Fluid for treatment by non-symmetrical peroxide diluting agent and method

FIELD: oil and gas production.

SUBSTANCE: method of treating underground formation through which goes the bore can be put into practice by forming treatment fluid from hydrated polymer water solution that is mixed with water-soluble, non-symmetric, heretolytically cleaved, nonorganic peroxide diluting agent and the fluid if injected into formation.

EFFECT: increasing the treatment efficiency.

14 cl, 5 ex, 4 dwg

 

The technical field to which the invention relates

The present invention relates to a fluid processing intended for use in the treatment of subterranean formations. In particular, the invention relates to a fluid to be processed, having increased viscosity, as well as to compositions and methods for liquefaction of such fluids.

The level of technology

The provisions of this section only provides introductory information regarding the present description, and may not constitute prior art.

Carbohydrate polymers, cross stitched by different ions, such as boron, zirconium and titanium, used in the oil and gas industry as a high-viscosity fluids for hydraulic fracturing. Polysaccharides, such as guar gums and derivatives Gurovich resins, usually applied as a fluid-thickeners for water-based hydraulic fracturing and to transport the proppant. The proppant remains in the created hydraulic fracture to keep the fracture open and education of the inlet channel leading from the well into the formation along the length of the crack. After the hydraulic fracture is finally formed, the extraction fluid for fracturing is crucial to accelerate the production of hydrocarbons through the formed channel.

Removing the fluid for fracturing is achieved p is the lowering of the viscosity of the fluid so to the fluid naturally passed through the proppant pack. To break down polymers in order to reduce their viscosity typically use chemical reagents such as oxidizing agents, acids and enzymes. These substances are commonly referred to as "thinners".

Regulation time dilution is an important factor. Premature destruction of the gels can cause settling of proppant from the fluid before reaching a sufficient distance in the created hydraulic fracture and lead to premature loss of proppant. Premature liquefaction can also lead to less than the required width of the hydraulic fracture. On the other hand, too much delay liquefaction of the gel is also undesirable. Slow liquefaction can cause a significant delay in production. These factors, including levels of activity depending on the temperature, the mechanisms delays and insufficient cleaning of the proppant packs dictate a significant challenge in developing an effective system for liquefaction.

The ammonium persulfate or (APS PSA) is one of the most widely used in industry thinners. If used ammonium persulfate, due to thermal decomposition of persulfate ions at the homolytic cleavage of peroxo-bond (O-O) vacant sulfa is by radicals. These free radicals initiate the process of breaking the circuit through interaction with the polymer chain by hydrogen, which leads to the primary splitting due mannose or galactose groups. Educated radicals speed up the process, further breaking down the polymer into fragments of lower molecular weight. This continues until the stop of the reaction, mainly due to the coupling of two radicals.

Although this process at temperatures below 120F (50C) occurs with very low speed, it becomes very rapid above this temperature, especially above 175F (80C). At such high temperatures, the thinner the ammonium persulfate decomposes too quickly, so that it can be effectively used as a thinner in most applications.

Thus, there is a need for a system for liquefaction, which allows to solve these drawbacks with a higher control in a wide temperature range.

The invention

Fluid composition for treatment of a subterranean formation through which the wellbore is formed from an aqueous fluid, Gidrodinamika polymer and water-soluble, single-ended, inorganic peroxide-thinning agent, which is able to undergo heterolytic R is salenew. The composition may further include a crosslinking agent capable of cross-stitching Gidrodinamika polymer. In some embodiments, the implementation of the thinning agent may be selected from at least one of the following compounds: peroxymonosulfate potassium, sodium or ammonium, peroxymonosulfate Tetra-n-butylamine.

Also proposes a method of processing an underground formation through which the wellbore, where the fluid to be processed is formed from an aqueous solution of hydrated polymer. In the fluid composition for treatment included water-soluble, single-ended, generalities split inorganic peroxide-thinning agent. The fluid to be processed is injected into the formation.

BRIEF DESCRIPTION of DRAWINGS

For a more complete understanding of the present invention and its advantages, the following description considered in conjunction with the accompanying figures, in which:

the figure 1 shows a graph of the dependence of viscosity on time gelled polymer solutions containing different amount of thinner on the basis of ammonium persulfate, heated to approximately 125F (51,6C);

the figure 2 shows a plot of viscosity against time gelled polymer solutions containing different amounts of peroxymonosulfate potassium, heated to approximately 150F (6.6C, C);

the figure 3 shows a plot of viscosity against time gelled polymer solutions containing different amounts of peroxymonosulfate Tetra-n-butylamine heated to approximately 175F (79,4C); and

the figure 4 shows a plot of viscosity against time gelled polymer solutions containing different amounts of peroxymonosulfate Tetra-n-butylamine heated to approximately 225F (107.2C).

Detailed description of the invention

First, it should be noted that in the development of any such concrete option implementation must be implemented in numerous practical solutions to achieve the specific goals of the developers, such as system and production constraints, which vary from one application to another. In addition, it should be understood that such developmental work can be long and complicated, but it is a daily practice for the average person skilled in the art to which the present description is applicable.

The description and examples are presented solely for the purpose of explanation of the preferred embodiments of the invention and should not be construed as limiting the scope and applicability of the invention. Although the composition of the present invention, as described in this application include the certain substances, it should be understood that the composition may optionally include two or more chemically different substances. In addition, the composition may also include some components in addition to those already indicated. In the section "summary of the invention" and its detailed description, each numerical value should once be interpreted as modified by the term "approximately" (if not changed), and then consider again how not changed so if the context is not specified. In addition, in the section "summary of the invention" and its detailed description it should be understood that the concentration range listed or described as being useful, suitable, or the like, means that any and every concentration within the range, including limit values, should be considered as stated. For example, range from 1 to 10" should be interpreted as an indication of each possible number within a continuum from approximately 1 to approximately 10. Thus, even if specific data points within the range were directly identified or listed only some of them, or even within the range did not specify any one experimental point, it should be understood that the inventors consider and understand that it is necessary to consider any and all experimental the point within the range as defined and that the authors of the invention have all range and all points within the range.

The present invention relates to the liquefaction of fluids for hydraulic fracturing or increase the viscosity of the fluid is adjustable by means of chemical oxidants with asymmetric O-O bond. Asymmetric O-O connection can be as homolytic and heterolytic cleavage, depending on the reaction conditions. Homolytic cleavage leads to the formation of two different radicals, probably with different half-lives. In particular, the invention is applied inorganic oxidants O-O bonds, which are known to undergo heterolytic cleavage that results in the breakdown of polymers is primarily not by free radical mechanism. Such chemical oxidants may further be referred to as "asymmetric" thinners, thinning agents, oxidizing agents, oxidizing agents, etc. Inorganic oxidizing agents with asymmetric O-O bonds, tend to heterolytic cleavage can be more stable and require higher temperatures to break the oxygen-oxygen due to differences in electronegativity of adjacent atoms. This differs from conventional thinners, such as ammonium persulfate, which is the tsya symmetrical and form the same radicals in the homolytic cleavage. Conventional thinners are less stable and tend to activate at lower temperatures.

Certain inorganic peroxymonosulfate oxidants known for its strong oxidizing activity, as well as their chemoselectivity properties, i.e. they are capable of selective oxidation of organic functional groups. This was due to the fact that they are less exposed to the mechanisms of radical reactions. As percolate, not the peroxides listed peroxymonosulfate compounds with sulfate as the leaving group, are exposed to non-radical, heterolytic cleavage compared with peroxides, where the hydroxide or alkoxide, as expected, is less effective leaving group.

An example of a suitable generalities split peroxymonosulfate thinning agent is peroxymonosulfate potassium, also known as the potassium salt of the acid Caro. Peroxymonosulfate potassium can exist as stable triple salt (2KHSO5KHSO4K2SO4), which is commercially available from E.I. du Pont de Nemours and Company in Wilmington, DE, and sold under the trademark Oxone in the form of an oxidizing composition. Because peroxymonosulfate potassium contains unbalanced Oh regard, it is unlikely that he will is to undergo homolytic cleavage to initiate a radical chain process. Thus, it can act as an efficient donor of one atom of oxygen. Can also be used salts peroxyketal with other alkali metals other than potassium, such as sodium salt. Can also be used ammonium salts.

In some application areas are suitable larger cations than that of a single alkali metal, such as peroxymonosulfate of tetraalkylammonium. Acidic pH peroxymonosulfate potassium may not be suitable for use as an effective thinner in some situations. For example, high pH may be necessary to maintain appropriate high viscosity when using polymers, crosslinked borate, and some fluids, comprising a zirconium cross-linking agents. In addition, galactomannan polymers are generally more stable at high pH, especially at temperatures higher than 80C. Encapsulating thinner or other mechanisms slow release can solve this problem. The need for higher pH, however, can be also solved by the use of tetraalkylammonium salts, such as peroxymonosulfate Tetra-n-butylamine (OTBA), the solution is basic. Other non-limiting examples of suitable salts include tetraalkylammonium peroxymonosulfate Tetra-n-pentylamine, PE is oxymonacanthus Tetra-n-hexylamine.

Although asymmetric inorganic oxidizing agents are preferred in the present invention, in some embodiments, the implementation can also be used for other asymmetric organic oxidants. They can include percolate, for example, peracetic acid or perventing acid, and their derivatives. Some alkylhydroperoxide, such as methylhydroperoxide, except tert-butylhydroperoxide, can also be used in some embodiments of the implementation.

Thinning agent may initially be in a solid or liquid form. If thinning agent is in solid form, it can be crystalline or granular substance. The solid form can be encapsulated or coated with a special coating to delay its release in the fluid. Encapsulated substances and methods encapsulate thinning substances known in the prior art. Such substances and methods can be used for thinning agent of the present invention. Non-limiting examples of substances and methods that can be used to encapsulate described, for example, in U.S. patent No. 4741401, 4919209, 6162766 and 6357527. In the case of use in the form of fluid-thinning salt is usually dissolved in an aqueous solution. Asymmetrical thinners soluble in water, the EU is they have a solubility, at least more than 1 g in 100 g of water at room temperature, as measured using methods iodometric titration. Asymmetrical thinner may have a solubility of 5 g, 10 g or more in 100 g of water.

Unbalanced oxidant can also be used in the presence of metal catalysts. Metal catalysts accelerate the reaction at a given temperature. General classes of catalysts include metalloporphyrins, manganese, copper, iron, cobalt, Nickel, silver, palladium and platinum.

When the hydraulic rupture of an underground reservoir fluids for hydraulic fracturing, which is typically aqueous fluids, can be thickened or transferred into the gel to provide sufficient viscosity to carry or suspending proppant, to prevent the absorption of fluid for fracturing a formation, etc. to give a higher viscosity of aqueous fluids for hydraulic fracturing, the fluid often add a water-soluble or hydratherapie polymers. These hydratherapie polymers typically crosslinked using crosslinking agents to obtain gelatinizing polymer network, which increases the viscosity of the fluid to the required level, although some fracturing fluids contain only linear polymer without the addition of crosslinking agents. In other cases, Association the th thickening reach with the help of suitable polymers and mixtures of surface-active substances.

Asymmetric thinning agent may be used in combination with such gidriruemyi polymers, which can be linear or cross stitched. As described previously, conventional thinners on the basis of persulfate ammonium decay too quickly to be effective for use as a thinner for such polymeric fluids in most applications at temperatures above about 125F (~50C). Asymmetrical thinners can be used in the liquefaction of such thickened fluids in the temperature range from about 125F (~50C) and above, more specifically, from about 125F (~50C) up to approximately 250F (121C). Because of the asymmetric Oh link thinners according to the invention are more stable within a given time gap is required at higher temperatures.

It should be understood that throughout the text of the present description, when the range of the concentration or quantity is described as applicable or suitable, or the like, this means that any and every concentration or amount within the range, including limit values should be considered as stated. In addition, each numerical value should be read once as modified by the term "approximately" (if it has not changed), and then to interpret SN the VA as unchanged as if context is not specified. For example, range from 1 to 10" should be interpreted as an indication of each possible number within a continuum from approximately 1 to approximately 10. In other words, when a specific range is specified, even if specific data points within the range were directly identified or listed only some of them, or even within the range did not specify any one experimental point, it should be understood that the inventors consider and understand that it is necessary to consider any and all data points within the range as defined, and that the authors have mastered the whole range and all points within the range.

Hydratherapie polymers suitable for the present invention can include any hydratherapie polymers, known to experts in the service industry wells as water-soluble. Examples of suitable hydroceramic polymers include, but are not necessarily limited to, guar gums, high-molecular polysaccharides consisting of Manasseh and galactose sugars, or derivatives Gurovich resins, such as hydroxypropanoic (HPG), carboxymethylate (CMG) and carboxyphenoxypropane (CMHPG), galactomannans resin, glucomannan resin, guar gum, derived Gurovich resins and proizvodi the e cellulose. Can also be used such cellulose derivatives as hydroxyethylcellulose (HEC), carboxymethylcellulose (CMC), hydroxypropylcellulose (HPC) and karboksimetiltselljuloza (CMHEC). In addition, there may be used synthetic polymers containing acrylamide, including polyacrylamides, partially hydrolyzed polyacrylamides, copolymers of acrylamide and acrylic acid and copolymers and terpolymers containing acrylamide, vinyl pyrrolidone, AMPS (2-acrylamide-2-methylpropanesulfonic acid), or acrylic acid. An agent that increases the viscosity, can be heteropolysaccharides thickener. Can be used such heteropolysaccharides as xanthan gum, and described in application for U.S. patent US2006/0166836, published on 27 July 2006. Heteropolysaccharide may include polymers that contain in the main polymer chain recurring tetrasaccharide link, as represented by the chemical formula (1):

where in the repeating part there are at least three different saccharide, such sugars include D-glucose, D-glucuronic acid and/or L-rhamnose or L-mannose; M+is ion; R1, R2, R3, R4, R5, R6, R7, R8, R9and R10selected from the group consisting of hydrogen, m is La, acetyl, glyceryl or sacharides group containing from one to three sharidny units; R11is a methyl or methylol group; and srednevekovaja molecular weight (Mw) of heteropolysaccharide ranges from approximately 105to about 107.

Hydratherapy polymer can be added in different concentrations to obtain the necessary viscosity. Can be used in concentrations of about 1% by weight of the total weight of the composition for processing. In some embodiments of the invention hydratherapy polymer may be used in amounts of from about 0.05% to about 0.5% of the total weight of the composition.

The polymers can be crosslinked using any suitable crosslinking agent such as a crosslinking agent based on the metal ion. Examples of such materials include multivalent ions of metals such as boron, aluminum, antimony, zirconium, titanium, etc. that interact with the polymers forming the composition with sufficient and suitable viscosities for specific operations. A crosslinking agent may be added in an amount which leads to a suitable viscosity and stability of the gel at the operating temperature. Typically, cross-linking agents are added in concentrations of from about 5 to about 500 parts per million (the./million) active atomic weight. This concentration may be adjusted based on the concentration of the polymer. A crosslinking agent is preferably added in the form of a solution, and it can include a ligand, which delays the reaction of cross-linking. This delay may be advantageous that the fracturing fluid with a high viscosity is not formed until, while in the bottom hole zone of the well is not minimized pressure losses by friction, and can prevent irreversible mechanical degradation of the gel, as, for example, when using Zr or Ti cross-linking agents. Slow crosslinking can be controlled by time, temperature, or time and temperature, and is crucial for the success of the process of hydraulic fracturing.

Thickener based on the polymer, if included in the composition may have any suitable viscosity. The minimum viscosity may be such that is appropriate for the suspension of proppant in terms of hydraulic fracturing. In some embodiments, the implementation of the viscosity may be from about 50 MPas or greater at a shear rate of about 100 to-1at a temperature of processing, more specifically, about 75 MPas or greater at a shear rate of about 100 to-1and, even more specifically, about 100 MPas or pain is E. As a rule, the maximum viscosity is less than about 1000 MPas, typically less than about 600 MPas at the shear rate of about 100 to-1. Higher viscosities usually try to avoid in order to minimize cost and to promote a better cleaning of the borehole from the fracturing fluid after the crack was closed and the well is in the phase of production.

Asymmetric thinning agent can be used in an amount of from more than 0% to about 1.5% or more by weight of fluid for processing, more specifically, from about 0.002% to about 0.5% by weight of the fluid to be processed. These substances can be used in the form of solids which are soluble in water or can be used in liquid form. Thinning agent and, optionally, a metal catalyst may be used in dry form or in the form of a slurry and added to aqueous fluid on the surface with the already added gidratirutmi polymer or without him. Alternatively, thinner and/or any metal catalyst can be kept in suspension. The catalyst can also be encapsulated. This can be useful when a single thinner effective only at the operating temperature in the presence of a catalyst. By encapsulating the cat who lyst activation thinner can be delayed until while the catalyst will not be freed.

Thinning agent can be suspended in non-aqueous or immiscible environment, such as diesel oil, mineral oil, etc. before mixing with the aqueous fluid and the introduction into the reservoir. The suspension may optionally include suspenders additive, such as hydroxypropylcellulose in glycolamine a solvent such as a glycol. Suspension may slow down the interaction thinning agent with the polymer solution. Thinning agent can be also added in the injection process, in the form of liquid or pre-mixed with water.

As described previously, in some applications the thinning agent can be encapsulated in encapsulating material to slow down the interaction with gelled polymer fluid. The encapsulating material may include grades or materials and polymers, which laboratorii or insoluble in the fluid to be processed.

Retarder thinners can also be added to the fluid to be processed with the purpose of inhibiting or slowing the reaction thinner. Examples of suitable retarders liquefaction may include sodium nitrite (NaNO2), NaNO, sodium thiosulfate (Na2S2O3), triethanolamine and urea. They can be added in amounts from about 0.02% to priblizitel the but of 0.05% by weight of the fluid to be processed. The moderators are especially useful at higher temperatures, for example at 60C or higher when higher temperatures the reaction may be accelerated. Retarder thinners may be encapsulated. In addition, the retarder thinners may be encapsulated together with the thinning agent. Alternatively, the retarder thinners can be entered separately from thinning agent.

Gelled polymer solutions, linear or crosslinked, foamed or nevspahannye, especially useful as a fluid carrier for proppants. The proppants may be such that essentially insoluble in the polymer solution and/or formation fluids. In the operations of hydraulic fracturing proppant particles contained in the composition for the treatment, remain in the crack, keeping, thus, the crack from closing when the pressure of hydraulic fracturing is reset, and the well is put into operation. The proppant can have a particle size of from about 0.15 mm to about 2.5 mm Suitable proppants include, but are not limited to, sand, walnut shells, sintered bauxite, glass beads, ceramic materials, natural materials, or similar materials. Can also be used a mixture of proppant. Suitable examples of natural materials in the form of particles suitable for use in quality is ve proppants, include, but are not necessarily limited to, ground or crushed shells of nuts such as walnut, coconut, walnut, pecans, almonds, phytelephas, Brazil nuts, etc.; chopped or crushed shells (including shells, fruit pits) of seeds of fruits such as plum, olive, peach, cherry, apricot, etc.; crushed or broken husks of the seeds of other plants, such as maize (e.g., cobs or kernels of grain), and so on; processed wood materials such as those derived from wood of such trees as oak, Hickory, walnut, poplar, mahogany, etc. including wood which has been processed by crushing, processing into chips or other grinding method, process, etc.

The proppant concentration in the composition may be any concentration which is suitable to perform a specific desired processing. For example, the proppant can be used in the amount of approximately 3 kilograms per liter of the composition. In addition, any of the particles of the proppant may be coated with resin for the potential increase strength, ability to aggregation and improve the external properties of the proppant.

The fibrous component may be included in compositions according to the invention in order to achieve a variety of properties, including improved suspension of the particles and SP is the ability of the transport of particles, as well as the stability of the foam. Used fibers may be hydrophilic or hydrophobic in nature. Fibers can be any fibrous material, such as, without limitation, natural organic fibers, comminuted plant materials, synthetic polymer fibers (non-limiting examples of which include polyester, polyaramid, polyamide, novoloid or polymer type novoloid), fibrillated synthetic organic fibers, ceramic fibers, inorganic fibers, metal fibers, metal fiber, carbon fiber, glass fiber, ceramic fiber, natural polymer fibers and any mixtures thereof. The most suitable fibers are polyester fibers with a coating, which imparts high hydrophilicity, such as, without limitation, polyethylene terephthalate (PET, PET) fiber DACRONavailable from Invista Corp., Wichita, Kans., USA, 67220. Other examples of suitable fibers include, but are not limited to, polyester fibers, polylactic acid, polyester fibers, polyglycolic acid, fiber, polyvinyl alcohol, etc. In the case of the use in the compositions according to the invention the fibrous component may be included at a concentration of from about 1 to about 15 grams per liter of the composition, more spiral is but the concentration of fibers may be from about 2 to about 12 grams per liter of the composition and, more specifically, from about 2 to about 10 grams per liter of composition.

Also in the fluid processing may be added other additives, which are known to be widely used by specialists in the field of oil production. They may include stabilizers unstable clays, surfactants, stabilizers fluids, oxygen scavengers, alcohols, scale inhibitors, corrosion inhibitors, fluid filter, antibacterial additives, blowing agents, cleaning surfactants, wetting agents, friction reducers, etc.

Compositions according to the invention may be a foamed and activated fluid treatment fluids zone containing "penoobraznaya additives, which may include a surfactant or mixture of surfactants that facilitate the dispersion of gas in the composition with the formation of bubbles or drops and gives the stability of the dispersion, inhibiting coalescence or re-connection of such bubbles or drops. Foam and activated fluids are usually described by their quality foam, i.e. the ratio of gas volume to the volume of the foam. If the quality of the foam is 52-95%, fluid about is commonly referred to as foamed fluid, and if below 52% - activated (fizzy) fluid. Therefore, the composition of the invention may include ingredients that form a foamed or activated fluids, such as, without limitation, foaming surfactant or mixture of surfactants, as well as gas or supercritical fluid, which effectively form a foam or activated fluid. Suitable examples of such gases include carbon dioxide, nitrogen, or any mixtures thereof.

In most cases, the fluids according to the invention used in hydraulic fracturing. Hydraulic fracturing consists of pumping the composition without proppant, or pack in well with such speed that the composition could not be absorbed by the reservoir, causing the pressure increases, and the array breed destroyed with the formation of artificial cracks and/or expansion of existing cracks. Then in the song add particles of proppant, such as described above, to obtain a suspension, which is injected into the gap, preventing its closure, after which the injection is stopped, and the pressure of the fracture is reduced. The proppant suspension and transport ability of the composition fundamentals for treatment usually depends on the viscosity of the fluid. Methods of fracturing a subterranean formation known average specifications the leaves in this area and include the injection of fracturing fluid in the borehole, and from it into the surrounding formation. The fluid pressure exceeds the minimum voltage in the solid rock, which causes the formation or enlargement of fractures in the reservoir. Cm. Stimulation Engineering Handbook, John W. Ely, Pennwell Publishing Co., Tulsa, Okla. (1994), US Pat. No. 5551516 (Normal et al), "Oilfield Applications", Encyclopedia of Polymer Science and Engineering, vol. 10, pp. 328-366 (John Wiley & Sons, Inc. New York, N. Y., 1987), and references cited in these sources.

Fracturing fluid compositions of the present invention can be applied when processing without proppant, proppant stage, or at both stages. The components are mixed on the surface. Alternatively, the composition may be prepared on the surface and injected into the booster tube, while the gas component, such as carbon dioxide or nitrogen, may be injected into the annulus, with mixing in the borehole bottom, or Vice versa, with the formation of foam or the activated fluid composition.

In another embodiment, the composition can be used for gravel packing the wellbore. As compositions for gravel packing composition may contain gravel or sand, as well as other optional additives, such as reagents for washing the filter cover, for example, chelating agents or acids (for example, chloromethane, hydrofluoric, formic, acetic, citric acid), inhibitors corros and, the scale inhibitors, biocides, regulators, filter, etc. For this application use suitable gravel or sand, usually having a particle size corresponding to the size of the holes of the sieve of 0.2 mm (~70 mesh) to 2.4 mm (~8 mesh).

The following examples serve to further illustrate the invention.

EXAMPLES

Peroxymonosulfate potassium, available under the trademark Oxone, and peroxymonosulfate Tetra-n-butylamine or OTBA, tested as thinners for polymer based on the guar resin, crosslinked with boric acid. The activation temperature for Oxonerequired to divide transversely crosslinked guar exceeds 150F (65,6C), according to tests on a water bath and rheological tests. Rheological tests showed that OTBA active at temperatures above 175F (79,4C) and operates best at 200F (93,3C).

In examples 1-4 was used 25-pound base solution (i.e. 25 gel/1000 gallons or 3 kg of gel/1000 l), obtained by hydration of 3.0 g of the guar gum 1.0 l deionized (DI) water using a mixer for 20 minutes. Then 2 ml of 50% by weight aqueous solution of Tetramethylammonium was added as a stabilizer unstable clays. Then the linear fluid was made by adding a certain amount of cross-linking agent containing 0,38 g of boric acid and from 0.76 g of sodium gluconate,followed by slow addition of 30 wt.% the sodium hydroxide solution, increasing the pH to about 11.

In example 5, 40-pound base solution (that is, 40 pounds of gel/1000 gallons or 4.8 kg of gel/1000 l) was obtained by hydration of 4.8 g of the guar gum 1.0 l with DI water using a mixer for 20 minutes, after which the solution was added to 0.2 vol.% 50% by weight aqueous solution of Tetramethylammonium as a stabilizer unstable clays. Then the linear fluid was made by adding a certain amount of cross-linking agent containing 0,57 g of boric acid and 1.14 g of sodium gluconate, followed by slow addition of 30 wt.% the sodium hydroxide solution, raising the pH to approximately 11,5.

To compare the effectiveness of dilution of the sample in 50 ml of crosslinked fluid was heated to a certain temperature in a water bath. Then each sample was added to different reducers. After shaking the sample, with the aim of mixing the contents, the fluids were placed back on a water bath at the specified temperature. Their visually analyzed for liquefaction at intervals of 30 minutes. Clean the sample, which was not added to the thinner, also was placed on a steam bath for comparison.

Rheological parameters were measured using a viscometer Grace M5500, available from Grace Instrument, using the rotor 1 and the load 5. This model 50 viscometer meets the requirements of ISO 13503-1 "Measure the viscous properties of fluids for drilling". Viscosity values are given for a shear rate of 100 s-1.

Example 1

The test was conducted using ammonium persulfate and peroxymonosulfate potassium, available under the trademark Oxone, tests on a water bath held at 125F (51,6C) for 1.5 h, showed that the ammonium persulfate at a concentration of 0.12 wt.% fully Raziel fluid at the same temperature, whereas the fluid, which contained 0.12 wt.% Oxonedid not split and remained very viscous.

Example 2 (comparative)

As a comparison of the rheological study was performed using a solution of the guar crosslinked resin, without thinner and thinner (ammonium persulfate) in various concentrations: 0,012%, 0,024% and 0.06% by weight. As can be seen in figure 1, the ammonium persulfate was caused by oxidation of the fluid and the viscosity reduction at a temperature of approximately 125F (51,6C).

Example 3

Rheological studies were performed on solutions of the guar crosslinked resin without the use of thinner and using peroxymonosulfate potassium, available under the trademark Oxonein various concentrations: 0,09% and 0.18% by weight. As can be seen in figure 2, Oxone at both concentrations was caused by the oxidation of the fluid at a temperature of approximately 150F (56,6C).

Example 4

Rheological studies were performed on custom made solutions without the sing thinner and using peroxymonosulfate Tetra-n-butylamine (OTBA) in various concentrations: 0.03%, the of 0.09% and 0.18% by weight. As can be seen in figure 3, OTBA in both concentrations caused oxidation of the fluid at a temperature of approximately 175F (79,4C).

Example 5

Rheological studies were performed on custom made solutions without the use of thinner and using peroxymonosulfate Tetra-n-butylamine (OTBA) in various concentrations: 0,06%, of 0.12% and 0.24% by weight. The solutions were heated to a temperature of approximately 225F (107.2C). The results are shown in figure 4.

Although the invention has been shown only in some of its forms, specialist, skilled in the art, it will be obvious that the invention is not limited to this, and allows various changes and modifications without departure from the scope of the invention. Thus, the attached formula should be interpreted widely and is compatible with the scope of the invention.

1. The method of processing an underground formation through which a borehole, comprising receiving fluid to be processed, formed from an aqueous solution of hydrated polymer;
combining water-soluble, single-ended, generalities split inorganic peroxide-thinning agent with the fluid to be processed and the introduction of the fluid to be processed in a reservoir.

2. The method according to claim 1, where the fluid to be processed is formed from an aqueous solution gidratirovana is about the stitching of the polymer and crosslinking agent, capable of crosslinking of the polymer.

3. The method according to claim 1, where the peroxide-thinning agent is selected from at least one of the following compounds: peroxymonosulfate potassium, sodium or ammonium and peroxymonosulfate Tetra-n-alkylamine.

4. The method according to claim 1, additionally comprising combining a metal catalyst with the fluid to be processed.

5. The method according to claim 1, where the polymer is selected from polysaccharides, galactomannans, guar Gurovich resins, Gurovich derivatives, cellulose and cellulose derivatives, polyacrylamides, partially hydrolyzed polyacrylamides, copolymers of acrylamide and acrylic acid, terpolymers containing acrylamide, vinyl pyrrolidone, 2-acrylamide-2-methylpropanesulfonic acid, and heteropolysaccharides containing tetrasaccharide duplicate link in the main chain of the polymer represented by the chemical formula:

where in the repeating part there are at least three different saccharide, such sugars include D-glucose, D-glucuronic acid and/or L-rhamnose or L-mannose; M+denotes ion; R1, R2, R3, R4, R5, R6, R7, R8, R9and R10selected from the group consisting of hydrogen, methyl, acetyl, glyceryl or sacharides group containing from one to three sharidny units; R is a methyl or methylol group; and srednevekovaja molecular weight (Mw) of heteropolysaccharide ranges from approximately 105to about 107.

6. The method according to claim 1, where the peroxide-thinning agent is peroxymonosulfate.

7. The method according to claim 1, where the input fluid processing layer includes introducing a fluid to be processed in a part of the reservoir with a temperature of from about 50to about 125C.

8. The method according to claim 1, where the fluid to be processed is injected at a pressure above the fracture pressure.

9. The method according to claim 1, where the peroxide-thinning agent is combined with the fluid to be processed in the amount of from more than 0% to about 1.5% by weight of the fluid to be processed.

10. The method according to claim 1, where the peroxide-thinning agent is at least one of the encapsulated or contained in suspension agents.

11. The method according to claim 10, further comprising merging retarder thinners with the fluid to be processed.

12. The method according to claim 1, where the fluid is foamed or activated fluid.

13. The method according to claim 10, where the fluid includes a retarder thinners.

14. The method according to item 13, where the moderator dilution of the selected at least one of the following compounds: NaNO2, NaNO, Na2S2O3, triethanolamine and urea.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: proppant is a material in form of particles, where each particle contains a proppant particle base, a water-soluble outer coating deposited on said base, and microparticles of an insoluble reinforcing and filling agent, at least partially immersed in the water-soluble outer coating such that said microparticles are essentially released from the proppant particle base when the water-soluble coating dissolves or breaks down. The material in form of particles for improving operation and/or efficiency of a bore hole in an underground formation, having a particle base from the underground formation, a water-soluble outer coating on said base and a reinforcing agent from microparticles at least partially immersed in said coating such that it is essentially released when the water-soluble coating dissolves or breaks down. The method of improving operating characteristics of a bore hole in an underground formation, involving feeding said material into one or more objects selected from an underground formation, a well shaft in said formation or bore hole in said underground formation.

EFFECT: high strength and wear-resistance of the proppant and permeability of the filling made from said proppant.

18 cl, 1 ex, 1 tbl, 4 dwg

FIELD: oil and gas production.

SUBSTANCE: method of formation hydraulic breakdown (FHB) consists in descending the tubing casing (TS) into hydraulic breakdown zone, pressurisation of casing string annulus by packer, pumping of gas, breakdown agent under pressure through TS. Note that the gas is supplied together with the breakdown agent that is crude oil. Propping agent is supplied after breakdown agent pumping. Note that the gas is inert and it is pumped at 20-30% of breakdown agent volume at a pressure 8 MPa. As propping agent there used is acid-oil emulsion fluid with adding of inert gas at 20-30% of propping agent volume at a pressure 9 MPa. After that the pumping cycle of breakdown agent with gas and propping agent is repeated 3-6 times. Before development the process fluid with inert gas is pumped into tubing casing at 10 MPa in the volume of 20-30% of total volume equal to 1.5-fold inner volume of tubing casing with the following technological exposure for 2-3 h. Note that breakdown agent and propping agent are pumped by equal portions of total volume in each cycle.

EFFECT: simplification of FHB technological process.

1 dwg

FIELD: oil and gas industry.

SUBSTANCE: well treatment method involves introduction to the well of treatment liquid containing polymer, binder, organic peroxide, soluble amine connection and functional dilution retarder, where soluble amine connection has chemical structure R3R4N((CR5R6)2-NR7)n-R8, in which n is equal to 2 to 8 and in which R3, R4, R5, R6, R7 and R8 are chosen independently from each other from hydrogen, alkyl, hydroxyalkyl and their combinations, where mass ratio of soluble amine to organic peroxide is approximately 1:1 to approximately 20:1; and treatment liquid dilution. Invention has been developed in dependent claims.

EFFECT: increasing monitoring efficiency of viscosity reduction.

16 cl, 15 ex, 15 dwg

FIELD: chemistry.

SUBSTANCE: liquid composition contains the following: suspension on oil basis, which includes base oil, organophilic clay, polar activating agent, wetting agent, and composition improving the operability in winter conditions, which contains one or many composite monoesters of polyols and/or composite diesters of polyols. Composition is meant for hydraulic fracturing of underground formation, removal of combined wafer from productive underground formation. Hydraulic fracturing method of underground formation involves pumping to the formation under the pressure which is enough for fracturing, liquid for fracturing, which contains propping agent and suspension on oil base, which includes base oil, organophilic clay, polar activating agent, wetting agent and the above composition, or according to the other version - fracturing liquid containing the above suspension, and pumping to the formation subjected to fracturing under pressure which is enough for protection of cracks against joining of carrying liquid with propping agent. Production method involves circulation and/or pumping to production well of the liquid including the above suspension.

EFFECT: improving operability in winter conditions.

25 cl, 18 tbl, 3 ex, 4 dwg

FIELD: oil and gas industry.

SUBSTANCE: methods involving the use of composition for slow increase in adhesive ability, which includes water agent for increasing the adhesive ability and activating agent of slow separation of the acid which is used for stabilisation of particles and minimisation of particle migration inside underground formation. Invention has been developed in dependent claims.

EFFECT: improvement of operating flexibility and controllability of operations and mechanical elasticity of stabilised masses.

20 cl, 1 ex

FIELD: chemistry.

SUBSTANCE: free flowing coated particles, having size ranging from 6 mesh to 200 mesh, where each particles has a substrate and a coating on the substrate. Said coating contains a continuous phase which contains a curable resol phenol-formaldehyde resin, and reactive powdered particles embedded into the continuous phase or adhered to said phase, wherein the powdered particles contain at least one component selected from a group consisting of resol phenol-formaldehyde resin, phenol-formaldehyde novolac resin, ester, an acrylic compound and urethane. The method of producing said particles involves the following steps: mixing a substrate with a liquid coating material from the curable resol phenol-formaldehyde resin at temperature ranging from approximately 10C to approximately 65C to form a resin curable coating in form of a continuous phase on the substrate; mixing the reactive powdered particles with the resin-coated substrate to embed said particles into the continuous phase of the resin coating or adhere said particles to the substrate.

EFFECT: possibility of cost-effective production of highly effective particles in industrial conditions.

43 cl, 4 tbl, 5 ex, 10 dwg

FIELD: oil-and-gas production.

SUBSTANCE: proposed fluid to be used in oil fields comprises: 0.001 wt % to 0.5 wt % of surfactant reducing drag and at least one activator of drag reduction selected from the following group: polymer drag reduction activators selected from the group comprising low-molecular water-soluble polymers and copolymers containing at least one aromatic cycle, or their mixes with monomer drag reduction activator. Note here that said fluid allows drag reduction percentage making at least 20%. Proposed method of regulating clay swell in brine-free well shaft comprises: preparing above fluid suspending reduction agent and injecting it into well shaft. Method of processing in-situ in oil filed whereat said suspending reduction agent is prepared, injected into well shaft to reach drag reduction percentage equal to at least 20%. Invention is developed in dependent claims.

EFFECT: improved viscosity and power to suspend solid substances at low surfactant concentrations.

20 cl, 33 ex, 4 tbl, 36 dwg

FIELD: oil and gas industry.

SUBSTANCE: in processing method of bottom-hole formation zone, which involves pumping to the formation of magnesium granules with further pumping of acid compound, first, hydraulic fracturing of the formation is performed with further pumping of mixture of magnesium granules and propane with fluids on hydrocarbon or water basis. Then, to the processed zone of the formation there pumped is combustible oxidation composition (COC) which contains oxidiser, catalyst decreasing the value of the temperature required for the beginning of oxidation reaction, surface-active substance required for removal of hydrocarbon film from magnesium, and water. After oxidation reaction is completed and additional cracks are formed, acid compound increasing the size of the formed cracks is pumped.

EFFECT: increasing processing efficiency of the bottom-hole formation zone at increasing safety of the work execution process.

2 ex

FIELD: gas and oil production.

SUBSTANCE: water composition for reservoir hydraulic fracturing contains water, ion-bound gel-like system including charged polymer, oppositely charged foaming agent and gas. The gel-like system and gas are present in amount sufficient for production of ion-bound foamed composition for hydraulic fracturing. Composition contains liquid for hydraulic fracturing including 5.5-7 gpt of the above said gel-like system and de-ionised water. The procedure for production of foamed compositions consists in production of the first composition, the second composition and in adding it to the first one at their specified ratio. The procedure for reservoir hydraulic fracturing includes production of liquid for hydraulic fracturing containing the above said gel-like system and proppant and in its pumping into the reservoir. The procedure for reservoir hydraulic fracturing includes production of liquid for hydraulic fracturing containing the above said gel-like system, its pumping into the reservoir at pressure of hydraulic fracturing and in pumping proppant after hydraulic fracture.

EFFECT: facilitating reservoir hydraulic fracturing at deficiency of hydration units.

45 cl, 1 tbl

FIELD: gas and oil production.

SUBSTANCE: procedure for treatment of underground formation with processing thickened liquid consists in: mixing water, carbonyl containing first compound and amine containing second compound. The carbonyl containing first compound contains at least one carbonyl group and corresponds to either gel forming agent or to modifying agent. The amine containing second compound contains at least one amine group and corresponds to a gel forming agent when the carbonyl containing first compound is a modifying agent, and to a modifying agent when the carbonyl containing first compound corresponds to the gel forming agent. The gel forming agent corresponds to at least one following compounds: polysaccharide, natural polymer, bio-polymer or synthetic polymer and the modifying agent corresponds to at least one of the following compounds: halogenide, epoxide, polysaccharide, natural polymer, bio-polymer or synthetic polymer. Further, the procedure consists in interaction between at least one carbonyl group of the first compound and at least one amine group of the second compound with formation of modifying bond and production of the modified gel forming agent and in introduction or thickened liquid into a section of an underground formation. The procedure for formation of break of a section of the underground formation by means of processing thickened liquid includes the above said stages. Also, processing thickened liquid is pumped into a section of the underground formation under pressure sufficient for creation or expansion of at least one break in it.

EFFECT: production of modified thickened agents.

16 cl

FIELD: oil and gas industry.

SUBSTANCE: in method for balancing of injection well water-intake capacity profile and restriction of water influx to production wells, which involves pumping to the formation of gel-forming composition containing, wt %: sodium silicate 1-10, chrome acetate 0.5-2, water is the rest, pumping of the above composition to formation, technological pause, prior to pumping of the above composition to wells there pumped is fresh water; induction period of gel-forming composition at formation temperature is set so that it is equal to 6-10 hours, and technological pause is chosen so that its duration is equal to 24-36 hours.

EFFECT: improving the efficiency of oil displacement from formation due to water isolation of highly water-flooded formations in production wells either due to equalising the water-intake capacity profile of injection wells by partial or complete blocking of highly washed channels or interlayers for movement of injection water.

1 ex, 2 dwg

FIELD: oil and gas industry.

SUBSTANCE: well treatment liquids include water, at least one hydratable polymer, granules of sodium percarbonate with the coating retarding its liberation. As per the first version, the above coating is non-organic material. As per the second version, the above coating includes mixture of styrene-acrylate and butyl acrylate. Underground formation hydraulic fracturing method involves granules of sodium percarbonate with coating from non-organic material retarding its liberation. Inventions have been developed in dependent claims.

EFFECT: avoiding premature viscosity reduction of treatment liquid due to using sodium percarbonate granules with the coating retarding its liberation.

23 cl, 4 tbl, 6 ex, 6 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to oil industry, particularly reagents for treating an oil reservoir and methods of extracting oil and can be used on oil deposits in a wide range of reservoir temperature (20-90C), total content of salts in the stratal and injected water (0.034-24.0 wt %) with carbonate, terrigenous and mudded rocks. The reagent is a mother solution of ammonium sulphate from stripping aqueous acidic wastes from caprolactam production containing not less than 41 wt % dry residue, not less than 2.1 wt % amino organic acids in form of amino caproic acid and having pH higher than 4.4. The method of extracting oil involves pumping said reagent and aqueous solution of electrolyte and/or organic solvent.

EFFECT: high well productivity and high reservoir recovery.

2 cl, 4 tbl

FIELD: oil and gas industry.

SUBSTANCE: in formation permeability control method involving subsequent pumping to the well through separating bank of fresh water or oil, liquid wastes of produced zeolites and gel formation initiator, forcing-through of pumped reagents to formation with waste water or oil, the solution of by-product of produced polyethylenepolyamines - reagent of ammonium chloride is used as gel formation initiator.

EFFECT: reducing corrosive activity of composition; increasing technological efficiency for restriction of water and gas breakthrough.

4 ex, 2 tbl, 1 dwg

FIELD: oil and gas industry.

SUBSTANCE: above described formation is brought into contact with fluid medium, where fluid medium is at least the medium which at least partially dissolves or at least partially displaces the brine in the above formation, and subsequently, the above formation is brought into contact with composition including the following: non-ionic fluorated polymer surface-active substance - NFPSAS, which contains at least one bivalent unit represented with structural formulae, and solvent; at that, when composition is brought into contact with the above formation, the above mentioned NFPSAS has turbidity point which is higher than the temperature of the above formation. Invention is developed in dependent claims.

EFFECT: increasing production rate of wells, where brine or gas condensate is present.

25 cl, 3 ex, 20 tbl, 3 dwg

FIELD: mining.

SUBSTANCE: viscoelastic composition for the use in underground formations includes, at least, one quaternary alkylamidoamine of the given formula and at least one indicated sub-additive when the ratio by weight is within 1000:1 and 5:1. Water-base fluid for the use in oil deposit includes indicated composition. Composition of high-density brine for oil deposit includes within 30-70 wt % of organic and/or inorganic salt and the composition mentioned above. Fluid of oil deposit termination in the form of high-density brine contains within 30-70 wt % of, at least, one organic or inorganic acid, within 0.1-4 wt % of, at least, one cationic surfactant from the modified group and, at least, one sub-additive from the modified group. The method of cracking underground formation includes provision of thickened fluid for water-base hydraulic fracturing, which includes water environment and effective amount of the above mentioned composition and injection of aqueous fluid through the well bore into the underground formation at a pressure, sufficient to break the formation. The invention is developed in the formula subclaims.

EFFECT: improvement of efficiency in upgrading permeability of underground formations.

24 cl, 4 ex

FIELD: oil-and-gas production.

SUBSTANCE: proposed method comprises the following steps: a) forcing flooding fluid into deposit, and b) extracting oil from borehole in location other than that of forcing flooding liquid. Flooding liquid includes water and some amount of one or more specified viscoelastic nonpolymeric surfactants sufficient for interfacial surface tension approximating to 1 mNm or smaller, and viscosity of 10 sP or larger. Proposed invention is developed in dependent claims.

EFFECT: higher efficiency of tertiary oil extraction.

24 cl

FIELD: oil and gas production.

SUBSTANCE: method of bottom-hole zone treatment of low-permeable terrigenous formation according to the first version consists in flushing of killed well, sequential pumping of methanol, 18-20% solution of hydrochloric acid for acid bath installation, then the well is repeatedly pumped by 18-20% solution of hydrochloric acid and buffer-gas condensate, acid composition is squeezed into bottom-hole zone of formation by inert gas, then mud acid solution is pumped, gas influx from formation is caused and then reaction products are removed together with gas flow, the well is treated through flare line with removal of reaction products till it reaches design conditions and then the well is placed under production. Method of bottom-hole zone treatment of low-permeable terrigenous formation according to the second version consists in sequential pumping of methanol, 18-20% solution of hydrochloric acid and buffer-gas condensate into non-killed well through tubing casing, acid composition is squeezed into bottom-hole zone of formation by inert gas, then mud acid solution is pumped, gas influx from formation is caused and then reaction products are removed together with gas flow, the well is treated through flare line with removal of reaction products till it reaches design conditions and then the well is placed under production.

EFFECT: recovery of gas-hydro-dynamic connection of well with low-permeable and highly colmataged terrigenous productive formation in condition of abnormally low formation pressure.

2 cl

FIELD: oil and gas production.

SUBSTANCE: method of formation face zone development consists in pumping the gas-generating and acid-based reagents, where gas-generating reagent is the compound that includes, wt %: urea 28.4-38.4, sodium nitrite 18.2-27.6, water - the rest, and acid-based reagent is the compound that includes, wt %: inorganic acid 5.2-60.9, surface acting agent 2.4-3.5, ferrum inhibitor 1.4-2.3, flotation agent 7.0-11.4, water - the rest. Note that the proportion of gas-generating and acid-based reagents amounts 1:(1-3), after pumping of the reagents they are held.

EFFECT: increase of injection capacity of intake well and influx to the producing wells, start of development of leak-proof zones not covered by influence.

3 cl, 2 tbl, 2 ex, 1 dwg

FIELD: oil and gas industry.

SUBSTANCE: method for control of flooding area of oil formations includes oil extraction through production wells and pumping of margins of working agent and silicate in water phase with varying concentration of components trough injection wells. At that watering out of produced oil, capacity of injection wells, allowable pumping pressure and minimal pumping pressure are additionally checked. Pumping is started from injection wells of high capacity, connected hydrodynamicly to highly watered out production wells. At least one injection well is stopped till formation pressure is decreased by 6-24% from formation pressure in area of injection well. Pumping of working agent is started from composition of high-viscosity in quantity not less than 0.5 m3 per 1 m of productive formation with high capacity under pumping pressure exceeding minimal pumping pressure not more than by 20%, at which well accepts. Then margins of water solution of alkaline silicate and polymer are pumped in succession or jointly. Solution of alkaline silicate is used in quantity 0.1-15.0 wt %, and polymer is used in quantity 0.001-3.0 wt %, the other part of solution is water.

EFFECT: increasing oil recovery from formations.

4 cl, 3 ex

FIELD: oil and gas production.

SUBSTANCE: plugging material contains cement, reinforcing fibre-polyacrylic or polypropylene or basalt fibre, polydiallyldimetylammonium chloride-VPK-402, hydroxyethyl cellulose, super plastifier CEMPLAST or C-3 or Melflux, anti-foaming agent POLYCEM DF, calcium chloride and water with the following component ratio, wt %: cement 65.0-69.0, said reinforcing fibre 0.08-0.33, hydroxyethyl cellulose 0.07-0.2, said super plastifier 0.08-0.33, said anti-foaming agent 0.08-0.13, calcium chloride 0.08-1.3, polydiallyldimetylammonium chloride-VPK-402 0.08-0.33, water the rest.

EFFECT: improvement of crash resistance, including conditions of hard dynamic influences.

1 ex, 2 tbl

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