Abstract: Methods for controlling particulate segregation comprising providing a mixture of an aqueous tackifying composition with a treatment fluid; slurrying the mixture with a first type of solid particulates and a second type of solid particulates and wherein the first type of solid particulates have a tendency to segregate from the second type of solid particulates when slurried into a liquid; and, placing the slurry into a portion of a subterranean formation. Methods for controlling particulate segregation comprising providing a treatment fluid; at least partially coating with an aqueous tackifying composition: a first type of solid particulates and a second type of solid particulates and wherein the first type of solid particulates have a tendency to segregate from the second type of solid particulates when slurried into a liquid; slurrying the two types of particulates into the treatment fluid; and, placing the slurry into a portion of a subterranean formation.

Abstract: A method of injecting a stream of treatment fluid into an earth formation in the course of drilling a borehole into the earth formation, using an assembly having a drill string provided with at least one sealing means arranged to selectively isolate a selected part of the borehole from the remainder of the borehole, the drill string further being provided with a fluid passage for the stream of treatment fluid into the selected part of the borehole, the method involving: operating the drill string, and stopping the drilling operation when a zone for which treatment is desired is arranged adjacent to the part of the selected part of the borehole; isolating the selected part of the borehole using the sealing means so as to seal the drill string relative to the borehole wall; and, pumping the stream of treatment fluid via the fluid passage into the selected part of the borehole and from there into the treatment zone.

Abstract: Particulate compositions that comprise macro-particulates, and degradable particulates in an amount sufficient to reduce friction between the macro-particulates, the degradable particulates having a mean particle diameter of at least about 20 times smaller than the mean particle diameter of the macro-particulates are disclosed herein. Also disclosed are fluids that comprise a liquid component, and a particulate composition, the particulate composition comprising macro-particulates and degradable particulates having a mean particle diameter of at least about 20 times smaller than the mean particle diameter of the macro-particulates, wherein the degradable particulates are present in the particulate composition in an amount sufficient to reduce friction between the macro-particulates. Methods of using the particulate compositions and fluids are also disclosed.

Abstract: A method is described for treating a subterranean formation with a low viscosity fluid system that contains a viscoelastic surfactant at a concentration too low to viscosify the fluid, but that is concentrated in the formation so that the fluid system gels. The fluid optionally contains a formation-dissolving agent. The fluid is used in matrix acidizing, acid fracturing, and diversion.

Abstract: Among the methods provided are methods of treating a subterranean formation comprising placing a solid treatment chemical and a tacky polymer onto a solid substrate to create a coated solid substrate; placing the coated solid substrate into a portion of a subterranean formation; and, allowing the tacky polymer to degrade and allowing the solid treatment chemical to be released into the portion of the subterranean formation. Also provided are methods of creating a particulate pack comprising a treatment chemical in a subterranean formation comprising placing a solid treatment chemical and a tacky polymer onto a particulate to create a coated particulate; creating a slurry comprising the coated particulates slurried into a treatment fluid; placing the slurry into a portion of a subterranean formation so as to create a particulate pack; and, allowing the tacky polymer to degrade and allowing the solid treatment chemical to be released into the portion of the subterranean formation.

Abstract: The addition of one or more stimulants to a petroleum well in order to enhance the production of the well. If the well is suffering from asphaltene or paraffin build up, the well may be heated either chemically or with steam prior to introduction of the stimulant. Additionally, a solvent may be added to dissolve the asphaltenes and paraffins. The stimulants are allowed to soak into the formation and then the well is returned to production. The stimulants increase the ability of oil to flow through the formation and decrease the ability of water to flow through the formation by coating the water wet portions of the formation with oil soluble chemicals. The stimulants also decrease the viscosity of the oil in formation.

Abstract: Methods for preparing slurries that include depolymerized polysacoharides and depolymerized and derivatized polysaccharides that may be useful in subterranean well operations including fracturing, gravel packing, and frac-packing, are provided. One embodiment provides a method for making a slurry, comprising combining a polysaccharide with an organic solvent to form a slurry; and, depolymerizing the polysaccharide in the slurry. Another embodiment provides a method of treating subterranean formation with slurry comprising the steps of creating a slurry using a method comprising the steps of combining a polysacchande with an organic solvent to form a slurry; and, depolymerizing the polysaccharide in the slurry; and, placing that slurry into a subterranean formation.

Abstract: The present invention relates to acidic treatment fluids that comprise an acid fluid and an ester-containing quaternary ammonium compound (“esterquat”) and methods of their use. One embodiment of the present invention provides a method of inhibiting metal corrosion during a subterranean treatment operation comprising using an acidic treatment fluid comprising an acidic fluid and an esterquat. Another embodiment of the present invention provides a method of reducing sludge formation during a subterranean treatment operation formation comprising the step of using an acidic treatment fluid comprising an acidic fluid and an esterquat. Another embodiment of the present invention provides a method of inhibiting the formation of emulsions during a subterranean treatment operation comprising using an acidic treatment fluid comprising an acidic fluid and an esterquat. Another embodiment of the present invention provides an acidic subterranean treatment fluid comprising an acidic fluid and an esterquat.

Abstract: A formulation containing a copolymer derived from a cationic monomer effectively inhibits and controls the formation of inorganic scales. The formulation has particular application in the removal of zinc sulfide and iron sulfide scales formed when zinc bromide brines are used as completion fluids. The copolymer exhibit high solubility in high-density brines, such as zinc bromide brines. The polymers may be introduced into an oil or gas well as a portion of a carrier fluid or with brine. The preferred copolymer for use in the invention contains an acrylamide unit and a diallyldimethylammonium salt and, optionally, an acrylic acid or a salt thereof. The weight average molecular weight of such inhibitor copolymers is generally between from about 500,000 to about 5,000,000.

Abstract: Compositions containing a peroxide or peracid and an organic acid salt buffer are provided. Also provided is a method for utilizing such compositions for removing polymers from oil and gas wells, while simultaneously dissolving encountered calcium carbonate deposits.

Abstract: The present invention relates to methods useful during sand control operations and, more particularly, to using water-soluble relative permeability modifiers that are useful for controlling fluid loss during sand control operations. In one embodiment, the present invention provides a method of providing fluid loss control during sand control operations comprising introducing a fluid that comprises a water-soluble relative permeability modifier into a well bore; and stabilizing unconsolidated formation particulates in a section of a subterranean formation penetrated by the well bore. In other embodiments, the present invention provides methods of providing fluid loss control during sand control operations and methods of reducing fluid loss from carrier fluids used in sand control operations.

Abstract: Methods for the removal of alkaline and sulfate scales from aqueous saline streams such as seawater, oil-gas fields produced waters, formation waters, and the like. Such processing methods can also be extended for the simultaneous removal of hydrogen sulfide, and/or sulfur dioxide, and/or oxides of nitrogen, and/or carbon dioxide from gaseous streams. The same processing concept with modified methods can further be employed for the removal of gases such as radon, hydrogen sulfide, sulfur dioxide, oxides of nitrogen, and carbon dioxide from gaseous streams.

Abstract: The invention includes methods of inhibiting microbial growth in a well. A packing material containing a mixture of a first material and an antimicrobial agent is provided to at least partially fill a well bore. One or more access tubes are provided in an annular space around a casing within the well bore. The access tubes have a first terminal opening located at or above a ground surface and have a length that extends from the first terminal opening at least part of the depth of the well bore. The access tubes have a second terminal opening located within the well bore. An antimicrobial material is supplied into the well bore through the first terminal opening of the access tubes. The invention also includes well constructs.

Abstract: An in situ process for treating a hydrocarbon containing formation is provided. The process may include providing heat from one or more heaters to at least a portion of the formation. The heat may be allowed to transfer from the reaction zone to a part of the formation such that heat from one or more heaters pyrolyzes at least some hydrocarbons within the part of the formation. A blending agent may be produced from the part of the formation, wherein a mixture produced with the blending agent has at least one selected property.

Abstract: Methods of reducing the viscosity of a viscosified treatment fluid are provided which comprise the steps of: providing a viscosified treatment fluid that comprises water, a crosslinked gelling agent, and a delinking composition capable of delinking at least a portion of the crosslinked gelling agent wherein the delinking composition comprises a delinking agent; and allowing the crosslinked gelling agent and the delinking composition to interact so as to delink at least a portion of the crosslinked gelling agent. Also provided are methods of reusing viscosified treatment fluids, methods of fracturing subterranean formations, and methods of gravel packing subterranean formations.

Abstract: Methods of diverting treating fluids in subterranean zones penetrated by well bores are provided. The methods basically comprise the following steps. A degradable particulate diverting material is placed in a subterranean zone that contains releasable water. A treating fluid is then introduced into the subterranean zone which is diverted by the degradable particulate diverting material therein. Thereafter, the degradable particulate diverting material is allowed to at least partially degrade in the presence of the released water in the subterranean zone.

Abstract: Methods and compositions relating to fluid loss control operations are provided. Examples of compositions may comprise ceramic particulate bridging agents and improved fluid loss control additives, and methods of using those compositions to provide fluid loss control. An embodiment of a method of providing fluid loss control from a first location to a second location may comprise the steps of: providing a treatment fluid comprising ceramic particulate bridging agents, a modified starch composition, and a base fluid; introducing the treatment fluid to the first location; and allowing the treatment fluid to form a filter cake to prevent fluid loss from the first location to the second location.

Abstract: A method for retaining a treatment chemical in a subterranean formation containing hydrocarbons is disclosed. The method includes first preparing an emulsion. The emulsion contains an oil continuous phase and first and second aqueous phases. The first aqueous phase includes a treatment chemical, such as a scale inhibitor. The second aqueous phase comprises a retention enhancing chemical which is to be reacted with the treatment chemical in the subterranean formation. Preferably, the first and second aqueous phases remain generally separately dispersed and stable within the oil continuous phase prior to being introduced into the subterranean formation. The emulsion is then placed down a well bore and into the subterranean formation.

Abstract: Methods of treating subterranean zones using gelled aqueous treating fluids containing environmentally benign sequestering agents are provided. The methods basically comprise the steps of preparing or providing a treating fluid comprising water containing divalent metal ions, a gelling agent, a borate crosslinking agent and an environmentally benign sequestering agent, and then introducing the treating fluid into the subterranean zone.

Abstract: Aqueous treatment fluids that comprise water, and a friction reducing copolymer that comprises acrylamide in an amount in the range of from about 60% to about 90% by weight and acrylic acid in an amount in the range of from about 10% to about 20% by weight. Methods of treating portions of subterranean formation using the aqueous treatment fluid that comprise providing an aqueous treatment fluid comprising water, and a friction reducing copolymer that comprises acrylamide in an amount in the range of from about 60% to about 90% by weight and acrylic acid in an amount in the range of from about 10% to about 20% by weight; and introducing the aqueous treatment fluid into the portion of the subterranean formation.

Abstract: Embodiments provide systems and methods in which a non-viscous fluid, having a heavy concentration of an appropriate breaker, is pumped into a well in front of viscosified fluid, such as a cross-linked polymeric fracturing fluid, to saturate permeable media with a breaker agent. When a polymer filter cake is subsequently formed on the surfaces of the media the breaker is provided good communication with the polymer filter cake for its breakdown and removal. Communication between the breaker and the polymer filter cake is substantially controlled by an operator in that the breaker remains saturated in the permeable media until such time as the operator decreases hydraulic pressure within the well to a point at which the hydraulic pressure of the media forces the breaker back into the well.

Abstract: A method to reduce water influx into a producing well is described comprising the steps of pumping a chemical composition into a production interval and into surrounding formation; said composition being capable of forming, firstly, a physically stabilized structure and, secondly, a chemically stabilized structure, wherein said physically stabilized structure being dissolvable by hydrocarbon containing fluids; letting said composition form said physically stabilized structure within the formation surrounding said production interval; changing pressure condition in said production interval such that the fluid flow within the surrounding formation is reversed; letting thereby in some portions of the formation hydrocarbon containing fluids dissolve said physically stabilized structure and chemically stabilize said structure in the remaining portions by a cross-linking reaction.

Abstract: Methods and compositions for treating subterranean zones penetrated by well bores utilizing environmentally safe viscous fluids including a solubility increasing boron complex or ester forming compound. A method of the invention comprises the following steps. A viscous treating fluid composition is provided comprising water, a viscosity increasing polymer and a water soluble delayed polymer breaker that comprises a mixture of sodium perborate tetrahydrate and a solubility increasing boron complex or ester forming compound. The viscous treating fluid composition is introduced into the subterranean zone wherein the viscous treating fluid is allowed to break into a thin fluid of reduced viscosity.

Abstract: This invention is directed to treating fluid production and subterranean formation treating methods as well as compositions for treating fluids that reuse at least part of a prior treating fluid, particularly a fluid having one or more constituents that can be relinked. This includes conditioning a selected at least partially delinked flow-back fluid, recovered from a first treating fluid pumped into a well, such that the conditioned selected at least partially delinked flow-back fluid provides a constituent for a second treating fluid. Also included are pricing considerations. A composition for a treating fluid includes a treating fluid residual recovered from a well, preferably conditioned as described. Examples of such fluids include fracturing fluids and gravel pack fluids.

Abstract: A combined scale inhibitor treatment and water control treatment requires fewer steps than the sum of each treatment procedure practiced separately. The control of water production simultaneously further reduces the amount of scale formed. Conventional water control chemicals and scale inhibitors of a wide variety of types can still be employed to advantage, and the same equipment may be used as employed for the treatments implemented separately.

Abstract: Methods of uniformly introducing aqueous treating fluids into subterranean producing zones are provided. The methods are basically comprised of the steps of packing perforation tunnels in the producing zone with a particulate solid anhydrous borate material which degrades and dissolves in water over time. A treating fluid is then introduced into the subterranean zone by way of the packed perforation tunnels whereby the treating fluid uniformly flows into the producing zone. The particulate solid anhydrous borate material in the perforation tunnels is allowed to degrade and dissolve in an aqueous fluid in contact therewith so that the aqueous fluid and produced formation fluids freely flow into the well bore.

Abstract: For extracting a liquid (such as oil) from a porous medium, the liquid is subjected to pulses that propagate through the liquid flowing through the pores of the medium. The pulses cause momentary surges in the velocity of the liquid, which keeps the pores open. The pulses can be generated in the production well, or in a separate excitation well. If the pulses travel with the liquid, the velocity of travel of the liquid through the pores can be increased. The solid matrix is kept stationary, and the pulses move through the liquid. The pulses in the liquid can be generated directly in the liquid, or indirectly in the liquid via a localized area of the solid matrix.

Abstract: The present invention relates to enhancing fluid flow from subterranean formations. More particularly, this invention relates to providing improved proppant matrixes within fractures in a subterranean formation. An example of the methods of increasing the conductivity of a fracture in a subterranean formation comprises the steps of providing a fracturing treatment fluid comprising a proppant composition, the proppant composition comprising proppant particulates and a degradable material capable of undergoing an irreversible degradation downhole; introducing the proppant composition to the fracture; and allowing the proppant composition to form a proppant matrix having voids in the fracture.

Abstract: Methods of diverting treating fluids in subterranean zones penetrated by well bores are provided. The methods basically comprise the following steps. A degradable particulate diverting material is placed in a subterranean zone that contains releasable water. A treating fluid is then introduced into the subterranean zone which is diverted by the degradable particulate diverting material therein. Thereafter, the degradable particulate diverting material is allowed to at least partially degrade in the presence of the released water in the subterranean zone.

Abstract: An apparatus and method used for sealing a wellbore. The apparatus includes a swelling elastomer disposed around an outer surface of the tubular body. The swelling elastomer is isolated from wellbore fluid in an annulus. However, upon the application of an outwardly directed force to an inner surface of the tubular body, the tubular body expands radially outward causing the swelling elastomer to contact the wellbore while exposing the swelling elastomer to an activating agent via the one or more apertures, thereby causing the swelling elastomer to create a pressure energized seal with one or more adjacent surfaces in the wellbore.

Abstract: Methods of reducing or preventing particulate flow-back in subterranean zones. In accordance with the methods, a treating fluid having a mixture of reticulated foam fragments and particulate solids are suspended therein. The treating fluid is introduced into a subterranean zone and the mixture of the reticulated foam fragments and the particulate solids are deposited in the subterranean zone whereby the reticulated foam fragments retard or prevent the flow-back of the particulate solids and the transport of formation fines from the subterranean zone upon the flowing-back of fluid from the zone.

Abstract: A well service fluid composition comprises a fracturing fluid and a gas hydrate inhibitor. Preferably, the gas hydrate inhibitor does not affect the function of the fracturing fluid and is present in an amount sufficient to control and/or minimize the formation of gas hydrates. The well service fluid composition is useful in hydraulic fracturing in which the composition is injected into a subterranean formation under sufficient pressure to initiate and propagate a fracture in the formation. The fracturing fluid may be subsequently recovered when the fracturing operation is completed.

Abstract: Degradable polylactic or polyhydroxyalkanoate polymers may be used to viscosify aqueous fluids for use in wells, Sand control screen or liner can be coated with a solid degradable polymer during placement in a well. Mechanical changes or flow changes in a well can be caused by solid degradable polymer that changes physical properties after it is placed in a well. Parts of devices or entire devices can be made of solid degradable polymer that converts to a fluid after selected times in an aqueous environment in a well.

Abstract: A method of the preparation and utilization of polymerized alpha-hydroxycarboxylic-acid-coated proppants for gravel pack and removal of filter cake that was deposited by reservoir drilling fluid. In a preferred example, polyglycolic-acid-coated sand is used to replace conventional gravel pack sand typically used for gravel packing. Under downhole conditions, the acidic by-product generated from the hydration of polyglycolic-acid-coated sand can break down acid-soluble and/or acid-breakable components embedded in the filter cake. This reaction enhances the filter cake removal and the flow of hydrocarbon from the producing formation. The polyglycolic-acid-coated sand may be produced by polymerizing a glycolic acid with a natural or synthetic proppant like 20-40 mesh commercial sand, at temperatures of about 210° F. or higher.

Abstract: The invention includes methods of inhibiting microbial growth in a well. A packing material containing a mixture of a first material and an antimicrobial agent is provided to at least partially fill a well bore. One or more access tubes are provided in an annular space around a casing within the well bore. The access tubes have a first terminal opening located at or above a ground surface and have a length that extends from the first terminal opening at least part of the depth of the well bore. The access tubes have a second terminal opening located within the well bore. An antimicrobial material is supplied into the well bore through the first terminal opening of the access tubes. The invention also includes well constructs.

Abstract: The present invention provides a well treatment fluid for use in a well, the well treatment fluid comprising water; an amine-based polymer; an polysaccharide-based polymer; and an oxidizing agent that is capable of at least partially oxidizing at least the polysaccharide-based polymer. The present invention also provides a method of treating a subterranean formation penetrated by a wellbore, the method comprising the steps of: (a) forming a well treatment fluid comprising water; an amine-based polymer; a polysaccharide-based polymer; and an oxidizing agent that is capable of at least partially oxidizing at least a portion of the polysaccharide-based polymer; and (b) contacting the well treatment fluid with the subterranean formation.

Abstract: A method of treating a hydrocarbon containing formation is described. The method may include providing a hydrocarbon recovery composition to the hydrocarbon containing formation. Hydrocarbons in the hydrocarbon containing formation may interact with the hydrocarbon recovery composition. The hydrocarbon recovery composition may include an aliphatic anionic surfactant and an aliphatic nonionic additive. In some embodiments, an aliphatic anionic surfactant may be branched. In other embodiments, an aliphatic nonionic additive may be branched.

Abstract: Pollutants are extracted from sub-surface water using an aqueous solution of cyclodextrin and a vertical circulating well. Complexes of the pollutant and cyclodextrin are recovered from the bottom of the well. When the pollutant is volatile, the complexes are separated into pollutant and cyclodextrin by air stripping.

Abstract: A method for evaluating the permeability and formation damage in the porous rock around a well bore. This method relates to the use of a single string coiled tubing and a down hole assembly which includes a microcontroller, an electrically operable fluid control valve and electrically operable pressure sensing devices which allow for real time pressure transient analysis techniques before, during and after formation stimulation treatments.

Abstract: A formation treatment tool assembly is conveyed within a well casing by a tubing string and has a housing defining treatment fluid supply and discharge passages and a fluid injection port through which treatment fluid is directed from the supply passage into a packer isolated casing interval and a fluid inlet port permitting flow from the isolated casing interval to the fluid discharge passage. Spaced straddle packer elements of the tool are energized to establish sealing engagement with the well casing and define an isolated casing interval and are de-energized to retract from sealing engagement with the well casing and permit tubing conveyance. A dump valve connected with the tool housing is opened to permit flow of treatment fluid from the isolated casing interval through the treatment fluid discharge passage and is closed to confine treatment fluid to the isolated casing interval.

Abstract: Methods of completing unconsolidated hydrocarbon producing zones penetrated by cased and cemented well bores are provided. The methods include the steps of forming spaced openings through the casing and cement and injecting a first hardenable resin composition through the openings into the unconsolidated producing zone adjacent to the well bore. Without waiting for the first hardenable resin composition to harden, a fracturing fluid containing proppant particles coated with a second hardenable resin composition is injected through the openings into the unconsolidated producing zone at a rate and pressure sufficient to fracture the producing zone. The proppant particles coated with the second hardenable resin composition are deposited in the fractures and the first and second hardenable resin compositions are allowed to harden by heat.

Abstract: A method of microbial enhanced oil recovery for recovering oil from an oil-bearing rock formation (13). The method comprises: injecting water containing a source of vitamins, phosphates and an electron acceptor such as nitrate into the formation at first location (10) and allowing anaerobic bacteria, which are either already present in the formation (13) or which are introduced simultaneously to multiply using the oil as their main carbon source. This establishes a biomass layer (16) which acts to dissociate the oil from the rock formation (13). The dissociated oil is removed via an outlet (15).

Abstract: A method and apparatus for improving reservoir communication includes, in one arrangement, causing creation of tunnels in surrounding formation of a well interval, and applying treatment fluid to the tunnels. A local transient underbalance condition is created in the well interval after creation of the tunnels in the formation and application of the treatment fluids.

Abstract: Apparatus and method for explosive and chemical rehabilitation of existing oil wells' perforations and formation, to stimulate oil production therefrom, comprising a combination of detonating cord with a plurality of hardened steel tubes, disposed at predetermined distances thereabout, effectuating a time sequencing of the detonating cord explosions and burn rate. A high-pressure detonator, surrounded by a protective shield, which absorbs the explosive power of the detonator while preserving its desired release of kinetic energy, is used to ignite the detonating cord. An external plastic tube, adjacent to the detonating cord, is filled with oil well production enhancing chemicals such as acid etchers or paraffin dispersants, wherein upon ignition of the detonating cord, the chemicals are explosively propelled through perforations into the formation thereabout, to stimulate and chemically react therewith. A Sample basket and weight are mounted to the bottom of the apparatus. A 0.

Abstract: The invention provides a method for the treatment of a hydrocarbon well which method comprises administering down said well polymeric particles having covalently bound to a polymeric component thereof a well treatment chemical or a precursor thereof, said particles containing covalent bonds scissile in an aqueous environment to release or expose said chemical or precursor.

Abstract: Methods of uniformly introducing aqueous treating fluids into subterranean producing zones are provided. The methods are basically comprised of the steps of packing perforation tunnels in the producing zone with a particulate solid anhydrous borate material which degrades and dissolves in water over time. A treating fluid is then introduced into the subterranean zone by way of the packed perforation tunnels whereby the treating fluid uniformly flows into the producing zone. The particulate solid anhydrous borate material in the perforation tunnels is allowed to degrade and dissolve in an aqueous fluid in contact therewith so that the aqueous fluid and produced formation fluids freely flow into the well bore.

Abstract: Compositions comprising a base fluid and a monoester copolymer of styrene and maleic anhydride are disclosed. The compositions can further comprise an alkyl orthophosphate ester. The base fluid can be an aqueous or organic base fluid. The monoester copolymer is at least partially soluble or dispersible in the base fluid. Preferably, the composition may further include a cross-linking agent capable of increasing the viscosity of the composition, such as aluminum isopropoxide or other metal source compounds. The composition can form a gel which is stable at a temperature of about 250° F. (121° C.) or higher. Some gels of the present invention exhibit stability up to about 300° F. (149° C.) to 350° F. (177° C.) or higher. The compositions have many applications, such as pipeline treatment, conformance, hydraulic fracturing, well completion, gravel packing, drilling fluids, process facility treatment fluids, and other well treatment applications.

Abstract: An acidizing composition and a method of acidizing a hydrocarbon bearing subterranean formation in the presence of ferric ions are provided. The acidizing composition includes a strong mineral acid solution, an electron donor agent, a primary electron transfer agent and a secondary electron transfer agent. The primary electron transfer agent is a source of rhenium ions. The secondary electron transfer agent is a source of iodide ion or iodine. The electron donor agent and primary and secondary electron transfer agents function together to reduce ferric ion present in the mineral acid solution to ferrous ion which in turn prevents ferric hydroxide and/or free sulfur from precipitating out of the solution and reduces the formation of sludge in crude oil in the formation. The particular electron transfer agents used in connection with the invention function with virtually all known electron donor agents.

Abstract: Apparatus and methods are disclosed for sequentially treating multiple zones in underground formation in a single trip of the well treatment work string. In the one embodiment, the work string includes composite tubing having electrical conductors embedded within the walls, the conductors enabling power transmission and two way communication between the surface and the sensor or detectors downhole so that real time data can be sensed and communicated. Isolation packers are actuated via electrical signals from the surface communicated to the bottom hole assembly via the conductors. A detector located in the bottom hole assembly may be provided to detect perforations or other anomalies in the casing, such as joints, enabling the surface controller to position packers properly in blank segments of casing so that well intervals can be properly isolated and the adjacent formation effectively treated.

Abstract: An acidizing composition and a method of acidizing a hydrocarbon bearing subterranean formation in the presence of ferric ions are provided. The acidizing composition includes a mineral acid solution, an electron donor agent, a primary electron transfer agent and a secondary electron transfer agent. The primary electron transfer agent is a source of vanadium ions. The secondary electron transfer agent is a source of iodide ion or iodine. The electron donor agent and primary and secondary electron transfer agents function together to reduce ferric ion present in the mineral acid solution to ferrous ion which in turn prevents ferric hydroxide and/or free sulfur from precipitating out of the solution and reduces the formation of sludge in crude oil in the formation.