Abstract: Mesophase fluids may be pre-formed or formed in situ and may be used downhole for various treatments including, but not limited to, cleaning up and removing non-polar materials from reservoir production zones, removing wellbore damage, releasing stuck pipe, components in spacers and pills and the like in oil and gas wells. These treatments involve solubilization of the non-polar material into the emulsion when the treatment fluid contacts non-polar materials. These mesophase fluids use extended chain surfactants having propoxylated/ethoxylated spacer arms. The extended chain surfactants are intramolecular mixtures containing hydrophilic and lipophilic portions. They attain high solubilization in the mesophase fluids (e.g. single phase microemulsions), are in some instances insensitive to temperature and are useful for a wide variety of oil types.

Abstract: A debris cleanup tool uses a movable eductor to reconfigure the flow scheme through the tool. During the debris pickup mode, pressurized fluid is delivered to through the tubing to the eductor inlet. The outlet of the eductor is into the surrounding annulus where the flow splits with most going to the surface and the rest down and into a mill making cuttings. The flow into the mill takes the cuttings to a collection volume and then screens the internal flow stream before directing it into the eductor inlet. The eductor body can be repositioned to close the eductor outlet to the annulus and open the outlet into the housing to allow reverse flow. In one embodiment a ball is dropped and pressure is built to break a shear pin to shift the eductor body and to open a bypass around the ball.

Abstract: A method of cleaning a wellbore drilled with a drilling fluid that forms a filter cake that includes emplacing a breaker fluid into the wellbore, the breaker fluid comprising: an aqueous fluid; a fragmentation agent; and an amphoteric chemotrope; and shutting in the well for a period of time sufficient to initiate breaking of the filter cake is disclosed.

Abstract: Of the many methods and compositions provided herein, in one embodiment, the invention provides a method comprising: providing an oil-wet well bore surface; providing a surfactant wash treatment fluid that comprises an acid-compatible surfactant, an acid and/or an acid-generating component, and an aqueous fluid; contacting the oil-wet well bore surface with the surfactant wash treatment fluid; allowing the oil-wet well bore surface to become water-wet; and producing fluids from the formation. In another embodiment, the invention provides a surfactant wash treatment fluid for use in a subterranean formation comprising an aqueous fluid, an acid-compatible surfactant, an acid and/or an acid-generating component.

Abstract: Single-phase microemulsions (SPMEs) and in situ-formed microemulsions in water-wetting pills may be used to reverse the wettability of subterranean rock previously drilled with an oil-based mud or synthetic-based mud before pumping a high fluid loss squeeze pill or crosslink pill or other water-based pill. This wettability reversal occurs by solubilization of the non-polar material into the microemulsion when the water-wetting pill contacts the non-polar material. An in situ microemulsion may be formed when one or more surfactant and a polar phase (e.g. water or brine), and eventually some amount of organic phase, contacts the reservoir formation and reverses the wettability encountered in the porous media. The microemulsions are effective for reversing the wettability that occurs from non-polar materials which include, but are not necessarily limited to, oil-based mud, synthetic-based mud, paraffins, asphaltenes, emulsions, slugs, and combinations thereof.

Abstract: A method and system for cleaning the perforations of well casings employs a non-rotating tubing string attached to a hydraulic jet carrier body. The carrier body has outwardly extending arms which terminate in spray nozzles, each of the nozzles expelling a stream of fluid under pressure against the well casing with an inertial force. The nozzles are oriented on the carrier body such that the reactive force for each jet is directionally offset with respect to the central axis of the carrier, thereby creating a twisting moment tending to rotate the carrier body about its central axis. The nozzles are located a fixed distance from the carrier body which is between about ½ and 1½ inches from the well casing perforations in use.

Abstract: A method of removing debris from a well is disclosed, comprising RIH to required depth with coiled tubing having at least one closed check valve, moving a sleeve through the check valve to hold it open, opening a flow control valve located on the coiled tubing below the check valve; then reverse circulating a fluid to entrain debris in the wellbore and bring it to surface through the coiled tubing, before releasing the sleeve from the check valve; and POOH with the at least one check valve returned to the closed configuration. By holding the check valves open, reverse circulation can be performed in the well using coiled tubing, so sufficient lift can be achieved to bring the debris to surface even in underbalanced or low pressure wells. Safety measures can be maintained by having at least one check valve in the conventional closed configuration on RIH and POOH.

Abstract: The current application discloses a method of removing debris from a wellbore including contacting debris in a wellbore with a treatment fluid, wherein the fluid contains degradable fibers, collecting at least a portion of the treatment fluid, and allowing the degradable fibers to degrade. The current application also discloses a method of removing debris from a wellbore including contacting debris in a wellbore with a treatment fluid, wherein the fluid contains degradable fibers, collecting the treatment fluid, and exposing the fluid to a composition to encourage the degradable fibers to degrade.

Abstract: The method of displacing fluids in the annulus between pressurized casing strings inside an active oil or gas well by providing a controlled turndown insert and guides then inserting and retrieving a flexible hose without it folding or buckling while being pushed or pulled through a wellhead system orifice with relatively sharp edges at the annulus opening where the hose must make a 90 degree turn from horizontal to vertical within a short radius without cutting, crimping or tearing the hose then seating and holding the hose while fluids are injected, all the while providing protection against well blow out or other pressure problems.

Abstract: Purging of fiber optic conduits in subterranean wells. A downhole optical sensing system includes an optical line, at least two tubular conduits, one conduit being positioned within the other conduit, and the optical line being positioned within at least one of the conduits, and a purging medium flowed in one direction through one conduit, and flowed in an opposite direction between the conduits. A method of purging a downhole optical sensing system includes the steps of: installing at least two conduits and an optical line in a well as part of the sensing system, one conduit being positioned within the other conduit, and the optical line being positioned within at least one of the conduits; and flowing a purging medium through the conduits in the well, so that the purging medium flows in one direction through one conduit and in an opposite direction between the conduits.

Abstract: A composition comprising a nonionic fluorinated polymeric surfactant having a weight average molecular weight of least 100,000 grams per mole, the nonionic fluorinated polymeric surfactant comprising: divalent units independently represented by formula (I): in a range from 30% to 65% by weight, based on the total weight of the nonionic fluorinated polymeric surfactant; and divalent units independently represented by formula (II): in a range from 70% to 35% by weight, based on the total weight of the nonionic fluorinated polymeric surfactant. Rf is a perfluoroalkyl group having from 3 to 4 carbon atoms; R and R2 are each independently hydrogen or alkyl of 1 to 4 carbon atoms; R1 is alkyl of 16 to 24 carbon atoms; and n is an integer from 2 to 11. Foams comprising the nonionic fluorinated polymeric surfactant and a liquid hydrocarbon and methods of making and using the foams are also disclosed.

Abstract: An apparatus and method for drawing down a fluid level in a well bore. The apparatus and method includes a first tubular disposed within the well bore forming a well bore annulus therein, an annular nozzle connected to an end of the first tubular, and a second tubular concentrically disposed within the first tubular forming a micro annulus. The annular nozzle includes an annular adapter and a suction tube having an internal section and an external section with an outer diameter less than the outer diameter of the first tubular. The external section of the suction tube may be positioned within a restricted section of the well bore, for example, within a restricted well bore section containing a casing liner to drawn down the fluids and solids within the well bore to produce hydrocarbons.

Abstract: A method and system for cleaning the perforations of well casings employs a non-rotating tubing string attached to a hydraulic jet carrier body. The carrier body has outwardly extending arms which terminate in spray nozzles, each of the nozzles expelling a stream of fluid under pressure against the well casing with an inertial force. The nozzles are oriented on the carrier body such that the reactive force for each jet is directionally offset with respect to the central axis of the carrier, thereby creating a twisting moment tending to rotate the carrier body about its central axis. The nozzles are located a fixed distance from the carrier body which is between about ½ and 1½ inches from the well casing perforations in use.

Abstract: Nanoemulsion, macroemulsions, miniemulsions, microemulsion systems with excess oil or water or both (Winsor I, II or III phase behavior) or single phase microemulsions (Winsor IV) improve the removal of filter cakes formed during hydrocarbon reservoir wellbore drilling with OBM. The macroemulsion, nanoemulsion, miniemulsion, microemulsion systems with excess oil or water or both or single phase microemulsion removes oil and solids from the deposited filter cake. In one non-limiting embodiment, the emulsion system (e.g. single phase microemulsion, nanoemulsion, or other emulsions) may be formed in situ (downhole) rather than produced or prepared in advance and pumped downhole. Skin damage removal from internal and external filter cake deposition can be reduced.

Abstract: Single phase microemulsions (SPMEs) and in situ-formed microemulsions may be used to clean up and remove non-polar materials from reservoir production zones of oil and gas wells. This clean up occurs by solubilization of the non-polar material into the microemulsion when the treatment fluid contacts the non-polar material. An in situ microemulsion may be formed when one or more surfactant and a polar phase (e.g. water or brine), and eventually some small amount of organic phase, contacts the reservoir formation and solubilizes the non-polar material encountered in the porous media. The microemulsions are effective for removing the formation damage caused by non-polar materials which include, but are not necessarily limited to oil-based mud, synthetic-based mud, paraffins, asphaltenes, emulsions, slugs, and combinations thereof.

Abstract: The present invention provides a conveyance tool and a tool string having one or more sensors or cameras for detecting the performance of pre-existing perforations in a cased wellbore, and one or more perforation intervention tools mounted on the tool string and capable of performing remedial actions directed at most one perforation and its nearest neighbors or at a single perforation.

Abstract: A method for drilling a well with a drilling apparatus comprising a drill string and a bit, comprising attaching a cleaning tool comprising a coaxial pipe and at least one vortex spinner to a portion of the drill string above the bit, inserting the drill string into a wellbore, extending the wellbore while simultaneously pumping fluid through the cleaning tool to create a fluid flow, and loosening debris attached to the wellbore.

Abstract: An efficient truck-mounted injection system for injecting a combined aqueous or hydrocarbon-based liquid stream and a liquid carbon dioxide stream via a well into a subterranean formation.

Abstract: Disclosed herein is a safety valve with a chemical injection configuration. The device includes a hydraulic fluid pressure operated piston at the housing. The device further includes a flow tube in operable communication with the piston and a chemical injection configuration disposed within the housing. Further disclosed herein is a method of maintaining the operation of a safety valve by injecting chemical fluid through a configuration within the safety valve. Still further disclosed herein is check valve. The check valve includes a seal, a dart having a closed head and sealable against the seal, one or more flutes on the dart, and a spring applying a biasing force to the dart to a sealing position, that force being overcomeable by a fluid pressure acting in a direction opposing the spring force.

Abstract: The invention relates to cleaning wellbores and the near wellbore areas adjacent to a hydrocarbon bearing formations and coal bed methane formations. In a particular aspect, the invention relates to removing liquids such as water and/or oil from the formation near the wellbore. The cleaning and liquid removal is accomplished with liquid carbon dioxide or a treatment medium that includes liquid carbon dioxide. The treatment medium is injected into the wellbore through tubing in a controlled manner so that the treatment medium enters the formation in a liquid state, although a portion may be allowed to vaporize upon introduction into the wellbore. The treatment medium is then allowed to vaporize and loosen and entrain undesirable materials from the formation and from within the wellbore or casing, and mobilize water and oil present by effervescing and by dissolving.

Abstract: A scale removal tool with adjustably positionable fluid dispensing arms. The scale removal tool may be configured for delivery to within a hydrocarbon well via coiled tubing. Thus, fluid may be driven through the coiled tubing and through the tool at the fluid dispensing arms. The fluid may thereby be jetted at high pressure toward scale at the wall of the well in order to achieve its removal. In the case of a well having scale of varying thicknesses, the fluid dispensing arms may be dynamically positioned and repositioned while downhole in the well, depending on scale thickness.

Abstract: A device for use in retrieving debris from a well, including an elongate body; a main bore extending part way along a length of the body; an opening towards a lower end of the body; a main fluid chamber in the body in fluid communication with the main bore; a flow restriction provided in the main bore, through which fluid flows from the main bore and into the main fluid chamber; at least one chamber outlet for directing fluid from the main fluid chamber into an annulus defined between the device and a well borehole wall; a return flow passage extending between the body opening and the main fluid chamber, for return flow of fluid from the annulus to the main fluid chamber, to facilitate retrieval of debris from the well; and at least one fluid exit, for flow of fluid out of the device.

Abstract: There is provided an apparatus (100) for use in top filling of tubulars, the apparatus (100) comprising an inlet (200) for fluid communication with a top drive for providing top filling fluid, and an outlet (300) for fluid communication with a tubular, wherein the apparatus (100) comprises a filter configuration (120), in fluid communication with the inlet (200) and the outlet (300) and configured to remove debris from a top filling fluid flow flowing from the inlet (200) to the outlet (300) during top filling of a tubular.

Abstract: An enclosed circulation tool for a well including a tubular body having a top end, a bottom end and an interior cavity. A progressive cavity pump positioned at the bottom end of the body, the pump having a rotor mounted within a stator. The rotor has an upper end and a lower end, with the upper end extending into the interior cavity. A drive is coupled to and adapted to rotate the rotor in order to draw sand into the interior cavity. A first fluid passage is provided along which fluids from pumped from surface pass to fluidize solids within the interior cavity. A second fluid passage is provided along which fluidized solids from within the interior cavity pass to surface.

Abstract: A method of top-filling a drill pipe string comprises injecting fluid into the upper end of the string. Apparatus for use in top-filling a drill pipe string comprises an injector adapted to co-operate with the upper end of a drill pipe string, whereby fluid may be pumped through the injector and into the string.

Abstract: A method of servicing a wellbore is provided. The method comprises running a toolstring into a wellbore to a first depth, actuating a controllably rotating sub-assembly of the toolstring to rotate, and activating a pressure activated bendable sub-assembly of the toolstring to bend, wherein actuating the controllably rotating sub-assembly to rotate and activating the pressure activate bendable sub-assembly are performed in any sequence or concurrently. The method also comprises running the toolstring into the wellbore beyond the first depth and stabbing the toolstring into a window in a wall of the wellbore to enter a lateral wellbore, wherein no whipstock is used to facilitate stabbing into the window. The method further includes running the toolstring into the lateral wellbore and performing a wellbore servicing operation in the lateral wellbore.

Abstract: Methods and apparatus for forming a fluid for use within in a subterranean formation including combining a partitioning agent and viscosifying polymer into a fluid, introducing the fluid into the subterranean formation, and recovering at least a portion of the fluid at a uppermost surface of the subterranean formation. Methods and apparatus of forming a fluid for use within in a subterranean formation including combining a partitioning agent and viscosifying polymer into a fluid, introducing the fluid into the subterranean formation at a temperature of about 45° C. or higher, and recovering at least a portion of the fluid at a uppermost surface of the subterranean formation at a temperature of about 45° C. or lower.

Abstract: A method of acidizing and cleaning up a formation is disclosed, the formation being above 150 degrees C. The formation is treated with a mutual solvent system comprising a mutual solvent of oil and water, an aqueous acid, a corrosion inhibitor, and an iron control agent. In some embodiments, the iron control agent is present in an amount of less than 1% by weight of the mutual solvent system. In some embodiments, the corrosion inhibitor may be present in an amount of less than 10% by weight of the mutual solvent system. In some embodiments, the mutual solvent system further comprises an intensifier.

Abstract: Disclosed is an improved process for removing heavy oil, bitumen and/or paraffinic materials in oil production or storage wells including onshore and offshore petroleum wells, petroleum residual disposal wells and Steam Assisted Gravity Drainage (SAGD) or Cyclic Steam Stimulation (CSS) producing wells used in the oil sands industry. This process helps restore the operating efficiency of organically contaminated hydrocarbon producing wells in a safe, fast and effective manner without the need to insert any equipment to mechanically remove organic contaminants. Used is a heated terpene-based chemical injected with or without steam following a hot water or steam pre-heat to create a very effective cleaning process.

Abstract: A method of treating a subterranean formation penetrated by a wellbore of a well having iron-containing components is carried out by introducing a treatment fluid into the wellbore of the well. The treatment fluid is formed from an aqueous solution, a mineral acid, a viscoelastic surfactant gelling agent and corrosion inhibitor system containing at least one of an alkyl, alkenyl, alicyclic or aromatic substituted aliphatic ketone and aliphatic or aromatic aldehyde. The treatment fluid is substantially free of any formic acid or precursor formic acid. In certain embodiments, the corrosion inhibitor system comprises a mixture of at least one of an alkenyl phenone or ?,?-unsaturated aldehyde, an unsaturated ketone or unsaturated aldehyde other than the alkenyl phenone and ?,?-unsaturated aldehyde, a dispersing agent, an extender and an alcohol solvent. A corrosion inhibitor intensifier may also be used in certain embodiments, which may include a mixture of cuprous iodide and cuprous chloride.

Abstract: This invention relates to enhancing hydrocarbon production from a subterranean formation via a well completed with a gravel pack. Gravel packs suffer plugging and damage over time from produced particles and other plugging materials brought into the pack as production continues. This invention relates to a chemical treatment for the gravel pack designed to remove damaging particulate matter from the pack via dissolution or displacement. Damaging material is forced sufficiently far into the producing reservoir to prevent its remigration back into the pack.

Abstract: The invention provides a method for perforating a well with a perforating fluid comprising a viscoelastic surfactant that essentially stops fluid leak-off after perforation in an overbalanced condition. Another aspect of the invention provides the perforating fluid in itself. The well has a wellbore defined by a generally cylindrical casing in at least a portion of the wellbore (i.e., the wellbore is cased, although it is not necessary cased in its entire length). The wellbore passes through a subterranean formation that comprises hydrocarbon formation fluids (such as oil and/or gas), at least in certain strata. The method comprises placing a perforating device in a wellbore which includes at least one explosive perforating charge that can be detonated in order to perforate the casing and allow the formation fluids to enter the wellbore. The casing is located between the subterranean formation and the perforating device.

Abstract: Methods for cleaning out horizontal wellbores using coiled tubing are provided for use during downhole operations. A coiled tubing having a bottom hole assembly is deployed into a horizontal wellbore. Fluid is circulated down the annulus of the wellbore and up the bottom hole assembly while the bottom hole assembly is moved upward at a selected rate and distance. This method may be used to remove downhole solids, such as formation sands and proppant.

Abstract: Embodiments of this invention relate to a method of removing debris from a wellbore including contacting debris in a wellbore with a treatment fluid, wherein the fluid contains degradable fibers, collecting at least a portion of the treatment fluid, and allowing the degradable fibers to degrade. Embodiments of this invention also relate to a method of removing debris from a wellbore including contacting debris in a wellbore with a treatment fluid, wherein the fluid contains degradable fibers, collecting the treatment fluid, and exposing the fluid to a composition to encourage the degradable fibers to degrade.

Abstract: Subterranean formation treatment methods incorporating a rheology model which enables prediction of fluid rheology properties during a treatment operation, where the foundation of the model is a description of the reaction chemistry which describes how the number of crosslinks and broken polymer linkages develops in time under the influence of crosslinkers, breakers, and/or thermally induced effects and pressure effects. In one aspect, when used as a tool for simulating the fluid viscosity, the model can help optimizing the fluid design and optional breaker schedule for a hydraulic fracturing treatment.

Abstract: Methods and compositions including a method comprising: providing a treatment fluid comprising a carrier fluid and a solid particle comprising a crosslinked aliphatic polyester; and placing the treatment fluid into a subterranean formation.

Abstract: A water based drilling fluid contains as additive one or more alkyl ethoxylates having the formula RO(CH2CH2O)nH; wherein: R is a C16-22alkyl group (preferably R is aliphatic and more preferably R is linear), and n is an integer in the range 2-30. The fluid further contains one or more viscosifying agents, and is substantially clay-free.

Abstract: The present invention relates to a method for cleaning and possibly sealing a subsurface well. According to the method a multichannel tool string comprising an adapter on a first end of the tool string, a guide device at the second end of the tool string are run into the well, whereupon the guide device is activated in order to permit the well to be flushed by the supply of fluid through at least one of the channels in connection with the tool string and fluids and particles from the well are transported back to the surface through at least one other of the channels in connection with the tool string. The invention also relates to a device for cleaning and possibly sealing a subsurface well.

Abstract: A jet bushing for a wellbore cleanup tool features a jet looking uphole to reduce turbulence at the outlet ports that look downhole to accommodate the recirculation flow around the tool that captures the cuttings. The uphole oriented port keeps the pumped fluid downhole from having to make a u-turn to get back uphole and reduces turbulence to allow a higher recirculation flow at the tool to pick up and capture cuttings within the tool.

Abstract: Methods for treating wellbores using fluids containing a sphingan heteropolysaccharide which contributes viscosity stability and a decrease in friction pressure. Some methods are clean-out operations using recyclable-viscosity fluids containing at least a sphingan heteropolysaccharide and an optional salt. Others include methods of pumping fluids incorporating sphingan heteropolysaccharides to reduce pumping frictional pressure.

Abstract: A wellbore servicing apparatus, comprising a housing comprising a plurality of housing ports, a sleeve being movable with respect to the housing, the sleeve comprising a plurality of sleeve ports to selectively provide a fluid flow path between the plurality of housing ports and the plurality of sleeve ports, and a sacrificial nozzle in fluid communication with at least one of the plurality of the housing ports and the plurality of sleeve ports. A method of servicing a wellbore, comprising placing a stimulation assembly in the wellbore, the stimulation assembly comprising a housing comprising a plurality of housing ports, a selectively adjustable sleeve comprising a plurality of sleeve ports, and a sacrificial nozzle in fluid communication with one of the plurality of the housing ports and the plurality of sleeve ports, the sacrificial nozzle comprising an aperture, a fluid interface, and a housing interface.

Abstract: A completion method isolates a lower zone while circulation at high rates takes place above to clean debris out of the wellbore. Pressure fluctuation sensitive equipment in a lower completion is isolated with a tubing valve during circulation. This further prevents debris from clogging inlet pressure passages to equipment below the isolation valve during circulation to get the debris out. After circulation the packer is unset and the tubing valve is opened and a wellbore filter tool directs well fluids through a screen and captures the debris as the string is pulled toward the surface.

Abstract: An apparatus that is usable with a well includes a tool and a shroud. The tool is to be disposed in a wellbore and includes an opening to inject fluid into the well. The shroud at least partially surrounds the tool to eccentrically dispose the tool with respect to a longitudinal axis of the wellbore.

Abstract: Of the many compositions and methods provided herein, an example method includes a method of treating a subterranean formation that comprises combining components comprising water and a density-matched suspension to prepare a treatment fluid, wherein the density-matched suspension comprises a suspending liquid and a solid particle suspended in the suspending liquid, and introducing the treatment fluid into a well bore. An example composition includes a suspension that comprises a suspending liquid comprising a hydrophobic liquid, wherein the hydrophobic liquid hydrolyzes when placed in contact with an aqueous fluid to form hydrophilic products, and a solid particle suspended in the suspending liquid, wherein the suspension is a density-matched suspension.

Abstract: A wellbore cleaning tool having a plurality of fluid jets arranged on one side of a tool body and brushes or other implements for applying an abrasion force arranged on a second side of the tool body. In operation, the fluid jets, when turned on, bias the tool body and the supported brushes toward the casing wall with a resilient jet-biasing effect. Furthermore, the tool body is intended to be rotated. Thereby, the resilient jet-biasing effect rotates accordingly so that the brushes remain biased toward the casing wall during rotation.

Abstract: Methods for cleaning out horizontal wellbores using coiled tubing are provided for use during downhole operations. A coiled tubing having a bottom hole assembly is deployed into a horizontal wellbore. Fluid is circulated down the annulus of the wellbore and up the bottom hole assembly while the bottom hole assembly is moved upward at a selected rate and distance. This method may be used to remove downhole solids, such as formation sands and proppant.

Abstract: A method for the controlled de-functionalization of downhole polymers comprising contacting downhole, water-dispersible, polymeric material with a dehydrating agent until the water-dispersible polymeric material is sufficiently de-functionalized to be removed. The water-dispersible polymeric material can be found in the downhole formation of a filtercake on production walls, other downhole polysaccharide materials and in fluid loss pills. The contact between the dehydrating agent and the polymeric material is prolonged until the water-dispersible, polymeric material is sufficiently de-functionalized to allow the de-functionalized material to be removed by flushing the drilling fluid. The dehydrating agent is selected from concentrated inorganic salt solutions, concentrated organic salt solutions, acid anhydrides, esters, alcohols, ethers, ketones, aldehydes, amides, organic acids and mixtures thereof.

Abstract: The permeability of a subterranean formation is improved by introducing into the formation a water-in-oil emulsion. Unwanted particulates deposited in the formation during the production of oil are dissolved or loosened by the outer phase of the emulsion and dispersed in the aqueous phase.

Abstract: A treatment fluid and a method are disclosed for cleaning borehole filtercake using the treatment fluid, wherein the filtercake contains reservoir drilling fluid (RDF) solids. The method includes pumping the treatment fluid downhole in contact with the filtercake to be removed to establish a differential pressure between the treatment fluid and the formation adjacent the filtercake, and evenly propagating treatment of the filtercake during the differential pressure period to delay breakthrough by the treatment fluid for a period from 1 to 12 hours. The treatment fluid comprises a fluoride source providing a 1.2 to 5 molar fluoride concentration, and another acid or combination of acids to provide a pH between 1.8 and 5. The treatment fluid is balanced for a dissolving power high enough to have significant dissolution of the filtercake, but low enough for even propagation to avoid premature leak-off.

Abstract: Method and system for use in a subsurface formation traversed by a wellbore. An energized fluid, which when subjected to a low pressure environment liberates or releases gas from solution, is disposed in the formation. Reduced pressure in a region of the wellbore below pressure in the surrounding formation liberates a gas in the energized fluid near a tunnel created in the formation.