Utilization of metakaolin based geopolymer as a mud-cake solidification agent to enhance the bonding strength of oil well cement-formation interface

This research work designed a novel mud-cake solidification method to improve zonal isolation of oil and gas wells. The calculation methodology of mud-cake compressive strength was proposed. The optimal formula of activator and solid precursors, the proper activating time and the best activator concentration were selected by compressive strength test. The effects of solid precursors on the properties of drilling fluid were evaluated. The performances of this novel method were measured. Test results show that the respective percentage of bentonite, metakaolin, slag and activator is 1:1:0.3:0.8, as well as the optimum ratio of Na2SiO3/NaOH is 40:1. The optimum concentration of activator is 0.21 due to the limited proportion of solid precursors in mud-cake, and the activating time should not lower than 10 min. The solid precursors did not show bad influence on the rheological property of drilling fluids in different conditions. Even though the compressive strength decreased when the solid ...

本研究设计了一种新型泥饼固化方法，以提升油气井的层间封隔性能。提出了泥饼抗压强度的计算方法。通过抗压强度试验，确定了激发剂与固体前驱体的最优配比、适宜的激发时长以及最佳激发剂掺量。评估了固体前驱体对钻井液性能的影响，并测试了该新型方法的应用性能。试验结果表明，当膨润土、偏高岭土、矿渣与激发剂的质量比为1:1:0.3:0.8，且Na₂SiO₃与NaOH的配比为40:1时，效果最优。考虑到泥饼中固体前驱体的占比有限，激发剂的最佳掺量为0.21，且激发时长不应低于10分钟。在不同工况下，固体前驱体均未对钻井液的流变性产生不利影响。尽管当固体[...]时，抗压强度会有所下降