The invention is directed to delayed gelation agents comprising a degradable polymeric cage containing therein one or more gelation agents. The cage degrades in situ, e.g, in an oil reservoir, thus releasing the gelation agent(s), which can then crosslink second polymers in situ to form a gel.

Systems and methods for hydrofluoric (HF) acidizing compositions compatible with sensitive metallurgic grades. The systems and methods may include preparing an aqueous acidizing composition comprising one or more acid components, hydrofluoric acid, and one or more corrosion inhibitors; and injecting the aqueous composition into a subterranean formation containing sensitive metallurgic components via a wellbore.

Dual-purpose additives that may be used as viscosifying agents and surface active agents in fluids, subterranean treatments and oilfield operations are provided. In one embodiment, the methods comprise: providing a treatment fluid comprising a base fluid and a polymeric dual-purpose additive comprising a base polymer comprising a plurality of monomer units, and one or more hydrophobic groups bonded to at least one of the monomer units; introducing the treatment fluid into at least a portion of a subterranean formation; and depolymerizing at least a portion of the dual-purpose additive to form one or more surface active fragments, each of the surface active fragments comprising one or more of the hydrophobic groups bonded to one or more of the monomer units.

Described is a method for treating hydrocarbons in a reservoir. A foaming surfactant solution and a foaming gas are introduced into the upper portion of a reservoir such that barrier foam bubbles form. Then, super/critical carbon dioxide is introduced such that a CO2 cap forms. The CO2 cap is formed above a foam barrier of aggregated barrier foam bubbles positioned at an interface between hydrocarbons to be treated in the reservoir and the CO2 cap. The super/critical carbon dioxide is introduced into the reservoir at an injection rate that is greater than a pre-treatment critical gas injection rate. Hydrocarbons are recovered from a lower portion of the reservoir.

Aqueous compositions contain hydrochloric acid at a concentration between 8 wt % and 28 wt % inclusive. The amino acid; hydrochloric acid mole ratio may be between 0.2 and 1.5. Sufficient water is present to dissolve the hydrochloric acid and the amino acid. Such compositions have utility as retarders for acid compositions employed in the stimulation of subterranean formations. Slowing the reaction between the acid and formation helps maximize formation permeability and productivity.

Complexation of metal ions using chelating agents within a subterranean formation can often be desirable, such as to temper the formation of metal-containing precipitates. However, many chelating agents are produced commercially in an alkali metal salt form that may not be entirely suitable for use downhole, particularly in subterranean formations containing a siliceous material. The working pH range of some types of chelating agents may also be limiting. Treatment fluids comprising an aqueous carrier fluid having an acidic pH, a sulfonated iminodialkanoic acid, and ammonium ions may at least partially address downhole precipitation issues, while providing further advantages as well. Methods for forming sulfonated iminodialkanoic acids can comprise reacting an iminodialkylnitrile with a sultone under acidic conditions to form a fluid comprising a sulfonated iminodialkanoic acid and ammonium ions.

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.

Methods of treating a subterranean formation are described. The methods include introducing a treatment fluid that includes a friction reducing polymer (e.g., a cationic friction reducing polymer) into the subterranean formation. The cationic friction reducing polymer is allowed to degrade and release choline chloride or polyDADMAC, which can each act as a clay stabilizer.

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.

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.