Abstract: Sized-bridging agents, wellbore fluid compositions including the agents, and methods utilizing said compositions control, reduce, or prevent fluid losses in wellbores and/or formation damages. One or more divalent organic salts disclosed herein are designed to help mitigate fluid loss by temporarily reducing the permeability of the formation around the wellbore. The sized-bridging agents include sized-divalent organic salts for forming one or more filter cakes to seal one or more portions of the wellbores thereby reducing rates of fluid loss and damages to formations.

Abstract: Methods for making and using an invert-emulsion drilling fluid, and the invert-emulsion drilling fluid are provided. An exemplary invert-emulsion drilling fluid includes a C-36 dimer diamine dihydrochloride salt (CDDH), an aqueous solvent, a non-aqueous solvent, an emulsifier, and calcium chloride.

Abstract: A wellbore fluid may include an oleaginous continuous phase; a non-oleaginous discontinuous phase; an emulsifier stabilizing the non-oleaginous phase within the oleaginous phase; a low density material selected and in an amount to result in a specific gravity of the wellbore fluid that is less than 0.83; and at least one rheology modifier selected to suspend the low density material within the wellbore fluid.

Abstract: A UV disinfectant system may include a chamber having a wall that is transparent to a disinfecting radiation. Liquid may be flowed through the chamber for treatment by exposure to the radiation. The chamber may include a static mixer having vanes to impede laminar flow of the liquid during treatment. The vanes extend into the flow path of the liquid through the chamber. A gap is defined between the vanes and the transparent wall. A cabinet may house the chamber and radiation emitting bulbs. Blowers may be operably coupled to a temperature sensor and flow meter and positioned at a lower end and upper end of the cabinet to urge air out of the cabinet. The temperature sensor may include a thermocouple. The blowers may be variable speed blowers. The system may include a controller to control system operations. The controller may be remotely accessible to monitor or control operations.

Abstract: A wellbore fluid may include an oleaginous fluid forming a continuous phase; a non-oleaginous fluid forming a discontinuous phase; at least one emulsifier stabilizing an emulsion of the non-oleaginous continuous phase within the oleaginous continuous phase; and at least one viscosifier dispersed into the oleaginous continuous phase in a concentration of at least 4 ppb; wherein upon subjecting the wellbore fluid to shear rate of at least 10,000 s-1, the emulsion is disrupted and the non-oleaginous fluid contacts the at least one viscosifier, thereby solidifying the wellbore fluid.

Abstract: The present invention relates to a mixture of esters obtainable by reacting components of an esterifiable composition with each other, wherein the esterifiable composition comprises at least one trimer fatty acid, at least one fatty acid and at least one hydroxy monocarboxylic acid and a production process of the mixture of esters. Furthermore, the present invention relates to environmental friendly, preferably oil based, drilling fluids comprising the above-mentioned mixture of esters, water and an organic phase and the use of said mixture as viscosifier for drilling fluids.

Abstract: The invention discloses a testing device and method for evaluating effects of CO2 reaction rate of acid rock plate. The testing device includes an acid fluid conveying unit, a CO2 conveying unit, a mixing tank, a plate holder, a recycling fluid tank, and a vacuum pump. The mixing tank includes an acid fluid inlet, a CO2 inlet, and a miscible fluid outlet. The acid fluid inlet is connected with the acid fluid conveying unit, the CO2 inlet is connected with the CO2 conveying unit, the miscible fluid outlet is connected with the plate holder, the plate holder is connected with the recycling fluid tank, and the recycling fluid tank is connected to the vacuum pump. The CO2 conveying unit includes a CO2 cylinder and a gas booster pump which is connected to the cylinder. The outlet of the pump is connected to the gas inlet of the mixing tank.

Abstract: A composition includes a borehole or pipeline fluid and a delivery molecule, the delivery molecule stable under conditions external to a borehole or pipeline and including a precursor having an end terminating in degradable linkages bonding the precursor to bridged groups and another end terminating in a leaving group, where under in situ conditions in the pipeline or downhole from the borehole surface contact with an initiator acid catalyzes degradation of the degradable linkages and elimination of the leaving group, releasing the precursor and generating an additive from the precursor. A method includes placing the delivery molecule in the borehole or pipeline; and after the placing, contacting the composition with an initiator acid under in situ conditions.

Abstract: A method of preparing and a composition of an oil-based drilling fluid. An oil-based drilling fluid includes a base oil continuous phase, in which the base oil continuous phase includes a base oil, an aqueous dispersed phase, and at least one rheology modifier comprising a modified magnesium/aluminum carbonate layered-double hydroxide (Mg/Al—CO3 LDH) compound.

Abstract: Examples of techniques for monitoring and controlling the pH of a drilling fluid are disclosed. In one example implementation, a system may include a first sensor to sense a first pH-value and an associated first temperature of the drilling fluid prior to being heated by a drilling fluid heater and a second sensor to sense a second pH-value and an associated second temperature of the drilling fluid subsequent to being heated by the drilling fluid heater. The system may also include a controller comprising a memory having computer readable instructions and a processing device for executing the computer readable instructions. The computer readable instructions include receiving the first pH-value and first temperature from the first sensor, receiving the second pH-value and second temperature from the second sensor, and determining an amount of additive to add to the drilling fluid to maintain a desired pH-value at the second temperature.

Abstract: Suspension of proppants in hydraulic fracturing applications can be strongly affected by the cross-sectional shapes and lengths of the fibers present in the wellbore treatment compositions. For instance, it has been observed that crimped cellulose ester fibers with a trilobal cross-section and an optimized length can provide enhanced suspension of proppants in aqueous fracturing fluids. Furthermore, the present invention demonstrates that non-round cellulose ester fibers can provide superior proppant suspension properties relative to polylactic acid fibers with a round cross-section.

Abstract: Systems and methods for the use of degradable polymers that are dissolved and/or plasticized in an organic solvent in subterranean treatments. In some embodiments, the methods comprise: providing a treatment fluid that comprises at least one organic solvent and one or more degradable polymers, wherein the treatment fluid does not comprise a significant amount of solid material comprising the one or more degradable polymers; introducing the treatment fluid into a well bore penetrating at least a portion of a subterranean formation; and contacting the treatment fluid with one or more aqueous fluids to form a solid precipitate comprising the one or more degradable polymers in the portion of the subterranean formation.

Abstract: Examples of techniques for monitoring and controlling the pH of a drilling fluid are disclosed. In one example implementation, a method may include monitoring, by a first sensor, a first pH-value of the drilling fluid prior to the drilling fluid being heated. The method may further include monitoring, by a second sensor, a second pH-value of the drilling fluid subsequent to the drilling fluid being heated. The method may further include determining, by a processing system, an amount of additive being added to the drilling fluid to alter the pH of the drilling fluid.

Abstract: Various embodiments disclosed relate to proppant including a swellable coating thereon for treatment of subterranean formations. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in the subterranean formation a proppant including a coating thereon. The coating is swellable with aqueous medium in response to a trigger including acidic pH, CO2, H2S, or a combination thereof.

Abstract: An additive package is disclosed for preparing an automotive crankcase lubricating oil composition for an internal combustion engine. The additive package is made by admixing: (i) 50 mass % or less of an oil of lubricating viscosity; (ii) 50 mass % or less of at least one overbased metal detergent, preferably at least one overbased metal hydroxybenzoate detergent; (iii) 50 mass % or less of an oil-soluble block or graft co-polymer of at least one polymeric block A which is derived from a hydroxycarboxylic acid and at least one polyalkylene block B which is a residue of a polyalkylene glycol, and (iv) optionally, at least one further additive selected from a dispersant, an antioxidant and/or an antiwear agent. The additive package includes less than 2.00 mass % preferably less than 1.50 mass %, of a friction modifier which is a monoester of a C5 to C30 carboxylic acid and which is free of nitrogen. Component (ii) is preferably an overbased metal hydroxybenzoate detergent.

Abstract: Examples of techniques for monitoring and controlling the pH of a drilling fluid are disclosed. In one example implementation, a system may include a first sensor to sense a first pH-value and an associated first temperature of the drilling fluid prior to being heated by a drilling fluid heater and a second sensor to sense a second pH-value and an associated second temperature of the drilling fluid subsequent to being heated by the drilling fluid heater. The system may also include a controller comprising a memory having computer readable instructions and a processing device for executing the computer readable instructions. The computer readable instructions include receiving the first pH-value and first temperature from the first sensor, receiving the second pH-value and second temperature from the second sensor, and determining an amount of additive to add to the drilling fluid to maintain a desired pH-value at the second temperature.

Abstract: The invention relates an additive composition for a drilling fluid, as well as a method of increasing the lubricity and reducing the coefficient of friction of a drilling fluid. The additive composition may further contain a sulfurized olefin and/or a metal dithiophosphate compound, which further enhances the lubricating effect.

Abstract: This invention provides zinc-free aqueous brine compositions. These zinc-free aqueous brine compositions have a density of about 14.3 pounds per gallon or more, and a true crystallization temperature of about 20° F. or less, and comprise water and one or more inorganic bromide salts, with the provisos that when calcium bromide is present, one or more other water-soluble inorganic salts are also present, when lithium bromide is present, calcium bromide is absent, when bismuth(III) bromide is present, one or more other water-soluble inorganic salts are also present, and for a true crystallization temperature of about 10° F. or less, when manganese(II) bromide is present, one or more other water-soluble inorganic salts are also present. Processes for forming these zinc-free aqueous brine compositions are also provided.

Abstract: A method of treating a subterranean formation including combining a long chain hydrocarbon viscosifier, an ene curing agent, and a thiol crosslinking agent to form a resin compound; coating the resin compound onto at least a portion of proppant particles to create resin-coated proppant particles; and placing the coated proppant particles into the subterranean formation zone, wherein the resin compound does not substantially cure prior to placing the resin coated proppant particles into the subterranean formation zone.

Abstract: The invention relates to a drilling fluid in the form of a water-in-oil (W/O) emulsion comprising at least components (A) to (D), wherein component (D) is at least one (meth)acrylic copolymer, which contains at least one of structural units (D1), (D2) and (D3) to introduce at least one hydroxyl and/or amino functionality into the copolymer and which further contains at least one structural unit (D4), a use of said (meth)acrylic copolymer as rheological agent in drilling fluids, which are water-in-oil (W/O) emulsions, as well as to a method of producing oil and/or natural gas or of preparing the production thereof comprising the step of using the inventive drilling fluid for generating and/or operating a drill hole.

Abstract: A method for wellbore stimulation of a subterranean formation that includes preparing an emulsified acid, preparing a resin coated proppant, combining the emulsified acid and the resin coated proppant, mixing to form an acid fracturing slurry and performing a fracturing stimulation of a subterranean formation with the acid fracturing slurry containing the resin coated proppant.

Abstract: An oil-soluble coated particle flow modifier, a preparation method thereof, and a use thereof in fractured-vuggy carbonate reservoirs mining. The oil-soluble coated particle flow modifier is of a core-shell structure, which has a core layer of a coated core and a shell layer of a coating agent, wherein the coated core is made of a plugging material, and the coating agent consists of petroleum resin and hollow beads. Based on the total weight of the coated particle flow modifier, the content of the petroleum resin, the hollow beads, the cotton linters, and the coated cores is 10-40 wt %, 9-40 wt %, 1-10 wt %, and 35-80 wt %, respectively. A preparation method of the coated particle flow modifier and a use of the coated particle flow modifier in fractured-vuggy carbonate reservoirs mining to improve oil recovery is also provided.

Abstract: A layer of permeable material is positioned on an area of lost circulation lithology in a wellbore. An example of the permeable material includes a planar member with perforations that is rolled into and retained in an annular configuration. The permeable material is lowered into the wellbore adjacent the area of lost circulation and allowed to unroll and expand radially outward against walls of the wellbore. The wellbore wall along the area of lost circulation lithology can be reamed out so the layer of permeable material is out of the way of a drill bit. Applying a bridging agent on the interface where the permeable material contacts the wellbore wall forms a flow barrier.

Abstract: Methods and apparatuses that measure thermal conductivity and electrical conductivity of a emulsified drilling fluid may be used to indirectly measure the salinity and the average specific gravity of the solids in the emulsified drilling fluid. For example, a drilling assembly may comprise a drill string extending into a wellbore penetrating a subterranean formation; a pump configured to circulate a drilling fluid through the drilling assembly; a first flow line fluidly coupling the wellbore to a retention pit; a second flow line fluidly coupling the retention pit to the pump; a third flow line fluidly coupling the pump to the drill string; and an in-line analysis system fluidly coupled to the retention pit, fluidly coupled to the second flow line, or fluidly coupled to the third flow line, the in-line analysis system comprising a thermal conductivity meter and/or an electrical conductivity meter to a sample container.

Abstract: A composition includes an oil phase; a water phase emulsified in the oil phase; a viscosifier including a carbon chain and a polar group disposed along the carbon chain; and a hydrophobic nanomaterial having an average particle size of less than about 1 ?m. The hydrophobic nanomaterial including a silane or siloxane molecule having a nonpolar chain disposed on a surface thereof.

Abstract: Capped nanoparticles may be added to an oil-based fluid to improve the electrical conductivity of the oil-based fluid. The oil-based fluid may be a drilling fluid, a completion fluid, a drill-in fluid, a stimulation fluid, a servicing fluid, and combinations thereof. In a non-limiting embodiment, the oil-based fluid composition may be circulated in a subterranean reservoir wellbore.

Abstract: Polymer-modified asphalt is used in drilling fluids for filtration control, lost circulation control, drill string differential sticking prevention, or wellbore stabilization. The latex modified asphalt provides a mixture of latex-asphalt complex, asphalt, and latex particles that help maintain wellbore stability while drilling into shale formations. The polymer-modified latex is effective for controlling laminated and microfractured shale. Polymers may be functionalized to react with the asphalt to create copolymer modifications of the asphalt for improved performance as drilling fluid additives. The drilling fluids may be water-based or oil-based, or based on an emulsion of oil and water.

Abstract: A method of foam fracturing a subterranean formation includes providing an fracturing foam fluid comprising an aqueous base fluid, a cationic polymer, optionally a foam surfactant comprising at least one of an amphoteric surfactant, cationic surfactant, an anionic surfactant, and combinations thereof, and sufficient gas to form a foamed fracturing fluid; and fracturing the subterranean formation with the foamed fracturing fluid. Stable fracturing foams include an aqueous base fluid, a cationic polymer, optionally a foam surfactant comprising at least one of an amphoteric surfactant, cationic surfactant, an anionic surfactant, and combinations thereof, and sufficient gas to form a foamed fracturing fluid.

Abstract: Adding shapeable particles to drilling fluids may be useful for curing lost circulation. When the shapeable particles are pumped downhole through the drillpipe and the drillbit, they may deform when exposed to shear as they pass through the drillbit nozzles. While circulating back toward the surface they may relax at least partially and assume the shape of cracks or voids they encounter along the formation wall, thereby stopping losses.

Abstract: The present invention generally relates to methods for increasing recovery of crude oil from a subterranean hydrocarbon-containing formation and for removing or inhibiting deposits in a well, the methods comprising contacting an acid composition that comprises a salt of a nitrogen base having a fluoro inorganic anion with the well or the formation.

Abstract: A layer of permeable material is positioned on an area of lost circulation lithology in a wellbore. An example of the permeable material includes a planar member with perforations that is rolled into and retained in an annular configuration. The permeable material is lowered into the wellbore adjacent the area of lost circulation and allowed to unroll and expand radially outward against walls of the wellbore. The wellbore wall along the area of lost circulation lithology can be reamed out so the layer of permeable material is out of the way of a drill bit. Applying a bridging agent on the interface where the permeable material contacts the wellbore wall forms a flow barrier.

Abstract: A fracturing fluid system for increasing hydrocarbon production in a subterranean reservoir formation comprising a fluid composition and a base fluid, the fluid composition comprising a nano-crosslinker, and a base polymer; and the base fluid operable to suspend the fluid composition, the base fluid comprising water; wherein the fluid composition and the base fluid are combined to produce the fracturing fluid system, wherein the fracturing fluid system is operable to stimulate the subterranean reservoir formation. In certain embodiments, the nano-crosslinker is an amine-containing nano-crosslinker and the base polymer is an acrylamide-based polymer. In certain embodiments, the fracturing fluid systems comprise proppants for enhancing hydraulic fracturing stimulation in a subterranean hydrocarbon reservoir.

Abstract: A fluid pressure transmission pill (FPTP) having an ultra-high viscosity for use in association with hydrocarbon drilling and exploration operations, particularly, managed pressure drilling (MPD) operations, is described. The ultra-high viscosity pill is a weighted pill composition that includes a hydrocarbon fluid, a thixotropic viscosifying agent, one or more activators, an emulsifier/wetting agent, a fluid loss control additive, and a weighting material. In accordance with selected aspects of the described fluid pressure transmission pill, the ratio of the amount of the thixotropic viscosifying agent to the activator is a ratio of about 7:1, and the weighting material is a barium-containing solid-phase material. Also described are methods of use of such FPTP products in subterranean operations, such as well killing operations during managed pressure drilling.

Abstract: Disclosed are treating fluid compositions for use in subterranean workover and hydrocarbon recovery operations, as well as methods of treating subterranean formations penetrated by a wellbore utilizing the treating fluid. The treating fluid compositions contain a first, aqueous liquid, and a crosslinkable organic polymer that is at least partly soluble in the liquid. The treating fluid further contains a borate crosslinking agent solution containing a primary, un-refined borate and a secondary, refined borate, the borate solution being present as a crosslinking agent upon addition to the first fluid admixture so as to crosslink the organic polymer and increase the viscosity and/or accelerate the crosslink time of the treating fluid.

Abstract: A gravel packing fluid and method for brine-sensitive formations. The fluid comprises an invert oil emulsion compatible with oil based drilling fluids and having a suspension agent comprising polyurea and dimer diamine. The fluid is capable of carrying gravel yet has a viscosity less than 100 cp, often eliminating the need for an emulsion breaker during flow-back of the fluid to the well surface after deposition of gravel in the well.

Abstract: The present invention relates to a method for removing water from swollen superabsorbent polymers in a gel state, and a method for recycling sanitary absorbent articles using the same. According to the method of the present invention, water is removed from swollen superabsorbent polymers by immersing swollen superabsorbent polymers in a gel state into a composition wherein sea water that is readily available and calcium chloride that is readily available at low cost are mixed for a specified period of time. The method makes it possible to easily and economically remove water from swollen SAPs in a gel state. Thus, the method provides an economical and environmentally-friendly means for recycling sanitary absorbent articles comprising an absorbent that consists of SAP and cellulose pulp, after being used for absorbing human waste.

Abstract: The invention provides a method, composition, and system for inhibiting sulfide stress cracking of metal that is exposed to aqueous sulfide and aqueous acid, and optionally brine, where the composition comprises a thietane compound, a thiirane compound, or a combination thereof.

Abstract: Use of two different methods, either each by itself or in combination, to enhance the stiffness, strength, maximum possible use temperature, and environmental resistance of thermoset polymer particles is disclosed. One method is the application of post-polymerization process steps (and especially heat treatment) to advance the curing reaction and to thus obtain a more densely crosslinked polymer network. The other method is the incorporation of nanofillers, resulting in a heterogeneous “nanocomposite” morphology. Nanofiller incorporation and post-polymerization heat treatment can also be combined to obtain the benefits of both methods simultaneously. The present invention relates to the development of thermoset nanocomposite particles.

Abstract: Fluid treatment systems and compositions are provided including (a) at least one material including (1) at least one carboxylic acid functional group and (2) at least one sulfur-containing group selected from the group consisting of sulfonyl functional groups, sulfonate functional groups and mixtures thereof; and (b) at least one friction reducing agent selected from the group consisting of guar gums, polyacrylamides, hydratable cellulosic materials, viscoelastic surfactants, and mixtures thereof. The fluid treatment systems and compositions can be used to treat aqueous systems, for example as fracturing fluids for use in fracturing subterranean formations. Methods for inhibiting formation and/or precipitation of metal oxides in an aqueous composition using the fluid treatment systems or compositions also are provided.

Abstract: Fluid treatment systems and compositions are provided including (a) at least one material including (1) at least one carboxylic acid functional group and (2) at least one sulfur-containing group selected from the group consisting of sulfonyl functional groups, sulfonate functional groups and mixtures thereof; and (b) at least one scale control agent. The fluid treatment systems and compositions can be used to treat aqueous systems, for example as fracturing fluids for treating aqueous compositions found in subterranean formations. Methods for inhibiting formation and/or precipitation of calcium salts in an aqueous composition using the fluid treatment systems or compositions also are provided.

Abstract: PGA short fibers having the following characteristics of (a) to (c): (a) strength of 1 to 20 gf/D; (b) a mass loss of at least 10% after 14 days in water at a temperature of 60° C.; and (c) a pH of 1 to 5 after 3 days in water at a temperature of 60° C. with a solid content concentration of 2 mass %. The PGA short fibers preferably further having (d1) an outside diameter of 1 to 120 ?m, (e1) a fiber length of 2 to 30 mm, and (f1) a fineness of 0.1 to 25 D, or the PGA short fibers preferably further having (d2) an outside diameter of 1 to 200 ?m, (e2) a fiber length of less than 2 mm, and (f2) an aspect ratio of 2 to 1,200. Also, a well treatment fluid containing the PGA short fibers.

Abstract: Use of two different methods, either each by itself or in combination, to enhance the stiffness, strength, maximum possible use temperature, and environmental resistance of thermoset polymer particles is disclosed. One method is the application of post-polymerization process steps (and especially heat treatment) to advance the curing reaction and to thus obtain a more densely crosslinked polymer network. The other method is the incorporation of nanofillers, resulting in a heterogeneous “nanocomposite” morphology. Nanofiller incorporation and post-polymerization heat treatment can also be combined to obtain the benefits of both methods simultaneously. The present invention relates to the development of thermoset nanocomposite particles.

Abstract: The invention provides a composition made of fibers and a material able to exhibit reverse solubility. The invention preferably is used in a well and as a method to cure lost circulation.

Abstract: A dispersion liquid for supporting oil drilling, including: an aqueous medium and a particulate solid polyglycolic acid resin dispersed in the aqueous medium; wherein the particulate polyglycolic acid resin has a weight-average molecular weight of at least 70,000 and at most 500,000, and exhibits weight retentivities in water at 80° C. of at least 85% after 12 hours, at most 80% after 72 hours, and at most 45% after 168 hours. The particulate solid polyglycolic acid resin included in the above-mentioned dispersion liquid for supporting oil drilling, functions as a fluidity control material exhibiting ideal degradation charateristics in the drilling operation for expansion of oil production capacity, demanded for suppressing the liquid permeability in the early stage and recovery of the liquid permeability after completion of the operation of the formation around the oil well.

Abstract: A polyester resin composition comprising: 100 parts by mass of a polyester resin having at least 50% by mass of a glycolic acid resin; and from 0.5 to 50 parts by mass of a carboxylic acid anhydride.

Abstract: A composition made of fibers and a material able to exhibit reverse solubility has utility for treating subterranean wells. The composition may used to cure lost circulation. The composition may be added to drilling fluids, spacer fluids or cement slurries. As the fluid temperature increases in a well, the reverse solubility material may precipitate and migrate to the fibers, causing the fibers to stick to each other and form a network, thereby forming a barrier that reduces further egress of treatment fluid from the wellbore.

Abstract: Methods of treating a subterranean formation are disclosed that include placing a treatment fluid into a subterranean formation, the treatment fluid containing a one or more polymers capable of consolidating to form a polymeric structure at a downhole location. Also disclosed are treatment fluids including a polymeric structure for treating a subterranean formation.

Abstract: Fluid treatment systems and compositions are provided including (a) at least one material including (1) at least one carboxylic acid functional group and (2) at least one sulfur-containing group selected from the group consisting of sulfonyl functional groups, sulfonate functional groups and mixtures thereof; (b) at least one friction reducing agent selected from the group consisting of guar gums, polyacrylamides, hydratable cellulosic materials, viscoelastic surfactants, and mixtures thereof; and (c) at least one scale control agent. The fluid treatment systems and compositions can be used to treat aqueous systems, for example as fracturing fluids for treating aqueous compositions found in subterranean formations. Methods for inhibiting formation and/or precipitation of metal oxides in an aqueous composition using the fluid treatment systems or compositions also are provided.

Abstract: Invert emulsion fluids comprising a fatty dimer diamine having 28 to 48 carbon atoms per molecule and an acid or an acid derivative and methods of using such invert emulsion fluids for the treatment of at least a portion of a subterranean formation are provided. The invert emulsion fluids can be suitable for use as, for example, packer fluids and drilling fluids.

Abstract: Providing high energy materials that can be placed in previously created fractures and activating them in place to extend or change an existing fracture system. Also detecting the location of fractures or permeable pathways and a means to assess the extent and efficiency of proppant emplacement.