Experiments on integrated solidification and cementation of the cement-formation interface using the Mud Cake to Agglomerated Cake (MTA) method

Based on the scientific concept of Mud Cake to Agglomerated Cake (MTA), the integrated solidification and cementation of materials at the cement-formation interface was studied by mechanical evaluation, microstructure analysis (XRD, TG and ESEM), and fluid dissolution tests. The results of the mechanical evaluation show that compared with the existing method of MTC, the bond strength of the cement-formation interface increased by 37.81% (increasing up to 1 606.31% with longer curing time) with the MTA method. The results of microstructural analysis show that the synchronous hydration and hardening reaction between the mud cake and cement slurry occurred locally, and a little CSH(I) (calcium silicate hydrate) gel and heulandite gel formed. The results of fluid dissolution tests show that the mud cake in a finished sample made by the old method was dissolved and became a turbid drilling fluidr after it was immersed in water for 28 days. However, based on the MTA method, the agglomerated cake and hardened cement paste bonded together. The agglomerated cake was not dissolved and the water remained clear. All the above results corroborate two facts, one is that the mud cake has converted to agglomerated cake, the other is that the cement-formation interface has solidified and cemented integrally.