Compositions for wells treatment with sustained release for use in well treatment liquids

FIELD: oil and gas industry.

SUBSTANCE: invention relates to compositions for wells treatment for use in oil industry. Composition for well treatment containing chemical for well treatment adsorbed using water-insoluble adsorbent, where composition is produced by the well treatment chemical deposition from liquid, at that the well treatment chemical is adsorbed on the water-insoluble adsorbent, and where the well treatment chemical is deposited upon metal salt presence. Well treatment liquid containing the above mentioned composition and carrying liquid. Method of the underground reservoir or wellbore treatment including the above mentioned well treatment liquid injection in the reservoir or wellbore. Method to monitor the well treatment chemical release in the wellbore including the above composition injection in the wellbore. Invention is developed in subclaims.

EFFECT: improved efficiency of treatment in environments with high pH.

38 cl, 3 dwg, 4 ex

 

The technical field to which the invention relates

The present invention relates to compositions for well treatment for use in the oil field, obtained by precipitation of the reagent for treatment of the well from the liquid on a water-insoluble adsorbent and in the presence of metal salts.

The level of technology

Fluids extracted from wells usually contain a complex mixture of components including aliphatic hydrocarbons, aromatic compounds, heteroatomic molecules, anionic and cationic salts, acids, sand, sedimentary rocks and clay. The nature of such fluids in conjunction with the harsh conditions of heat, pressure and turbulence to which they are often exposed during the removal from the wellbore, are factors that contribute to the formation, salification, superfinishing, emulsification (type water-in-oil or oil-in-water), hydrate formation, corrosion, the formation of asphaltene deposits and the formation of paraffin oil and/or gas production wells and surface equipment. Such conditions, in turn, reduce the permeability of underground strata, reduce well productivity and shorten the lifetime of production equipment. To clear the well and equipment from sediments, it is necessary to stop production, �it is time-consuming, and expensive.

Reagents for the well treatment is often used in production wells to prevent the devastating impact caused by such deposits and sediments. For example, scale formation in reservoir and/or production lines within the borehole and at the surface is often controlled by the inhibitors of calcification.

In this area there are several ways of introducing treatment chemicals wells into production wells. For example, a liquid reagent for treatment of the well can be forcibly taken in the layer by applying hydraulic pressure from the surface, which pushes the reagent for treatment of the well in the target zone. In most cases, such treatment is carried out at a downhole discharge pressure less than the fracturing pressure. On the other hand, the shipping method may consist of the placement of the solid reactant for the treatment of wells in the productive layer in combination with the hydraulic fracturing operation. This method is often preferred as it introduces a reagent for processing into contact with the fluids in the reservoir, before these fluids will enter the well bore, which usually have a devastating impact.

A principal disadvantage of such methods is the difficulty of releasing the reagent sobrasada in the well for a long period of time. As a result, treatment must be undertaken repeatedly to ensure that the required amount of reagent for treatment is constantly present in the well. Such treatment, lead to revenue losses of production due to downtime.

Thus, searching for treatment methods for the introduction of reagents for the well treatment in the oil and/or gas wells, where the reagent for treatment of the well may be released over an extended period of time and where there is no need for constant attention of operators for a long period.

U.S. patent No. 7491682 and U.S. patent No. 7493955 describe how well treatment by using a composition containing a reagent for treatment of the well adsorbed on the water-insoluble adsorbent, such as fossil meals earth. Reduced efficacy of such compositions can occur in environments with high pH value. A search for alternative compounds for use in environments with high pH value.

Summary of the invention

Disclosed is a composition containing a reagent for treatment of the well, which is especially useful in liquids for treatment of wells with high pH value. The composition contains a reagent for well treatment, precipitated water-insoluble adsorbent in the presence of alkali metal or alkaline earth metal. INTEG� can be prepared in the presence of caustic soda.

The composition is particularly effective in the treatment of a wellbore or a subterranean formation penetrated by the wellbore. For example, the composition may be introduced into the subterranean formation or wellbore in a fluid for hydraulic fracturing. The composition is particularly effective in cases where it is desirable to control the rate of release of the reagent for treatment of the well over a long period of time.

The reagent for treatment of the well can be an inhibitor of scale formation, corrosion inhibitor, paraffin deposition inhibitor, scale inhibitor, an inhibitor of hydrate formation of gas, formation inhibitor asphaltene deposits, oxygen scavenger, biocide, a foaming agent, a reagent for the destruction of emulsions or surfactant.

Water-insoluble adsorbent may be fossil meals earth, activated carbon, silica particulate, precipitated silica, zeolite, crushed walnut shell, fallerovo earth or organic synthetic high molecular weight water-insoluble adsorbents. The surface area of the adsorbent is preferably from about 1 m2/g to 100 m2/g.

Also disclosed composition for the treatment of wells containing the composition.

In one embodiment, the implementation of the composition is prepared about�adenium reagent for treatment of the well from the liquid, the reagent for treatment of the well adsorb to the water-insoluble adsorbent in the presence of metal salts.

The reagent for treatment of the well can be initially introduced to the adsorbent and is then deposited on the adsorbent by adding metallic salts. For example, when the composition is to function as an inhibitor of scale formation, the composition may be prepared first by mixing phosphate with alkaline earth metal such as calcium or alkali metal, and adsorbirovannym of phosphonate on the water-insoluble adsorbent until it is deposited.

After the introduction of the reagent for treatment of the well to the adsorbent, and before the deposition of the reagent for treatment of the well with the help of metallic salts on the adsorbent, the pH value can then be neutralized. After deposition of the adsorbent may be further added caustic to the adsorbent containing precipitated reagent for the treatment wells.

In another embodiment of the composition can be obtained by introducing a first alkali metal salt or alkaline earth metal onto the adsorbent and then through the introduction of the adsorbent reagent for treatment of the well. In addition to the adsorbent can be entered after adding caustic reagent for treatment of the well.

The invention also relates to a composition for the treatment of wells containing� water-insoluble adsorbent and the crystallized precipitate of metal and reagent for treatment of the well, and composition for the treatment of wells containing water-insoluble adsorbent and salt reagent for treatment of the well. The composition may be prepared or by introducing metallic salts and reagent for treatment of wells in the water-insoluble adsorbent, neutralizing the precipitate and crystallization neutralized precipitate on the adsorbent or reagent deposition for well treatment and metal salts from aqueous caustic liquid on the water-insoluble adsorbent and crystallization neutralized precipitate on the adsorbent. Metal salt and reagent for treatment of the well may be imposed on the water-insoluble adsorbent in two separate stages. The reagent for treatment of the well and the metal salt may be introduced to the water-insoluble adsorbent in the form of an aqueous liquid containing a liquid acidic reagent for the treatment wells and a metal salt. In addition, the composition may be prepared by precipitation reagent for treatment of the well and a metal salt from an aqueous alkaline liquid on a water-insoluble adsorbent.

Mass or molar ratio of the metal or metal salt and reagent for treatment of the well, introduced to the water-insoluble adsorbent in the preparation of the composition may be between about 1:4 and 4:1.

Mass or molar ratio of salt and Rea�cient of well treatment introduced to the water-insoluble adsorbent may be about 1:1.

Brief description of the drawings

For a more complete understanding of the drawings referring to the detailed description of the present invention, and a brief description of each drawing, in which:

Fig.1 shows a curve of return of the inhibitor for products prepared in accordance with the invention as described in example 1.

FG.2 shows the curve of the return of the inhibitor for products prepared in accordance with the invention as described in example 3.

Fig.3 demonstrates the effect that the order of addition of the metal and caustic soda has on the rate of desorption of the compounds produced in accordance with the invention as described in example 4.

Detailed description of preferred embodiments

The compositions described in this case, contain a reagent for treatment of the well adsorbed on the water-insoluble adsorbent. When used in oil, gas or geothermal well or a subterranean formation penetrated by such wells, the reagent for treatment of the well is slowly released from the adsorbent.

The composition is prepared by adsorbirovannym reagent for treatment of the well from the liquid on a water-insoluble adsorbent in the presence of metal salts. The product containing adsorbed reagent d�I of well treatment then can be dried.

In one embodiment, the implementation of the composition is prepared by introducing a first reagent for treatment of the well to the adsorbent with the formation of the treated adsorbent. The reagent for treatment of the well is then deposited on the adsorbent or the adsorbent is impregnated with salt by introducing a metal salt to the treated adsorbent. Before the introduction of the metal salt to the treated adsorbent-treated adsorbent can be neutralized by adding caustic soda. On the other hand, caustic may be introduced to the treated adsorbent after adding the metal salt.

The amount of caustic soda is added to treated water-insoluble adsorbent is from about 2 to 6 equivalents per 1 equivalent of the compound for the treatment wells and preferably about 4 equivalents to 1 equivalent of the compound for the treatment wells.

Composition for well treatment can also be prepared by adsorption of the first metal salt on the adsorbent and then through the introduction of the reagent for treatment of the well to the adsorbent containing a metal salt. Caustic can be introduced to the adsorbent after adding reagent for treatment of the well.

In addition, the composition for well treatment may be prepared in a way that gives the adsorbent and crystallized about�adok reagent for treatment of the well and either metal, or a metal salt on the adsorbent. In this method, the composition may be prepared by introducing a metal salt and reagent for treatment of wells in the water-insoluble adsorbent. Metal salt and reagent for treatment of the well may be imposed on the water-insoluble adsorbent in one stage or in two separate stages. The resulting product can then be dried and neutralized. The neutralized reagent for treatment of the well is then deposited on the adsorbent. The product is then enable to dry.

In another method, the reagent for treatment of the well and the metal salt is precipitated from aqueous alkaline liquid on the water-insoluble adsorbent. Neutralized precipitate is then crystallized on the adsorbent. This method is especially effective where an aqueous alkaline liquid contains an acidic reagent for the treatment wells.

Typically, the molar ratio of metal salt to the reagent for treatment of wells used for deposition of the reagent for the treatment of wells in the adsorbent is from about 10:1 to 1:10, more typically from about 4:1 to 1:1.

The amount of reagent for treatment of the well in the composition for well treatment is usually from about 20 to 55 wt%.

Metal, and also metal salt is preferably an alkali metal, Sch�lonesomely metal and transition metal, such as sodium, potassium, calcium, magnesium, cobalt, Nickel, copper, zinc and iron. The ammonia in this case is also included in the definition of metallic salts. In a preferred embodiment of the salt is an alkali metal or alkaline earth metal and include halides, hydroxides and sulfates of such metals, such as calcium chloride, magnesium chloride, sodium sulfate, potassium hydroxide, sodium hydroxide and potassium sulfate. In the most preferred embodiment of the metal is calcium and the metal salt is calcium chloride. Usually when applied on the adsorbent metals or metal salts are placed in aqueous solution.

In a preferred embodiment of the reagent for treatment of the well may represent at least one component selected from the group including demulsifiers (as water-in-oil or oil-in-water), corrosion inhibitors, inhibitors of scale formation, inhibitors, inhibitors of the formation of gas hydrates, salt formation inhibitors and dispersants asphaltene deposits.

In addition, other suitable reagents for treatment wells include foaming agents, oxygen scavengers, biocides and surfactants, and other reagents, where it is desirable slow release in extractive SC�ageny.

Adsorption of the reagent for the treatment of wells in the adsorbent reduces (or limits) the amount of the reagent for treatment of wells required in the solution. As the reagent for treatment of the well represents the adsorbent on the substrate, only a small amount of the reagent for treatment of the well can be released into the aquatic environment.

The reagent for treatment of the well preferably is a liquid material. If the reagent for treatment of the well is solid, it can be dissolved in a suitable solvent that turns it into a liquid.

In a preferred embodiment of the machining bore the composition of the present invention effectively inhibits, controls, prevents or affects the formation of inorganic deposits that are deposited in underground layers, such as a wellbore, oil wells, gas wells, water wells and geothermal wells. The compositions of the present invention is particularly effective when processing the salt deposits of calcium, barium, magnesium salts and such salts, including deposits of barium sulfate, calcium sulfate and calcium carbonate. The compositions may also find use in the impact on other inorganic deposits, such as zinc sulfide, iron sulfide, etc.

Suitable in�ibicarai of scale formation are anionic inhibitors of scale formation.

Preferred inhibitors of scale formation include strong acidic materials, such as phosphonic acid, phosphoric acid or phosphorous acid, phosphate esters, phosphonate/phosphonic acid, various aminopolycarboxylate acid, helatoobrazovateli and polymeric inhibitors, and salts thereof. Also included organophosphonate, organophosphates, and phosphate esters and the corresponding acids and their salts.

Inhibitors of scale formation type phosphonate/phosphonic acid is often preferred with regard to their effectiveness for controlling sediments at relatively low concentrations. Polymeric inhibitors of scale formation, such as polyacrylamides, salts of a copolymer acrylamidoethyl-sulfonate/(acrylic acid) (AMPS/AA), fastidiously maleic copolymers (PHOS/MA) or the sodium salt of terpolymers (primulina acid)/(acrylic acid)/acrylamidoethyl-propanesulfonate (PMA/AMPS) are also effective inhibitors of scale formation. The preferred sodium salt.

Also useful, especially in the case of salt solutions, are helatoobrazovateli, including diethylenetriaminepenta-methylenephosphonate acid and ethylenediaminetetraacetic acid.

The reagent for treatment of the well may also be any of or derived fructans fructans, for example inulin derivatives of inulin, described in patent publication U.S. No. 2009/0325825, which is included in the description by reference.

Examples of demulsifiers that may be used include, but are not limited to, condensation polymers of alkalisation and glycols, such as ethyleneoxide and propyleneoxide condensation polymer of dipropyleneglycol, and trimethylolpropane; alkyl-substituted phenol-formaldehyde resins, diepoxide of bisphenol, and esters and dietary such difunctional products. Particularly preferred as nonionic demulsifiers are oxyalkylated phenol-formaldehyde resin, oxyalkylene amines and polyamines, diepoxybutane oxyalkylene polyethers, etc. Suitable demulsifiers oil-in-water are Quaternary poly(triethanolaminato), sour melamine colloid, aminomethylpropanol polyacrylamide, etc.

The inhibitors, useful in the implementation of the present invention include, but are not limited to, ethylene/vinyl acetate copolymers, acrylates (such as polyacrylate esters and methacrylate esters of fatty alcohols and olefin/maleic esters.

Typical corrosion inhibitors, useful in the implementation of the present invention, include, but are not limited to, fatty imidazoline, alkylpyridine, quarters�nye alkylpyridine, Quaternary fatty amines and phosphate salts of fatty imidazolines solution.

Processing chemicals gas hydrates, which are useful when implementing the present invention, include, but are not limited to, polymers and the homopolymers and copolymers of vinylpyrrolidone, vinylcaprolactam and inhibitors of hydrate formation based on amines, such as inhibitors, are described in patent publications U.S. No. 2006/0223713 and No. 2009/0325823, which are both included in the description by reference.

Typical chemicals for treatment of asphaltene deposits are, but without limitation, homopolymers and copolymers of fatty esters (such as fatty esters of polymers and copolymers of acrylic and methacrylic acid and sorbitan-monooleate.

Suitable blowing agents include, but are not limited to, oxyalkylated sulfates or sulfates of ethoxylated alcohols, or mixtures thereof.

Typical surfactants include cationic, amphoteric, anionic and nonionic surfactants. As cationic surfactants include surfactants containing a Quaternary ammonium residue (such as the linear Quaternary amine, Quaternary benzylamine halide or Quaternary ammonium), Quaternary sulfanilyl balance or Quaternary postnewly residue or mixtures thereof. �othodyashie surfactants, containing Quaternary group are Quaternary ammonium halide or Quaternary amine, such as Quaternary ammonium chloride or a Quaternary ammonium bromide. As amphoteric surfactants include glycinate, atacamite, propionates, betaine and mixtures thereof. Cationic or amphoteric surfactant may have a hydrophobic tail (which may be saturated or unsaturated), such as C12-C18-carbon chain. Furthermore, the hydrophobic tail can be obtained from natural oils from plants, such as one or more oils from coconut oil, rapeseed oil and palm oil.

Preferred surfactants are N,N,N-trimethyl-1-octadecanethiol, N,N,N-trimethyl-1-hexadecanaminium and N,N,N-trimethyl-1-(soybean oil)chloride and mixtures thereof. Suitable anionic surfactants are sulfonates (type cellsurface sodium and naphthalenesulfonate sodium), phosphonates, amoxicullin and mixtures thereof.

Typical oxygen absorbers are triazine, maleimide, formaldehyde, amines, carboxamide, alkylcarboxylic-azo compounds, Jeera-peroxide compounds, morpholino - and amino-derivatives of morpholine and piperazine derivatives, aminoxide, alkanolamines, aliphatic and aromatic�quarter polyamines.

The composition of the present invention does not require excessive amounts of reagent for treatment of wells. The amount of reagent for treatment of the well in the composition is an amount sufficient to achieve the desired result over a long period of time and may amount to less than 1 ppm. Typically, the amount of reagent for treatment of the well in the composition is in the range from about 0.05 to 5 (preferably from about 0.1 to 2) % of the mass. based on the total weight of the composition.

For example, when the reagent for treatment of wells is an inhibitor of scale formation, the amount of an inhibitor of scale formation that is present in the composition, represents the amount required to prevent or at least significantly reduce the formation of scaling. For most applications the amount of an inhibitor of scale formation in the composition for well treatment can reach to less than 1 ppm. Such a small amount of an inhibitor of scale formation can be sufficient for almost 1000 pore volumes and, as a rule, provide up to six months of continuous inhibition. Thus, the costs of operation are significantly reduced.

The water-insoluble adsorbent may be any of various types of commercially available mate�of yalow with high surface area, having an affinity to a desired reagent for treatment of the well. Typically, the surface area of the adsorbent composition for the treatment of the hole is between approximately 1 m2/g and 100 m2/g.

Suitable adsorbents are finely divided materials, fibers, crushed shell almonds, finely ground walnut shell and crushed coconut shells. Other suitable water-insoluble adsorbents are activated carbon and/or carbon, silica particulate, precipitated silica, silicon dioxide (quartz sand), alumina, aluminosilicate, such as silica, mica, silicate, for example, organosilicate or metasilicate, calcium silicate, sand (for example, 20-40 mesh), bauxite, kaolin, talc, Zirconia, boron and glass, including glass microspheres or beads, fly ash, zeolites, fossil meals earth, crushed walnut shell, fallerovo earth and organic synthetic high molecular weight water-insoluble adsorbents. Especially preferred are fossil meals, ground and crushed walnut shells.

Also useful as adsorbents include clays, such as natural clay, preferably a clay having a relatively highly negatively charged surface and a much smaller surface, which is the batte�on positively. Other examples of such materials with high surface area include such clays as bentonite, illite, montmorillonite and synthetic clay.

The mass ratio of reagent for treatment of the well to the water-insoluble adsorbent is typically from about 90:10 to 10:90.

Adsorption liquid reagent (or solution) for the treatment of wells on a solid adsorbent is limited by the availability of free reagent for treatment of the well water. In addition, the composition has limited solubility in water. When placed in a producing well reagent for well treatment slowly dissolves usually at a constant speed for a long period of time in the water, which is in the reservoir. Controlled slow release of the reagent depends on the surface charges between the reagent for treatment of the well and the adsorbent, which, in turn, depends on the characteristics of adsorption/desorption reagent to the adsorbent.

Usually the duration of a single treatment using the composition of the present invention is from six to twelve months and may exceed 3 years depending on the volume of water produced at the production wells, and the amount of the reagent for treatment of wells associated with water-insoluble adsorbent.

Compositions for the treatment �of Kvasiny in accordance with the invention contain the composition. Carrier fluid may be a brine, salt water, potable water, liquid hydrocarbons, or gas, such as nitrogen or carbon dioxide. Suitable compositions include liquids for hydraulic fracturing, fluids for well completion, compositions for acid treatment of wells, etc. When used in hydraulic fracturing fluid may contain or may not contain a propping agent.

The compositions are especially effective when used in environments with high pH such as a pH in excess of 7.0. Such compositions are also effective in liquids having a pH in excess of 11.0.

The amount of composition present in the composition for well treatment, typically is from about 15 to 100,000 ppm depending on the severity of sedimentation. When the carrier fluid is a brine, the mass percentage of the composition in the composition is typically from about 0.02 to 2 wt%.

The composition can also contain 0 to 10 wt%. inorganic salt. Suitable inorganic salts are KCl, NaCl and NH4Cl.

The treatment composition of the well can be used to control and/or prevention of undesirable scale formation, salts, paraffins, gas hydrates, asphaltene and corrosion in the seams or on the equipment surface. Chrome�, other suitable reagents for treatment include foaming agents, oxygen scavengers, biocides, emulsifiers (such as water-in-oil or oil-in-water) and surfactants, and other reagents can be used with the help of the adsorbent when it is desirable slow release of such reagents in the production well.

The composition for treatment of a borehole of the present invention may be used in the processing, in order to intensify the flow as a component of the fluid for hydraulic fracturing or fluid for acid treatment of wells, such as a matrix zakislate liquid. The composition has particular use in fluids for well completion, saline solutions containing zinc bromide, calcium bromide, calcium chloride and sodium bromide. Such fluids may be introduced below the annulus of the well and, when this is desirable, washed with formation water.

In a particularly preferred embodiment of the compounds of the present invention is used in fluids for machining gas wells or oil wells where it is desirable to prevent or inhibit the formation of scale, to control the formation of scale or slow down the release of inhibitors of scale formation in the well. For example, the composition can be used in t�detailed technical service in the completion of the well or its operation. The compositions of the invention can be used in the well for descaling or for control of scale formation on pipe surfaces of equipment within the wellbore.

The following examples are illustrative of embodiments of the present invention. Other options for implementation within the scope of the claims will be apparent to the skilled in this field specialist when considering the descriptions provided in the invention. I believe that the description together with examples should be considered only as examples, with the volume and nature of the invention, which is defined below by the claims.

All the percentages given in the examples are indicated in the values of mass units, except when otherwise indicated.

Example 1

Preparing inhibitors of scale formation containing phosphonate calcium adsorbed on earth fossil meals, by introducing 740 g of calcium chloride in liquid form (30% calcium chloride) to 930 g earth fossil meals (10/50 mesh celite may®MP-79). (Celite may is a trademark celite may Corporation). To this mixture was then added 598 g of a 50% aminotri(methylene phosphinic acid) (ATMP). This mixture is then dried for two hours at 220ºF (104,44 ° C) to give product A1. Was then added 160 g of 50% sodium hydroxide and again dried, received products� A2. Product A1 and product A2 was obtained in accordance with the following equation (where "DE" means fossil meals earth):

Each of the products A1 and A2 contains 20% of the mass. ATMP. The percentage of active salt in A1 and A2 is 25.1 and 30.8 respectively.

Example 2

The elution characteristics of the products A1 and A2 of example 1 was compared with the composition of an inhibitor of scale formation obtained in the examples of U.S. patent No. 7491682. Each sample contained as an inhibitor of scale formation ATMP. Approximately 55 g of 20/40 Ottawa white propping agent and 1.1 g each of the dried product of example 1 was placed on a column of stainless steel 35 cm in length, having an inside diameter of 1.08 cm Column was suirable using a synthetic brine of 0.025 mol/l calcium chloride, of 0.015 mol/l sodium bicarbonate and 1 mol/l sodium chloride, spraying with 100% carbon dioxide at 60 ° C, where the flow rate was 120 ml/h, which corresponded to a linear flow speed of 275 ft/day (8382 cm/day). The outcoming solution was collected and analyzed for the concentration of phosphonate and Sa, to get the curve of inflow of inhibitor Fig.1, where the pore volume of the column was approximately 12 ml. Fig.1 illustrates the product A2 in comparison with the composition of the prior art, showing the best�their efficiency characteristics of the inhibitor, followed by the product A1.

Example 3

Studied barium inhibitors of scale formation, different from the inhibitors presented in U.S. patent No. 7491682. Prepared products similar to the product A1, except that instead of ATMP used bis(hexamethylene)traminette(methylene)-phosphonic acid (VNMC), and 1-hydroxyethylidene-1,1-difosfonovoy acid (HEDP). These products were compared with an inhibitor of scale formation, made in accordance with the example of U.S. patent No. 7491682, as well as an inhibitor of scale formation in accordance with the example of U.S. patent No. 7491682, except for the replacement of phosphinic acid HEDP. Got curves reverse flow inhibitor, as detailed in example 2 are shown in Fig.2. As shown, HEDP is unacceptable, as it is desorbed too fast unlike the calcium salt of HEDP.

Example 4

This example illustrates the impact on the rate of desorption of order of addition on the composition of calcium and caustic soda. The compositions were prepared by adding first, 50 g of a 60% solution of 1-hydroxyethylidene-1,1-difosfonovoy acid (HEDP) 70 g of the earth's fossil meals (10/50 mesh celite may MP-79) with stirring manually and with subsequent drying for two hours at 220ºF (104,44 ºC). Below this product called basic HEDP/DE mixture. Calcium and caustic were added in different sequences, presented� below:

HEDP + (Ca + 2NaOH): 1 equivalent of calcium chloride was dissolved in 2 equivalents of sodium hydroxide, which was then added to the main mixture of HEDP/DE with stirring manually. Then this mixture was dried;

HEDP + NaOH + Ca: 1 equivalent of sodium hydroxide was added to HEDP/DE mixture in a fluidized bed, and then dried. Then 1 equivalent of calcium chloride was added to this mixture in a fluidized bed and dried. This product is in Fig.3 shows how (HEDP + NaOH + Ca). This method gave the most uniform particle size;

HEDP + 2NaOH + Ca: 2 equivalent of sodium hydroxide was added to a mixture of HEDP/DE with stirring by hand and dried. Then 1 equivalent of calcium chloride was added with stirring manually and following this the mixture is drying;

HEDP + Ca + NaOH: added 1 equivalent of calcium chloride to a mixture of HEDP/DE, stirred manually and dried. Then, while manually stirring was added 1 equivalent of sodium hydroxide, and the following mixture was also dried. This product is in Fig.3 is designated as (HEDP + Ca + NaOH);

HEDP + Ca + 2NaOH: 1 equivalent of calcium chloride was added to a mixture of HEDP/DE with stirring manually. After drying was added 2 equivalent of sodium hydroxide, stirred manually and again dried.

Fig.3 shows curves of inflow inhibitor (in accordance with the method of example 2), where "ATMP" means a composition prepared in the example of U.S. patent No. 7491682

Of the above it will be seen that various variations and modifications can be made without deviation from the true meaning and scope of the new concept of the present invention.

1. Composition for treatment of wells containing the reagent for treatment of the well adsorbed on the water-insoluble adsorbent, where the composition is prepared by precipitation of the reagent for treatment of oil well fluid, wherein the reagent for treatment of the well adsorb to the water-insoluble adsorbent and reagent for treatment of the well is precipitated in the presence of metal salts.

2. Composition for treatment of a borehole of claim 1, wherein the reagent for treatment of the well represents at least one component selected from the group comprising inhibitors of scale formation, corrosion inhibitors, paraffin inhibitors, scale inhibitors, inhibitors of the formation of gas hydrates, inhibitors of the formation of asphaltene deposits, oxygen scavengers, biocides, blowing agents, reagents for the destruction of emulsions or surfactants.

3. Composition for well treatment according to claim 2, where the reagent for treatment of the well is an inhibitor of scale formation.

4. Composition for treatment of a borehole of claim 1, wherein the metal salt is selected from the group including alkali or alkaline earth halide�on metal.

5. Composition for treatment of a borehole of claim 1, wherein the composition is prepared in the presence of caustic soda.

6. Composition for treatment of a borehole of claim 1, wherein the composition is prepared (a) introducing a first reagent for treatment of the well to the adsorbent and then (b) deposition of the reagent for treatment of the well to the adsorbent by adding metallic salts.

7. Composition for well treatment according to claim 6, where the product of step (a) is neutralized prior to step (b).

8. Composition for well treatment according to claim 6, where caustic is further added to the adsorbent after stage (b).

9. Composition for treatment of a borehole of claim 1, wherein the composition is prepared (a) the introduction of the first metal salt on the adsorbent and then (b) introducing a reagent for treatment of the well to the adsorbent.

10. Composition for treatment of a borehole of claim 1, wherein the water-insoluble adsorbent is selected from the group comprising activated carbon, silica particulate, precipitated silica, zeolite, fossil meals the ground, crushed walnut shells, fuller's earth and organic synthetic high molecular weight water-insoluble adsorbents.

11. Composition for well treatment according to claim 1, containing a water-insoluble adsorbent and the crystallized precipitate or (A) metal and reagent for treatment of the well or (B) salt reagent for treatment of the well received or:
(a) the introduction of metal�tration of salt and reagent for treatment of wells in the water-insoluble adsorbent and neutralization of the product and then the precipitation of neutralized reagent for treatment of the well to the adsorbent; or
(b) deposition of the reagent for treatment of the well and a metal salt from an aqueous alkaline liquid on a water-insoluble adsorbent and then neutralized by crystallization of the precipitate on the adsorbent.

12. Composition for well treatment according to claim 11, where the metal salt and the reagent for treatment of the well is introduced to the water-insoluble adsorbent in two separate stages.

13. Composition for well treatment according to claim 11, where the reagent for treatment of the well and the metal salt is introduced to the water-insoluble adsorbent in the form of an aqueous liquid containing a liquid acidic reagent for the treatment wells and a metal salt.

14. Composition for well treatment according to claim 11, where the composition is prepared by precipitation of the reagent for the treatment wells and metal salts from aqueous alkaline liquid on a water-insoluble adsorbent.

15. Composition for well treatment according to claim 11, where the reagent for treatment of the well represents at least one component selected from the group comprising inhibitors of scale formation, corrosion inhibitors, paraffin inhibitors, scale inhibitors, inhibitors of the formation of gas hydrates, inhibitors of the formation of asphaltene deposits, oxygen scavengers, biocides, foaming, reage�you for breaking emulsions and surfactants.

16. Composition for well treatment according to claim 15, where the reagent for treatment of the well is an inhibitor of scale formation.

17. Composition for well treatment according to claim 11, where the mass or molar ratio of metal salt and reagent for treatment of the well, introduced to the water-insoluble adsorbent is from about 1:4 to 4:1.

18. Composition for well treatment according to claim 1, where the mass or molar ratio of metal salt and reagent for treatment of the well, introduced to the water-insoluble adsorbent is about 1:1.

19. Composition for well treatment according to claim 8, wherein the amount of caustic soda added to the water-insoluble adsorbent is from about 2 to 6 equivalents per 1 equivalent of the compound for the treatment wells.

20. Composition for well treatment according to claim 19, where the amount of caustic soda added to the water-insoluble adsorbent is approximately 4 equivalent per 1 equivalent of the compound for the treatment wells.

21. Composition for well treatment according to claim 3, where the inhibitor of scale formation is anionic.

22. Composition for well treatment according to claim 11, where the metal (s) or metal salt (b) selected from the group comprising alkali metals, alkaline earth metals, transition metals or ammonium.

23. Composition for well treatment according to claim 22, wherein the salt represented�is an alkali metal or alkaline earth metal.

24. Composition for well treatment according to claim 23, wherein the salt is an alkaline earth metal.

25. Composition for well treatment according to claim 24, where alkaline earth metal is calcium.

26. Composition for treatment of a borehole of claim 1, wherein the surface area of the adsorbent is from about 1 m2/g to 100 m2/g.

27. Composition for treatment of a borehole of claim 1, wherein the amount of reagent for treatment of the well in the composition is from about 20 to 55 wt%.

28. Composition for treatment of a borehole of claim 1, wherein the mass ratio of reagent for treatment of the well to the water-insoluble adsorbent in the composition for the treatment of wells is from about 90:10 to 10:90.

29. Composition for well treatment according to claim 10, wherein the water-insoluble adsorbent is a fossil meals ground or crushed walnut shells.

30. Fluid treatment of a borehole containing the composition for well treatment according to claim 1 and a carrier fluid.

31. The fluid for the well treatment according to claim 30, further comprising the propping agent.

32. The fluid for the well treatment according to claim 30, where the number of composition for well treatment in the liquid is from about 0.1 to 2 wt%. propping agent.

33. The fluid for the well treatment according to claim 30, where the pH of the fluid for the well treatment has tractible than 7.0.

34. A method of processing a subterranean formation or well bore which comprises introducing into the formation or wellbore fluid for the well treatment according to claim 30.

35. A method according to claim 34, where the fluid for the well treatment is a fluid for hydraulic fracturing or fluid for acidizing.

36. A method according to claim 34, where the pH of the fluid for the well treatment has a value of more than 7.0.

37. A method according to claim 36, where the pH of the fluid for the well treatment has a value of more than 11,0.

38. Method of controlling release rate of the reagent for the treatment of a borehole in a borehole, comprising administering to the wellbore composition for the treatment of a borehole of claim 1.



 

Same patents:

FIELD: oil and gas industry.

SUBSTANCE: method of filter cake removal of bottom hole area of low-permeable low-temperature terrigenous reservoir located near the permafrost rocks comprises sequential injection through the column of oil-well tubing to the bottom hole area of mudded low-permeable low-temperature terrigenous reservoir of methanol in a volume of 1-2 m3 per 1 m of perforated thickness, phosphoric acid of 5-6% concentration with technological thermal equilibrium time of not more than 0.5 hours. Then aerated dispersed aqueous solution of hydrogen peroxide of low concentration of not more than 10-15 wt % is injected in the volume of 2-3 m3 per 1 m of the perforated thickness with forcing the orthophosphoric acid in a distal part of the reservoir. Then aerated dispersed aqueous solution of hydrogen peroxide is injected and forced again in the reservoir using the gas condensate with short-term technological thermal equilibrium time of not more than 0.5-1.0 h. Then removal and taking away of the remaining part of the aerated dispersed aqueous solution of hydrogen peroxide from the reservoir and the well to the surface is carried out. Then the well is developed by feeding to the well of inert gas, such as nitrogen, worked out, and the well is brought into production. At that injection of aerated dispersed aqueous solution of hydrogen peroxide is carried out by pulsed-cyclical method with alternate pumping the aqueous solution of hydrogen peroxide and inert gas, such as nitrogen.

EFFECT: increased permeability of dried bottom hole area of the reservoir, increase in the degree of filter cake removal of the bottom hole area and increase in productivity of the wells.

3 ex

FIELD: oil and gas industry.

SUBSTANCE: method of acid treatment of bottom-hole zone of carbonate reservoir includes injection of the acid composition containing in wt %: inorganic or organic acid, or their mixture 9.0-24.0; zwitterion surface-active substance - oleinamidopropylbetaine 1.0-10.0; hydrophobically-modified polyurethane polymer 0.05-3.0; water - rest, at that the acid composition is injected by single stage or by portions with holding between injections. The acid composition can additionally contain anionic surface-active substance in amount of 0.1-3.0 wt %. The above specified acid composition is injected alternating with injection of hydrochloric acid at 12-24% concentration.

EFFECT: alignment of profile of inflow of the production wells in carbonate reservoirs with non-uniform permeability, creation of new fluid conducting channels through entire perforated thickness of the reservoir, restoration of reservoir characteristics of bottom-hole zone due to its cleaning of mud solid particles.

3 cl, 1 tbl, 16 ex, 4 dwg

FIELD: chemistry.

SUBSTANCE: method for interval acidising of a horizontal well using a carbonate reservoir, which includes lowering a pipe string into a well; pumping acid compositions into the formation through the pipe string; conducting geophysical investigations in the horizontal well before treatment; selecting and separating intervals of the horizontal well into two groups; the first group includes intervals with permeability of 40-70 mD and water cut of the extracted product of 70-80%; the second group includes intervals with permeability of 5-39 mD and water cut of the extracted product of 50-69%; lowering into the horizontal well a pipe string plugged at the bottom and fitted with two packers with a perforated connecting pipe in between; performing consecutive treatment of the intervals of the horizontal well relating to the first group by sealed cut-off of each interval with subsequent alternating pumping into each interval in three cycles a temporary blocking composition at a rate of 6-12 m3/h, the temporary blocking composition used being a water-in-oil emulsion with dynamic viscosity of 120 mPa·s at 20°C, and an acid composition at a rate of 54-66 m3/h; after treatment of the intervals of the horizontal well relating to the first group, retrieving the pipe string from the horizontal well; at the mouth of the horizontal well, the pipe string is fitted with a liquid pulsator above the perforated connecting pipe and the pipe string which is plugged at the bottom and fitted with two packers with a perforated connecting pipe in between is once more lowered into the horizontal well; treating the intervals of the horizontal well of the second group by sealed cut-off of each interval with subsequent pulsed pumping into each interval a self-deviating acid composition based on a gelling agent at a rate of 24-36 m3/h.

EFFECT: intensifying oil extraction from a horizontal well, increasing oil yield and reducing the water cut of the extracted product.

3 dwg

FIELD: oil and gas industry.

SUBSTANCE: method of acid treatment of the oil reservoir includes geophysical survey in open horizontal wellbore to determine dislocations crossed by the bore in the reservoir, i.e. cracks, fractures, cavities, run in the horizontal wellbore on pipes string the filters with variable perforation density, packers installation, acid injection in horizontal wellbore, acid flush, well washing and commissioning. At that one packer is installed upstream the opened wellbore between the casing string and pipes string, and rest packers (expansing packers) are installed at places where the bore crosses dislocations. For each dislocation packer is selected with length exceeding width of the dislocation determined according to geophysical curves by at least 10 times. In pipes string hydrochloric acid with concentration 10-20% is injected on the basis 5-30 m3 per meter of oil-saturated reservoir thickness under wellhead pressure Pwh=(0.008…0.011)·H, MPa, where H is average depth of the reservoir, m. Perforation holes of filters are made round with diameter 5-10 mm, similar along the wellbore. Density of filters perforation for each section created between the packers, and between packer and bore end is increased linearly from zero at periphery to maximum in centre, in its turn this is determined via the hydrodynamical perfection coefficient as follows: k1h1Lnl1rc+С1=k2h2Lnl2rc+С2=...=knhnLnlnrc+Сn, where C1, C2, Cn are hydrodynamical perfection coefficients of the well as per character of opening on each nth section along the horizontal wellbore; l1, l2, ln are length of nth section, m; k1, k2, kn are average permeability of nth section, m2; h1, h2, hn are average oil saturated thickness of nth section, m; rc is well radius, m.

EFFECT: increased oil recovery of the reservoir due to increased reservoir coverage by action.

2 dwg, 2 ex

FIELD: oil-and-gas industry.

SUBSTANCE: oil field development method involves working fluid pumping in through the injection wells and formation products withdrawal through the retrieving wells. The oil field is developed with the established ratio of formation products withdrawal compensation through working fluid pumping in. The borehole zone is treated with acid in the injection wells. The oil field is developed with the newly established ratio of formation products withdrawal compensation through working fluid pumping in until approach of the displacement front, changed as the result of acid treatment, to the retrieving well. Hydrofracturing is performed in the retrieving well with withdrawal compensation recovered to the initial value after recovery of formation products water content changed as a result of hydrofracturing.

EFFECT: field oil yield increase.

1 ex

FIELD: oil and gas industry.

SUBSTANCE: invention is related to the technology intended for well productivity improvement. Large-volume selective acid treatment (LVSAT) for producers in carbonate reservoirs includes the injection to the well of an acid composite band with the specific volume of 1.5-3m3 per 1 m of an oil-saturated interval and non-linear viscous deflecting fluid before and/or upon the injection of the acid composite band, at that the injection of the acid composite is carried out with an optimal flow rate and an optimal ratio of a deflecting fluid volume to the acid composite volume, which are defined by mathematic modelling of the process considering changes in the wellhead and bottomhole pressure, type of the acid composite, type of the deflecting fluid, porosity and permeability of rock; at that for the purpose of the optimal flow rate optimisation for the acid composite injection dependencies of the optimal flow rate of injection on the specific volume of reagents injection are obtained with different constants of the reaction.

EFFECT: improved efficiency of large-volume selective acid treatment (LVSAT) for carbonate reservoirs.

2 cl, 5 tbl, 1 ex, 11 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: proposed process comprises lowering of flow string in hydrofrac zone and sealing of well annulus by packer. Rock is subjected to hydrofracturing to produce cracks by forcing gasified fluid via said flow string with the fracture propping. After sealing of casing string-borehole annuity packer is used to cool bottom hole zone by nitrogen gas with temperature of minus 40 to minus 45 degrees Centigrade. Then, hydrofrac is performed by injection of the mix of hydrochloric acid and nitrogen in amount sufficient for production of hydrochloric acid foam with foam content of 57% at well bottom. Then, 220°C superheated steam is forced via said flow string to hydrofracture. Note here that volume of said steam is selected to equal or to exceed that of forced hydrochloric acid foam and that of flow string. Now, the well is operated.

EFFECT: higher efficiency of fracturing.

1 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: composition for bottom hole formation zone processing comprises following elements in wt %: hydrochloric acid - 10.0-20.0, anionic surfactant, or non-ionic surfactant, or cationic surfactant, or mix thereof - 0.4-3.0, phosphorus compound AFON 300M - 0.01-15.0, solvent - 5.0-25.0, water making the rest. Proposed process comprises injection of said acid compound and its driving. Said compound is held to remove the reaction products. Note here that said acid compound is forced in pulse mode or in continuous mode in amount of 1-3 m3 per running meter of perforated depth of the bed at pressure allowable for this bed.

EFFECT: higher capacity of injection wells and fluid inflow due to decelerated reaction with bed rock, lower intensity of acid corrosion.

4 cl, 2 tbl, 17 ex

FIELD: oil and gas industry.

SUBSTANCE: in a carbonaceous oil deposit development method that includes drilling of horizontal wells with a core sampling from the productive formation, performance of core laboratory tests, acid treatment and multiple hydraulic fracturing of the formation in these wells, according to the invention the core is sampled at different sections along the whole length of the horizontal shaft. The sampled core is subjected to the laboratory tests to determine the fracturing pressure, at that the sections are identified along the shaft where the minimum fracturing pressure Pmin, MPa, and the maximum fracturing pressure Pmax, MPa is required. Each section is treated by acid; at that the acid concentration for each section is set as identical. During the acid treatment each treated section of the formation is isolated temporarily by packers from the remaining part of the well. Then multiple proppant hydraulic fracturing of the formation is made under pressure that does not exceed Pmax. At that at the sections, where Pmax is required the acid treatment is performed in a volume of Qmax, m3/m, at the sections where Pmin is required the acid treatment is performed in a volume not exceeding 10% of the maximum value. At the remaining sections the volume of the injected acid is defined proportionally to the obtained fracturing pressure in compliance with the following ratio: Qn=QminQmaxPminPmax(PnPmin)+Qmin, where Qn is the specific volume per meter of the thickness, which is required for the injection to the nth section of the formation along the horizontal shaft, m3/m, Pn is the required fracturing pressure at the nth section of the formation along the horizontal shaft, MPa.

EFFECT: improved sweep efficiency and increased oil recovery of the oil deposit.

1 dwg

FIELD: oil and gas industry.

SUBSTANCE: acid composition for acid treatment of production and injection wells in carbonate and terrigenous reservoirs contains the following, wt %: hydrochloric acid (24% or 36%) 25.0-50.0, alkyl benzene sulphonic acid containing in an alkyl group 12-14 atoms of carbon, 0.1-2.0, citric acid 0.5-3.0, acetic acid 3.0-12.0, methyl alcohol 3.0-10.0, OS-20 preparation 0.5-2.5, IKU-118 corrosion inhibitor 1.0-5.0, hydrofluoric acid (40%) 0.0-7.5, Feriks iron stabiliser 0.0-5.0, and water is the rest. An acid treatment method of the bottom-hole zone of a carbonate, terrigenous or mixed formation involves pumping to the well of the acid composition in the amount of 1.0-5.0 m3 per 1 m of perforated thickness of the formation, its forcing-through into the formation, exposure for the reaction during not more than 8 hours and further removal of reaction products; as an acid composition, there used is the above said composition or its solution in fresh water at the ratio of the above said composition to fresh water, which is equal to 1:1-1:2 respectively. The treatment method is developed in claims.

EFFECT: creation of a composition for acid treatment, which has low corrosion rate at formation temperatures; considerable improvement of efficiency of acid treatment.

3 cl, 3 tbl, 4 ex

FIELD: mining.

SUBSTANCE: method comprises a test injection of fracturing fluid and a pack of fracturing fluid with proppant, correction of the fracturing project and carrying out the main fracturing process. At that in the high-permeability reservoirs having an absolute permeability of not less than 100 mD, the main process of hydraulic fracturing is carried out using standard working fluid flow rate of 2.2 m3/min to 4.0 m3/min. When pressing the proppant-gel mixture the stepwise reduction of flow rate is carried out with the reduction step in the range of 0.1 m3/min to 0.5 m3/min, but to the value of not less than 2.0 m3/min. The final concentration of proppant is set of not less than 800 kg/m3.

EFFECT: increase in efficiency of intensification of operation of the well by creating a wider and conducting crack in the bottom-hole area of the layer.

1 tbl

FIELD: oil and gas industry.

SUBSTANCE: method involves landing of tubing string with packer to a well, packer seating, hydraulic fracture liquid injection by the tubing string with packer to a low-permeable formation, hydraulic fracturing of the low-permeability formation with further fracture fixation by injection of liquid carrier with propping agent via the tubing string, pressure relief in the well. Before tubing string landing to the well, water-bearing interlayer interval of the low-permeable formation is perforated to form perforation holes. Then at the wellhead the tubing string is filled upwards from the bottom with a plug, lower hole rows, packer, upper hole rows and additional packer. Inside the tubing string, a mobile bushing with radial channels is inserted to seal lower hole rows of the tubing string tightly in initial position and connecting the tubing string via upper hole rows and perforation holes to the ware-bearing interlayer. A seat is installed inside the mobile bushing, the mobile bushing and the seat are fixated in initial position against the tubing string by a differential shear element. The tubing string is landed to the well, packer and additional packer are seated in the well so as to shot water-bearing interlayer off tightly at two sides, upper water0bearing interlayer is isolated by injection and flushing of water isolation composition via the tubing string through upper hole rows to the water-bearing interlayer through perforation holes under pressure twice lower than hydraulic fracture pressure of the formation, process break is made for solidification of the water isolation composition, then a ball is dropped to the tubing string from wellhead, and overpressure is formed in the tubing string. First the shear element is destroyed, and under impact of overpressure above the ball, mobile bushing is shifted down along the tubing string to a stop against the tubing string plug, overpressure increase in the tubing string is continued, and the shear element is destroyed again. The seat is brought down to a stop against the plug under impact of overpressure above the ball. Upper hole rows of the tubing string are shut off tightly by the mobile bushing, and lower hole rows are connected to the tubing string by radial channels of the mobile bushing.

EFFECT: improved efficiency of hydraulic fracturing.

2 dwg

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises drilling the well horizontal shaft in oil-saturate section of production bed, cementing of annulus between casing and bed rock. Casing pipe is perforated in said well shaft oriented in azimuth by intervals with the help of slot perforator lowered in the well on string in a single trip. String with packer is lowered in the well to fit the packer in place. Fracturing fluid is injected via said string for hydrofracturing in said horizontal well shaft. Well shaft us drilled in the bed parallel with direction of minimum main strain. Plug is fitted at string lower end and two packers are arranged at flexing pipe string. Note here that through holes are made at the latter. Said flexing pipe string with packers is lowered into well shaft for hydraulic fracturing via perforated intervals by cutting of every interval of perforation on both sides. Bed fracturing is started from horizontal well interval nearby the bottom and fluid is forced via flexible pipe string via through holes at flow rate of 2 m3/min to produce transverse fractures from perforation interval relative to well shaft. Note here that fracturing fluid is composed of hydrocarbon-based cross-linked gel. Made fractures are secured by injection of proppant of 12/18 mesh fraction with cross-linked gel, a carrier fluid. Packers are removed to displace flexible pipe string for hydraulic fracturing of the bed in the next perforation interval. Then, above jobs are reiterated. Then, flexible piper string with packers is withdrawn from the well to lower pipe string therein. Packer is fixed at well vertical part for hydraulic fracturing by injection of fluid via horizontal well shaft to produce lengthwise fractures at flow rate of 8 m3/min. Linear gel is used as fracturing fluid. Said lengthwise fractures are secured by injection of ground quartz with linear gel as carrier fluid.

EFFECT: higher efficiency of fracturing.

2 dwg

FIELD: oil and gas industry.

SUBSTANCE: group of inventions is referred to intensification of hydrocarbons production from formation by hydraulic fracturing. The method of proppant induced aggregation in hydraulic fracture crack includes makeup of the proppant carrier fluid, which viscosity is increased by usage of polymer gel capable of syneresis; injection of the proppant suspension and the above fluid to the well; initiation of gel syneresis with formation of proppant aggregations. According to the second version the method includes initiation of polyelectrolyte complex formation with proppant aggregations. According to the third version the method includes makeup of the proppant carrier fluid containing polymer at temperature less than its critical solution temperature; injection of the proppant suspension and the above fluid to the underground formation at temperature more than the lowest limit of polymer critical solution temperature with formation of proppant aggregations.

EFFECT: inhomogeneous distribution of proppant in hydraulic fracture cracks, which increases conductivity and productivity of the well.

31 cl, 2 tbl, 12 ex, 5 dwg

FIELD: oil and gas industry.

SUBSTANCE: treatment method of underground hydrocarbon-containing formations involves the following: a) provision of a composition including a thickening initiator measuring pH, and a polymer capable of hydration in a certain pH range; b) pumping of a composition with pH value beyond the limits of the above pH range; c) activation of an action of pH thickening initiator for displacement of pH composition to the above range of its values, and d) provision of a possibility of increasing viscosity of the composition and shaping of a plug. According to another version, a processing method of underground hydrocarbon-containing formations involves the following: a) provision of a composition containing a polymer capable of hydration in a certain pH range; b) pumping of the composition with pH value beyond the limits of the above pH range; c) provision of a pH changing thickening initiator; d) activation of the action of the thickening initiator for displacement of pH composition to the above range of its values, and e) provision of a possibility of increasing viscosity of a composition and shaping of a plug. The invention has been developed in dependent claims.

EFFECT: improving efficiency of initiation and control of plug formation.

15 cl, 5 ex, 3 dwg

FIELD: oil and gas industry.

SUBSTANCE: in a carbonaceous oil deposit development method that includes drilling of horizontal wells with a core sampling from the productive formation, performance of core laboratory tests, acid treatment and multiple hydraulic fracturing of the formation in these wells, according to the invention the core is sampled at different sections along the whole length of the horizontal shaft. The sampled core is subjected to the laboratory tests to determine the fracturing pressure, at that the sections are identified along the shaft where the minimum fracturing pressure Pmin, MPa, and the maximum fracturing pressure Pmax, MPa is required. Each section is treated by acid; at that the acid concentration for each section is set as identical. During the acid treatment each treated section of the formation is isolated temporarily by packers from the remaining part of the well. Then multiple proppant hydraulic fracturing of the formation is made under pressure that does not exceed Pmax. At that at the sections, where Pmax is required the acid treatment is performed in a volume of Qmax, m3/m, at the sections where Pmin is required the acid treatment is performed in a volume not exceeding 10% of the maximum value. At the remaining sections the volume of the injected acid is defined proportionally to the obtained fracturing pressure in compliance with the following ratio: Qn=QminQmaxPminPmax(PnPmin)+Qmin, where Qn is the specific volume per meter of the thickness, which is required for the injection to the nth section of the formation along the horizontal shaft, m3/m, Pn is the required fracturing pressure at the nth section of the formation along the horizontal shaft, MPa.

EFFECT: improved sweep efficiency and increased oil recovery of the oil deposit.

1 dwg

FIELD: oil and gas industry.

SUBSTANCE: method includes running of production string with packer in to the well, setting of the packer, hydraulic fracturing by injecting fracturing fluid through production string with packer to the producing reservoir with further proppant injecting through perforated interval in the low-permeable bed, pressure releasing from the well. Additionally perforated interval in the low-permeable bed is isolated temporary, the interval of clay layer is perforated using alternating charges of large diameter and deep invasion; then the production string with packer is lowered so that the lower end of the production string is at the level of clay layer roof, the packer is set in the well, the low-permeable bed is fractured with formation of cracks by injection of fracturing fluid along the production string through perforated intervals in clay layer. Then bank of oil-based cross-linked gel is injected to cracks in volume of 3-5 m3 with flow rate of 10 m3/min. Proppant moisture is used as proppant. Then cracks are reinforced by dosed injection of fracturing fluid and proppant mixture starting with concentration of 400 kg/m3 for proppant mixture with stepped increase of its concentration in fracturing fluid per 200 kg/m3 for each dose and flow rate of 5 m3/min. The proppant mixture is made at the wellhead with the following ratio of components, wt %: proppant 12/40 mesh - 30%; proppant 18/20 mesh - 30%; quartz flour - 40%. Upon completion of hydraulic fracturing of low-permeable bed temporary isolation is removed from the perforated interval of the low-permeable bed with formation of hydraulic connection between the borehole and created fracture.

EFFECT: improved reliability of hydraulic fracturing for low-permeable bed with clay layers and bottom water.

1 dwg

FIELD: oil and gas industry.

SUBSTANCE: in the method of well operation stimulation including test injection of breakdown fluid and package of breakdown fluid with proppant, correction of the breakdown project and performance of fracturing in low-permeable reservoirs having absolute permeability less than 1mD, hydraulic fracturing is made with injection of flush fluid on the basis of 1.0-3.0 m3 per 1 t of proppant using proppant fractions, which include only fine fraction with size less than 30/60 mesh with final concentration of proppant less than 300 kg/m3; at injection of the fluid flow rate of 3.5 m3/min and more and concentration of gel formation is set less than 2 kg/m3, with final underflush of the mixture in volume of 0.1-0.5 m3.

EFFECT: simulation of the well opening the low-permeable formation.

3 ex

FIELD: mining.

SUBSTANCE: method involves drilling of a horizontal well, lowering to a vertical part of the well of a casing string and its cementing, lowering of a pipe string with a packer to a well, seating of the packer, formation of fractures of formation hydraulic fracturing (FHF) in the horizontal well shaft by pumping via the pipe string of fracturing fluid, and fixation of fractures by pumping of carrier fluid with proppant. The horizontal shaft is drilled perpendicular to direction of minimum main stress. FHF is performed by pumping of fracturing fluid with flow rate of 2-3 m3/min with formation of a longitudinal fracture in the formation relative to the open horizontal part of the well; crosslinked gel is used as fracturing fluid; then, fixation of a longitudinal fracture is performed by pumping via the pipe string of proppant of large fraction with carrier fluid - crosslinked gel. Then, FHF is performed by pumping of fracturing fluid with flow rate of 7-9 m3/min; line gel is used as fracturing fluid; after that, fixation of branched FHF fractures is performed by pumping of proppant of small fraction with carrier fluid - line gel.

EFFECT: improving FHF efficiency and reliability.

2 dwg

FIELD: oil and gas industry.

SUBSTANCE: method comprises test forcing of fracturing fluid and pile of fracturing fluid with proppant, correcting the fracturing project and performing of the main fracturing process. In highly permeable reservoirs with absolute permeability not less than 100 mD the main fracturing process is carried out with usage of proppant fractions, which include initial fraction with mesh size from 30/40 up to 20/40 and the main coarse fraction with mesh size of 12/18 and more in the volume not less than 70% of the total proppant quantity with final proppant concentration not less than 750 kg/m3. While injecting fraction with mesh size of 12/18 and more through perforated openings fluid consumption is set so that it does not exceed 3 m3/min and wellhead pressure is maintained at the level less than 35 MPa.

EFFECT: improving the efficiency of hydraulic fracturing for highly permeable strata.

1 tbl

FIELD: oil and gas industry.

SUBSTANCE: lightweight plugging material contains cement PTsT-I-100, lightweight - expanded vermiculite, technical salt, chemical agent Crep, at the following ratio in wt %: cement PTsT-I-100 - 84.75; vermiculite - 9.42; Crep - 1.13; NaCl - 4.7. During the cement slurry preparation - expanded vermiculite, technical salt.

EFFECT: exclusion of the hydraulic fracture during wells cementation due to improved parameters of the packing cement, increased strength of cement stone at low and moderate temperatures at early stage of solidification upon simultaneous density reduction of the cement slurry.

1 tbl

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