CN110846011B

CN110846011B - Carbon dioxide gel foam with thiourea structure and preparation method and application thereof

Info

Publication number: CN110846011B
Application number: CN201911151329.7A
Authority: CN
Inventors: 王彦玲; 兰金城; 孟令韬; 蒋保洋; 许宁; 梁雷; 刘斌; 汤龙皓
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2019-11-21
Filing date: 2019-11-21
Publication date: 2021-09-24
Anticipated expiration: 2039-11-21
Also published as: CN110846011A

Abstract

The invention relates to a carbon dioxide gel foam containing a thiourea structure, and a preparation method and application thereof. The carbon dioxide gel foam containing the thiourea structure is prepared by introducing carbon dioxide gas into the gel solution. The gel solution comprises the following components in percentage by mass: 0.2 to 0.8 percent of methylene polyacrylamide, 0.2 to 1.4 percent of phenolic aldehyde crosslinking agent, 0.3 to 1.0 percent of foaming agent, 0.2 to 0.5 percent of phenol organic matter containing thiourea structure, 0.2 to 0.5 percent of auxiliary agent and the balance of water. The carbon dioxide gel foam has strong water plugging selectivity, does not block an oil flow channel, does not influence the flow of oil, and improves the crude oil recovery ratio.

Description

Carbon dioxide gel foam with thiourea structure and preparation method and application thereof

Technical Field

The invention relates to a carbon dioxide gel foam containing a thiourea structure, and a preparation method and application thereof, and belongs to the technical field of oilfield chemistry.

Background

The acidic oil and gas fields in China are widely distributed and rich in resources, but the development difficulty is high. The reason for this is that the formation, being acidic, limits the application of many stimulation treatments.

In the aspect of selective water plugging measures, the foam gel plugging agent is widely applied to oil fields because of low price and good selective water plugging effect. For example, CN 108203579a discloses a nitrogen foam gel plugging agent, wherein the foam gel skeleton is obtained by introducing the nitrogen into a gel-like material, and the gel-like material is prepared by performing a cross-linking reaction on the following components in percentage by mass: 1.5-2.5% of polyacrylamide, 0.3-1% of foaming agent, 1-3% of foam stabilizer, 1.5-2.5% of organic chromium crosslinking agent and the balance of water; the method is used for the exploitation of middle and low temperature oil fields at the temperature of 30-70 ℃.

At present, gel foams are basically only suitable for neutral or weakly alkaline oil reservoirs because a common anionic polyacrylamide phenolic gel system does not have acid resistance, and the gel foams are easy to break after the formation meets acid, so that the aim of selectively blocking water is not fulfilled. This has a great impact on the development of highly hydrated sour oil and gas fields. Therefore, the development of a foaming gel plugging agent with good selective water plugging effect under acidic formation conditions still remains one of the problems to be solved in the art.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a thiourea-containing carbon dioxide gel foam for selectively blocking water under an acidic formation condition and a preparation method thereof.

The invention also provides a carbon dioxide gel foam gel solution containing a thiourea structure.

The invention also provides a synthetic method of the phenol organic matter containing the thiourea structure.

The invention also provides application of the carbon dioxide gel foam containing the thiourea structure.

The technical scheme of the invention is as follows:

a gel solution comprises the following components in percentage by mass:

0.2 to 0.8 percent of methylene polyacrylamide, 0.2 to 1.4 percent of phenolic aldehyde crosslinking agent, 0.3 to 1.0 percent of foaming agent, 0.2 to 0.5 percent of phenolic organic matter containing thiourea structure, 0.2 to 0.5 percent of auxiliary agent and the balance of water;

the phenolic organic matter containing the thiourea structure is prepared by the following method:

mixing an organic matter with a benzene ring and a thiourea structure with liquid bromine, carrying out a bromine atom substitution reaction on the benzene ring under catalysis and heating conditions, mixing the obtained product with a sodium carbonate solution to obtain an organic matter containing a sodium phenolate and thiourea structure, and then mixing the organic matter with a strong acid to obtain a phenolic organic matter containing a thiourea structure; wherein the content of the first and second substances,

the compound with the benzene ring and the thiourea structure is selected from N-phenylthiourea, 4-pyridyl thiourea, 1-phenethyl-3-phenyl-2-thiourea, 4-fluorobenzothhiourea or N- (2-pyridyl) thiourea; the strong acid is selected from one or more of nitric acid, sulfuric acid and hydrochloric acid.

According to the present invention, it is preferable that the phenolic crosslinking agent is 0.1% to 0.7% of phenol or hydroquinone, and 0.1% to 0.7% of formaldehyde, paraformaldehyde, or hexamethylenetetramine, based on the total mass of the gel solution.

Further preferably, the dosage of the phenol or the benzenediol is 0.2 to 0.5 mass percent; based on the total mass of the gel solution.

Further preferably, the dosage of the formaldehyde, the paraformaldehyde or the hexamethylenetetramine is 0.2 to 0.5 percent by mass; based on the total mass of the gel solution.

According to the invention, the diphenol is catechol, resorcinol or hydroquinone, preferably resorcinol.

According to the invention, the hydrolysis degree of the methylene polyacrylamide is 10-20%, and the molecular weight is 1000-1800 ten thousand. More preferably, the hydrolysis degree of the methylene polyacrylamide is 12-15%, and the molecular weight is 1300-1600 ten thousand. The research of the invention finds that the hydrolysis degree and the molecular weight have great influence on the blocking property and the injection property of the gel foam; too much hydrolysis may result in short cross-linking time, affecting the injection of gel foam into the formation; too small a degree of hydrolysis results in lower cross-linking strength, which affects the blocking properties of the gel foam. Most preferably, the hydrolysis degree of the methylene polyacrylamide is 13-15%, and the molecular weight is 1400-1500 ten thousand.

The auxiliary agent is sodium sulfite, potassium sulfite or sodium thiosulfate. Further optimized, the auxiliary agent is 0.3-0.4% by mass percent.

The foaming agent is a nonionic surfactant and is selected from one or more of octyl phenol polyoxyethylene ether, nonyl phenol polyoxyethylene ether, lauryl alcohol and fatty acid polyoxyethylene ester.

In a second aspect:

a synthetic method of a phenolic organic substance containing a thiourea structure comprises the following steps:

(1) in the presence of a ferric halide catalyst, mixing an organic matter with a benzene ring and a thiourea structure with liquid bromine, and carrying out a bromine atom substituted hydrogen atom reaction on the benzene ring under the heating condition of 40-60 ℃;

the compound with the benzene ring and the thiourea structure is selected from N-phenylthiourea, 4-pyridyl thiourea, 1-phenethyl-3-phenyl-2-thiourea, 4-fluorobenzothhiourea or N- (2-pyridyl) thiourea;

(2) mixing the product obtained in the step (1) with a sodium carbonate solution at 120-140 ℃ to obtain an organic matter containing sodium phenolate and a thiourea structure, and then mixing the organic matter with a small amount of strong acid to obtain a phenolic organic matter containing a thiourea structure;

(3) and (3) mixing the phenol organic matter containing the thiourea structure in the step (2) with a proper amount of weak base for reaction, removing excessive hydrogen ions in the phenol organic matter, and cooling to obtain the phenol organic matter crystal containing the thiourea structure.

According to the method for synthesizing a phenolic organic compound containing a thiourea structure of the present invention, it is preferable that the reaction in the step (1) includes any one or more of the following conditions:

a1, wherein the iron halide can be one or more of ferric bromide or ferric chloride.

a2, wherein the heating temperature is 50-55 ℃.

a3, wherein the molar ratio of the organic matters with benzene ring and thiourea structures to the liquid bromine is 1: (2.0-2.5); more preferably, the molar ratio of the organic matters with benzene ring and thiourea structures to the liquid bromine is 1: (2.1-2.4).

According to the method for synthesizing a phenolic organic compound containing a thiourea structure, preferably, the reaction in the step (2) includes any one or more of the following conditions:

b1, wherein the high-temperature condition is 130 ℃.

b2, the strong acid is selected from one or more of nitric acid, sulfuric acid and hydrochloric acid.

b3, the molar ratio of the organic matter containing sodium phenolate and thiourea structure to the strong acid is 1: (0.5 to 1.5); more preferably, the molar ratio of the organic matter containing sodium phenolate and thiourea structures to the strong acid is 1: (0.7-1.2).

According to the method for synthesizing a phenolic organic compound containing a thiourea structure, preferably, the reaction of the step (3) includes any one or more of the following conditions:

c1, wherein the weak base is sodium carbonate or ammonia water;

c2, wherein the reaction temperature is 50-100 ℃;

c3, wherein the molar ratio of the phenolic organic matter containing the thiourea structure to the weak base is 1: (0.1 to 0.7); more preferably, the molar ratio of the phenolic organic compound containing a thiourea structure to the weak base is 1: (0.2-0.4).

When the weak base in the step (3) is ammonia water, the reaction temperature is lower than a certain temperature, and a condensing reflux pipe is added.

In a third aspect:

the carbon dioxide gel foam with the thiourea structure is prepared by introducing carbon dioxide gas into the gel solution.

Preferably, the gas-liquid volume ratio of the carbon dioxide to the gel solution is 100: 1 to 2.

In a fourth aspect:

a preparation method of a thiourea structure-containing carbon dioxide gel foam comprises the following steps:

1) and (3) preparing a phenolic organic matter containing a thiourea structure. As set forth in the foregoing second aspect of the invention;

2) preparation of gel solution:

weighing the following raw material components according to the mixture ratio of the carbon dioxide gel foam liquid phase gel containing the thiourea structure: fully mixing the components, and then placing the mixture in an environment at the temperature of 20-25 ℃ for 8-12 hours to prepare a gel solution;

3) preparation of carbon dioxide foam gel containing thiourea structure:

adding the mixture into the gel solution according to the gas-liquid volume ratio of 100: 1-2, introducing carbon dioxide gas, and then reacting for 40-50h at 70-80 ℃ to obtain the carbon dioxide foam gel containing the thiourea structure.

Preferably, according to the invention, the reaction temperature in step 3) is 70 ℃.

The inventor finds that the viscosity of the gel solution can be moderately increased by selecting the step 2) to place for 8-12 hours at the temperature of 20-25 ℃, and the viscosity of the gel solution can be increased by a small amount of polymerization reaction at room temperature in the placing process.

In a fifth aspect:

the carbon dioxide gel foam containing the thiourea structure is used for water shutoff, acidification, fracturing or profile control of oil fields. The method is particularly suitable for selective water plugging of acidic strata.

On one hand, the invention utilizes the phenol organic matters with thiourea structure (the main components are 4-phenol thiourea and a small amount of 2-phenol thiourea to generate cross-linking polymerization reaction with methylene polyacrylamide and phenols and aldehydes, the generated organic matters with thiourea structure can form a complex with hydrogen ions to enhance the acid resistance, on the other hand, the invention leads carbon dioxide gas into the obtained gel to form gel foam, and the gel foam has the characteristic of reducing the seepage capability of water flow without influencing the seepage capability of oil flow, thereby achieving the purpose of selectively blocking water.

1. According to the formula of the carbon dioxide gel foam liquid-phase gel containing the thiourea structure, the phenolic organic matter with the thiourea structure is used, and the organic matter with the thiourea structure, which is generated by cross-linking and polymerizing with other monomers, can form a complex with hydrogen ions, so that the acid resistance of the gel foam is enhanced; on the other hand, the invention also adds sodium sulfite, potassium sulfite or sodium thiosulfate auxiliary agents, which can remove dissolved oxygen therein and enhance the temperature resistance of the gel foam. The carbon dioxide gel foam with the thiourea structure has strong acid resistance, and can still maintain better water plugging selectivity under the acid formation condition. The temperature resistance is strong, and the high temperature of 80-150 ℃ can be resisted.

2. The carbon dioxide gel foam with the thiourea structure has strong water plugging selectivity, the foaming agent is easy to dissolve in oil, foam is not formed, an oil flow channel is not blocked, the flowing of oil is hardly influenced, but the foam formed in a water phase is stable, a water flow channel is blocked, and the water seepage capability is obviously reduced. The foaming agent is a surfactant, so that the oil-water interfacial tension can be reduced, the oil washing efficiency is improved, and the crude oil recovery rate is improved.

3. The raw materials required by the invention are easy to purchase and have lower price, and the preparation process is simple and convenient. The construction process is simple, the initial viscosity of the system is low, and the system is easy to pump to the stratum.

Drawings

FIG. 1 is an infrared spectrum of 4-phenol thiourea, a phenolic organic substance containing a thiourea structure, synthesized in example 1.

FIG. 2 is a photograph of the gel solution in example 1.

FIG. 3 is a photograph of the gel foam of example 1.

Detailed Description

The present invention will be further described with reference to the following examples. The concentration "%" in the examples is a mass percent concentration unless otherwise specified.

Example 1

A synthetic method of carbon dioxide gel foam with a thiourea structure for water shutoff in oil fields comprises the following steps:

1) preparation of phenolic organic matter containing thiourea structure

7.6g of N-phenylthiourea and 16g of liquid bromine are fully mixed in a constant-temperature round-bottom flask at 50 ℃, 2ml of ferric bromide is added, after 5min of reaction, the liquid in the flask is poured into a beaker filled with cold water, and the beaker is washed by water or 10% sodium hydroxide solution.

And (3) mixing the product obtained in the previous step with 25mL of 10% sodium carbonate solution in a 130 ℃ round-bottom flask, and reacting for 1h to obtain an organic matter containing sodium phenolate and thiourea structures. After cooling to room temperature, adding 100ml of 0.5mol/L nitric acid into the round-bottom flask, and reacting for 1h after gentle shaking to obtain the phenolic organic matter containing thiourea structure. And adding 5mL of 10% sodium carbonate solution into the obtained product, slightly shaking, heating at 90 ℃ for 2h for carrying out after-treatment on the product, and then cooling and crystallizing to obtain the 4-phenylthiourea. The structural characterization of the resulting product is shown in figure 1. The structural formula is as follows:

2) weighing the following components in percentage by mass: 0.3 percent of methylene polyacrylamide (the degree of hydrolysis is 13 percent, the molecular weight is 1400 ten thousand), 0.5 percent of phenol, 0.5 percent of paraformaldehyde, 0.4 percent of octyl phenol polyoxyethylene ether, 0.3 percent of 4-phenol thiourea and 0.3 percent of sodium sulfite. The balance being water. The components are fully mixed and then are placed in an environment with the temperature of 20 ℃ for 12 hours to prepare a gel solution.

3) Adding the mixture into the gel solution according to the gas-liquid volume ratio of 100: 1, introducing carbon dioxide gas, and then placing the mixture in an environment at 70 ℃ for 48 hours to prepare the carbon dioxide foam gel containing the thiourea structure.

Example 2

As shown in example 1, except that the mass percentages of the components in step 2) are changed to the following proportions:

0.4 percent of methylene polyacrylamide (the degree of hydrolysis is 13 percent, the molecular weight is 1400 ten thousand), 0.6 percent of phenol, 0.6 percent of paraformaldehyde, 0.5 percent of octyl phenol polyoxyethylene ether, 0.4 percent of 4-phenol thiourea and 0.4 percent of sodium sulfite. The balance being water.

Example 3

As shown in example 1, except that the phenol in step 2) was changed to catechol.

Example 4

As shown in example 1, except that the phenol in step 2) was changed to resorcinol.

Example 5

As shown in example 1, except that the aldehyde in step 2) was changed to hexamethylenetetramine.

Example 6

As shown in example 1, except that the auxiliary in step 2) was changed to sodium thiosulfate.

Example 7

As shown in example 1, except that the blowing agent in step 2) was changed to nonylphenol polyoxyethylene ether.

Example 8

As shown in example 1, except that the N-phenylthiourea in step 1) was changed to 1-phenethyl-3-phenyl-2-thiourea.

Comparative example:

the carbon dioxide gel foam comprises a liquid phase gel solution and a gas phase, wherein the gel solution comprises the following components in percentage by mass: 0.3% of methylene polyacrylamide (degree of hydrolysis 13%, molecular weight 1400 ten thousand), 0.5% of phenol, 0.5% of paraformaldehyde, 0.4% of octylphenol polyoxyethylene ether and 0.3% of sodium sulfite; the balance being water. Fully mixing the components, and then putting the mixture into an environment with the temperature of 20 ℃ for reaction for 12 hours to prepare a gel solution; adding the mixture into the gel according to the gas-liquid ratio of 100: 1 introducing carbon dioxide gas, and then placing the mixture at 70 ℃ for reaction for 48 hours to obtain a carbon dioxide gel foam sample.

Evaluation of the properties of the examples and comparative examples:

experiment one: evaluating the foam system by WARING method, placing 100mL of gel solution into a Waring Blender, and introducing CO for a certain period of time₂Gas to replace other dissolved gas in the liquid, and then introducing CO while introducing₂Stirring for 3 minutes (rotation speed 10000r/min), pouring out the foam into a 1000mL measuring cylinder, and recording the foaming volume and the liquid analysis volume at different times, thereby obtaining the foaming volume, the foaming rate and the liquid analysis half-life period of the system. The results are shown in Table 1.

TABLE 1 foam stability of the different examples

Product numbering	Half life/s	Bubbling volume/mL
			Example 1	362	360
Example 2	404	355
			Example 3	344	340
Example 4	425	440
			Example 5	358	280
Example 6	397	293
			Example 7	355	330
Example 8	298	335
			Comparative example	226	210

From the above table, the best results are seen from the foaming volume and half-life in example 4.

Experiment two: the gelling stability of the products of the different examples under acidic conditions was evaluated by laboratory experiments. The experimental method comprises the following steps: preparing an acidic solution with the pH value of 4 by using hydrochloric acid, then placing the prepared gel foam in the acidic solution for 10 days, and observing the stability and gel breaking condition of the gel (the gel breaking condition is determined by the strength reduction of the gel foam). The results are shown in Table 2.

TABLE 2 evaluation results of acid resistance characteristics of various examples

Product numbering	Gel strength before placing in acid liquor	Gel strength after putting into acid liquor	Whether to break gel
				Example 1	F	F	Whether or not
Example 2	G	F	Whether or not
				Example 3	F	E	Whether or not
Example 4	F	F	Whether or not
				Example 5	F	F	Whether or not
Example 6	G	F	Whether or not
				Example 7	F	E	Whether or not
Example 8	G	G	Whether or not
				Comparative example	F	C	Is that

Note: C. e, F, G is the gel strength rating specified using the GSC strength code method proposed by Sydansk, with higher alphabetical ordering indicating greater gel strength.

As can be seen from the above table, the gel strength of the prepared foam gel is almost unchanged before and after the prepared foam gel is put in an acid solution, and gel breakage does not occur, which indicates that the acid resistance of the foam gel is very strong.

Experiment three: the product of example 4 was subjected to an indoor experiment (refer to SY/T6424-2014, composite displacement system performance test method), and the selective water shutoff effect of the prepared carbon dioxide foam gel containing a thiourea structure was evaluated, and the evaluation results are shown in table 3 and the core breakthrough pressure results are shown in table 4.

TABLE 3 evaluation of plugging Rate Properties of plugging Agents

Table 4 core breakthrough pressure results

As can be seen from Table 3, the plugging rate of the gel foam provided by the invention to the saturated water phase core is more than 90%, and the plugging rate to the saturated oil phase core is less than 16%, which indicates that the gel foam has good water plugging selectivity; as can be seen from table 4, the gel foam has a high breakthrough pressure for the saturated water phase and a low breakthrough pressure for the saturated oil phase core.

Claims

1. The gel solution is characterized by comprising the following components in percentage by mass:

2. The gel solution of claim 1, wherein the phenolic crosslinker is phenol or hydroquinone 0.1% to 0.7%, and formaldehyde, paraformaldehyde, or hexamethylenetetramine 0.1% to 0.7%.

3. The gel solution of claim 1, wherein the phenolic crosslinker, phenol or hydroquinone is present in an amount of 0.2% to 0.5% by mass; the dosage of the formaldehyde, the paraformaldehyde or the hexamethylenetetramine is 0.2 to 0.5 percent by mass.

4. The gel solution of claim 1, wherein said methylene polyacrylamide has a degree of hydrolysis of 10% to 20% and a molecular weight of 1000 to 1800 ten thousand.

5. The gel solution of claim 1, wherein said methylene polyacrylamide has a degree of hydrolysis of 12% to 15% and a molecular weight of 1300 to 1600 ten thousand.

6. The gelling solution of claim 1, wherein said adjuvant is sodium sulfite, potassium sulfite or sodium thiosulfate; the foaming agent is selected from one or more of octyl phenol polyoxyethylene ether, nonyl phenol polyoxyethylene ether and fatty acid polyoxyethylene ester.

7. The gel solution according to claim 1, wherein the phenolic organic compound having a thiourea structure is synthesized by the following method:

8. The gel solution according to claim 7, characterized in that the reaction of step (1) of synthesis of phenolic organic compounds containing a thiourea structure comprises any one or more of the following conditions:

a1. the iron halide is one or more of ferric bromide or ferric chloride;

a2. the temperature of the heating condition is 50-55 ℃;

a3. the molar ratio of the organic matter with the benzene ring and the thiourea structure to the liquid bromine is 1: (2.0-2.5).

9. The gel solution according to claim 7, wherein the molar ratio of the organic substance having a benzene ring and a thiourea structure to the liquid bromine is 1: (2.1-2.4).

10. The gel solution according to claim 7, characterized in that the reaction of step (2) of synthesis of phenolic organics containing thiourea structure comprises any one or more of the following conditions:

b1. the reaction temperature is 130 ℃;

b2. the strong acid is selected from one or more of nitric acid, sulfuric acid and hydrochloric acid;

b3. the molar ratio of the organic matter containing sodium phenolate and thiourea structures to the strong acid is 1: (0.5 to 1.5).

11. The gel solution according to claim 7, wherein the molar ratio of the organic substances containing sodium phenolate and thiourea structures to the strong acid is 1: (0.7-1.2).

12. The gel solution according to claim 7, characterized in that the reaction of the step (3) of synthesis of phenolic organics containing thiourea structure comprises any one or more of the following conditions:

c1. the weak base is sodium carbonate or ammonia water;

c2. the reaction temperature is 50-100 ℃;

c3. the molar ratio of the phenolic organic matter containing the thiourea structure to the weak base is 1: (0.1-0.7).

13. The gel solution according to claim 7, characterized in that the molar ratio of the phenolic organic compound containing a thiourea structure to the weak base is 1: (0.2-0.4).

14. A carbon dioxide gel foam having a thiourea structure, which is obtained by introducing carbon dioxide gas into the gel solution according to any one of claims 1 to 6.

15. The thiourea-containing structural carbon dioxide gel foam of claim 14, wherein the gas-to-liquid volume ratio of carbon dioxide to gel solution is 100: 1 to 2.

16. A method for preparing a thiourea structure-containing carbon dioxide gel foam, comprising:

1) preparation of phenolic organic compounds containing a thiourea structure according to any of claims 7-13:

2) fully mixing the components of the gel solution as described in any one of claims 1 to 6, and placing the mixture in an environment with the temperature of 20-25 ℃ for 8-12 hours to prepare a gel solution;

3) according to the gas-liquid volume ratio of 100: 1-2, introducing carbon dioxide gas into the gel solution, and then reacting for 40-50h at the temperature of 60-75 ℃ to obtain the carbon dioxide foam gel containing the thiourea structure.

17. Use of the carbon dioxide gel foam of thiourea structure of claim 14 or 15 for oilfield water shutoff, acidizing, fracturing or profile control.

18. Use of the carbondioxide gel foam of thiourea structure as claimed in claim 14 or 15 for selective water shutoff of acidic formations.