A method for controlling loss circulation in a subterranean formation and a convertible drilling mud operable to convert into a solid gel lost circulation material. The method includes circulating in a wellbore a nanosilica drilling fluid having a pH in a range of from about 8 to about 11 and a gel pH of less than 8, where the nanosilica drilling fluid includes an aqueous-based drilling mud, an alkaline nanosilica dispersion, and at least one additive. The method also includes introducing into the nanosilica drilling fluid an amount of a chemical activator sufficient to produce a convertible drilling mud where the chemical activator is an acid and the pH of the convertible drilling mud is less than the gel pH. The method also includes allowing the convertible drilling mud to convert into a solid gel lost circulation material.

Compositions and methods for using those compositions to at least partially stabilize subterranean formations are provided. In one embodiment, the methods include providing a treatment fluid including an aqueous base fluid and an additive including a low molecular mass organic gelator; introducing the treatment fluid into at least a portion of a subterranean formation to contact at least a portion of the subterranean formation that includes shale; and allowing the additive to interact with the shale to at least partially stabilize the shale.

Compositions and methods for using those compositions to at least partially stabilize subterranean formations are provided. In one embodiment, the methods include providing a treatment fluid including an aqueous base fluid and an additive including a low molecular mass organic gelator; introducing the treatment fluid into at least a portion of a subterranean formation to contact at least a portion of the subterranean formation that includes shale; and allowing the additive to interact with the shale to at least partially stabilize the shale.

A method to control a heat transfer profile in a defined space, the method comprising the steps of introducing a thermally insulating packer fluid into the defined space such that the thermally insulating packer fluid forms a gelled solid and reduces a rate of heat transfer through the defined space as compared to a prior rate of heat transfer through the defined space before introducing the thermally insulating packer fluid, where the thermally insulating packer fluid comprises an acidic nanosilica dispersion and a polyamine.

A method to control a heat transfer profile in a defined space, the method comprising the steps of introducing a thermally insulating packer fluid into the defined space such that the thermally insulating packer fluid forms a gelled solid and reduces a rate of heat transfer through the defined space as compared to a prior rate of heat transfer through the defined space before introducing the thermally insulating packer fluid, where the thermally insulating packer fluid comprises an acidic nanosilica dispersion and a polyamine.

In one embodiment, a retarded acid system comprises an aqueous acid and a retarding surfactant. The aqueous acid may comprise from 5 wt. % to 25 wt. % of a strong acid, that is, an acid having a K.sub.a greater than or equal to 0.01. The aqueous acid may further comprise from 75 wt. % to 95 wt. % water. The retarding surfactant may have the general chemical formula R—(OC.sub.2H.sub.4).sub.X—OH where R is a hydrocarbon having from 11 to 15 carbon atoms and x is an integer from 6 to 10. The retarding surfactant may have a hydrophilic-lipophilic balance from 8 to 16.

In one embodiment, a retarded acid system comprises an aqueous acid and a retarding surfactant. The aqueous acid may comprise from 5 wt. % to 25 wt. % of a strong acid, that is, an acid having a K.sub.a greater than or equal to 0.01. The aqueous acid may further comprise from 75 wt. % to 95 wt. % water. The retarding surfactant may have the general chemical formula R—(OC.sub.2H.sub.4).sub.X—OH where R is a hydrocarbon having from 11 to 15 carbon atoms and x is an integer from 6 to 10. The retarding surfactant may have a hydrophilic-lipophilic balance from 8 to 16.

One or more embodiments presently described are directed to lubricants and methods for making such lubricants. According to one embodiment, a lubricant suitable for use in a water-based drilling fluid may comprise one or more alkyl esters and a fatty acid blend comprising one or more medium-chain fatty acids. The one or more medium-chain fatty acids may be at least 50 weight percent (wt. %) of the fatty acid blend. The weight ratio of the one or more alkyl esters to the fatty acid blend may be from 1:1 to 3:1.

One or more embodiments presently described are directed to lubricants and methods for making such lubricants. According to one embodiment, a lubricant suitable for use in a water-based drilling fluid may comprise one or more alkyl esters and a fatty acid blend comprising one or more medium-chain fatty acids. The one or more medium-chain fatty acids may be at least 50 weight percent (wt. %) of the fatty acid blend. The weight ratio of the one or more alkyl esters to the fatty acid blend may be from 1:1 to 3:1.

Solid shale inhibitor additives and methods of using such additives to, for example, inhibit shale are provided. In some embodiments, such methods include providing an aqueous treatment fluid that includes an aqueous base fluid and a solid shale inhibitor additive, the solid shale inhibitor additive including carrier particles and a treatment composition that includes a shale inhibitor; and introducing the treatment fluid into a wellbore penetrating at least a portion of a subterranean formation.