Cement compositions may contain a cement component and an oil-immiscible solvent and used in a number of cementing applications. In another aspect, methods for sealing subterranean zones may include emplacing a cement composition into a wellbore containing a cement component and an oil-immiscible solvent, contacting the cement composition with a water source, and reacting the cement composition with the water source to form a hardened cement.

Treating a subterranean formation with a composition including a maleic anhydride copolymer, an amine crosslinker, and a gelling agent. The maleic anhydride copolymer includes first repeat units I and II and at least one of second repeat units III and IV:

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where each R.sup.1 is independently-H, O(C.sub.1-C.sub.5) alkyl, or (C.sub.1-C.sub.5) alkyl; each R.sup.2 is independently-H, O(C.sub.1-C.sub.5) alkyl, or (C.sub.1-C.sub.5) alkyl; each R.sup.3 is independently OH or O.sup.M.sup.1, each M.sup.1 is independently an alkali metal, an alkaline earth metal, an ammonium ion, or a quaternary ammonium ion; and each R.sup.4 is independently-NH.sub.2 or OM.sup.1. The gelling agent includes at least one of: a calcium chelating agent, a calcium precipitating agent, a pH buffer, an agent reactive with hydroxide, and an acid generating agent, and promotes formation of a gel from the maleic anhydride copolymer and the amine crosslinker in contact with set cement.

A device for forming one or more wellbore sealants in a wellbore can include a wellbore barrier and a cured polymer. The wellbore barrier can be positioned in the wellbore. The cured polymer can be positioned with respect to the wellbore barrier for swelling the device from a compressed configuration to a swelled configuration for forming one or more wellbore sealants in the wellbore.

A self-adaptive cement formulation includes cement, water and thermoplastic block-polymer particles. The set cement demonstrates self-healing properties when exposed to methane, and is particularly suited for well-cementing applications. After placement and curing, the self healing properties help maintain zonal isolation should bonding be disrupted between the set cement and the formation or a casing string, should cracks or defects appear in the set-cement matrix, or both.

New cement-polymer composites and processes of making and using are detailed. One exemplary cement-polymer composite include a Portland cement, an epoxide polymer, a thiol-containing crosslinking agent, and an optional phase separation inhibitor. These composites are dynamically self-healing, mechanically robust, and thermally stable in high temperature environments and can be expected to increase service lifetimes in various applications including energy producing wellbores.

The present invention concerns compositions and methods of using the same that provide encapsulated polymer nanocomposites for efficient crack repair and monitoring of a cement-substrate interface.

A variety of methods and compositions are disclosed, including, in one embodiment, a settable composition comprising: water; and a cementitious component having a calculated reactive index.

Treating a subterranean formation with a composition including a maleic anhydride copolymer, an amine crosslinker, and a gelling agent. The maleic anhydride copolymer includes first repeat units I and II and at least one of second repeat units III and IV: ##STR00001##
where each R.sup.1 is independently H, O(C.sub.1-C.sub.5) alkyl, or (C.sub.1-C.sub.5) alkyl; each R.sup.2 is independently H, O(C.sub.1-C.sub.5) alkyl, or (C.sub.1-C.sub.5) alkyl; each R.sup.3 is independently OH or O.sup.M.sup.1, each M.sup.1 is independently an alkali metal, an alkaline earth metal, an ammonium ion, or a quaternary ammonium ion; and each R.sup.4 is independently NH.sub.2 or OM.sup.1. The gelling agent includes at least one of: a calcium chelating agent, a calcium precipitating agent, a pH buffer, an agent reactive with hydroxide, and an acid generating agent, and promotes formation of a gel from the maleic anhydride copolymer and the amine crosslinker in contact with set cement.

A method of treating lost circulation issues stemming from loss zones during the drilling and cementing process through the utilization of a thixotropic cement. The method comprises the steps of encountering a loss zone in a bore hole during drilling or running casing and pumping a treatment fluid into the loss zone, wherein the treatment fluid is a gel capable of gelling, breaking when sheared, and building back shear strength after shearing is removed.

A sealant is provided which is a curable resin external emulsion having a fluid internal phase comprising a curable material which expands during, after or before it cures. The resin external phase is, for example, an epoxy resin which may shrink as it cures. The internal phase is captured within micelles to provide discrete internal phase portions supported in an out resin matrix.