CN106753315A - A kind of temperature control type becomes mucic acid and preparation method thereof - Google Patents

Abstract

The invention discloses a temperature-controlled viscosifying acid and a preparation method thereof. 0.3-1.0% of acid activator, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of drainage aid, and the balance is water, of which corrosion inhibitor, Iron ion stabilizers, demulsifiers, and drainage aids are selected with good compatibility. The preparation method of the present invention comprises the following steps: preparation of viscosifying acid thickener, preparation of viscous acid activator, preparation of temperature-controlled viscous acid. The fracturing fluid prepared by the invention has the characteristics of low viscosity at low temperature and high viscosity at high temperature, realizes temperature control and becomes viscous, is conducive to prolonging the action distance of acid liquid, realizing deep acidification, and at the same time improves pumpability and reduces pipeline pressure. Friction resistance; In addition, it also has good temperature and shear resistance, corrosion and speed retardation, and can completely break the glue.

Description

A kind of temperature-controlled mucous acid and preparation method thereof

technical field

The invention belongs to the technical field of chemical synthesis, and in particular relates to a temperature-controlled viscosifying acid and a preparation method thereof.

Background technique

In the acidizing operation, the chemical dissolution of the acid liquid and the hydraulic action of the acid squeezed into the formation should be used to remove the clogging of the oil layer, expand and connect the pores of the oil and gas layer, and restore and increase the permeability of the oil and gas layer. A large number of operational data have confirmed that ensuring that the injected acid solution completely covers the entire layer to be treated is the key to the success of the acidification. However, the permeability of each fracture in the heterogeneous carbonate rock formation is different. When the acid solution is injected into the formation, it will preferentially enter the formation fractures with high permeability, while the layers with low permeability will not be treated. These untreated intervals mean less production and some loss of reserves. For this reason, people have developed mechanical and chemical methods to divert acid fluids to ensure consistent stimulation of carbonate reservoirs. Viscosity acid has been widely used as a chemical diversion method. According to the different thickeners used, viscosities can be divided into two categories: polymers and viscoelastic surfactants; according to the mechanism of viscosities, they can be divided into: temperature-controlled viscosities and pH values Control mucous acid. At present, there are mainly three types of viscosifying acids that have been applied in oil fields or reported in literature: polymer temperature-controlled viscosities, polymer pH-controlled viscous acids, and viscoelastic surfactants pH-controlled viscous acids.

Polymer pH value controlled viscosity-changing acid, also known as fluid loss control acid (LCA), strengthens the fluid loss control of acid liquid on the basis of maintaining the advantages of low friction and slow speed of thickened acid. LCA has a low initial viscosity (30-50mpa.s). When the pH value rises to 2-4, the high-valent metal ion cross-linking agent and the thickener undergo a cross-linking reaction, making the acid liquid cross-linked and thickened to 1000mpa. s or above; when the pH value further increases, the breaker will reduce or chelate the metal cross-linking agent to form a stable compound, destroy the cross-linking system formed by the polymer and the metal cationic cross-linking agent, and reduce the breaking viscosity of the system. The disadvantage of using the LAC acid system is that the viscosity of the acid system increases significantly when the pH value is 2 to 4, and at this time the acid solution has been exhausted, and it cannot be used in a high temperature environment, and the acid rock reaction is too fast under high temperature conditions , may cause the acid solution to be consumed before cross-linking. At the same time, the introduction of metal ions as cross-linking agents will cause secondary damage to the formation.

Polymer temperature-controlled viscosifying acid (TCA) controls the viscosity of the acid liquid system by changing the temperature of the acid liquid system. The viscosity of the acid solution is low at room temperature (less than 50mpa.s). After pumping into the formation, as the temperature of the system rises, the thickener and crosslinking agent in the acid solution undergo a crosslinking reaction at high temperature, making the acid The viscosity of the liquid system increases. It also requires the introduction of metal ion cross-linking agents to cause incomplete gel breaking, which is likely to cause secondary damage to the formation.

Viscoelastic surfactant pH value control viscoelastic acid is to add viscoelastic surfactant as a thickening agent in the acid solution, relying on the association between surfactants to form worm-like or rod-like micelles, the micelles Intertwined with each other to form a network structure in the solution to increase the viscosity of the acid. The mass fraction of viscoelastic surfactants used at this stage is all above 5%, which has high cost and poor temperature resistance.

Compared with polymer viscosities that easily cause secondary damage to the reservoir, surfactants viscous acids are easy to break the gel. Low damage is an important advantage, and it is also the development direction of viscous acids.

Contents of the invention

The technical problem to be solved by the present invention is to provide a temperature-controlled viscosifying acid and a preparation method thereof. The temperature-controlled viscosifying acid utilizes the mutual synergistic effect between supramolecular polymers and surfactants to achieve temperature-controlled viscosities. It avoids the secondary damage to the formation caused by the introduction of metal ion cross-linking agent into viscous acid of commonly used polymers.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a temperature-controlled viscosity-increasing acid, which utilizes the mutual synergy between supramolecular polymers and surfactants to achieve temperature-controlled viscosity-increasing, and is composed of the following components in mass percentage: 12-20% hydrochloric acid, 0.6-1.5% temperature-controlled viscosifying acid thickener, 0.3-1.0% temperature-controlled viscous acid activator, 1-2% corrosion inhibitor, 1-2% iron ion stabilizer, 1-2% demulsifier, 1-2% drainage aid, and water as the balance, among which corrosion inhibitor, iron ion stabilizer, demulsifier, and drainage aid are selected with good compatibility;

The temperature-controlled viscosifying acid thickener is a supramolecular polymer, which is composed of the following components in mass percentage: 15-20% of acrylamide, 15-20% of anionic unsaturated monomer, zwitterionic unsaturated mono Body 1~3%, ammonium persulfate-sodium bisulfite 0.1~0.5%, caustic soda 2~4%, soda ash 1~2%, dispersant 3%, and the rest is water, of which ammonium persulfate and sodium bisulfite The mass ratio is 3:1, and the dispersant is a polymer surfactant class dispersant;

The temperature-controlling viscosifying acid activator is a surfactant, which is composed of the following components in mass percentage: cetyl dimethyl tertiary amine 16-18%, n-dodecyl alcohol 22-27%, ion 15-20% of compound, 1.5-3% of sodium hydroxide, 1-3% of azobisisobutyronitrile, and the rest is solvent methanol.

Further, it is composed of the following components in mass percentage: 15% hydrochloric acid, 0.8% temperature-controlled viscosifying acid thickener, 0.5% temperature-controlled viscous acid activator, 2% corrosion inhibitor, iron ion stabilizer 1%, demulsifier 1%, drainage aid 1%, and the balance is water.

Further, the zwitterionic unsaturated monomer is N-n alkyl diallyl sultaine, wherein n is 12, 14, 16 or 18; the anionic unsaturated monomer is 2-acrylamido-2- Methylpropanesulfonic acid or sodium methacrylate.

Further, the N-n alkyl diallyl sultaine is hexadecyl diallyl sultaine.

Further, the polymeric surfactant-based dispersant is polyvinylpyrrolidone.

Further, the temperature-controlling viscous acid thickener is composed of the following components in mass percentage: 20% of acrylamide, 15% of 2-acrylamide-2-methylpropanesulfonic acid, cetyl di Allyl sulfobetaine 3%, ammonium persulfate-sodium bisulfite 0.2%, caustic soda 2.1%, soda ash 1.5%, polyvinylpyrrolidone 3%, the rest is water, of which ammonium persulfate and sodium bisulfite The mass ratio is 3:1.

Further, the ionic compound is calcium 2-ketogluconate.

Further, the temperature-controlled viscosifying acid activator is composed of the following components in mass percentage: cetyl dimethyl tertiary amine 16%, n-dodecyl alcohol 25%, 2-keto calcium gluconate 18% %, sodium hydroxide 3%, azobisisobutyronitrile 1%, and the rest is solvent methanol.

A preparation method of temperature-controlled mucous acid, comprising the following steps:

(1) Preparation of temperature-controlled viscous acid thickener

Take acrylamide, zwitterionic unsaturated monomers, anionic unsaturated monomers and water and mix evenly to obtain a mixed solution, first add caustic soda to neutralize the system to a pH value of about 7, then add soda ash to adjust the pH value of the system to 9-10 , adding a polymer surfactant as a dispersant, adding a redox initiator ammonium persulfate-sodium bisulfite, reacting at a reaction temperature of 25-30°C for 4-6 hours, and hydrolyzing at 90°C for 4 hours to obtain a colloidal product, The colloid is granulated, dried, and pulverized to obtain a temperature-controlled viscous acid thickener;

(2) Preparation of temperature-controlled mucous acid activator

Take methanol as a solvent, add cetyl dimethyl tertiary amine, n-dodecyl alcohol and calcium 2-ketogluconate as reactants, add sodium hydroxide to adjust the pH value to 8-9, add catalyst azodiiso Butyronitrile, under the condition of 45-55°C, carry out esterification reaction for 4-5 hours, after the reaction, add activated carbon, then cool, filter, and dry to obtain the solid product of temperature-controlled viscosifying acid activator; The solid product of the viscosifying acid activator is dissolved in water and prepared into a solution with a mass fraction of 50%. After the dissolution is complete, the mixture is evenly stirred to obtain the temperature-controlled viscosifying acid activator;

(3) Preparation of temperature-controlled mucous acid

Take the temperature-controlled viscosifying acid thickener prepared in step (1), the temperature-controlled viscous acid activator prepared in step (2), hydrochloric acid, corrosion inhibitor, iron ion stabilizer, demulsifier, drainage aid Mix the agent and water evenly to get the temperature-controlled mucous acid.

Further, the reaction temperature in the step (1) is 25° C., and the reaction time is 5 hours.

Beneficial effects of the present invention: the fracturing fluid prepared by the present invention has the characteristics of low-temperature low-viscosity and high-temperature high-viscosity. Injection, reducing pipeline friction; in addition, it has good temperature resistance and shear resistance, corrosion and speed retardation, and can completely break glue.

Description of drawings

Fig. 1 is a kind of temperature control type viscous acid thickening agent acid dissolution time measurement curve of the present invention;

Fig. 2 is the thickening ability test curve of a kind of temperature control type viscous acid thickener of the present invention;

Fig. 3 is a salt resistance test curve of a kind of temperature-controlled type viscous acid thickener of the present invention;

Fig. 4 is a comparison picture before a kind of temperature-controlled viscosifying acid of the present invention becomes viscous;

Fig. 5 is a comparison picture after a kind of temperature-controlled viscosifying acid of the present invention becomes viscous;

Fig. 6 is a 120°C temperature-resistant and shear-resistant test curve of a temperature-controlled viscosic acid of the present invention;

Fig. 7 is a kind of temperature control type variable viscosity acid retardation performance test curve of the present invention;

Fig. 8 is a test curve of the resistance reduction rate of a temperature-controlled variable viscosity acid of the present invention;

Fig. 9 is a field construction curve of a temperature-controlled variable viscosity acid of the present invention.

detailed description

A temperature-controlled viscosifying acid of the present invention uses the synergistic effect of supramolecular polymers and surfactants to realize temperature-controlled viscosities, and is composed of the following components in mass percentage: hydrochloric acid 12-20%, temperature-controlled viscosities Viscosity thickener 0.6-1.5%, temperature-controlled mucous acid activator 0.3-1.0%, corrosion inhibitor 1-2%, iron ion stabilizer 1-2%, demulsifier 1-2%, drainage aid 1 to 2%, the balance is water, among which corrosion inhibitor, iron ion stabilizer, demulsifier and drainage aid are selected with good compatibility;

The temperature-controlled viscosifying acid thickener is a supramolecular polymer, which is composed of the following components in mass percentage: 15-20% of acrylamide, 15-20% of anionic unsaturated monomer, zwitterionic unsaturated mono Body 1~3%, ammonium persulfate-sodium bisulfite 0.1~0.5%, caustic soda 2~4%, soda ash 1~2%, dispersant 3%, and the rest is water, of which ammonium persulfate and sodium bisulfite The mass ratio is 3:1, and the dispersant is a polymer surfactant class dispersant;

The temperature-controlling viscosifying acid activator is a surfactant, which is composed of the following components in mass percentage: cetyl dimethyl tertiary amine 16-18%, n-dodecyl alcohol 22-27%, ion 15-20% of compound, 1.5-3% of sodium hydroxide, 1-3% of azobisisobutyronitrile, and the rest is solvent methanol.

Further, it is composed of the following components in mass percentage: 15% hydrochloric acid, 0.8% temperature-controlled viscosifying acid thickener, 0.5% temperature-controlled viscous acid activator, 2% corrosion inhibitor, iron ion stabilizer 1%, demulsifier 1%, drainage aid 1%, and the balance is water.

Further, the zwitterionic unsaturated monomer is N-n alkyl diallyl sultaine, wherein n is 12, 14, 16 or 18; the anionic unsaturated monomer is 2-acrylamido-2- Methylpropanesulfonic acid or sodium methacrylate.

Further, the N-n alkyl diallyl sultaine is hexadecyl diallyl sultaine.

Further, the polymeric surfactant-based dispersant is polyvinylpyrrolidone.

Furthermore, in order to obtain the most excellent temperature-controlling viscous acid thickener with the best product performance, the temperature-controlled viscous acid thickener is composed of the following components in mass percentage: 20% acrylamide, 2-acrylamide Base-2-methylpropanesulfonic acid 15%, hexadecyl diallyl sulfobetaine 3%, ammonium persulfate-sodium bisulfite 0.2%, caustic soda 2.1%, soda ash 1.5%, polyvinyl Pyrrolidone 3%, the rest is water, wherein the mass ratio of ammonium persulfate to sodium bisulfite is 3:1.

Further, the ionic compound is calcium 2-ketogluconate.

Furthermore, in order to obtain the temperature-controlled viscosifying acid activator with the best product performance, the temperature-controlled viscous acid activator is composed of the following components in mass percentage: cetyl dimethyl tertiary amine 16%, 25% of n-dodecyl alcohol, 18% of calcium 2-ketogluconate, 3% of sodium hydroxide, 1% of azobisisobutyronitrile, and the rest is solvent methanol.

A preparation method of temperature-controlled mucous acid, comprising the following steps:

(1) Preparation of temperature-controlled viscous acid thickener

Take acrylamide, zwitterionic unsaturated monomers, anionic unsaturated monomers and water and mix evenly to obtain a mixed solution, first add caustic soda to neutralize the system to a pH value of about 7, then add soda ash to adjust the pH value of the system to 9-10 , adding a polymer surfactant as a dispersant, adding a redox initiator ammonium persulfate-sodium bisulfite, reacting at a reaction temperature of 25-30°C for 4-6 hours, and hydrolyzing at 90°C for 4 hours to obtain a colloidal product, The colloid is granulated, dried, and pulverized to obtain a temperature-controlled viscous acid thickener;

(3) Preparation of temperature-controlled mucous acid activator

Take methanol as a solvent, add cetyl dimethyl tertiary amine, n-dodecyl alcohol and calcium 2-ketogluconate as reactants, add sodium hydroxide to adjust the pH value to 8-9, add catalyst azodiiso Butyronitrile, under the condition of 45-55°C, carry out esterification reaction for 4-5 hours, after the reaction, add activated carbon, then cool, filter, and dry to obtain the solid product of temperature-controlled viscosifying acid activator; The solid product of the viscosifying acid activator is dissolved in water and prepared into a solution with a mass fraction of 50%. After the dissolution is complete, the mixture is evenly stirred to obtain the temperature-controlled viscosifying acid activator;

(3) Preparation of temperature-controlled mucous acid

Take the temperature-controlled viscosifying acid thickener prepared in step (1), the temperature-controlled viscous acid activator prepared in step (2), hydrochloric acid, corrosion inhibitor, iron ion stabilizer, demulsifier, drainage aid Mix the agent and water evenly to get the temperature-controlled mucous acid.

Wherein step (3) prepares the process of temperature-controlled mucous acid The present invention provides the preparation method in the laboratory and the construction site preparation method:

The preparation method in the laboratory is as follows: In the laboratory, add water and hydrochloric acid to the beaker according to the weight percentage of the viscous acid component, put the magnet, then place it on a magnetic stirrer, and slowly add water to the solution under stirring conditions. Add viscosifying acid thickener to the mixture, stir evenly, add viscosifying acid activator, corrosion inhibitor, iron ion stabilizer and other additives in sequence, and continue stirring to obtain temperature-controlled viscous acid.

The preparation method at the construction site is as follows: at the construction site, add water and hydrochloric acid into the liquid mixing tank according to the weight percentage of the viscous acid component, then add corrosion inhibitor, iron ion stabilizer and other additives, stir evenly, and then add Inhale the viscous acid thickener from the jet gun under the condition of stirring in the large tank. The thickener must be sucked slowly, that is, no agglomeration and no fish eyes are formed; after the thickener is added, stir for 20 minutes, and the liquid is allowed to stand After 2 hours, a temperature-controlled mucous acid can be obtained.

Further, the reaction temperature in the step (1) is 25° C., and the reaction time is 5 hours.

The invention provides a method for synthesizing a temperature-controlled viscosifying acid thickener and an activator, and a method for preparing a temperature-controlled viscous acid by using the thickener and the activator. The excellent properties of variable viscosity acid fracturing fluid are mainly summarized as follows:

(1) The apparent viscosity of the acid liquid of the viscous acid thickener increases with the increase of the use concentration. At room temperature, this thickener has a strong ability to increase the viscosity of the acid liquid;

(2) The molecule of the viscous acid thickener has a hydrophobic group, which can form a fluid with a reversible structure in the acid and has good viscoelasticity;

(3) At room temperature, the activator can shield the association between the molecular chains of the thickener, and the apparent viscosity of the polymer solution is low. After heating, the activator degrades in the acid solution, the concentration decreases, and thickens The synergistic effect of the agent molecular chain has changed, the association between the polymer molecular chains has been enhanced, a stronger three-dimensional structure has been formed, and the temperature-controlled viscosity of the acid liquid has been realized;

(4) It is precisely because of the interaction between the thickener and the activator that the viscosity of the temperature-controlled viscous acid is low at room temperature (30mPa·s～50mPa·s), which improves the pumpability of the acid solution and reduces Pipeline friction is reduced, and as the temperature rises, the viscosity increases, which reduces the acid-rock reaction rate and realizes deep acidification;

(5) The permeability of the oil layer in a certain area is low, and the start-up pressure of the water injection well is high. After the injection of a certain well was stopped for 5 hours, the water injection volume decreased. After using the temperature-controlled variable-viscosity acid acidification measure, the pores near the wellbore were dredged, and the water injection start-up pressure decreased. Up to the point of depressurization and injection increase, the well has accumulatively increased injection by 7169m ³ within seven months, and achieved good injection effect.

The specific implementation of the present invention will be further described below in conjunction with the examples, and the present invention is not limited to the scope of the examples. If not pointed out in particular, the fracturing fluid performance evaluation experimental conditions and experimental methods involved in the embodiments are all referred to in the petroleum and natural gas industry standard "SY/T6214-1996 acid liquid thickener evaluation method"; The percentage signs "%" involved are all mass percentages.

Example 1

A temperature-controlled viscosifying acid of the present invention is composed of the following components in mass percentage: 12% hydrochloric acid, 0.6% temperature-controlled viscosifying acid thickener, 0.3% temperature-controlled viscous acid activator, corrosion inhibitor 1% iron ion stabilizer, 1% iron ion stabilizer, 1% demulsifier, 1% drainage aid, and the balance is water. Among them, the corrosion inhibitor, iron ion stabilizer, demulsifier, and drainage aid are selected with good compatibility;

The temperature-controlled viscosifying acid thickener is composed of the following components in mass percentage: 20% of acrylamide, 15% of anionic unsaturated monomer, 3% of zwitterionic unsaturated monomer, ammonium persulfate-sodium bisulfite 0.2%, tablet soda 2.1%, soda ash 1.5%, dispersant 3%, and the rest is water, wherein the mass ratio of ammonium persulfate to sodium bisulfite is 3:1, and the dispersant is polymer surfactant agent;

The temperature-controlled viscosifying acid activator is composed of the following components in mass percentage: cetyl dimethyl tertiary amine 16%, n-dodecyl alcohol 25%, ionic compound 18%, sodium hydroxide 3%, even 1% azodiisobutyronitrile, the rest is solvent methanol.

Example 2

A temperature-controlled viscosifying acid of the present invention is composed of the following components in mass percentage: 20% hydrochloric acid, 1.5% temperature-controlled viscosifying acid thickener, 1.0% temperature-controlled viscosifying acid activator, corrosion inhibitor 2% iron ion stabilizer, 2% iron ion stabilizer, 2% demulsifier, 2% drainage aid, and the balance is water. Among them, the corrosion inhibitor, iron ion stabilizer, demulsifier, and drainage aid are selected with good compatibility;

The temperature-controlling viscous acid thickener is composed of the following components in mass percentage: 20% of acrylamide, 20% of anionic unsaturated monomer, 3% of zwitterionic unsaturated monomer, ammonium persulfate-sodium bisulfite 0.5%, tablet soda 4%, soda ash 2%, dispersant 3%, and the rest is water, wherein the mass ratio of ammonium persulfate to sodium bisulfite is 3:1, and the dispersant is polymer surfactant agent;

The temperature-controlled viscosifying acid activator is composed of the following components in mass percentage: cetyl dimethyl tertiary amine 18%, n-dodecyl alcohol 27%, ionic compound 20%, sodium hydroxide 3%, even 3% nitrogen bisisobutyronitrile, the rest is solvent methanol.

Example 3

A temperature-controlled viscosifying acid of the present invention is composed of the following components in mass percentage: hydrochloric acid 15%, temperature-controlled viscous acid thickener 0.8%, temperature-controlled viscosifying acid Mucic acid activator 0.5%, corrosion inhibitor 2%, iron ion stabilizer 1%, demulsifier 1%, drainage aid 1%, the balance is water, of which corrosion inhibitor, iron ion stabilizer, demulsifier, aid The discharge agent is selected with good compatibility;

The temperature-controlling viscous acid thickener consists of the following components in mass percent: 20% acrylamide, 15% 2-acrylamide-2-methylpropanesulfonic acid, hexadecyldiallylsulfonic acid 3% betaine, 0.2% ammonium persulfate-sodium bisulfite, 2.1% caustic soda, 1.5% soda ash, 3% polyvinylpyrrolidone, and the rest is water, wherein the mass ratio of ammonium persulfate to sodium bisulfite is 3:1;

The temperature-controlled viscosifying acid activator is composed of the following components in mass percentage: 16% cetyl dimethyl tertiary amine, 25% n-dodecyl alcohol, 18% 2-ketogluconate calcium, hydroxide Sodium 3%, azobisisobutyronitrile 1%, and the rest is solvent methanol.

The preparation method of a kind of temperature-controlled viscosifying acid of this embodiment is as follows:

(1) Preparation of temperature-controlled viscous acid thickener

Add acrylamide, N-hexadecyldiallyl sulfobetaine, 2-acrylamido-2-methylpropanesulfonic acid and water into the reaction kettle and mix evenly, add caustic soda and soda ash to adjust the pH value, The pH measured by the precise pH value is 9.6, the dispersant polyvinylpyrrolidone is added, the redox initiator ammonium persulfate-sodium bisulfite is added, the temperature is 25°C for 5 hours, and the colloid is obtained after hydrolysis at 90°C for 4 hours The colloidal product is granulated, dried, and pulverized to obtain a temperature-controlled viscous acid thickener.

(2) Preparation of temperature-controlled mucous acid activator

Add methanol to the reaction kettle as a solvent, add cetyl dimethyl tertiary amine, n-dodecyl alcohol and calcium 2-ketogluconate as reactants, add caustic soda to adjust the pH value, and measure the pH with precision pH test paper For 8.2, add the catalyst azobisisobutyronitrile, carry out the esterification reaction at 50°C for 4 hours, after the reaction, add activated carbon, then cool, filter, and dry to obtain the solid product of the activator for viscous acid.

The obtained solid product of the temperature-controlled viscosifying acid activator is dissolved in water to prepare a solution with a mass fraction of 50%. After the dissolution is complete, the mixture is evenly stirred to obtain the temperature-controlled viscosifying acid activator.

(3) Preparation of temperature-controlled mucous acid

Take the temperature-controlled viscosifying acid thickener prepared in step (1), the temperature-controlled viscous acid activator prepared in step (2), hydrochloric acid, corrosion inhibitor, iron ion stabilizer, demulsifier, drainage aid Mix the agent and water evenly to get the temperature-controlled mucous acid.

Various performance tests were carried out on the temperature-controlled viscous acid thickener prepared in Example 3 of the present invention

1. Measure the acid-dissolving time of the temperature-controlled type viscous acid thickener in the preparation process of step (3) in the above-mentioned embodiment 3

By weight percentage, the specific process of step (3) is: add water and hydrochloric acid altogether 198.4g in the beaker, and hydrochloric acid mass fraction is 20%, puts into magnetron, then places on the magnetic stirrer, carries out with magnetic stirrer Stir, adjust the stirring speed until the solution just forms a vortex (the rotation speed is about 500r/min), weigh 1.6g of the temperature-controlled viscous acid thickener prepared in step (1) and add it slowly and evenly, after stirring evenly, every 5min Use a six-speed rotational viscometer to measure the apparent viscosity of the acid solution at 170S ^-1 , see Figure 1 for the specific change curve. The temperature-controlled viscosity-changing acid thickener prepared by the invention has a short dissolution time in acid of about 26 minutes, which is beneficial to on-site liquid preparation and reduces construction costs.

2. Determination of the thickening ability of the temperature-controlled viscous acid thickener prepared in step (1) in Example 3 of the present invention

The apparent viscosity of the 20% hydrochloric acid solution of the temperature-controlled viscosifying acid thickener provided by the present invention increases with the increase of the concentration of the thickener, and the specific change curve is shown in FIG. 2 . At room temperature, this temperature-controlled viscosifying acid thickener has a strong ability to increase the viscosity of acid.

3. Test the salt resistance of the temperature-controlled viscous acid thickener prepared in step (1) in Example 3 of the present invention

By weight percentage, the concentration of the temperature-controlled type viscous acid thickener is prepared to be 20% hydrochloric acid solution of 0.8%, and then CaCl of a certain concentration and NaCl (mass ratio is ₁ :1) are added to adjust the total mass concentration of added salt , after it dissolves evenly, measure the apparent viscosity of the hydrochloric acid solution at 170S ^-1 with a six-speed rotational viscometer, see Figure 3 for the specific change curve. With the increase of salt concentration, the viscosity of the acid solution decreased slowly, but the decrease range was small, which indicated that the thickener had good salt-resistant performance.

Various performance tests were carried out on the temperature-controlled mucous acid prepared in Example 3 of the present invention

1. Comparison charts before and after the temperature-controlled mucous acid prepared in Example 3 of the present invention

A temperature-controlled mucous acid provided in Example 3 of the present invention can form a certain strength jelly after being heated, and has certain hanging properties. The experimental phenomena are shown in Figure 4 and Figure 5. The experiment shows that the temperature-controlled The viscosifying acid can increase the strength through the interaction between the thickener and the activator, thereby improving various properties of the viscous acid and realizing deep acidification.

2. The temperature-controlled variable viscosic acid prepared in Example 3 of the present invention was tested for temperature resistance and shear resistance at 120°C

The high-temperature rheology was measured by the RS-600 rheometer of Haake Company in Germany. The mass concentration of hydrochloric acid was 20%, the mass concentration of temperature-controlled viscosifying acid thickener was 0.8%, and the mass concentration of temperature-controlled viscosifying acid activator was 0.5%, then add 2% corrosion inhibitor WLD-31A, 1% iron ion stabilizer B-180, 1% drainage aid DJ-02 and 1% demulsifier NE-4240, set the shear rate It is 170S ^-1 , the test temperature is 120°C, and the time is 2h. The relationship between viscosity and time is investigated as shown in Figure 6.

3. Test of retarding performance of temperature-controlled variable viscosity acid prepared in Example 3 of the present invention

According to the weight percentage, the concentration of the prepared hydrochloric acid is 20%, the concentration of the thickener is 0.8%, the concentration of the activator is 0.5%, the concentration of the corrosion inhibitor is 2%, the concentration of the iron ion stabilizer is 1%, and the concentration of the drainage aid is 1%. And viscous acid with a demulsifier concentration of 1%, react with calcium carbonate at 90°C, take out a small amount of acid solution every 10 minutes and titrate it with standard sodium hydroxide solution. Compared with blank acid, viscous acid has a better retarding effect, which can delay the acid-rock reaction and help realize deep acidification. The retarding effect is shown in Fig. 7.

4. Corrosion performance test of the temperature-controlled viscous acid prepared in Example 3 of the present invention

According to the weight percentage, the concentration of the prepared hydrochloric acid is 20%, the concentration of the thickener is 0.8%, the concentration of the activator is 0.5%, the concentration of the corrosion inhibitor is 2%, the concentration of the iron ion stabilizer is 1%, and the concentration of the drainage aid is 1%. and viscous acid with a concentration of 1% demulsifier, and the corrosion rate was measured under normal pressure and 90°C. The test results are shown in Table 1.

Table 1 Temperature-controlled viscous acid corrosion rate test

The test results show that in addition to the effect of the corrosion inhibitor, the interaction between the polymers in the viscosifying acid also reduces the diffusion rate of H ⁺ . Corrosion, prolong the service life of the pipeline.

5. Gel-breaking performance test of the temperature-controlled variable viscosity acid prepared in Example 3 of the present invention

According to weight percentage, the concentration of hydrochloric acid is 20%, the concentration of thickener is 0.8%, the concentration of activator is 0.5%, the concentration of corrosion inhibitor is 2%, the concentration of iron ion stabilizer is 1%, and the concentration of drainage aid is 1%. Take 200ml of excess calcium carbonate at room temperature to react with viscous acid with a demulsifier concentration of 1%, and take the residual acid every 30 minutes to measure its apparent viscosity. The test results are shown in Table 2.

Table 2 The gel breaking situation of viscous acid

The test results show that the viscous acid can react completely with calcium carbonate and can completely break the glue. The density of the finally obtained residual acid was 1.05 g/ml, and its surface tension was 28.6 mN/m.

6. Test of the resistance-reducing performance of the temperature-controlled variable viscosity acid prepared in Example 3 of the present invention

According to the percentage by weight, the concentration of hydrochloric acid is 20%, the concentration of thickener is 0.6%~0.8%, the concentration of activator is 0.5%, the concentration of corrosion inhibitor is 2%, the concentration of iron ion stabilizer is 1%, and the concentration of drainage aid Viscosifying acid at 1% concentration and 1% demulsifier concentration. Select 8mm pipeline for testing, record the friction pressure drop after passing through the pipeline to calculate the drag reduction rate, and evaluate the drag reduction effect of the water-soluble drag reduction agent according to the drag reduction rate. The relationship between the drag reduction rate and the flow rate is shown in the figure 8. The maximum drag reduction rate can reach 57%.

Drag reduction calculation:

In the formula: Φ----drag reduction rate, %;

ΔΡwater--the pressure difference when clean _water passes through the test pipeline, MPa;

ΔΡ——The pressure difference when the fluid containing water-soluble drag reducer passes through the test pipeline, MPa.

On-site experiments were carried out on the temperature-controlled mucous acid prepared in Example 3 of the present invention

Well 95-96 was injected on October 25, 2015. On November 19, the water injection pipeline was connected and the injection was stopped for 5 hours. After the injection was started, the water injection pressure of the well increased and the injection volume decreased. Acidification treatment was implemented on the 10th. The dosage of compound viscosifying acid is 15m ³ , and the formula of viscosifying acid is: 15% HCL + 0.8% thickener + 0.5% activator + 2% corrosion inhibitor + 1% iron ion stabilizer + 1% drainage aid, the highest The pressure is 18MPa, the working pressure is 9MPa, and the pump is stopped at 9MPa. The construction curve is shown in Figure 9. The reservoir permeability in this area is low, and the start-up pressure of the water injection well is high. After the well was stopped for 5 hours, the water injection volume decreased. As of June 25, the well has accumulatively increased injection of 7169m ³ .

It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the protection scope of the appended claims of the present invention.

Claims (10)

1. A temperature-controlled viscosifying acid, characterized in that, utilizes the mutual synergy of supramolecular polymers and surfactants to realize temperature-controlled viscosities, and is composed of the following components in mass percentage: hydrochloric acid 12～20%, temperature 0.6-1.5% viscosifying acid thickener, 0.3-1.0% viscosifying acid activator, 1-2% corrosion inhibitor, 1-2% iron ion stabilizer, 1-2% demulsifier, Drainage aid 1-2%, the balance is water, among which corrosion inhibitor, iron ion stabilizer, demulsifier, and drainage aid are selected with good compatibility; The temperature-controlled viscosifying acid thickener is a supramolecular polymer, which is composed of the following components in mass percentage: 15-20% of acrylamide, 15-20% of anionic unsaturated monomer, zwitterionic unsaturated mono Body 1~3%, ammonium persulfate-sodium bisulfite 0.1~0.5%, caustic soda 2~4%, soda ash 1~2%, dispersant 3%, and the rest is water, of which ammonium persulfate and sodium bisulfite The mass ratio is 3:1, and the dispersant is a polymer surfactant class dispersant; The temperature-controlling viscosifying acid activator is a surfactant, which is composed of the following components in mass percentage: cetyl dimethyl tertiary amine 16-18%, n-dodecyl alcohol 22-27%, ion 15-20% of compound, 1.5-3% of sodium hydroxide, 1-3% of azobisisobutyronitrile, and the rest is solvent methanol. 2. A temperature-controlled viscosifying acid according to claim 1, characterized in that it consists of the following components in mass percentage: 15% hydrochloric acid, 0.8% temperature-controlled viscous acid thickener, and a temperature-controlled Viscosity acid activator 0.5%, corrosion inhibitor 2%, iron ion stabilizer 1%, demulsifier 1%, drainage aid 1%, and the balance is water. 3. a kind of temperature control type viscosifying acid according to claim 1, is characterized in that, described zwitterionic unsaturated monomer is N-n alkyl diallyl sulfobetaine, and wherein n is 12,14, 16 or 18; the anionic unsaturated monomer is 2-acrylamido-2-methylpropanesulfonic acid or the sodium salt of methacrylic acid. 4. A kind of temperature-controlled variable viscosity acid according to claim 3, is characterized in that, described N-n alkyl diallyl sultaine is hexadecyl diallyl sultaine. 5. A kind of temperature-controlled viscosifying acid according to claim 4, characterized in that, the polymer surfactant dispersant is polyvinylpyrrolidone. 6. A temperature-controlled viscosifying acid according to claim 5, characterized in that, the temperature-controlled viscous acid thickener consists of the following components in mass percent: 20% acrylamide, 2-propene Amino-2-methylpropanesulfonic acid 15%, cetyldiallyl sulfobetaine 3%, ammonium persulfate-sodium bisulfite 0.2%, caustic soda 2.1%, soda ash 1.5%, polyethylene Base pyrrolidone 3%, the rest is water, wherein the mass ratio of ammonium persulfate to sodium bisulfite is 3:1. 7. A kind of temperature-controlled mucous acid according to claim 1, is characterized in that, described ionic compound is calcium 2-ketogluconate. 8. A kind of temperature-controlled viscosifying acid according to claim 7, characterized in that, the temperature-controlled viscosifying acid activator is composed of the following components in mass percent: cetyl dimethyl tertiary amine 16%, n-dodecyl alcohol 25%, calcium 2-ketogluconate 18%, sodium hydroxide 3%, azobisisobutyronitrile 1%, and the rest is solvent methanol. 9. A preparation method for temperature-controlled mucous acid described in any one of claim 1～8, is characterized in that, comprises the following steps: (1) Preparation of temperature-controlled viscous acid thickener Take acrylamide, zwitterionic unsaturated monomers, anionic unsaturated monomers and water and mix evenly to obtain a mixed solution, first add caustic soda to neutralize the system to a pH value of about 7, then add soda ash to adjust the pH value of the system to 9-10 , adding a polymer surfactant as a dispersant, adding a redox initiator ammonium persulfate-sodium bisulfite, reacting at a reaction temperature of 25-30°C for 4-6 hours, and hydrolyzing at 90°C for 4 hours to obtain a colloidal product, The colloid is granulated, dried, and pulverized to obtain a temperature-controlled viscous acid thickener; (2) Preparation of temperature-controlled mucous acid activator Take methanol as a solvent, add cetyl dimethyl tertiary amine, n-dodecyl alcohol and calcium 2-ketogluconate as reactants, add sodium hydroxide to adjust the pH value to 8-9, add catalyst azodiiso Butyronitrile, under the condition of 45-55°C, carry out esterification reaction for 4-5 hours, after the reaction, add activated carbon, then cool, filter, and dry to obtain the solid product of temperature-controlled viscosifying acid activator; The solid product of the viscosifying acid activator is dissolved in water and prepared into a solution with a mass fraction of 50%. After the dissolution is complete, the mixture is evenly stirred to obtain the temperature-controlled viscosifying acid activator; (3) Preparation of temperature-controlled mucous acid Take the temperature-controlled viscosifying acid thickener prepared in step (1), the temperature-controlled viscous acid activator prepared in step (2), hydrochloric acid, corrosion inhibitor, iron ion stabilizer, demulsifier, drainage aid Mix the agent and water evenly to get the temperature-controlled mucous acid. 10 . The method for preparing a temperature-controlled mucous acid according to claim 9 , wherein the reaction temperature in the step (1) is 25° C., and the reaction time is 5 h. 11 .