In a well in a subterranean formation, treatment fluids for time-released iron control are utilized. These treatment fluids contain a time-released form of a complexing agent, wherein the complexing agent forms an insoluble complex with iron. The time-released form prevents loss of the agent prior to delivery to the desired site and at the desired time(s). Methods for controlling iron in a well in a subterranean formation utilize these treatment fluids containing a time-released form of a complexing agent and these methods create insoluble complexes of the agent with the iron to control the iron from the formation and/or well.

In a well in a subterranean formation, treatment fluids for time-released iron control are utilized. These treatment fluids contain a time-released form of a complexing agent or reducing agent, wherein the agent forms a soluble product with iron. The time-released form prevents loss of the agent prior to delivery to the desired site and at the desired time(s). Methods for controlling iron in a well in a subterranean formation utilize these treatment fluids containing a time-released form of a complexing agent or reducing agent and these methods create soluble products when the agent interacts with the iron to control the iron from the formation and/or well.

A method and reactive treatment fluid for treating a wellbore for filter cake removal, including providing the reactive treatment fluid having a viscoelastic surfactant (VES) into a wellbore in a subterranean formation and attacking the filter cake via the reactive treatment fluid.

A method and reactive treatment fluid for treating a wellbore for filter cake removal, including providing the reactive treatment fluid having a viscoelastic surfactant (VES) into a wellbore in a subterranean formation and attacking the filter cake via the reactive treatment fluid.

Release of hydrochloric acid, hydrofluoric acid and fluoroboric acid into a well may be controlled by introducing into the well an aqueous fluid containing ammonium chloride, ammonium bifluoride, ammonium fluoroborate, ammonium tetrafluoroborate or a mixture thereof and a breaker. After being introduced into the well, the ammonium salt reacts with the breaker and the acid is released into the well.

Certain particulates of encapsulated treatment chemicals, and methods of and systems for their use in subterranean formations, are provided. In one embodiment, the methods comprise: providing a plurality of treatment particulates, at least one of which comprising a polymer matrix that comprises and/or encages at least one treatment chemical and a coating disposed around an outer surface of the polymer matrix; and introducing the treatment particulates into a well bore penetrating at least a portion of a subterranean formation.

Certain particulates of encapsulated treatment chemicals, and methods of and systems for their use in subterranean formations, are provided. In one embodiment, the methods comprise: providing a plurality of treatment particulates, at least one of which comprising a polymer matrix that comprises and/or encages at least one treatment chemical and a coating disposed around an outer surface of the polymer matrix; and introducing the treatment particulates into a well bore penetrating at least a portion of a subterranean formation.

Nano-sized mixed metal oxide carriers capable of delivering a well treatment additive for a sustained or extended period of time in the environment of use, methods of making the nanoparticles, and uses thereof are described herein. The nanoparticles can have a formula of:

A/[M.sub.x.sup.1M.sub.y.sup.2M.sub.z.sup.3]O.sub.nH.sub.m

where x is 0.03 to 3, y is 0.01 to 0.4, z is 0.01 to 0.4 and n and m are determined by the oxidation states of the other elements, and M.sup.1 can be aluminum (Al), gallium (Ga), indium (In), or thallium (Tl). M.sup.2 and M.sup.3 are not the same and can be a Column 2 metal, Column 14 metal, or a transition metal. A is can be a treatment additive.

Nano-sized mixed metal oxide carriers capable of delivering a well treatment additive for a sustained or extended period of time in the environment of use, methods of making the nanoparticles, and uses thereof are described herein. The nanoparticles can have a formula of:

A/[M.sub.x.sup.1M.sub.y.sup.2M.sub.z.sup.3]O.sub.nH.sub.m

where x is 0.03 to 3, y is 0.01 to 0.4, z is 0.01 to 0.4 and n and m are determined by the oxidation states of the other elements, and M.sup.1 can be aluminum (Al), gallium (Ga), indium (In), or thallium (Tl). M.sup.2 and M.sup.3 are not the same and can be a Column 2 metal, Column 14 metal, or a transition metal. A is can be a treatment additive.

A method of treating a multi-zoned subterranean formation with composites having well treatment agents is disclosed. The well treatment agent treated in each zone is distinguishable. At least a portion of the well treatment agent is released from one of the composites into the well or formation. The formation of undesirable contaminants may be inhibited or prevented in the well or in the formation by the release of the well treatment agent from one or more of the composites. The well treatment agent also serves as a tracer. When fluid transported from the formation or well is collected, the source of the transported fluid may be determined by comparing a chemical or physical parameter of the well treatment agent with a working set of known taggants.