A method may include providing a cement composition comprising ground vitrified clay, hydrated lime, and water; and introducing the cement composition into a subterranean formation.

A method, apparatus, and system according to which first and second waveguides are adapted to be connected to a pipe and first and second transducers are adapted to be connected to the first and second waveguides, respectively, and to exchange ultrasonic wave signals through the first and second waveguides, the pipe, and a fluid flowing in the pipe. A temperature of the fluid flowing in the pipe exceeds 600° C. The first and second waveguides are configured to, and each have a shape to: (i) insulate the first and second transducers from the pipe, and (ii) permit propagation of the ultrasonic wave signals between the pipe and the first and second transducers, respectively, while maintaining an acoustic attenuation through the first and second waveguides at an acceptable level.

A method, apparatus, and system according to which first and second waveguides are adapted to be connected to a pipe and first and second transducers are adapted to be connected to the first and second waveguides, respectively, and to exchange ultrasonic wave signals through the first and second waveguides, the pipe, and a fluid flowing in the pipe. A temperature of the fluid flowing in the pipe exceeds 600° C. The first and second waveguides are configured to, and each have a shape to: (i) insulate the first and second transducers from the pipe, and (ii) permit propagation of the ultrasonic wave signals between the pipe and the first and second transducers, respectively, while maintaining an acoustic attenuation through the first and second waveguides at an acceptable level.

The invention provides novel apparatus and processes for gas flow and conditioning to achieve optimal CO.sub.2 curing of articles of composite materials (e.g., precast objects made of carbonatable calcium silicate-based cements), with solid interior or having hollow interior ducts, channels and chambers or otherwise being hollowed out, as well as the precast objects so made, which are suitable for a variety of applications in construction, pavements and landscaping, and infrastructure.

The invention provides novel apparatus and processes for gas flow and conditioning to achieve optimal CO.sub.2 curing of articles of composite materials (e.g., precast objects made of carbonatable calcium silicate-based cements), with solid interior or having hollow interior ducts, channels and chambers or otherwise being hollowed out, as well as the precast objects so made, which are suitable for a variety of applications in construction, pavements and landscaping, and infrastructure.

A treatment fluid can be provided for controlling annular pressure-buildup in a wellbore. The treatment fluid can include a base fluid and a pozzolanic material that can be dispersed within the base fluid. The pozzolanic material can cause the treatment fluid to controllably consolidate in an annulus of the wellbore for controlling annular pressure-buildup in the wellbore.

A treatment fluid can be provided for controlling annular pressure-buildup in a wellbore. The treatment fluid can include a base fluid and a pozzolanic material that can be dispersed within the base fluid. The pozzolanic material can cause the treatment fluid to controllably consolidate in an annulus of the wellbore for controlling annular pressure-buildup in the wellbore.

A variety of methods and compositions are disclosed, including, in one embodiment a method a cementing in a subterranean formation comprising: providing a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder; foaming the set-delayed cement composition; 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. Additional methods, foamed set-delayed cement composition, and systems for cementing are also provided.

A variety of methods and compositions are disclosed, including, in one embodiment a method a cementing in a subterranean formation comprising: providing a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder; foaming the set-delayed cement composition; 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. Additional methods, foamed set-delayed cement composition, and systems for cementing are also provided.

A variety of methods and compositions are disclosed, including, in one embodiment a method a cementing in a subterranean formation comprising: providing a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder; foaming the set-delayed cement composition; 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. Additional methods, foamed set-delayed cement composition, and systems for cementing are also provided.