CN112111263A - A kind of preparation method of high temperature resistant clean fracturing fluid - Google Patents

Abstract

The invention relates to a preparation method of a high-temperature-resistant clean fracturing fluid, belonging to the technical field of oilfield chemistry. Preparing an amidation product by reacting a piperazine compound containing a hydroxyl group with an organic acid, and preparing an amphoteric surfactant by reacting the amidation product with a sulfonating agent; the high temperature stabilizer is prepared by reacting trimethyl borate with a diamino compound. The clean fracturing fluid is prepared by taking an amphoteric surfactant and a high-temperature stabilizer as raw materials, has good dissolving, tackifying, temperature resistance, salt resistance and sand carrying performances, and can be used as a working fluid for fracturing construction under high temperature and high salt.

Description

A kind of preparation method of high temperature resistant clean fracturing fluid

technical field

The invention relates to a preparation method of high temperature resistant clean fracturing fluid, belonging to the technical field of oilfield chemistry.

Background technique

Oil is an important strategic resource, and its exploitation and utilization play an important role in the development of the national economy. With the increasing difficulty of oil and gas field exploitation, low-permeability and unconventional oil reservoirs are the main directions for future oilfield development. Low-permeability reservoirs have complex formation conditions, poor production effect and low recovery. As one of the main measures for low-permeability reservoir development, hydraulic fracturing is a highly efficient means of stimulation. Fracturing fluid plays the role of transmitting pressure, generating and extending fractures, and suspending proppant in hydraulic fracturing operation. The performance of fracturing fluid plays a decisive role in fracturing operation and oil and gas well stimulation effect after construction. For low-permeability oil reservoirs, conventional guar gum fracturing fluid has a lot of residues and great damage to the reservoir, and there are many deficiencies in its use. Therefore, the research and application of new fracturing fluids have gradually become a hot spot.

Clean fracturing fluid, also known as viscoelastic surfactant fracturing fluid, has the advantages of simple preparation, good viscoelasticity, no need for cross-linking agents, automatic gel breaking when encountering oil and formation water, easy flowback, and little damage to the formation. Its application is more and more extensive. Spherical micelles of viscoelastic surfactants grow in one dimension to form rod-like or linear aggregates, called worm-like micelles. The worm-like micelle network structure is formed by intermolecular forces such as electrostatic interaction, hydrophobic interaction and hydrogen bonding of surfactants. These network structures can be restored by intermolecular interactions after shearing, so they are also called living polymers.

The current clean fracturing fluids still have the following deficiencies in the field use of oilfields: (1) the concentration of surfactants is high and the cost is high; (2) the viscosity of the system decreases significantly with the increase of temperature, and the viscosity increases under the condition of high temperature resistance. The effect is not good; (3) The self-assembled structure of the system is easily damaged under high shear conditions, and the shear resistance performance needs to be improved. Therefore, it is necessary to develop a new type of viscoelastic surfactant and construct a clean fracturing fluid system with low concentration, excellent temperature resistance and shear resistance.

SUMMARY OF THE INVENTION

The invention provides a preparation method of high temperature resistant clean fracturing fluid.

SUMMARY OF THE INVENTION

In the present invention, an amidated product is prepared by reacting a hydroxyl-containing piperazine compound with an organic acid, and the amidated product is reacted with a sulfonated reagent to prepare an amphoteric surfactant; trimethyl borate and a diamino compound are reacted to prepare an aminoboron type High temperature stabilizer; using amphoteric surfactant and high temperature stabilizer as raw materials to prepare high temperature resistant clean fracturing fluid. After testing, the fracturing fluid system has good dissolution, viscosity, temperature resistance, salt resistance, and sand-carrying properties, and can be used as a working fluid for fracturing construction under high temperature and high salt conditions.

Detailed description of the invention

The technical scheme of the present invention is as follows:

(1) Preparation of viscoelastic surfactant

①Preparation of amidated products

Add compound-1, compound-2 and sodium fluoride into a four-neck glass bottle equipped with a stirrer, a nitrogen-passing tube, a drying tube and a thermometer, heat up and stir until all the raw materials are dissolved, and after nitrogen is introduced for 20min, the reaction temperature is Control the temperature at 120～190℃, react for 3～48h, and remove the volatile components by distillation under reduced pressure at 180℃. The mass ratio with sodium fluoride is 1:(0.003～0.02);

② Preparation of amphoteric surfactants

Add the amidated product, ethyl acetate and compound-3 into a three-neck glass bottle equipped with a stirrer, a spherical condenser and a thermometer, heat up and stir until all raw materials are dissolved, control the reaction temperature at 60-130 ° C, and react 4 ~24h, cooling, filtering, drying, and obtaining; the mass ratio of amidation product, compound-3, and ethyl acetate is 1:(0.3~2):(1.5~10);

(2) Preparation of high temperature stabilizer

Add trimethyl borate, compound-4 and ethanol into a three-neck glass bottle equipped with a stirrer, spherical condenser and thermometer, control the temperature at 50-80 °C, react for 1-10 h, and reduce the pressure at 60 °C The volatile components are removed by distillation, that is, the mass ratio of trimethyl borate, compound-4 and ethanol is 1:(0.2～0.7):(1～6);

(3) Preparation of fracturing fluid system

Add tap water, sodium chloride, calcium chloride and viscoelastic surfactant into a beaker equipped with a stirrer, heat up and stir until all the surfactants are dissolved, add a high temperature stabilizer aqueous solution with a mass fraction of 20%, and stir evenly , that is, the mass ratio of tap water, sodium chloride, calcium chloride and viscoelastic surfactant is 1:(0.005～0.1):(0.0001～0.02):(0.002～0.04), viscoelastic surfactant, high temperature The mass ratio of the stabilizer aqueous solution is 1:(0.002～0.25).

According to the present invention, preferably, the compound-1 described in the preparation of the amidated product in step (1) is a compound of hexadecanoic acid, octadecanoic acid, eicosic acid, behenic acid, palmitoleic acid, oleic acid and erucic acid. A sort of;

Preferably, the compound-2 is one of 1-(2-hydroxyethyl)piperazine and 1-(4-hydroxyphenyl)piperazine;

Preferably, the mass ratio of compound-1 to compound-2 is 1:(0.4-0.8), and the mass ratio of compound-2 to sodium fluoride is 1:(0.005-0.015);

Preferably, the reaction temperature is controlled at 150-190° C., and the reaction is performed for 6-24 hours.

According to the present invention, preferably, the compound-3 described in the preparation of the amphoteric surfactant in step (1) is one of sodium 3-chloropropanesulfonate and sodium 3-chloro-2-hydroxypropanesulfonate;

Preferably, the mass ratio of amidation product, compound-3 and ethyl acetate is 1:(0.45～1.2):(2～6);

Preferably, the reaction temperature is controlled at 65-85°C, and the reaction is performed for 8-15 hours.

According to the present invention, preferably, the compound-4 described in step (2) is a kind of ethylenediamine, 1,3-propanediamine, 1,4-butanediamine and 1,6-hexanediamine ;

Preferably, the mass ratio of trimethyl borate, compound-4 and ethanol is 1:(0.2～0.55):(1～5);

Preferably, the reaction temperature is controlled at 65-80° C., and the reaction is performed for 2-6 hours.

According to the present invention, preferably, the mass ratio of tap water, sodium chloride, calcium chloride and viscoelastic surfactant in step (3) is 1:(0.01～0.05):(0.001～0.01):(0.004～0.025 ), the mass ratio of viscoelastic surfactant and high temperature stabilizer aqueous solution is 1:(0.005～0.15).

The excellent effects of the present invention are as follows:

1. Using the amphoteric surfactant structure with anions and cations in the molecule, the product has good solubility, salt resistance and other properties. In addition, the amphoteric structure can also control the adsorption amount of the product during the injection process.

2. The introduction of a piperazine group into the surfactant molecule enhances the rigidity of the molecule, and the molecule can form a strong aggregate structure in the solution, which improves the viscosity-increasing performance of the product and reduces the amount of the product.

3. Through the dynamic covalent reaction between the amino boron compound and the hydroxyl group, the interaction between the hydrophilic groups of the surfactant is improved, and the viscosity-increasing ability of the product at high temperature is enhanced.

4. The surfactant molecules do not contain easily hydrolyzable groups, and the product has excellent high temperature aging resistance.

5. The preparation process of the present invention is simple, and it is easy to realize industrialized production.

6. The products prepared by the present invention have good compatibility with conventional cleaning fracturing fluid additives and construction techniques.

Detailed ways

The experimental methods used in the following examples are conventional methods unless otherwise specified.

The materials, reagents, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

Example 1:

(1) Preparation of viscoelastic surfactant

①Preparation of amidated products

100g of eicosic acid, 60g of 1-(2-hydroxyethyl)piperazine, and 0.6g of sodium fluoride were added to a four-neck glass bottle equipped with a stirrer, a nitrogen-passing tube, a drying tube and a thermometer. The raw materials were dissolved, and after nitrogen gas was introduced for 20 min, the reaction temperature was controlled at 180 °C, the reaction was performed for 12 h, and the volatile components were distilled off under reduced pressure at 180 °C to obtain an amidated product;

② Preparation of amphoteric surfactants

100g of amidation product, 400g of ethyl acetate, 65g of sodium 3-chloro-2-hydroxypropanesulfonate were added to the three-necked glass bottle equipped with a stirrer, spherical condenser and thermometer, heated and stirred until all raw materials were dissolved, the The reaction temperature was controlled at 75°C, reacted for 10h, cooled, filtered and dried to obtain the amphoteric surfactant product;

(2) Preparation of high temperature stabilizer

Add 100g trimethyl borate, 36g 1,4-butanediamine, 400g ethanol into a three-neck glass bottle equipped with a stirrer, spherical condenser and thermometer, control the temperature at 70°C, react for 3h, at 60°C The volatile components are removed by distillation under reduced pressure to obtain a high temperature stabilizer;

(3) Preparation of fracturing fluid system

Add 1000g of tap water, 20g of sodium chloride, 4g of calcium chloride, and 10g of viscoelastic surfactant to the container.

In a beaker with a stirrer, after heating and stirring until all the surfactants are dissolved, add 0.5 g of a high-temperature stabilizer aqueous solution with a mass fraction of 20%, and stir evenly to obtain a fracturing fluid system.

Example 2:

As described in Example 1, the difference is that the compound-1 in the preparation of the amidated product in step (1) is erucic acid.

Example 3:

As described in Example 1, the difference is that the compound-1 in the preparation of the amidated product in step (1) is hexadecanoic acid.

Example 4:

As described in Example 1, the difference is that the amount of 1-(2-hydroxyethyl)piperazine in the preparation of the amidated product in step (1) is 75 g.

Example 5:

As described in Example 1, the difference is that the compound-2 in the preparation of the amidated product in step (1) is 1-(4-hydroxyphenyl)piperazine.

Example 6:

As described in Example 1, the difference is that the reaction temperature in the preparation of the amidated product in step (1) is 165° C. and the time is 10 h.

Example 7:

As described in Example 1, the difference is that the amount of ethyl acetate in the preparation of the amphoteric surfactant in step (1) is 300 g.

Example 8:

As described in Example 1, the difference is that the amount of sodium 3-chloro-2-hydroxypropanesulfonate in the preparation of the amphoteric surfactant in step (1) is 90 g.

Example 9:

As described in Example 1, the difference is that the reaction temperature in the preparation of the amphoteric surfactant in step (1) is 65° C. and the time is 12 h.

Example 10:

As described in Example 1, the difference is that 1,4-butanediamine in step (2) is 48 g.

Example 11:

As described in Example 1, the difference is that 1,4-butanediamine in step (2) is 30 g.

Example 12:

As described in Example 1, the difference is that the compound-4 in step (2) is 1,6-hexanediamine, and the added amount is 42 g.

Example 13:

As described in Example 1, the difference is that the reaction temperature in step (2) is 80°C and the time is 2h.

Example 14:

As described in Example 1, the difference is that the viscoelastic surfactant in step (3) is 6 g.

Example 15:

As described in Example 1, the difference is that the viscoelastic surfactant in step (3) is 15 g.

Example 16:

As described in Example 1, the difference is that the high temperature stabilizer aqueous solution with a mass fraction of 20% in step (3) is 0.25 g.

Example 17:

As described in Example 1, the difference is that the high temperature stabilizer aqueous solution with a mass fraction of 20% in step (3) is 0.8 g.

Example 18:

As described in Example 1, the difference is that in step (3), sodium chloride is 45g.

Comparative Example 1:

Clean fracturing fluid industrial products produced by Xi'an Yabang Petroleum Technology Co., Ltd.

Comparative Example 2:

The clean fracturing fluid industrial product produced by Shaanxi Senrui Petroleum Technology Development Co., Ltd.

Performance evaluation

The process of preparing fracturing fluid in Comparative Example 1 and Comparative Example 2: Add 1000g of tap water, 20g of sodium chloride, 4g of calcium chloride, and 25g of sample into a beaker equipped with a stirrer, heat up and stir until all components are dissolved, and set aside.

The viscosity-increasing performance and the sand-suspending performance of Examples 1 to 18 and the comparative example were evaluated, and the test methods were as follows.

1. Evaluation of viscosity increasing performance

Put the prepared fracturing fluid into the high-temperature and high-pressure rheometer to heat the sample. The heating rate of the rheometer is kept at (3±0.2)°C/min, the initial temperature is set to 25°C, and the rotor shear rate is 170s. ^-1 . After the temperature was raised to 90°C, the temperature and shear rate remained unchanged, and the total test duration was 2h.

2. Evaluation of imbibition performance

(1) Put 100 mL of fracturing fluid into a graduated cylinder, and heat the fracturing fluid to 90°C with a constant temperature water bath;

(2) Select ceramsite with a particle size between 20 and 40 meshes, and use tweezers to take a ceramsite and place it 2 cm below the liquid surface;

(3) Release the tweezers and let them settle naturally, record the time required for the ceramsite to settle evenly for a certain distance (greater than 20cm), and calculate the settling velocity.

The evaluation results are shown in Table 1.

Table 1 Performance evaluation results

It can be seen from the experimental results that, compared with industrial clean fracturing fluid products, the clean fracturing fluid system prepared by the present invention has the advantages of small dosage, excellent viscosity increasing effect and good temperature resistance. sand carrying effect.

Claims (8)

1. A preparation method of high-temperature-resistant clean fracturing fluid comprises the following steps:

(1) preparation of viscoelastic surfactants

Preparation of amidated product

Adding the compound-1, the compound-2 and sodium fluoride into a four-neck glass bottle provided with a stirrer, a nitrogen introducing pipe, a drying pipe and a thermometer, heating and stirring until all raw materials are dissolved, introducing nitrogen for 20min, controlling the reaction temperature at 120-190 ℃, reacting for 3-48 h, and distilling under reduced pressure at 180 ℃ to remove volatile components to obtain the compound-2; the mass ratio of the compound-1 to the compound-2 is 1 (0.3-1), and the mass ratio of the compound-2 to the sodium fluoride is 1 (0.003-0.02);

preparation of amphoteric surfactant

Adding the amidated product, ethyl acetate and the compound-3 into a three-neck glass bottle provided with a stirrer, a spherical condenser tube and a thermometer, heating and stirring until all raw materials are dissolved, controlling the reaction temperature at 60-130 ℃, reacting for 4-24 hours, cooling, filtering and drying to obtain the compound; the mass ratio of the amidation product to the compound-3 to the ethyl acetate is 1 (0.3-2) to 1.5-10;

the compound-1 is one of hexadecanoic acid, octadecanoic acid, eicosanoic acid, docosanoic acid, palmitoleic acid, oleic acid and erucic acid;

the compound-2 is one of 1- (2-hydroxyethyl) piperazine and 1- (4-hydroxyphenyl) piperazine;

the compound-3 is one of 3-chloropropanesulfonic acid sodium salt and 3-chloro-2-hydroxypropanesulfonic acid sodium salt;

(2) preparation of high temperature stabilizers

Adding trimethyl borate, a compound-4 and ethanol into a three-neck glass bottle provided with a stirrer, a spherical condenser tube and a thermometer, controlling the temperature at 50-80 ℃, reacting for 1-10 hours, and distilling under reduced pressure at 60 ℃ to remove volatile components to obtain the compound; the mass ratio of trimethyl borate to the compound-4 to the ethanol is 1 (0.2-0.7) to 1-6;

the compound-4 is one of ethylenediamine, 1, 3-propanediamine, 1, 4-butanediamine and 1, 6-hexanediamine;

(3) preparation of fracturing fluid system

Adding tap water, sodium chloride, calcium chloride and a viscoelastic surfactant into a beaker provided with a stirrer, heating and stirring until all the surfactant is dissolved, adding a high-temperature stabilizer aqueous solution with the mass fraction of 20%, and uniformly stirring to obtain the water-soluble calcium phosphate; the mass ratio of the tap water, the sodium chloride, the calcium chloride and the viscoelastic surfactant is 1 (0.005-0.1): 0.0001-0.02): 0.002-0.04), and the mass ratio of the viscoelastic surfactant to the high-temperature stabilizer aqueous solution is 1 (0.002-0.25).

2. The preparation method of the high-temperature-resistant clean fracturing fluid as claimed in claim 1, wherein the mass ratio of the compound-1 to the compound-2 in the preparation of the amidation product in the step (1) is 1 (0.4-0.8), and the mass ratio of the compound-2 to the sodium fluoride is 1 (0.005-0.015).

3. The preparation method of the high-temperature-resistant clean fracturing fluid as claimed in claim 1, wherein the reaction temperature in the preparation of the amidation product in the step (1) is 150-190 ℃ and the reaction time is 6-24 h.

4. The method for preparing high temperature resistant clean fracturing fluid as claimed in claim 1, wherein the mass ratio of amidation product, compound-3 and ethyl acetate in the preparation of amphoteric surfactant in step (1) is 1 (0.45-1.2) to (2-6).

5. The preparation method of the high-temperature-resistant clean fracturing fluid as claimed in claim 1, wherein the reaction temperature in the preparation of the amphoteric surfactant in the step (1) is 65-85 ℃ and the reaction time is 8-15 h.

6. The method for preparing high temperature resistant clean fracturing fluid as claimed in claim 1, wherein the mass ratio of trimethyl borate, compound-4 and ethanol in step (2) is 1 (0.2-0.55) to (1-5).

7. The preparation method of the high-temperature-resistant clean fracturing fluid as claimed in claim 1, wherein the reaction temperature in the step (2) is 65-80 ℃ and the reaction time is 2-6 h.

8. The method for preparing high temperature resistant clean fracturing fluid as claimed in claim 1, wherein the mass ratio of tap water, sodium chloride, calcium chloride and viscoelastic surfactant in step (3) is 1 (0.01-0.05): (0.001-0.01): 0.004-0.025), and the mass ratio of viscoelastic surfactant to high temperature stabilizer aqueous solution is 1 (0.005-0.15).