Some embodiments of the present invention comprise a method of cementing comprising: placing a settable composition into a well bore, the settable composition comprising remediated coal ash, hydraulic cement, and water; and allowing the settable composition to set. Other embodiments comprise a method of cementing comprising: placing a settable composition into a well bore, the settable composition comprising remediated coal ash, calcium hydroxide (lime), and water; and allowing the settable composition to set. Other embodiments comprise a settable composition comprising: remediated coal ash, hydraulic cement, calcium hydroxide, natural pozzolan and water; and allowing the composition to set. Other embodiments comprise a settable composition comprising remediated coal ash and any combination of hydraulic cement, calcium hydroxide, slag, fly ash, and natural or other pozzolan.

Some embodiments of the present invention comprise a method of cementing comprising: placing a settable composition into a well bore, the settable composition comprising remediated coal ash, hydraulic cement, and water; and allowing the settable composition to set. Other embodiments comprise a method of cementing comprising: placing a settable composition into a well bore, the settable composition comprising remediated coal ash, calcium hydroxide (lime), and water; and allowing the settable composition to set. Other embodiments comprise a settable composition comprising: remediated coal ash, hydraulic cement, calcium hydroxide, natural pozzolan and water; and allowing the composition to set. Other embodiments comprise a settable composition comprising remediated coal ash and any combination of hydraulic cement, calcium hydroxide, slag, fly ash, and natural or other pozzolan.

Expansive cements for use in cementing subterranean wells comprise water, an inorganic cement and one or more particulate materials that swell upon contact with a water immiscible fluid. The cements may further comprise a water immiscible fluid. Such cements are designed to seal microannuli arising from the presence of water immiscible fluids on casing surfaces, borehole wall surfaces or both.

Expansive cements for use in cementing subterranean wells comprise water, an inorganic cement and one or more particulate materials that swell upon contact with a water immiscible fluid. The cements may further comprise a water immiscible fluid. Such cements are designed to seal microannuli arising from the presence of water immiscible fluids on casing surfaces, borehole wall surfaces or both.

Microcapsule encapsulated microcapsule (MIM) material compositions and methods for preparing the same are provided for self-repairing cements that include a plurality of first microcapsules where each of the first microcapsule comprises a first core and a first shell and a plurality of second microcapsules that each comprise a second core and a second shell where the plurality of second microcapsules are dispersed within a continuous phase comprised within the first core of each of the first microcapsules. The MIM material may be prepared such that the first and second shell comprise a cross-linked material. Compositions for self-healing cement slurries are also provided and include cement, sand, water, and microcapsule encapsulated microcapsules (MIM) materials.

Composite cement compositions and slurries for treating a well following a water-based wellbore operation are provided and comprise cement comprising at least one of cement particles and cementitious material, water, and water swellable particulates that are embedded in the cement, derived from an elastomeric material, and present at a concentration of at least about 2% by weight of the cement but no more than about 30% by weight of the cement. Methods for treating a well drilled with a water-based drilling mud are provided and comprise pumping the composite cement compositions and slurries into the well and treating the well by allowing the composite cement compositions and slurries to set or cure after being pumped into the well.

Compositions and methods for plugging a zone of a subterranean formation includes a cement composition having an acid soluble cement, a low molecular weight polymer, a high molecular weight polymer, and water. The acid soluble cement is in amount in a range of 10% to 50% by weight of the composition.

Compositions and methods for plugging a zone of a subterranean formation includes a cement composition having an acid soluble cement, a low molecular weight polymer, a high molecular weight polymer, and water. The acid soluble cement is in amount in a range of 10% to 50% by weight of the composition.

An expandable porous framework, the framework containing a dry cementitious powder fill that when exposed to an aqueous media, will expand against the constraint of the framework and set to form a solid, hard and coherent material, the formwork being porous to liquids but substantially impermeable to the powder fill.

An expandable porous framework, the framework containing a dry cementitious powder fill that when exposed to an aqueous media, will expand against the constraint of the framework and set to form a solid, hard and coherent material, the formwork being porous to liquids but substantially impermeable to the powder fill.