CN114410287A

CN114410287A - Composite nano cross-linking agent and preparation method and application thereof

Info

Publication number: CN114410287A
Application number: CN202111671654.3A
Authority: CN
Inventors: 刘艳华; 邓青春; 吴向阳; 王耀国; 成瑾瑾; 刘哲宇; 李宜强
Original assignee: Ningbo Fengcheng Advanced Energy Materials Research Institute Co ltd
Current assignee: Ningbo Fengcheng Advanced Energy Materials Research Institute Co ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-04-29
Anticipated expiration: 2041-12-31
Also published as: CN114410287B

Abstract

The application discloses a composite nano cross-linking agent, a preparation method and application thereof, and belongs to the technical field of chemical additives. The cross-linking agent comprises, by mass, 70-80 parts of glycerol, 2-5 parts of lactic acid, 4-8 parts of zirconium oxychloride and 1-2 parts of trisodium citrate. The composite nano cross-linking agent provided by the application can be added to effectively reduce the dosage of the emulsion drag reducer, improve the viscosity of the emulsion drag reducer in a fracturing fluid system under the action of high temperature and high shear, prolong the cross-linking time, and improve the viscoelasticity and temperature resistance, so that the drag reduction effect is improved.

Description

Composite nano cross-linking agent and preparation method and application thereof

Technical Field

The application relates to a composite nano cross-linking agent, a preparation method and application thereof, belonging to the technical field of chemical additives.

Background

In the fracturing of shale gas horizontal wells, slickwater is used as a sand carrying liquid and a displacing liquid, the proportion of the slickwater accounts for more than 95% of the total liquid entering the well, and a drag reducer (drag reducer) is a core additive of a slickwater system, wherein the polyacrylamide type drag reducer in a synthetic polymer becomes a main current drag reducer for domestic and foreign slickwater with low product price and good drag reduction effect, and the current commonly used drag reducer is dry powder and emulsion. The dry powder drag reducer has long dissolving time, needs to occupy a large amount of equipment and fields, and is rarely used at present.

The emulsion drag reducer is synthesized by W/O emulsion polymerization, takes a nonpolar solvent as a continuous phase, dissolves a polymerization monomer in water, then disperses the polymerization monomer in an oil phase by an emulsifier to form a W/O emulsion for polymerization, and the formed product is the W/O emulsion which has the advantages of high dissolution speed, high molecular weight, low viscosity in polymerization reaction, easy heat dissipation and control, high production cost and more complex technology. And the polyacrylamide polymer has poor hardness and shear resistance, and seriously influences the flowback and sand carrying performance of the polyacrylamide polymer.

The prior fracturing fluid is commonly used with a zirconium crosslinking agent and an organic chromium crosslinking agent for tackifying a polymer. The cross-linking agent can form multi-nuclear hydroxyl bridged ions through hydration, hydrolysis and hydroxyl bridging under proper conditions, and the multi-nuclear hydroxyl bridged ions and groups in the polyacrylamide generate cross-linking action to form a three-dimensional network structure, so that the gel viscosity of a polymer system is increased.

However, hexavalent chromium ions in the organic chromium crosslinking agent are seriously harmful to underground water and reservoir stratum, and even if trivalent chromium is used to replace hexavalent chromium, the trivalent chromium is still oxidized to cause potential damage to the reservoir stratum, so that the popularization and application of the organic chromium crosslinking agent are limited. The zirconium cross-linking agent consisting of inorganic zirconium compounds such as zirconium oxychloride, zirconium tetrachloride, zirconium sulfate, zirconium nitrate and the like has short gelling time, is not beneficial to field construction operation, has low effective viscosity and is difficult to meet the requirements of field construction operation. And the organic ligand such as ethylenediamine is complexed with zirconium ions, so that the synthesized organic zirconium crosslinking agent still has the problems of short gelling time and poor temperature and shear resistance.

Disclosure of Invention

Based on the technical problems, the complex reaction is carried out by using a zirconium oxychloride, lactic acid, glycerol and sodium citrate system, and then the nano titanium dioxide is added to uniformly disperse the nano titanium dioxide, so that the composite nano cross-linking agent and the preparation method thereof are provided.

According to one aspect of the application, a composite nano cross-linking agent is provided, and the components of the cross-linking agent comprise, by mass:

optionally, the crosslinking agent further comprises 0.05-1 part of nano titanium dioxide and 10-20 parts of deionized water in parts by mass.

Optionally, the particle size of the nano titanium dioxide is 25-100 nm.

Optionally, the composite nano-cross-linking agent is composed of 70-80 parts of glycerol, 2-5 parts of lactic acid, 4-8 parts of zirconium oxychloride, 1-2 parts of trisodium citrate, 0.05-1 part of nano titanium dioxide and 10-20 parts of deionized water.

According to still another aspect of the present application, there is provided a method for preparing the composite nanocrosslinker, comprising the steps of:

(1) preparing a solution containing glycerol and lactic acid, and stirring to obtain a solution A; preferably placing the mixture on an oil bath pan, stirring and mixing;

(2) stirring and mixing a solution I containing zirconium oxychloride and a solution II containing trisodium citrate, and carrying out a complex reaction to obtain a solution B containing a complex product;

(3) and dropwise adding the solution B into the solution A, and reacting to obtain the composite nano cross-linking agent.

(3) dropwise adding the solution B into the solution A, and reacting to obtain a solution C;

(4) and adding the nano titanium dioxide into the solution C, and stirring and mixing to obtain the composite nano cross-linking agent.

Optionally, in the step (1), the rotation speed of stirring is 300-500 rpm, the stirring time is 10-30 min, and the stirring temperature is 20-30 ℃.

Optionally, in the step (2), the rotation speed of stirring is 300-500 rpm, and the stirring time is 30-60 min.

Optionally, in the step (3), the reaction temperature is 60-80 ℃, and the reaction time is 2-4 h; the stirring speed is 300-500 rpm, and the stirring time is 30-60 min.

In the step (3), the upper limit of the reaction temperature is independently selected from 75 ℃, 70 ℃ and 65 ℃, and the lower limit is independently selected from 62 ℃, 65 ℃ and 67 ℃; the upper limit of the reaction time is independently selected from 3.5h, 3h, 2.5h, and the lower limit is independently selected from 2.2h, 2.5h, 2.8h, 3 h.

Optionally, in the step (3), the mass ratio of the solution A to the solution B is 6: 1-2: 1, the upper limit is independently selected from 5.5:1, 5:1, 4.5:1, 4:1 and 3.5:1, and the lower limit is independently selected from 2.5:1, 3:1, 3.5:1 and 4: 1.

Optionally, in the step (3), the dropping rate is 1-2 mL/min.

Alternatively, the upper limit of the rate of the dropping is independently selected from 1.8mL/min, 1.6mL/min, 1.5mL/min, 1.2mL/min, and the lower limit is independently selected from 1.2mL/min, 1.4mL/min, 1.5 mL/min.

Optionally, in the step (1), the mass ratio of the glycerol to the lactic acid is 70-80: 2-5;

in the step (2), the mass ratio of the zirconium oxychloride, the trisodium citrate and the solvent is 4-8: 1-2: 10-20;

the mass number of the solvent is calculated by the total mass number of the solvent in the solution I and the solution II;

the solvent is at least one selected from deionized water, propylene glycol and ethylene glycol.

Optionally, in the solution C, the content of the nano titanium dioxide is 0.05 wt.% to 1 wt.%.

Optionally, the amount of the nano titania in solution C is 0.1 wt.%, 0.15 wt.%, 0.2 wt.%, 0.25 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, or 0.9 wt.%, or any value therebetween.

According to still another aspect of the application, the composite nano-crosslinking agent prepared by the preparation method and the application of the composite nano-crosslinking agent in slick water are provided.

As one embodiment of the present application, a composite nano-cross-linking agent is prepared by the following steps:

(1) taking glycerol and lactic acid, stirring and mixing uniformly, then adding into a three-neck flask, and placing into an oil bath kettle for stirring;

(2) adding zirconium oxychloride and trisodium citrate into deionized water, stirring and dissolving to fully complex the zirconium oxychloride and the trisodium citrate;

(3) slowly dripping the zirconium oxychloride-sodium citrate mixed solution complexed in the step (2) into a three-neck flask at the speed of 1mL/min, heating an oil bath, and reacting;

(4) and (3) weighing nano titanium dioxide, adding the nano titanium dioxide into the product obtained after the reaction in the step (3), and stirring to disperse and mix the nano titanium dioxide uniformly to obtain the composite nano cross-linking agent.

When the ratio of glycerin to lactic acid to zirconium oxychloride to sodium citrate is 90:4:5:1, the performance is excellent, and the obtained composite nano cross-linking agent can improve the viscosity of 0.2% emulsion polymer to 125cP after shearing for 10 minutes and still maintain 86cP after shearing for 60 minutes when the blank viscosity is 15 cP.

The beneficial effects that this application can produce include:

the composite nano cross-linking agent provided by the application can effectively reduce the dosage of the emulsion drag reducer, improve the viscosity of the emulsion drag reducer in a fracturing fluid system under the action of high temperature and high shear, prolong the cross-linking time, and improve the viscoelasticity and the temperature resistance, thereby improving the drag reduction effect.

Drawings

FIG. 1 is a graph of adhesion promoting performance of test example 2;

FIG. 2 is a graph showing the thickening performance of test example 3.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

Unless otherwise specified, the starting materials and catalysts in the examples of this application were purchased commercially, with nano-titania (25nm and 100nm, gold red, hydrophilic type) from a network of alatin reagent.

Example 1

A composite nano cross-linking agent is prepared by the following steps:

(1) taking 90g of glycerol and 4g of lactic acid, stirring and mixing uniformly, then adding into a three-neck flask, and placing into an oil bath kettle, and stirring for 30min at 25 ℃ and 300 rpm;

(2) adding 10ml deionized water into 5g of zirconium oxychloride and 1g of trisodium citrate, stirring for 30min for dissolution, and fully complexing;

(3) and (3) slowly dropwise adding the zirconium oxychloride-sodium citrate mixed solution complexed in the step (2) into a three-neck flask at the rate of 1mL/min, heating an oil bath to 70 ℃, and reacting for 3 hours to obtain the organic zirconium crosslinking agent.

Example 2

A composite nano cross-linking agent is prepared by the following steps:

(3) slowly and dropwise adding the zirconium oxychloride-sodium citrate mixed solution complexed in the step (2) into a three-neck flask at the speed of 1mL/min, heating an oil bath kettle to 70 ℃, and reacting for 3 hours.

(4) And (3) adding 0.5g of 25nm nano titanium dioxide into the product obtained after the reaction in the step (3), and stirring at 300rpm for 60min to uniformly disperse and mix the titanium dioxide to obtain the composite nano cross-linking agent.

Example 3

A composite nano cross-linking agent is prepared by the following steps:

(1) taking 80g of glycerol and 3.2g of lactic acid, stirring and mixing uniformly, then adding into a three-neck flask, and stirring for 30min at 25 ℃ and 300rpm in an oil bath kettle;

(3) slowly and dropwise adding the zirconium oxychloride-sodium citrate mixed solution complexed in the step (2) into a three-neck flask at the speed of 2mL/min, heating an oil bath kettle to 70 ℃, and reacting for 3 hours.

(4) And (3) adding 0.05g of 25nm nano titanium dioxide into the product obtained after the reaction in the step (3), and stirring at 300rpm for 60min to uniformly disperse and mix the titanium dioxide to obtain the composite nano cross-linking agent.

Example 4

A composite nano cross-linking agent is prepared by the following steps:

(2) taking 10g of zirconium oxychloride and 2g of trisodium citrate, adding 10ml of deionized water, stirring for 30min, and dissolving to fully complex;

(4) And (3) adding 0.5g of 100nm nano titanium dioxide into the product obtained after the reaction in the step (3), and stirring at 300rpm for 60min to uniformly disperse and mix the titanium dioxide to obtain the composite nano cross-linking agent.

Comparative example 1

A composite nano cross-linking agent is prepared by the following steps:

(1) adding 78g of deionized water into 7.8g of zirconium oxychloride, placing the mixture in an oil bath kettle at 300rpm, magnetically stirring the mixture until the zirconium oxychloride is dissolved, and then introducing N₂Discharging oxygen;

(2) sequentially adding 1g of lactic acid, 6.7g of ethylenediamine and 5g of thiourea into the step (1);

(3) and (3) heating the oil bath kettle to 70 ℃, and reacting for 3 hours to obtain the organic zirconium crosslinking agent.

(4) And (3) adding 0.5g of nano titanium dioxide into the product obtained after the reaction in the step (3), and stirring at 300rpm for 60min to uniformly disperse and mix the nano titanium dioxide to obtain the composite nano cross-linking agent.

Test example 1

The obtained composite nano cross-linking agent and the polymer are compounded and stirred, and are fully cross-linked, and then the mixture passes through a Haake rheometer to be tested for 170s at the high temperature of 70 DEG C^-1The viscosity was measured at shear rates of 10min and 60min, and the thickening effect of the crosslinking agent was evaluated, and the results are shown in Table 1.

The polymer is emulsion polyacrylamide, and the use concentration is 0.2%. Preparing by adopting 2% standard saline, firstly adding 2% standard saline into a Wuyi stirrer, then adding a polymer, stirring for 1min, then adding a cross-linking agent, and continuing to stir for 1 min. Standard brine configuration method: 2% KCl + 5.5% NaCl + 0.45% MgCl₂+0.55％CaCl₂。

Table 1.

Sample numbering	Polymer blank viscosity	The concentration of the cross-linking agent	Viscosity increasing (10min)	Viscosity increasing (60min)
					Example 1	15cP	0.5％	80cP	52cP
Example 2	15cP	0.5％	125cP	86cP
					Example 3	15cP	0.5％	55cP	35cP
Example 4	15cP	0.5％	62cP	38cP
					Comparative example 1	15cP	0.5％	18cP	15cP

The best performance of glycerin, lactic acid, zirconium oxychloride and sodium citrate is obtained by comparing the tackifying performances of the organic zirconium crosslinking agents with different proportions, wherein the ratio of the glycerin, the lactic acid, the zirconium oxychloride and the sodium citrate is 90:4:5: 1. Without the addition of the nanotitanium dioxide, the addition of 0.5% crosslinker increased the viscosity of the emulsion polymer from 15cP to 80cP at a 0.2% use concentration. The viscosity of the emulsion polymer with 0.2% use concentration can be improved from 15cP to 125cP by adding the composite nano cross-linking agent prepared by adding the nano titanium dioxide, namely, the addition of the nano titanium dioxide has a certain gain effect and can improve the shearing resistance of the emulsion polymer.

Test example 2

Passing through a Haake rheometer at 70 deg.C for 170s^-1The temperature is kept for 5min under the condition of shearing rate, the temperature is cut for 10min, the tackifying data of the composite nano cross-linking agent with the same nano titanium dioxide addition amount (0.5%), different use concentrations (0.2%, 0.33%, 0.5%, 0.67%, 1%, 2%) on 0.2% emulsion polymer are tested, and the tackifying data of the composite nano cross-linking agent with different use concentrations (0.2%, 0.33%, 0.5%, 0.67%, 1%, 2%) on 0.2% emulsion polymer are tested when the nano material is not added, and the result is shown in figure 1. As can be seen from FIG. 1, the viscosity increased greatly and then decreased with the increase of the amount of the nanocomposite crosslinking agent in the polymer use solution, and the thickening effect at 0.5% use concentration was the best.

Test example 3

Passing through a Haake rheometer at 70 deg.C for 170s^-1Under the condition of shear rate, the temperature is kept for 5min, the shearing is carried out for 10min, and the tackifying data of different nano titanium dioxide addition amounts (0.05%, 0.1%, 0.5% and 1%) and 0.5% composite nano cross-linking agent use concentration to 0.2% polymer are tested, as shown in figure 2. As can be seen from FIG. 2, the more the amount of the nanomaterial in the nanocomposite crosslinking agent is added, the better the tackifying effect is, and the viscosity tends to be stable after the amount of the nanomaterial added in the stock solution exceeds 0.5%.

Test example 4

The synthesized nano composite cross-linking agent has delayed cross-linking performance, and the longer the standing time is, the higher the viscosity is. Testing the viscosity of the polymer after cross-linking by a Haake rheometer for 0 day, 2 days and 7 days at 70 deg.C for 170s^-1And (3) under the condition of shear rate, keeping the temperature for 5min, and measuring the viscosity after shearing for 10min, wherein the test results are shown in Table 2.

Table 2.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. The composite nano cross-linking agent is characterized by comprising the following components in parts by mass:

2. the cross-linking agent according to claim 1, further comprising 0.05 to 1 part by mass of nano titanium dioxide and 10 to 20 parts by mass of deionized water;

preferably, the particle size of the nano titanium dioxide is 25-100 nm.

3. The crosslinking agent according to claim 2, wherein the crosslinking agent comprises 70 to 80 parts of glycerol, 2 to 5 parts of lactic acid, 4 to 8 parts of zirconium oxychloride, 1 to 2 parts of trisodium citrate, 0.05 to 1 part of nano titanium dioxide, and 10 to 20 parts of deionized water.

4. A method for preparing the composite nano-crosslinking agent according to claim 1, wherein the method comprises the following steps:

(1) preparing a solution containing glycerol and lactic acid, and stirring to obtain a solution A;

(2) mixing a solution I containing zirconium oxychloride with a solution II containing trisodium citrate, and carrying out a complex reaction to obtain a solution B containing a complex product;

5. A method for preparing the composite nanocrosslinker as claimed in claim 2 or 3, wherein the method comprises the following steps:

(4) and adding nano titanium dioxide into the solution C, and mixing to obtain the composite nano cross-linking agent.

6. The preparation method according to claim 4 or 5, wherein in the step (1), the rotation speed of the stirring is 300-500 rpm, the stirring time is 10-30 min, and the stirring temperature is 20-30 ℃;

in the step (3), the reaction temperature is 60-80 ℃, and the reaction time is 2-4 h.

7. The preparation method according to claim 4 or 5, wherein in the step (3), the mass ratio of the solution A to the solution B is 6: 1-2: 1;

the dropping rate is 1-2 mL/min.

8. The preparation method according to claim 4 or 5, wherein in the step (1), the mass ratio of the glycerol to the lactic acid is 70-80: 2-5;

the solvent is deionized water.

9. The preparation method according to claim 5, wherein the content of the nano titania in the solution C is 0.05 wt.% to 1 wt.%.

10. The use of the composite nano-crosslinking agent as defined in any one of claims 1 to 3 and the composite nano-crosslinking agent prepared by the preparation method as defined in any one of claims 4 to 9 in slick water.