Abstract: A synergistic blend for foaming concentrated brines comprises at least one foaming agent (in an amount between from about 10 to about 90 weight percent of the blend) and a compound of the formula: CnH2n+1—N—[(CH2)mCOOM]2??(I) wherein n is 4 to 11, M is an alkali metal and m is 1 to 3. Especially suitable as foaming agent are quaternary ammonium salts, alkyl betaines, alkylamidopropyl betaines, sulfabetaines, hydroxysultaines, amphoteric perfluorohydrocarbons, as well as alkylether sulfates. Such synergistic blends are especially useful in the foaming of saturated or near saturated brines.

Abstract: The invention relates to a method for producing a gaseous medium comprising steam, said steam being produced from a first fluid medium, energy for heating the first fluid medium being provided by burning a fuel, comprising the steps of mixing the steam with exhaust gas from combustion of said fuel characterised by the steps of prior to mixing the steam with exhaust gas, injecting fluid into the steam. The invention further relates to a device for producing a gaseous medium comprising steam. The invention also relates to a further method for producing a gaseous medium comprising steam The invention still further relates to a further device for producing a gaseous medium comprising steam. The invention finally relates to a turbine configuration.

Abstract: Of the many compositions and methods provided herein, an embodiment of a method comprises introducing a foamed cement composition into a subterranean formation, wherein the foamed cement composition comprises: a cementitious component; a foaming and stabilizing surfactant; an oil-swellable particle; gas; and water; and allowing the settable composition to set in the subterranean formation. Another embodiment of a method comprises introducing a foamed cement composition into an annulus between a pipe string and a subterranean formation, wherein the foamed cement composition comprises comprising: a cementitious component; a foaming and stabilizing surfactant; an oil-swellable particle; gas; and water; and allowing the settable composition to set in the annulus. An embodiment of a foamed cement composition comprises a cementitious component, a foaming and stabilizing surfactant, a swellable particle, gas, and water.

Abstract: A treatment fluid composition for treating a subterranean formation is formed from an aqueous fluid, a hydratable polymer and a polymer breaking system. The polymer breaking system includes an oxidizing breaking agent and an activator capable of providing a bisulfite ion source. A method of treating a subterranean formation may also be performed by forming a treatment fluid comprising an aqueous hydrated polymer solution and a polymer breaking system. The polymer breaking system includes a breaking agent of an oxidizer and an activator capable of providing a bisulfite ion source. The treatment fluid is introduced into the formation.

Abstract: An improved method of producing hydrocarbons from a subterranean formation in which a solids-stabilized emulsion (SSE) is formed, the SSE comprising oil as a first liquid, droplets of a second liquid suspended in the oil, and solid particles that are insoluble in both the oil and the second liquid at the conditions of the subterranean formation. The SSE with dissolved gas is injected into the subterranean formation as a drive fluid, and at least a portion of the SSE is placed into one or more area of the subterranean formation having an in situ pressure sufficiently lower than the selected partial pressure to permit evolution of at least a portion of the gas from the oil. Furthermore, a method of making the foamy SSE is also provided.

Abstract: This invention relates to compositions used in treating subterranean formations, which include a hydrated polymer, and a dry blended multi-functional component. The hydrated polymer and dry blended multi-functional component are mixed at the ground surface of a wellsite, and subsequently injected into the formation providing controlled delay in crosslinking to achieve targeted fluid viscosity properties. The hydrated polymer may be a guar, hydroxypropyl guar, carboxymethyl guar, carboxymethylhydroxypropyl guar, synthetic polymers, and guar-containing compounds. The dry blended multi-functional component may include a crosslinker and a chelating agent, and the well treatment fluid may further include an activator mixed with the hydratable polymer. The chelating agent may be a polyols, gluconate, sorbitol, mannitol, carbonate, or any mixtures thereof.

Abstract: This invention relates to compositions and methods of treating a subterranean formation penetrated by a well bore including providing a treatment composition comprising a rheological polymer, a partitioning agent, a charged polyelectrolyte, and a first liquid medium, forming a stabilized heterogeneous mixture comprising a dispersed rheological polymer-rich phase and a partitioning agent-rich phase, and injecting the treatment fluid into the well bore. The invention relates to methods and compositions for preparing a well treatment fluid, including mixing polyethylene glycol partitioning agent, a charged polyelectrolyte, a first aqueous medium, and one or more rheological polymers selected from the group consisting of guar, modified guar, cellulose, modified cellulose, heteropolysaccharide, heteropolysaccharide derivative, or polyacrylamide, to hydrate the one or more polymers and form a water-in-water emulsion, and mixing the water-in-water emulsion with a second aqueous medium to form a well treatment fluid.

Abstract: A composition and method for removing a filter cake from a horizontal wellbore in a subterranean formation using a composition containing a inorganic or organic acidic material, a cationic fluorocarbon surfactant, an alkyl alcohol, water optionally containing ammonium chloride and at least one of an alkyl polyglycoside and a betaine surfactant to produce a stable foam used to remove filter cake from a horizontal wellbore.

Abstract: A composition and method for removing a filter cake from a horizontal wellbore in a subterranean formation using a composition containing a inorganic or organic acidic material, a cationic fluorocarbon surfactant, an alkyl alcohol, water optionally containing ammonium chloride and at least one of an alkyl polyglycoside and a betaine surfactant to produce a stable foam used to remove filter cake from a horizontal wellbore.

Abstract: The invention provides for the use of 1-alkyl-5-oxopyrrolidine-3-carboxylic esters, preparable by esterifying alcohols having from 1 to 100 hydroxyl groups with 1-alkyl-5-oxopyrrolidine-3-carboxylic acid, in amounts of from 0.01 to 2% by weight for preventing the formation of gas hydrates in aqueous phases which are in contact with a gaseous, liquid or solid organic phase.

Abstract: A treatment fluid for treating a subterranean formation penetrated by a wellbore is formed from an aqueous medium, a diutan heteropolysaccharide having a tetrasaccharide repeating unit in the polymer backbone and a peroxide breaker. A method of treating a subterranean formation penetrated by a wellbore may be carried out by introducing the treatment fluid into the formation through the wellbore. Breaking aids or catalysts may also be used with the treatment fluid.

Abstract: This invention relates to fluid compositions used in treating a subterranean formation. In particular, the invention is aqueous wellbore treatment compositions which are foams containing a viscosifying agent, a foam extender, a gas component, and a surfactant, as well as methods of forming such fluids, and uses thereof. The viscosifying agent may be a hydratable polymer, viscoelastic surfactant, or heteropolysaccharide. The foam extender may be a material such as a polyoxyalkyleneamines, ethylenepolyamines, tertiary polyamines, bicarbonate, carbonate, phosphate, or sesquicarbonate.

Abstract: Methods of gravel packing comprising providing a gravel packing fluid comprising a base fluid and substantially hydrated cement particulates, introducing the gravel packing fluid into a subterranean formation, and depositing at least a portion of the substantially hydrated cement particulates in the subterranean formation to form a gravel pack. Gravel packing fluids that comprise a base fluid, and gravel comprising substantially hydrated cement particulates. Methods of gravel packing and fracturing a subterranean formation comprising fracturing the subterranean formation so as to create or enhance one or more fractures in the subterranean formation; introducing a fluid comprising a base fluid and substantially hydrated cement particulates through a well bore into the one or more fractures; and depositing at least a portion of the substantially hydrated cement particulates in the one or more fractures in the subterranean formation and in the well bore to form a gravel pack.

Abstract: Coacervate gels having excellent shear viscosities and other properties are made with anionic or cationic polymers, a smaller amount of a surfactant having a charge opposite that of the polymer, and a hydrophobic alcohol. The Zeta Potential of the gel is maintained at an absolute value of at least 20. Optional gel promoting additives include betaines and amine oxides. A preferred gel comprises poly diallyl dimethyl ammonium chloride, a lesser amount of sodium lauryl sulfonate, and lauryl alcohol. The gels are particularly useful in well drilling fluids and well fracturing fluids.

Abstract: A method of fracturing a subterranean zone penetrated by a well bore preparing a foamed fracturing fluid containing a self-degrading foaming composition with a mixture of anionic surfactant and nonionic surfactant, and a composition thereof. The fracturing fluid containing self-degrading foaming composition forms a substantially less stable foam when the foamed fracturing fluid is recovered during reclaim.

Abstract: An improved method and fracturing fluid for hydraulic fracturing of a subterranean formation, the fracturing fluid including a surfactant, a water soluble or dispersible anionic organic salt, an acid and a low molecular weight organic solvent.

Abstract: Sintered, spherical composite pellets having high strength and low density, are described, along with processes for their manufacture. One method includes forming a green pellet from a mixture of clay, bauxite or a clay-bauxite mixture with a sacrificial phase such that upon sintering of the pellet, the sacrificial phase is removed from the pellet. The use of such sintered pellets in hydraulic fracturing of subterranean formations is also described.

Abstract: A method for minimizing the amount of metal crosslinked viscosifier necessary for treating a wellbore with proppant or gravel is given. The method includes using fibers to aid in transporting, suspending and placing proppant or gravel in viscous carrier fluids otherwise having insufficient viscosity to prevent particulate settling. Fibers are given that have properties optimized for proppant transport but degrade after the treatment into degradation products that do not precipitate in the presence of ions in the water such as calcium and magnesium. Crosslinked polymer carrier fluids are identified that are not damaged by contaminants present in the fibers or by degradation products released by premature degradation of the fibers.

Abstract: The present invention provides settable compositions that comprise water and cement kiln dust. The settable compositions optionally may comprise an additive that comprises at least one of the following group: fly ash; shale; slag cement; zeolite; metakaolin; and combinations thereof. The settable compositions optionally may be foamed with a gas. Methods of cementing also are provided that comprise: providing the settable composition; introducing the settable composition into a location to be cemented; and allowing the settable composition to set therein. The location to be cemented may be above ground or in a subterranean formation.

Abstract: A wellbore treatment fluid is formed from an aqueous medium, a gas component, a viscosifying agent, and a surfactant. The surfactant is represented by the chemical formula: [R—(OCH2CH2)m—Oq—YOn]pX wherein R is a linear alkyl, branched alkyl, alkyl cycloaliphatic, or alkyl aryl group; O is an oxygen atom; Y is either a sulfur or phosphorus atom; m is 1 or more; n is a integer ranging from 1 to 3; p is a integer ranging from 1 to 4; q is a integer ranging from 0 to 1; and X is a cation. The fluid may be used in treating a subterranean formation penetrating by a wellbore by introducing the fluid into the wellbore. The fluid may be used in fracturing a subterranean formation penetrated by a wellbore by introducing the fluid into the formation at a pressure equal to or greater than the fracture initiation pressure.

Abstract: Of the many methods provided, in one aspect, the present invention provides a method comprising: providing a treatment fluid comprising: an aqueous base fluid, a first surfactant, and a surfactant-based fluid loss control agent capable of forming a viscoelastic fluid; and introducing the treatment fluid into a well bore that penetrates the subterranean formation.

Abstract: An oil-in-water-in-oil emulsion (O/W/O) comprising a first oil-in-water emulsion dispersed in a second oil, and a method of preparing the same. The O/W/O emulsion can be used as a drive fluid in an enhanced oil recovery process. The O/W/O emulsion of this invention may also be used as a lubricant, and has the beneficial property of being resistant to shear forces.

Abstract: Gas hydrate formation in a well completion fluid in the annular space of a hydrocarbon producing well may be controlled by the incorporation of effective amounts of one or more low dose gas hydrate inhibitors, including but not limited to, low dosage hydrate inhibitors (LDHIs), kinetic hydrate inhibitors, dendrimeric or branched compounds, linear polymers and copolymers and onium compounds.

Abstract: A method of treating a subterranean formation comprising the steps of providing a servicing fluid comprising carbon dioxide and a hydrocarbon blend, wherein the hydrocarbon blend comprises at least about 65% hydrocarbons having from six carbons (C6) to eleven carbons (C11); and placing the servicing fluid into the subterranean formation. A subterranean servicing fluid comprising carbon dioxide and a hydrocarbon blend wherein the hydrocarbon blend comprises and at least about 65% hydrocarbons having from six carbons (C6) to eleven carbons (C11).

Abstract: The invention provides a fluid for use in a subterranean formation penetrated by a wellbore, the fluid comprising: (a) water; (b) delayed release acid; (c) a surfactant comprising a tertiary alkyl amine etboxylate generally represented by the following formula: wherein R is an alkyl group or groups, X is about 2 to about 15, and Y is about 2 to about 15; and (e) a gelling agent. The invention also provides a method of fracturing a subterranean formation, comprising the step of forming a foamed fracturing fluid comprising water; a surfactant comprising a tertiary alkyl amine ethoxylate generally represented by the formula above; a gelling agent; and a gas. The method also provides the step of introducing the foamed fracturing fluid into a subterranean formation at a pressure sufficient to create a fracture in the subterranean formation. The method also provides the step of introducing an acid into the subterranean formation.

Abstract: A method for minimizing the amount of metal crosslinked viscosifier necessary for treating a wellbore with proppant or gravel is given. The method includes using fibers to aid in transporting, suspending and placing proppant or gravel in viscous carrier fluids otherwise having insufficient viscosity to prevent particulate settling. Fibers are given that have properties optimized for proppant transport but degrade after the treatment into degradation products that do not precipitate in the presence of ions in the water such as calcium and magnesium. Crosslinked polymer carrier fluids are identified that are not damaged by contaminants present in the fibers or by degradation products released by premature degradation of the fibers.

Abstract: Provided herein are defoaming agents that comprise lecithin and a solvent. Optionally, they may comprise hydrophobic particles. One embodiment provides a method comprising: providing a well fluid that comprises foam; providing a defoaming agent that comprises lecithin and a solvent; and contacting the well fluid with the defoaming agent so that the amount of foam present in the well fluid is reduced.

Abstract: A method of fracturing a subterranean formation comprising the steps of: providing a coarse-foamed fracturing fluid comprising a liquid fracturing fluid component, a gas, proppant particulates, and a foaming agent; and placing the coarse-foamed fracturing fluid into a portion of a subterranean formation at a pressure sufficient to create or extend at least one fracture therein.

Abstract: Methods of treating subterranean formations using foamed treatment fluids comprising water, a gas, and a foaming and foam stabilizing surfactant mixture comprising a plurality of alkali salts of alkyl ether sulfates wherein the alkyl group in each of the alkyl ether sulfates has in the range of from 4 carbon atoms to 10 carbon atoms, an alkyl amidopropyl hydroxysultaine or an alkyl amidopropyl betaine, and an alkyl amidopropyl dimethylamine oxide.

Abstract: Exemplary embodiments relate to cementing operations and, more particularly, to foamed cement compositions, foaming and stabilizing additives, and associated methods. A foaming and stabilizing additive, that comprises a mixture of an alkali salt of an alkyl ether sulfate surfactant, wherein the alkali salt of the alkyl ether sulfate surfactant comprises a mixture of an alkali salt of a C6-10 alkyl ether sulfate surfactant, and an alkali salt of a C2-4 alkyl ether sulfate surfactant, an alkyl or alkene amidopropyl betaine surfactant, an alkyl or alkene amidopropyl dimethylamine oxide surfactant, sodium chloride, and water, is provided. Also provided are foamed cement compositions that comprise the foaming and stabilizing additive, and associated methods.

Abstract: The present invention relates to curable, permeable resin compositions and methods of using such compositions. One embodiment of provides a method of creating a resin mass comprising the steps of combining a resin, a hardening agent, a hydrocarbon diluent, a silane coupling agent, a foaming agent, a compressible gas, and a degradable material to form a resin composition; placing the resin composition in a subterranean formation; and, allowing the resin to substantially cure and the degradable material to substantially degrade so as to form a permeable, hardened resin mass. Another embodiment of the present invention provides a resin composition useful in subterranean applications comprising a resin, a hardening agent, a hydrocarbon diluent, a silane coupling agent, a foaming agent, a compressible gas, and a degradable material.

Abstract: Method of treating a portion of a subterranean formation comprising: placing a pre-pad fluid into a portion of a subterranean formation wherein the pre-pad fluid comprises a low-viscosity aqueous tackifying composition that comprises an aqueous tackifier compound and an aqueous fluid; placing a fracturing fluid into the portion of the subterranean formation at a pressure sufficient to create or extend at least one fracture therein; and, activating the aqueous tackifier compound with an activator so as to consolidate the unconsolidated particulates.

Abstract: Fracturing fluids and methods of fracturing a subterranean formation using such fluids are provided. A fracturing fluid having a first pH is foamed by introducing a gas to the fluid. The fracturing fluid comprises a surfactant that facilitates formation of the foam at the first pH. The foamed fracturing fluid is subsequently pumped to the subterranean formation to fracture it. The pH of the fracturing fluid is then changed to a second pH at which the surfactant facilitates reduction of the foam. The fracturing fluid releases proppant contained in the fluid to the subterranean formation. The fracturing fluid is then allowed to flow back to the surface. It can be recycled by changing the pH of the fracturing fluid back to the first pH and adding a gas to the fluid, causing it to foam again.

Abstract: Disclosed herein is a method of treating a subterranean formation utilizing a fluid having a splittable foamer, i.e., a fluid that creates a stable foam when it contacts the formation but that loses its ability to foam as it remains in contact with the formation for extended time. The present method has the advantage that the fluid can be recovered from the well unhindered by the difficulties involved with recovering a foamed fluid from a well. The present method does not require the use of breakers, though the splitting of the foam can be accelerated by introducing an organic or inorganic acid into the well, if so desired.

Abstract: The present invention generally relates to improved clay-based compositions comprising colloidal or colloidal-like phases (e.g., emulsions, aphrons) and methods of using those compositions. The compositions generally comprise an aqueous continuous phase, one or more palygorskite-sepiolite group clays, one or more surfactants, aphrons and optionally one or more Aphron Stabilizers. The compositions of the present invention are capable of being used in high-pressure applications.

Abstract: Self-generating foamed fluids for circulation through a well during drilling operations and methods for circulating such self-generating foamed drilling fluids are provided for. The drilling fluid comprises an aqueous solvent, a polymer, a surfactant, a first foam generating agent, and a second foam generating agent. The first and second foam generating agents react to generate a gas within the drilling fluid and thereby to foam the drilling fluid. Preferably, the foam generating agents are selected such that they react to generate carbon dioxide. Preferably a base fluid comprising excess amounts of only one of the foam generating agents is pumped into the drill string using a hydraulic pump. The other foam generating agent then is injected in a controlled manner downstream of the circulation pump such that the drilling fluid is foamed after being pumped for circulation through the well. The novel drilling fluids preferably have a density of from about 5.8 lb/gal to about 0.

Abstract: A method of cementing in a subterranean formation that comprises providing a foamed cement composition that comprises water, a cement, a gas, and an additive, the additive comprising an anionic foaming agent and at least one of an anionic foam stabilizer or a Zwitterionic foam booster; placing the cement composition into the subterranean formation; and allowing the cement composition to set therein is provided. Foamed cement compositions, additives for foaming and stabilizing a cement composition, and methods of reducing the density of a cement composition, also are provided.

Abstract: The present invention relates to methods of chemically generating gas in aqueous fluids utilized in the drilling and completion of wells such as drilling fluids, spacer fluids, and aqueous acid solutions. In one embodiment, the invention provides a method of preventing the formation of fractures in a subterranean formation during a drilling operation. In other embodiments, the present invention provides methods of separating a first fluid and a second fluid in a subterranean formation; methods of forming lightweight well treatment fluids; methods of enhancing the permeability of a subterranean zone; lightweight drilling fluids; lightweight spacer fluids; foamed aqueous acidic well treatment fluids; and methods of making foamed aqueous and aqueous acidic well treatment fluids.

Abstract: Well completion spacer fluids containing fibers and methods of using the spacer fluids are provided. A method of the invention for displacing a first fluid from a well bore with an incompatible second fluid comprises the following steps. A spacer fluid is placed between the first and second fluids to separate the first and second fluids and to remove the first fluid from the walls of the well bore. Thereafter, the first fluid and the spacer fluid are displaced from the well bore with the second fluid. The spacer fluid comprises water, a weighting material, a dispersing agent, a suspending agent and friction reducer and fibers. The spacer fluid containing the components mentioned above is preferably also foamed.

Abstract: Foamed completion fluids and methods of completing subterranean zones penetrated by well bores are disclosed. A method of completing a subterranean zone penetrated by a well bore comprises the steps of providing or preparing a foamed completion fluid comprising water, one or more salts, a gas and a capryl/capramidopropylbetaine surfactant foaming agent, introducing the foamed treating fluid into the subterranean zone, and then carrying out a completion operation in the subterranean zone.

Abstract: Reduced friction fluids comprising an aqueous liquid, carbon dioxide, and a polymer comprising acrylamide and an acrylamide copolymer derivative. And methods of treating a subterranean formation comprising the steps of providing a reduced friction fluid comprising an aqueous liquid, carbon dioxide, and a polymer comprising acrylamide and an acrylamide copolymer derivative; and, introducing the reduced friction fluid to a subterranean formation.

Abstract: The present invention provides variable density fluid compositions and methods for using such compositions in a subterranean formation. One exemplary embodiment of the variable density fluid compositions of the present invention comprises a variable density fluid comprising: a base fluid, and a portion of variable pressure weighting material particles.

Abstract: A process for the recovery of oil from a subsurface reservoir in combination with the production of liquid hydrocarbons from a hydrocarbonaceous stream involving: (i) separating an oxygen/nitrogen mixture into a stream enriched in oxygen and an oxygen depleted stream; (ii) partial oxidation of the hydrocarbonaceous feed at elevated temperature and pressure using enriched oxygen produced in step (i) to produce synthesis gas; (iii) converting synthesis gas obtained in step (ii) into liquid hydrocarbons; and (iv) recovering oil from a subsurface reservoir using at least part of the oxygen depleted gas stream produced in step (i).

Abstract: In one embodiment, this invention presents a foaming additive that comprises at least one amidopropyl betaine having the formula: R—CONHCH2CH2CH2N+(CH3)2CH2COO? wherein R is a capryloyl, a capryl, an octyl, a decyl, a cococyl radical, or a mixture thereof. This foaming additive may be utilized in foamed treatment fluids, and those foamed treatment fluids may be utilized in fracturing and sand control treatments in subterranean operations. Associated methods also are presented herein.

Abstract: The present invention provides compositions of treating subterranean zones penetrated by well bores in primary well cementing operations, well completion operations, production stimulation treatments and the like. The invention includes aqueous well treating fluids comprised of water and a water soluble polymer complex fluid loss control additive. Preferred polymer complexes comprise water-soluble polymers made in the presence of hydroxyethylcellulose.

Abstract: Methods in which temperature is used to control the foaming and/or defoaming of foamed treatment fluids comprising an aqueous liquid, an ionic foaming surfactant, and a gas are provided. A method of treating at least a portion of a subterranean formation is provided, the method comprising: providing a treatment fluid having a foam transition temperature, the treatment fluid comprising an aqueous liquid, and an ionic foaming surfactant; foaming the treatment fluid to form a foamed treatment fluid; circulating the foamed treatment fluid in a well bore penetrating the subterranean formation; and defoaming at least a substantial portion of the foamed treatment fluid, the defoaming comprising lowering the temperature of the foamed treatment fluid to about at or below the foam transition temperature.

Abstract: The current invention provides improved methods and compositions for completing a well bore. In one aspect, the current invention provides a process for preparing a foamed well composition. The process utilizes air to foam the composition after the air has been treated to lower the oxygen content below that concentration necessary to support combustion. Additionally, the current invention provides a process for completing and/or treating a well bore using a foamed composition wherein the foam is generated with reduced oxygen content air. Finally, a preferred embodiment of the invention provides a foamed cement composition wherein the gaseous portion of the composition is air having a reduced oxygen content.

Abstract: The present invention discloses two stage subterranean zone fracturing fluids and methods. A two stage subterranean zone fracturing fluid of the invention comprises a first stage fluid comprising a foamed liquid containing a water soluble gel breaker and a second stage fluid that comprises a viscous liquid containing a metal cross-linked gelling agent. Another two stage subterranean zone fracturing fluid comprises a first stage fluid comprising a foamed liquid containing a water soluble gel breaker and a second stage fluid comprising a viscous liquid containing a borate cross-linked gelling agent.

Abstract: The present invention generally relates to improved compositions comprising stabilized colloidal or colloidal-like phases (e.g., emulsions, aphrons) and methods of using those compositions. The compositions generally comprise an aqueous continuous phase, one or more viscosifiers, one or more surfactants, aphrons and one or more Aphron Stabilizers. The compositions of the present invention possess aphrons with significantly increased half-life and enhanced ability to seal permeable formations, and are capable of being used in high pressure applications.

Abstract: The present invention provides the use of surface-modified nanoparticles in fluids used to recover hydrocarbon from underground formations. The use of surface-modified nanoparticles in such fluids provides foams that are stable under pressure yet have a shorter foam lifetime than typical surfactant-stabilized foams after the pressure is released or lowered.