the study of lithological characteristics of Longmaxi formation and the analysis of the mechanism of well wall instability,it has been determined that the strengthening of blocking properties is the key point for the research,development and improvement of the technology of oil-based drilling fluids in the Zheng’an workover area.Through the research of key treating agent emulsifier and blocking agent,the formulation of strong blocking oil-based drilling fluid system was formed and its performance was evaluated.The results showed that the drilling fluid had good immediate and long-lasting blocking performance,effectively inhibited the hydration and dispersion of rock cuttings in Zheng’an block and expansion and shrinkage,had good resistance to rock cuttings contamination in Zheng’an area,and the overall performance was basically stable within 20%of the rock cuttings,and its comprehensive performance was much better than that of conventional oil-based drilling fluids,which could satisfy the demand for wall stabilization in Zheng’an area.Meanwhile,the strong blocking oil-based drilling fluid was tried in Anye 2-3HF well,and compared with the drilled neighboring wells,there was no well wall instability in the three open sections,which improved drilling efficiency,and provided a certain reference direction for the optimization and improvement of the drilling fluid in this work area.