“多元协同”稳定井壁新理论

A multivariate cooperation principle for well-bore stabilization

全面总结了井壁稳定技术研究发展历程,深入分析了井壁失稳机理及防塌技术措施。在此基础上,提出了“物化封固井壁阻缓压力传递—加强抑制水化—化学位活度平衡—合理密度有效应力支撑”的“多元协同”钻井液稳定井壁新理论。通过对胜利、塔河、吐哈等油田复杂泥页岩地层井壁失稳机理的系统研究,依据“多元协同”井壁稳定新理论,研制出了相应的防塌钻井液配方。现场验证结果表明,该理论方法大大减少了井下复杂事故,缩短了钻井周期,节约了钻井成本。

The developing history of well-bore stability technology,the mechanism of borehole instability and anti-sloughing means were analyzed. A multivariate cooperation principle for stabilizing well-bore by improving the performance of drilling fluid was put forward. This method includes the technologies of sealing and consolidating side well-bore physic-chemically to prevent or stay the pressure transmission, enhancing inhibition against hydration balancing chemical potential and activity, and providing the effective stress support of reasonable drilling fluid density. The new principle was used to study the instability mechanism of complicated shale in Shengli, Tahe and Tuha oilfields. The responding anti-sloughing drilling fluid was developed. The field verification showed that the new principle could enormously decrease the complicated failure at down-hole, short the drilling circle and save the drilling cost.