Yielding of hydrated lime in set-delayed and other settable compositions

A method of controlling a rheology of a settable composition, the method comprising:

• providing a settable composition comprising water, hydrated lime, and a material selected from the group consisting of a Portland cement, a pozzolanic cement, a gypsum cement, a soil cement, a calcium phosphate cement, a high-alumina content cement, a silica cement, a high-alkalinity cement, a slag cement, cement kiln dust, pumice, and mixtures thereof, wherein the material is present in a material-to-hydrated-lime weight ratio of about 3:1 to about 5:1;
• shearing the settable composition until a log-log-slope value is about 1.05 or lower to substantially prevent solids settling;
• pumping the settable composition in a fluid state into a subterranean formation;
• and
• allowing the settable composition to set in the subterranean formation.

A system for controlling a rheology of a set-delayed cement composition, the system comprising:

• a set-delayed cement composition comprising:
• water;
• pumice;
• hydrated lime, wherein the set-delayed cement composition has a pumice-to-hydrated-lime weight ratio of about 3:1 to about 5:1;
• and
• a set retarder, wherein the set retarder is present in an amount of about 0.01% to about 2% by weight of the pumice;
• and
• mixing equipment configured to shear the set-delayed cement composition until a log-log-slope value is about 1.05 or lower to substantially prevent solids settling in the set-delayed cement composition;
• and
• pumping equipment configured to pump the set-delayed cement composition in a fluid state into a wellbore.

A method of controlling a rheology of a set-delayed cement composition, the method comprising:

• providing a set-delayed cement composition comprising water, pumice, hydrated lime, a set retarder, and a dispersant, wherein the set-delayed cement composition has a pumice-to-hydrated-lime weight ratio of about 3:1 to about 5:1, wherein the set retarder is present in an amount of about 0.01% to about 2% by weight of the pumice, and wherein the dispersant is a polycarboxylated ether dispersant, and the polycarboxylated ether dispersant is present in an amount of about 0.01% to about 2% by weight of the pumice;
• shearing the set-delayed cement composition until a log-log-slope value is about 1.05 or lower to substantially prevent solids settling;
• storing the set-delayed cement composition in a pumpable fluid state for at least 1 day;
• activating the set-delayed cement composition;
• introducing the set-delayed cement composition into a subterranean formation;
• and
• allowing the set-delayed cement composition to set in the subterranean formation.