A graphene oxide Janus nanosheets relatively permeability modifier (RPM) for carbonate formations. The graphene oxide Janus nanosheets RPM may be used to treat a water and hydrocarbon producing carbonate formation to reduce water permeability in the formation and increase the production of hydrocarbons. The graphene oxide Janus nanosheet RPM includes a first side having negatively charged functional groups and a second side having alkyl groups. The alkyl groups may include C8 to C30 alkyls. The negatively charged functional groups may include carboxyl groups, epoxy groups, and hydroxyl groups. Methods of reducing water permeability of a carbonate formation using the graphene oxide Janus nanosheets RPM and methods of manufacturing the graphene oxide Janus nanosheets RPM are also provided.

A graphene oxide Janus nanosheets relatively permeability modifier (RPM) for carbonate formations. The graphene oxide Janus nanosheets RPM may be used to treat a water and hydrocarbon producing carbonate formation to reduce water permeability in the formation and increase the production of hydrocarbons. The graphene oxide Janus nanosheet RPM includes a first side having negatively charged functional groups and a second side having alkyl groups. The alkyl groups may include C8 to C30 alkyls. The negatively charged functional groups may include carboxyl groups, epoxy groups, and hydroxyl groups. Methods of reducing water permeability of a carbonate formation using the graphene oxide Janus nanosheets RPM and methods of manufacturing the graphene oxide Janus nanosheets RPM are also provided.

A silicon oxide Janus nanosheets relatively permeability modifier (RPM) for carbonate and sandstone formations. The silicon oxide Janus nanosheets RPM may be used to treat a water and hydrocarbon producing carbonate or sandstone formation to reduce water permeability in the formation and increase the production of hydrocarbons. The silicon oxide Janus nanosheets RPM for carbonate formations includes a first side having negatively charged functional groups and a second side having alkyl groups. The silicon oxide Janus nanosheets RPM for sandstone formations includes a first side having positively charged functional groups and a second side having alkyl groups. The negatively charged functional groups may include a negatively charged oxygen group groups and hydroxyl groups. The positively charged functional groups may include amino groups and an amine. Methods of reducing water permeability using the silicon oxide Janus nanosheets RPM and methods of manufacturing the silicon oxide Janus nanosheets RPM are also provided.

A silicon oxide Janus nanosheets relatively permeability modifier (RPM) for carbonate and sandstone formations. The silicon oxide Janus nanosheets RPM may be used to treat a water and hydrocarbon producing carbonate or sandstone formation to reduce water permeability in the formation and increase the production of hydrocarbons. The silicon oxide Janus nanosheets RPM for carbonate formations includes a first side having negatively charged functional groups and a second side having alkyl groups. The silicon oxide Janus nanosheets RPM for sandstone formations includes a first side having positively charged functional groups and a second side having alkyl groups. The negatively charged functional groups may include a negatively charged oxygen group groups and hydroxyl groups. The positively charged functional groups may include amino groups and an amine. Methods of reducing water permeability using the silicon oxide Janus nanosheets RPM and methods of manufacturing the silicon oxide Janus nanosheets RPM are also provided.

A method of enhancing carbonate precipitation in a downhole environment comprises introducing into the downhole environment a treatment composition comprising: a carbonate producing agent comprising a microbe, an enzyme, or a combination comprising at least one of the foregoing, and a substrate comprising N-oxyurea, semicarbazide, N,N-dioxyurea, or a combination comprising at least one of the foregoing. An organic feedstock and a geobacter can also be used to treating a wellbore or a subterranean formation. Encapsulated carbonate producing agent such as encapsulated bacterial spores are used to form self-healing cemented structure in a downhole environment.

A method of enhancing carbonate precipitation in a downhole environment comprises introducing into the downhole environment a treatment composition comprising: a carbonate producing agent comprising a microbe, an enzyme, or a combination comprising at least one of the foregoing, and a substrate comprising N-oxyurea, semicarbazide, N,N-dioxyurea, or a combination comprising at least one of the foregoing. An organic feedstock and a geobacter can also be used to treating a wellbore or a subterranean formation. Encapsulated carbonate producing agent such as encapsulated bacterial spores are used to form self-healing cemented structure in a downhole environment.

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.

A method of reducing water saturation onto surfaces exposed to hydrocarbons during the production of hydrocarbons from subterranean formations by altering the wettability of the surface of the formation with surface modified nanoparticles.

A method of reducing water saturation onto surfaces exposed to hydrocarbons during the production of hydrocarbons from subterranean formations by altering the wettability of the surface of the formation with surface modified nanoparticles.

A lost circulation material (LCM) is provided having an alkaline nanosilica dispersion and an ester activator. The alkaline nanosilica dispersion and the ester activator may form a gelled solid after interaction over a contact period. Methods of lost circulation control using the LCM are also provided.