Preshearing method for the control of the rheology and the injectability of aqueous inorganic cements

A method to control the setting kinetics and the resultant shear viscosity function of aqueous inorganic cements, characterized by the sequential stages of:

• Initial characterization of the setting kinetics by monitoring the variations of the dynamic rheological properties with time, temperature, and shearing conditions after rest periods (i.e. quiescently) in a rotational rheometer with the ability to generate steady and oscillatory torsion, thus pinpointing the characteristic linear viscoelastic strain or stress limit, the dough time, the initial setting time and the final setting time;
• Subjecting the cement paste to various oscillatory preshearing frequencies at a strain or stress amplitude lower than the values corresponding to the predetermined linear viscoelastic strain or stress limit, measuring the dynamic rheological properties at the end of the preshearing periods at a strain or stress amplitude lower than the values corresponding to the predetermined linear viscoelastic strain or stress limit and then comparing them to the dynamic rheological properties of the quiescently tested cements, thus pinpointing the characteristic setting promoting frequency limit;
• Applying a time dependent preshearing history to promote or delay setting of the cement by adjusting the oscillatory strain amplitude and frequency or the steady torsion shear strain rate according to its predetermined characteristic properties and the targeted injection time;
• Delivery of the cement paste after application of the preshearing history by shear induced drag flow or normal pressure induced flow.