RU2272127C1 - Method for mudding formation removing from bottomhole terrigenous formation area - Google Patents

Abstract

FIELD: oil production industry, particularly to stimulate production by forming crevices or fractures with the use of eroding chemicals.

SUBSTANCE: method involves injecting technological acid solution in bottomhole formation area; holding it in formation to provide reaction; removing reaction products from formation. The acid solution comprises acid and surfactant, wherein acid-surfactant reagent is used as the acid and the surfactant. The acid-surfactant reagent comprises surfactant in amount of 0.5-5.0% by weight, waterproofing agent in amount of 0.5-5.0% by weight, corrosion inhibitor or acetyl benzene or methyl ethyl ketone in amount of 0.1-3.0 % by weight, citric acid in amount of 1.0-10.0 % by weight, remainder is sulfonic acid. The technological acid solution comprises potassium persulfate or sodium persulfate in amount of 1.0-5.0% by weight, above acid-surfactant reagent in amount of 10.0-50.0 % by weight, remainder is water.

EFFECT: increased efficiency and improved technological effectiveness, prevention of secondary precipitations and emulsions formation.

7 ex, 3 tbl

Description

The invention relates to the oil and gas industry, in particular to methods for removing clogging formations from the bottomhole zone of the terrigenous reservoir, and can be used in the process of stimulating oil production and well development by acidizing the terrigenous reservoir, and can also be used to restore the permeability of the bottomhole zone of the wells that left from drilling, when there is absorption of a clay solution, or wash liquids based on water-soluble polymers, or intensifiers tion of flow of oil wells after fracturing, or other processing operations, when there is incomplete destruction primenyamyh liquids based on water soluble polymers.

There is a method of reagent treatment of the bottom-hole zone of wells with the aim of wedging, consisting in the fact that at the wellhead in the tank prepare an aqueous solution containing 15-30% wt. ammonium sulfate and 6-10% wt. sodium peroxocarbonate [1].

The prepared solution is pumped through tubing, lowered to the depth of the lower part of the filter, into the well, then fresh water is forced out of the tubing into the filter interval. Next, the tubing is closed and the reagent solution is crushed with fresh water into the bottomhole zone to a depth exceeding the clay radius of the filter zone and maintained at the created pressure for 8-10 hours, after which the pressure is released and the well is pumped.

The known method of processing the bottom-hole zone of the well provides a clay formation due to spontaneous dispersion of clay particles resulting from the interaction of a water-salt solution with clay minerals.

However, due to the interaction of an aqueous solution of salts with mineralized formation water, insoluble sediments form, leading to an increase in filtration resistances in the bottomhole formation zone.

Closest to the proposed invention by technical essence is a method of removing colmatizing formations from injection wells, including the injection of an acidic technological solution, the following component composition,% wt.:

Sodium or potassium salts sulfur-containing acids 5-10 Hydrofluoric acid 2-4 Surface-active substance 0.2-1.5 Water Rest

holding it in the reservoir for a reaction followed by removal from the reservoir [2 - prototype].

The disadvantage of using this method is that as a result of the reaction of hydrofluoric acid with quartz, clay and mineralized formation water, poorly soluble fluorides and hexafluorosilicates are formed, and when the acid is neutralized, silicic acid gel precipitates, leading to a decrease in the permeability of the bottomhole formation zone [3 ].

The invention is aimed at creating an effective and technologically advanced method for removing clogging formations from the bottomhole zone of a terrigenous formation, eliminating the formation of secondary sediments and emulsions by pumping an acidic technological solution containing salts of sulfur-containing acid, acid, surfactant and water, holding it in the formation for a reaction followed by removal from the formation of reaction products, as salts of sulfur-containing acid containing potassium persulfate, or sodium persulfate, or ammonium persulfate Ia and the acid and surfactant - SAW acid reagent at the following component ratio,% wt .:

Potassium persulfate or sodium persulfate, or ammonium persulfate 1.0-5.0 Surfactant acid reagent 10.0 - 50.0 Water Rest,

and as a surfactant - an acid reagent - a pasty composition, including a bifunctional surfactant, which has non-inogenic and anionic properties, obtained on the basis of ethoxylated nonylphenol surfactants Nezhegol, an aqueous solution of quaternary ammonium salts - condensation products of tertiary amines and benzyl chloride, a hydrophobizing agent, Nephtenol hydrophobizator 1 or acetophenone or methyl ethyl ketone, citric acid and sulfamic acid, in the following ratio, wt.%:

Surfactant Nezhegol 0.5-5.0 Neftenol GF 0.5-5.0 Corrosion Inhibitor IKU-1, or acetophenone, or methyl ethyl ketone 0.1-3.0 Lemon acid 1.0-10.0 Sulfamic acid Rest

The result is achieved by introducing the required amount of potassium persulphate, or sodium, or ammonium into the acidic technological solution, effectively destroying and dispersing clay particles, reducing the clay swelling coefficient, destroying water-soluble polymers used in drilling, hydraulic fracturing and well treatment and surfactant-acid a reagent containing a bifunctional surfactant with non-inogenic and anionic properties, obtained on the basis of hydroxyethylated nonylphenols surfactants Nezhegol and an aqueous solution of quaternary ammonium salts, the condensation products of tertiary amines and benzyl chloride, the Neftenol GF hydrophobizer, which reduce the surface tension, prevent the formation of emulsions and precipitates upon contact of an acidic technological solution with hydrocarbons that also contain sulfamic and citric acids, which maintain a low pH value, contribute to the destruction of clay and prevent the formation of secondary precipitation; corrosion inhibitor IKU-1, or acetophenone, or methyl ethyl ketone, which can reduce the corrosion activity of persulfates and acids.

The features of the invention "Method for the removal of clogging formations from the bottomhole zone of the terrigenous formation" are the following.

1. Injection of an acidic technological solution.

2. The exposure of the injected acidic technological solution in the reservoir to the reaction.

3 Removal of reaction products from the formation.

4. As the acidic technological solution, a composition is used containing salts of sulfur-containing acid, acid, surfactant and water.

5. Potassium persulfate is used as the salt of the oxygen-containing acid.

6. Sodium persulfate is used as the salt of the oxygen-containing acid.

7. Ammonium persulfate is used as the salt of the oxygen-containing acid.

8. As an acid and surfactant, a surfactant-acid reagent is used, including a bifunctional surfactant, which has non-inogenic and anionic properties, obtained on the basis of ethoxylated nonylphenols surfactants Nezhegol, an aqueous solution of quaternary ammonium salts - condensation products of tertiary amines and benzyl chloride hydrophobizing agent Neftenol GF, citric acid and sulfamic acid.

9. The surfactant-acid reagent as an inhibitor of corrosion contains an inhibitor of IKU-1.

10. The surfactant acid reagent contains acetophenone as a corrosion inhibitor.

11. Surfactant-acid reagent as a corrosion inhibitor contains methyl ethyl ketone.

Signs 1-4 are common with the prototype, and signs 5-11 are the essential distinguishing features of the invention.

SUMMARY OF THE INVENTION

A method is proposed for removing clogging formations from the bottomhole zone of a terrigenous reservoir, including pumping an acidic technological solution containing salts of sulfur-containing acid, acid, surfactant and water, keeping it in the formation for a reaction, followed by removal of reaction products from the formation, containing potassium sulfate as salts of sulfur-containing acid , or sodium persulfate, or ammonium persulfate, and as an acid and surfactant - surfactant-acid reagent in the following ratio of components, wt.%:

Potassium persulfate or sodium persulfate, or ammonium persulfate 1.0-5.0 Surfactant acid reagent 10.0-50.0 Water Rest.

and as a surfactant, an acid reagent contains a pasty composition, including a bifunctional surfactant, which has non-inogenic and anionic properties, obtained on the basis of ethoxylated nonylphenol surfactants Nezhegol, an aqueous solution of quaternary ammonium salts - condensation products of tertiary amines and benzyl chloride, a hydrophobizing agent, Neftenol hydrophobizator I, Nephtenol or acetophenone or methyl ethyl ketone, citric acid and sulfamic acid, in the following ratio, wt.%:

Surfactant Nezhegol 0.5-5.0 Neftenol GF 0.5-5.0 Corrosion Inhibitor IKU-1, or acetophenone, or methyl ethyl ketone 0.1-3.0 Lemon acid 1.0-10.0 Sulfamic acid Rest

For research were used:

1. Potassium persulfate is a crystalline white powder containing at least 99.0% wt. the main substance, is produced according to TU 38.103270-87.

2. Sodium persulfate is a white crystalline powder containing at least 99.0% wt. the main substance, qualification of PSA, is produced according to TU 6-09-840-63.

3. Ammonium persulfate is a white crystalline powder containing at least 99.0% wt. the main substance, qualification H, is produced according to GOST 20478-75.

4. Sulfamic acid is a crystalline white powder containing at least 86.0% of the mass. the main substance, is produced according to TU 6-36-00204197-1030-89 with amendment 1.2.

5. Citric acid is a crystalline white powder containing at least 99.0% wt. main substance, is produced according to GOST 908-79.

6. Surfactant Non-colic - a viscous mass of grayish-brown color with a weak specific odor, is a bifunctional surfactant with non-inogenic and anionic properties, obtained on the basis of ethoxylated nonylphenols, is produced according to TU 2381-050-17197708-99.

7. Water repellent Neftenol GF - a liquid from yellow to dark brown in color, is an aqueous solution of Quaternary ammonium salts - condensation products of tertiary amines and benzyl chloride, is produced according to TU 2484-035-17197708-97.

8. IKU-1 corrosion inhibitor - a viscous brown liquid, manufactured according to TU 2415-005-12749890-2000.

9. Acetophenone (methylphenylketone) - a clear liquid, qualification of ChP, is produced according to TU 6-01-406-90.

10. Methyl ethyl ketone - a clear liquid, qualification H, is produced according to TU 38-10243-80.

11. Sodium pyrosulfate is a white powder containing 97.0% wt. the main substance, is produced according to TU 2621-002-00205050-98.

12-Hydrofluoric acid (hydrofluoric) containing 40% wt. HF, is produced according to TU 48-5-184-78.

13. Nonionic surfactant - reagent OP-10, is an oily liquid from light yellow to light brown in color with a moisture content of not more than 0.5%, is produced according to GOST 8244-81.

Examples of the preparation of a surfactant acid reagent

Example 1

In a 250 ml beaker, to 97.9 g of sulfamic acid, with stirring with a glass rod, 1.0 g of citric acid, 0.5 g of PAS-Nezhegol, 0.5 g of Neftenol-GF, 0.1 g of IKU-corrosion inhibitor were successively added. one.

After stirring for 5-10 minutes, a composition was obtained with the following content of ingredients,% wt .: SAW-Nezhegol - 0.5, Neftenol-GF - 0.5; corrosion inhibitor IKU-1 - 0.1, citric acid - 1.0; sulfamic acid - the rest.

Example 2

In a 250 ml beaker, to 88.5 g of sulfamic acid, with the stirring with a glass rod, 5.0 g of citric acid, 2.5 g of surfactant-Nezhegol, 2.5 g of Neftenol-GF, 1.5 g of acetophenone were successively added.

After stirring for 5-10 minutes, a composition was obtained with the following content of ingredients,% wt .: SAW-Nezhegol - 2.5;

Neftenol-GF - 2.5; acetophenone - 1.5, citric acid - 5.0; sulfamic acid - the rest.

Example 3

In a 250 ml glass beaker, 10.0 g of citric acid, 5.0 g of surfactant-Nezhegol, 5.0 g of Neftenol-GF, 3.0 g of methyl ethyl ketone were successively added to 77.0 g of sulfamic acid with stirring with a glass rod.

After stirring for 5-10 minutes, a composition was obtained with the following content of ingredients,% wt.: Surfactant-Nezhegol - 5.0;

Neftenol-GF - 5.0; methyl ethyl ketone - 3.0; citric acid - 10.0; sulfamic acid - the rest.

Examples of the preparation of acidic technological solution.

Example I.

In a 250 ml glass beaker in 89.0 ml of water, 1.0 g of potassium persulfate and 10.0 g of the surfactant-acid reagent described in Example 1 were successively dissolved with stirring with a glass rod.

After stirring for 5-10 minutes, a composition was obtained with the following content of ingredients,% wt .: potassium persulfate - 1.0; Surfactant acid reagent - 10.0; water is the rest.

Example II

In a 250 ml glass beaker in 67.0 ml of water, 3.0 g of sodium persulfate and 30.0 g of the surfactant-acid reagent described in Example 2 were successively dissolved with stirring with a glass rod.

After stirring for 5-10 minutes, a composition was obtained with the following content of ingredients,% wt .: sodium persulfate - 3.0; Surfactant acid reagent - 30.0; water is the rest.

Example III

In a 250 ml glass beaker in 45.0 ml of water with stirring with a glass rod, 5.0 g of ammonium persulfate and 50.0 g of the surfactant-acid reagent described in Example 3 were successively dissolved.

After stirring for 5-10 minutes, a composition was obtained with the following content of ingredients,% wt .: ammonium persulfate - 5.0; Surfactant acid reagent - 50.0; water is the rest.

Example IV (prototype, composition No. 9 in table No. 1).

In a 250 ml Teflon beaker in 86.0 ml of water, 6.0 g of sodium pyrosulfate, 7.5 g of 40% hydrofluoric acid and 0.5 g of surfactant-OP-10 were successively dissolved with a plastic stick.

After stirring for 5-10 minutes, a composition was obtained with the following content of ingredients,% wt .: sodium pyrosulfate - 6.0; hydrofluoric acid - 3.0, surfactant - 0.5; water is the rest.

The content of components in the acid compositions are presented in table 1.

Table 1
The content of components in acid compositions No. Components based on the main substance The content in the acid composition,% wt. one 2 3 four 5 6 one. Sample Numbers one 2 3 4 Prototype 2. Water 89.0 67.0 45.0 90.5 3. Potassium persulfate 1,0 four. Sodium persulfate 3.0 5. Ammonium persulfate 5,0 6. Surfactant acid reagent (example 1) 10.0 7. Surfactant acid reagent (example 2) 30,0 8. Surfactant acid reagent (example 3) 50,0 9 Sodium pyrosulfate 6.0 10. Hydrofluoric acid 3.0 eleven. SAW-OP-10 0.5

In laboratory conditions, the following properties of the proposed acidic technological solution were determined: the ability not to form precipitates and emulsions upon contact with hydrocarbons; the ability to retain iron ions in solution, interfacial surface tension at the border with a hydrocarbon; the corrosion rate of steel, the dissolution rate of bentonite clay at a temperature of 70 ° C, typical for most deposits of Western Siberia, the rate of destruction of a water-soluble polymer used in drilling, hydraulic fracturing and in well treatments.

и динамической вязкостью при 20°С

и керосин ТС-1.The ability of the proposed acidic technological solution to not form precipitates and emulsions upon contact with hydrocarbons was determined by the volume of the aqueous and hydrocarbon phases after shaking equal volumes of the hydrocarbon and acidic technological solution in a graduated tube, followed by heating to 40-50 ° C, settling for 30 minutes and pouring the contents of the tube through a sieve with a mesh size of 0.149 mm In the event of the formation of a precipitate or emulsion, traces remained on the sieve. The experiments used oil Samotlor field density at 20 ° C

and dynamic viscosity at 20 ° C

and kerosene TS-1.

One of the important characteristics of acid solutions used in oil production is their ability to retain iron ions, thereby not forming secondary precipitates - iron hydrates. Sources of iron ions can be corrosion products of tubing, pumps and other equipment, as well as formation minerals. The precipitation of iron depends on the ratio between the ions of Fe ³⁺ and Fe ²⁺ and the pH of the medium. Fe ³⁺ ions precipitate at pH 2-3, and Fe ^{2+ ions} precipitate at pH 6-7. Thus, the bottom-hole zone of the formation of both producing and injection wells is saturated with iron hydroxide of colloidal degree of dispersion, which is characterized by good adhesion on the rock, as a result of which gel-like iron compounds precipitate in the bottom-hole zone and block the flow channels. As sources of iron ions, a 10% aqueous solution of ferric chloride (FeCl ₃ ) was used. To 10 ml of the proposed acidic technological solution and the prototype solution was added 10-20 vol.% 10% solution of FeCl ₃ , after which chalk (CaCO ₃ ) was added to pH 3-4. After the reaction, precipitation of Fe (OH) ₃ precipitate was visually observed. The experiments were carried out at 20 ° C, the mixture in which precipitation was not observed, was heated to 30-40 ° C. A brown precipitate indicates the formation of iron hydroxide.

The research results are presented in table 2.

Interfacial tension, mN / m at the border with a hydrocarbon (TS-1 kerosene) was determined using an automatic LCA 2.784.001 stalagmometer according to the procedure attached to the device.

The research results are presented in table 3.

The corrosion rate of steel g / m ² · hour was determined according to the generally accepted method by weight loss of St3 steel plates with a size of 25 · 20 · 0.5 mm after holding them for 24 hours in the tested acidic technological solution at 20 ° С.

The research results are presented in table 3.

To test the dissolution of bentonite clay, three paper filters and three clay samples of 2 g each were taken. The weights were dried to constant weight at a temperature of 105 ° C. Next, the clay was transferred to a paper filter and weighed on an analytical balance to the fourth digit.

The amount of test solution was 15 ml (2.5 times the mass of the sample multiplied by the number of measurements).

Filters with clay were placed in a Teflon funnel, mounted on a 100 ml Teflon cup. A glass with a funnel was placed in a heating cabinet. The test solution was heated for 15 min in a Teflon cup at a temperature of 70 ° C. Then the solution was poured into the first funnel and the clay was dissolved for 5 minutes. In this case, part of the solution was filtered off. The resulting filtrate was transferred to a second funnel to dissolve the next clay sample. The duration of the second filtration was 10 minutes. The resulting filtrate was transferred to dissolve the third clay sample. The duration of the third suspension filtration was 15 minutes.

After filtering, the spent clay was washed with distilled water in an amount of 200 ml portions at a temperature of 70 ° C.

After washing, the samples were dried in an oven at a temperature of 105 ° C to constant weight.

The solubility of clay,%, was calculated by the formula

P _G = (m ₁ -m ₂ ) 100% / m ₁ ,

where m ₁ - clay mass before the experiment, g;

m ₂ - clay mass after the experiment, g

The rate of destruction of the water-soluble polymer used in drilling, hydraulic fracturing and in well treatments was investigated as follows: 10 ml of the proposed acidic technological solution or acidic technological solution according to the prototype was added to 90 ml of a 3.0% aqueous solution of KMC-600 with stirring, the rate of destruction water-soluble polymer was estimated by the time during which the viscosity of the polymer solution disappeared, it ceased to stretch and began to dig from the stick. It is known that the rate of destruction of a water-soluble polymer strongly depends on the concentration of the oxidizing agent; therefore, the compositions with the maximum salt content of sulfur-containing acid are subject to comparison (compositions 3 and 4). The test was carried out at a temperature of 70 ° C.

The lower limit of the concentration of salts of sulfur-containing acid was determined by the dissolution of bentonite clay and the destruction of a water-soluble polymer, the upper - by the solubility of salts in the composition.

The lower concentration limit of the surfactant-acid reagent was determined by dissolving the bentonite clay, the necessary interfacial tension of the acid composition at the border with the hydrocarbon (not higher than 10.0 mN / m), corrosion rate (not higher than 1.0 g / m ² · h), the ability of the composition to keep 3-valent iron ions in the solution, not to form precipitates and emulsions in contact with hydrocarbons, and the top one - by the solubility of salts of sulfur-containing acid in the composition.

The lower limit of the concentration of surfactants in a surfactant-acid reagent was determined by the necessary interfacial tension of the acid technological composition at the border with the hydrocarbon (not higher than 10.0 mN / m), the ability not to form precipitation and emulsion upon contact with hydrocarbons, and the upper one - economic feasibility.

The lower concentration limit of sulfamic and citric acids was determined by the dissolution of bentonite clay and the destruction of a water-soluble polymer, the upper - by the solubility of acids in the acidic technological solution.

The lower concentration limit of corrosion inhibitors: IKU-1, acetophenone and methyl ethyl ketone was determined by the permissible corrosion rate in an acidic technological solution (not more than 1.0 g / m ² · h), and the upper one was determined by economic feasibility.

Studies of the emulsifying ability of the proposed acidic technological solution showed that emulsions do not form when interacting with oil and kerosene (TS-1): mixtures of oil or TS-1 and the proposed composition (formulations 1-3 in table No. 1) after shaking were completely separated into water and the organic phase for 5-30 minutes, subsequent pouring of the contents of the test tube through a sieve did not leave any traces on the sieve with a mesh size of 0.149 mm, while the prototype composition forms emulsions with oil and kerosene (TC-1), leaving traces on the s those.

table 2
The ability of an acidic technological solution to retain iron ions in a solution Composition number in table 1 The content of a 10% solution of FeCl ₃ ,% vol Brown sediment one 2 3 one. 10 No one. fifteen No one. twenty No 2. 10 No 2. fifteen No 2. twenty No 3. 10 No 3. fifteen No 3. twenty No one 2 3 four. 10 there is four. fifteen there is four. twenty there is

As follows from table 2, the composition of the prototype does not have the ability to retain iron ions, while the proposed acidic technological solution effectively retains iron ions in solution after neutralization.

Table 3
Properties of acidic technological solutions Composition number in table 1 Interfacial tension at the border with TS-1, mN / m The corrosion rate, g / m ² · h The rate of viscosity loss of a 3.0% solution of KMC-600 at a temperature of 70 ° C Clay dissolution 70 ° C Contact time, min The dissolution of clay,% hour 5 4.21 3.0 one. 3.15 0.95 10 5.48 fifteen 3.18 5 4.97 2. 2,38 0.84 10 7.54 2.0 fifteen 4.08 5 5.57 3. 2.25 0.89 10 8.14 1,5 fifteen 4.32 four. 5 25.16 proto 3.62 141.5 10 1.37 2.0 type of fifteen 0.18

As follows from table 3, while maintaining low values of interfacial tension and a lower corrosion rate, the dissolving ability of clay in the proposed acidic technological solution at a temperature of 70 ° C for the first 5 minutes of processing is significantly lower than in the method of the prototype, while it remains in time, while in the method according to the prototype, it is significantly reduced, which will allow, when applying the proposed method, to increase the coverage of the reservoir and, therefore, the processing efficiency, also with an equal salt content sulfur-containing acids in the composition No. 3 - 5% wt. ammonium persulfate and in the composition No. 4 - 5% wt. sodium pyrosulfate - destruction with the addition of the proposed acidic technological solution is faster than in the composition of the prototype.

As follows from the data presented, the proposed method has higher performance compared to the prototype, and a surfactant prepared at the factory, an acid reagent, will simplify the technology for preparing an acidic technological solution in the field.

Sources of information taken into account

1. USSR author's certificate No. 1721220 (Е 21 В 43/27), published March 23, 1992, Bull. No. 11 - analogue.

2. RF patent No. 2086760 (Е 21 В 43/27), published on 08/10/1997, Bull. No. 22 is a prototype.

3. Curtis Crowey, Jacques Masmontale, Ron Thomas "Trends in acid matrix processing." Oil review. Schlumberger. - Autumn. - 1996. S. 20-31.

Claims (1)

A method for removing colmatizing formations from the bottomhole zone of a terrigenous formation, including pumping an acidic technological solution containing a salt of sulfur-containing acid, acid, a surfactant surfactant and water, holding it in the formation for a reaction, followed by removal of reaction products from the formation, characterized in that it contains potassium persulfate or sodium persulfate, or ammonium persulfate as a salt of oxygen-containing acid, and a surfactant-acid reagent composition, wt.%: as acid and surfactant: Surfactant Nezhegol 0.5-5.0, Neftenol GF 0.5-5.0, corrosion inhibitor IKU-1 or acetophenone, or methyl ethyl ketone 0.1-3.0, citric acid 1.0-10.0, sulfamic acid the rest, in the following ratio of the components of the acidic technological solution, wt.%: Potassium persulfate or sodium persulfate, or ammonium persulfate 1.0-5.0 Surfactant acid reagent 10.0-50.0 Water Rest