Insulating fluids for use in drilling, production, and other applications are provided, the insulating fluids containing a porous medium (such as a sponge or foam) to limit the mobility of the liquid phase of the insulating fluid. The porous medium in the insulating fluid provides a mechanical means for reducing convective heat transfer, as the small pore spaces within the porous media create tortuous paths for the liquid moving therethrough. Methods include introducing the insulating fluid into an annulus of a drilling, riser, production, packer, or pipeline assembly to reduce heat transfer therethrough.

A method includes disposing a device into a borehole in proximity to a subterranean formation where a filter cake has been formed adjacent thereto, the device comprising a support structure and a shape-memory article disposed at the support structure, the shape-memory article comprising a shape-memory polymer, wherein the device is disposed when the shape-memory article is in a compacted shape; exposing the shape-memory article to a fluid system to cause the shape-memory article to expand and conform to a surface of the borehole; exposing the filter cake to the fluid system; and removing the filter cake with the fluid system. The fluid system comprises a chelating agent, an activator, a non-emulsifier, and water or a brine.

A pH-sensitive temporary plugging agent and its preparation method, and the use thereof in exploitation of a low-permeability oil reservoir are disclosed. The temporary plugging agent is prepared by raw materials including, in percentages by mass, 3-8% of carboxymethyl chitosan, 0.2-0.7% of gelatin, 0.1-0.6% of an initiator, 5-15% of a toughener, and a balance of water, wherein the initiator is a solution of AgNO.sub.3 in ammonia water having a concentration of 0.1-0.3 mol/L, and the toughener is a carboxyl-terminated hyperbranched polyester.

A pH-sensitive temporary plugging agent and its preparation method, and the use thereof in exploitation of a low-permeability oil reservoir are disclosed. The temporary plugging agent is prepared by raw materials including, in percentages by mass, 3-8% of carboxymethyl chitosan, 0.2-0.7% of gelatin, 0.1-0.6% of an initiator, 5-15% of a toughener, and a balance of water, wherein the initiator is a solution of AgNO.sub.3 in ammonia water having a concentration of 0.1-0.3 mol/L, and the toughener is a carboxyl-terminated hyperbranched polyester.

The present specification refers to a patent of invention for a foam formulation and its use in the temporary plugging of pipes, where the foam has volumetric and time stability, is prepared from a solution containing surfactant, co-surfactant, alkaline substance and LDH nanoparticles, is able to have its viscosity increased over time and remain intact for 8 hours or more even under pressure differences of up to 0.1 bar and a temperature of 60° C. and then it is able to disperse simply by using water or even the fluid transported in the pipeline. The LDH nanoparticle reinforced foam of the present invention can be applied in pipes that need to be plugged when they are undergoing maintenance, either to prevent incandescent soldering splashes from coming into contact with an explosive atmosphere or to avoid contamination in the pipe interior, among other applications. The present invention belongs to (but is not limited to) the field of plugs for pipes with explosive atmospheres and can be applied in systems that require temporary plugs that can be easily remover by using water or another solvent.

The present specification refers to a patent of invention for a foam formulation and its use in the temporary plugging of pipes, where the foam has volumetric and time stability, is prepared from a solution containing surfactant, co-surfactant, alkaline substance and LDH nanoparticles, is able to have its viscosity increased over time and remain intact for 8 hours or more even under pressure differences of up to 0.1 bar and a temperature of 60° C. and then it is able to disperse simply by using water or even the fluid transported in the pipeline. The LDH nanoparticle reinforced foam of the present invention can be applied in pipes that need to be plugged when they are undergoing maintenance, either to prevent incandescent soldering splashes from coming into contact with an explosive atmosphere or to avoid contamination in the pipe interior, among other applications. The present invention belongs to (but is not limited to) the field of plugs for pipes with explosive atmospheres and can be applied in systems that require temporary plugs that can be easily remover by using water or another solvent.

A variety of fluid loss control compositions and methods are provided for controlling fluid loss in a cementing operation. As described herein, polyelectrolyte complex nanoparticles and fluid loss control compositions containing polyelectrolyte complex nanoparticles can be effective for fluid loss control in a variety of cementing operations. Methods of making and methods of using the electrolyte complex nanoparticles and fluid loss control compositions containing polyelectrolyte complex nanoparticles are also provided. The polyelectrolyte complex nanoparticles can include a polycation polymer such as a branched chain polyethylenimine, and a polyanion polymer such as polyacrylic acid or poly(vinylsulfonic) acid. The polyelectrolyte complex nanoparticles can contain additional additives such as metal ions or fluid loss additives such as a cellulose polymer.

A variety of fluid loss control compositions and methods are provided for controlling fluid loss in a cementing operation. As described herein, polyelectrolyte complex nanoparticles and fluid loss control compositions containing polyelectrolyte complex nanoparticles can be effective for fluid loss control in a variety of cementing operations. Methods of making and methods of using the electrolyte complex nanoparticles and fluid loss control compositions containing polyelectrolyte complex nanoparticles are also provided. The polyelectrolyte complex nanoparticles can include a polycation polymer such as a branched chain polyethylenimine, and a polyanion polymer such as polyacrylic acid or poly(vinylsulfonic) acid. The polyelectrolyte complex nanoparticles can contain additional additives such as metal ions or fluid loss additives such as a cellulose polymer.

Accordingly, this disclosure describes systems, compositions, and methods that may use pelletized diverting agent particulates for diversion, fluid loss control, and/or other subterranean treatments for controlling fluid flow in subterranean formations. In an embodiment, a method comprising: introducing a treatment fluid into a wellbore penetrating a subterranean formation wherein the treatment fluid comprises: a base fluid; a pelletized diverting agent comprising a degradable polymer, wherein the pelletized diverting agent at least partially plugs a zone in the subterranean formation; and diverting at least a portion of the treatment fluid and/or a subsequently introduced fluid away from the zone. In an embodiment, a treatment fluid comprising: a base fluid; and a pelletized diverting agent comprising a degradable polymer.

Accordingly, this disclosure describes systems, compositions, and methods that may use pelletized diverting agent particulates for diversion, fluid loss control, and/or other subterranean treatments for controlling fluid flow in subterranean formations. In an embodiment, a method comprising: introducing a treatment fluid into a wellbore penetrating a subterranean formation wherein the treatment fluid comprises: a base fluid; a pelletized diverting agent comprising a degradable polymer, wherein the pelletized diverting agent at least partially plugs a zone in the subterranean formation; and diverting at least a portion of the treatment fluid and/or a subsequently introduced fluid away from the zone. In an embodiment, a treatment fluid comprising: a base fluid; and a pelletized diverting agent comprising a degradable polymer.