CN117384667A - Demulsifier for deep dehydration of crude oil in settling tank of combined station and preparation method and application thereof - Google Patents

Abstract

The invention relates to the field of petrochemical auxiliary agents for oil field development, and discloses a demulsifier for deep dehydration of crude oil in a settling tank of a combined station, and a preparation method and application thereof. The demulsifier consists of the following components in parts by mass: 30-50 parts by mass of polyoxyethylene polyoxypropylene block polyether; 1-10 parts by mass of a counterweight agent; 2-10 parts by mass of pH regulator; 1 part by mass of an acidification corrosion inhibitor; 23-62 parts by mass of a solvent. The demulsifier is mainly used for the situation that the settling time of the crude oil in the settling tank is prolonged after the inferior crude oil after operation enters the production system of the combined station, and the oil-water emulsification in the settling tank can be eliminated after the demulsifier is added to the tank top, so that the deep dehydration effect is achieved, the water content (in mass) of the crude oil in the settling tank is reduced to below 0.3%, and the settling time is shortened by more than 4 hours.

Description

Demulsifier for deep dehydration of crude oil in settling tank of combined station and preparation method and application thereof

Technical Field

The invention relates to the field of petrochemical assistants for oil field development, in particular to a demulsifier for deep dehydration of crude oil in a settling tank of a combined station, and a preparation method and application thereof.

Background

In recent years, in order to ensure national energy safety, as crude oil production progresses to the direction of heavy and poor quality in the whole country, crude oil production is increasing and the production of poor quality crude oil is increasing year by year due to the exploitation of crude difficult reserves (such as high-viscosity oil, super-viscosity oil, reservoirs with poor geological conditions) by various working measures. Such crudes generally have the following characteristics:

(1) High density, high acid value, and contains various natural emulsifying agents;

(2) The inorganic salts in the crude oil are easy to be wrapped in the crude oil, and the colloid and asphaltene contents are high;

(3) Chemical oil extraction aids are used during the operation, resulting in severe emulsification of the crude oil.

Because the inferior high-acid crude oil has the characteristics, the demulsification and dehydration difficulty of the inferior crude oil is greatly increased, and particularly after the inferior crude oil is mixed with normal crude oil, the demulsification and dehydration of the normal crude oil are seriously influenced, the stable production operation of the combined station is influenced, and the operation efficiency of the combined station is reduced.

At present, crude oil demulsifiers at home and abroad are various in variety, and most of the demulsifiers are nonionic demulsifiers, and the demulsifier effects are thousands of years. But in terms of its molecular composition is mainly a copolymer of ethylene oxide and propylene oxide. The demulsifier is used for treating normal crude oil, but has an unsatisfactory demulsification effect on the inferior crude oil after operation, particularly has poor effect after the normal crude oil is mixed with part of the inferior crude oil, prolongs the sedimentation time, is difficult to further descend after the comprehensive water content of a sedimentation tank is reduced to about 1%, seriously reduces the operation efficiency of a combined station, and even causes the explosion warehouse of the combined station. Therefore, demulsifier is needed to be added to the top of the settling tank of the combined station at a specific time, so that the demulsification and dehydration time is shortened.

Patent publication No. CN104673359A discloses a phenolic amine resin demulsifier, but the demulsifier has poor effect on inferior crude oil after operation; patent publication No. CN105316028A discloses an organic acid-polyether type dirty oil demulsifier, and patent publication No. CN102140365A discloses an acid-containing crude oil demulsifier, but none of them is suitable for use in top-loading of settling tanks of a combined station.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a demulsifier for deep dehydration of crude oil in a settling tank of a combined station, and a preparation method and application thereof, and the technical scheme is as follows:

the demulsifier for deep dehydration of crude oil in a settling tank of a combined station comprises the following components in parts by mass: 30-50 parts by mass of polyoxyethylene polyoxypropylene block polyether; 1-10 parts by mass of a counterweight agent; 2-10 parts by mass of pH regulator; 1 part by mass of an acidification corrosion inhibitor; 23-62 parts by mass of a solvent.

Further, the polyoxyethylene polyoxypropylene block polyether adopts phenolic amine resin polyoxyethylene polyoxypropylene block polyether. Wherein: the synthetic reaction formula of the phenolic amine resin is as follows:

further, the weighting agent adopts tetrakis (hydroxymethyl) phosphonium sulfate.

Further, the pH regulator adopts a mixture of citric acid and sulfamic acid.

Further, the mass ratio of the citric acid to the sulfamic acid is 1:1.

Furthermore, the acidizing corrosion inhibitor adopts an imidazoline corrosion inhibitor.

Further, the mass ratio of the alcohol to water is 1 (0.5-1.5) as a mixture of water and any one of the alcohols of the solvents C1-C2.

Further, the alcohol is methanol.

Based on the preparation method of the demulsifier for deep dehydration of crude oil in the settling tank of the combined station, the method comprises the following steps:

(1) polymerizing phenolic amine resin and propylene oxide according to a mass ratio of 1 (25-199) to obtain an intermediate polymerization product, wherein the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, and the reaction temperature is kept between 130 and 140 ℃;

(2) Polymerizing the intermediate polymerization product with ethylene oxide to obtain phenolic resin polyoxyethylene polyoxypropylene block polyether, wherein the use amount of the ethylene oxide is 15-65 times of the mass of the phenolic amine resin in the step (1); the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, the reaction temperature is kept between 130 and 140 ℃, and the polymerization reaction takes the reaction pressure not to drop as the end point;

(3) Adding the phenolic resin polyoxyethylene polyoxypropylene block polyether prepared in the step (2), a weighting agent, a pH regulator, an acidification corrosion inhibitor and a solvent into a reactor according to the mass parts, and stirring for 20-40 minutes at 40-50 ℃ to form a uniform mixture, namely the demulsifier.

The application of the demulsifier for deep dehydration of crude oil in a settling tank of a combined station in oil field development is based on the above.

Compared with the prior art, the invention has the following beneficial technical effects:

1. the demulsifier is mainly used for supplementing the agent on the top of the tank under the condition that the settling time of the crude oil in the settling tank is prolonged after the inferior crude oil after operation enters the production system of the combined station; after the demulsifier is added to the tank top, the oil-water emulsification of the settling tank can be eliminated, the deep dehydration effect is achieved, the water content (in mass) of crude oil in the settling tank is reduced to below 0.3%, and the settling time is shortened by more than 4 hours.

2. The counterweight agent adopted by the invention is the tetrakis (hydroxymethyl) phosphonium sulfate, can quickly carry the demulsifier to enter the middle lower part of the crude oil in the settling tank from the top of the crude oil in the settling tank, and the demulsifier damages the charge balance of the emulsion membrane interface in the descending process, so that the interface strength is reduced, and the purpose of dehydration is achieved.

3. The pH regulator adopted by the invention is a mixture of citric acid and sulfamic acid, can quickly assist a demulsifier to enter an oil-water emulsion interface, damage charge balance of an emulsion film interface and reduce interface strength.

4. The demulsifier provided by the invention has the advantages of reasonable preparation process, simplicity and convenience in operation and convenience in popularization and application.

Detailed Description

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

Example 1

(1) Polymerizing phenolic amine resin and propylene oxide according to a mass ratio of 1:25 to obtain an intermediate polymerization product; the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, and the reaction temperature is kept at 130 ℃;

(2) Polymerizing the intermediate polymerization product with ethylene oxide to obtain phenolic resin polyoxyethylene polyoxypropylene block polyether, wherein the use amount of the ethylene oxide is 15 times of the mass of the phenolic amine resin in the step (1); the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, the reaction temperature is kept at 130 ℃, and the polymerization reaction takes the reaction pressure not to drop as the end point;

(3) Adding the phenolic resin polyoxyethylene polyoxypropylene block polyether prepared in the step (2), a weighting agent, a pH regulator, an acidification corrosion inhibitor and a solvent into a reactor according to the mass parts in the following formula, and stirring for 20 minutes at 40 ℃ to form a uniform mixture, namely the demulsifier.

The demulsifier formula is as follows:

30 parts by mass of the amine phenolic amine resin polyoxyethylene polyoxypropylene block polyether prepared by the method;

1 part by mass of tetrakis (hydroxymethyl) phosphonium sulfate;

1 part by mass of citric acid;

1 part by mass of sulfamic acid;

1 part by mass of imidazoline corrosion inhibitor;

15 parts by mass of methanol;

8 parts of water.

The five-stage comprehensive water content (by mass) of the No. 5 tank of the No. 5 combined station of the second oil extraction plant of the tower and the oil field is reduced from 0.8% to 0.7% within 5 hours after production is finished, and the reduction is slow; after the demulsifier is added on the tank top, the five-stage comprehensive water content (by mass) of the No. 5 tank is reduced from 0.7% to 0.3% within 4 hours, and the oil is qualified.

Example 2

(1) Polymerizing phenolic amine resin and propylene oxide according to a mass ratio of 1:199 to obtain an intermediate polymerization product; the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, and the reaction temperature is kept at 140 ℃;

(2) Polymerizing the intermediate polymerization product with ethylene oxide to obtain phenolic resin polyoxyethylene polyoxypropylene block polyether, wherein the use amount of the ethylene oxide is 65 times of the mass of the phenolic amine resin in the step (1); the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, the reaction temperature is kept at 140 ℃, and the polymerization reaction takes the reaction pressure not to drop as the end point;

(3) Adding the phenolic resin polyoxyethylene polyoxypropylene block polyether prepared in the step (2), a weighting agent, a pH regulator, an acidification corrosion inhibitor and a solvent into a reactor according to the mass parts in the following formula, and stirring for 40 minutes at 50 ℃ to form a uniform mixture, namely the demulsifier.

The demulsifier formula is as follows:

50 parts by mass of the amine phenolic amine resin polyoxyethylene polyoxypropylene block polyether prepared by the method;

10 parts by mass of tetrakis (hydroxymethyl) phosphonium sulfate;

5 parts by mass of citric acid;

5 parts by mass of sulfamic acid;

1 part by mass of imidazoline corrosion inhibitor;

25 parts by mass of methanol;

37 parts of water.

The five-stage comprehensive water content (by mass) is reduced from 0.8% to 0.6% within 6 hours after the production of the No. 6 tank of the second oil extraction station of the tower and oil field, and the reduction is slow; after the demulsifier is added on the top of the tank, the five-stage comprehensive water content (by mass) of the No. 6 tank is reduced from 0.6% to 0.25% in 3 hours, and the oil is qualified.

Example 3

(1) Polymerizing phenolic amine resin and propylene oxide according to a mass ratio of 1:99 to obtain an intermediate polymerization product; the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, and the reaction temperature is kept at 135 ℃;

(2) Polymerizing the intermediate polymerization product with ethylene oxide to obtain phenolic resin polyoxyethylene polyoxypropylene block polyether, wherein the amount of the ethylene oxide is 45 times of the mass of the phenolic amine resin in the step (1); the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, the reaction temperature is kept at 135 ℃, and the polymerization reaction takes the reaction pressure not to drop as the end point;

(3) Adding the phenolic resin polyoxyethylene polyoxypropylene block polyether prepared in the step (2), a weighting agent, a pH regulator, an acidification corrosion inhibitor and a solvent into a reactor according to the mass parts in the following formula, and stirring for 30 minutes at 45 ℃ to form a uniform mixture, namely the demulsifier.

The demulsifier formula is as follows:

40 parts by mass of the amine phenolic amine resin polyoxyethylene polyoxypropylene block polyether prepared by the method;

5 parts by mass of tetrakis (hydroxymethyl) phosphonium sulfate;

3 parts by mass of citric acid;

sulfamic acid 3 parts by mass

1 part by mass of imidazoline corrosion inhibitor;

20 parts by mass of methanol;

20 parts of water.

The five-stage comprehensive water content (by mass) of the 8# tank of the fourth joint station of the second oil extraction plant of the tower and the oil field is reduced from 0.9% to 0.75% within 6 hours after production is finished, and the reduction is slow; after the demulsifier is added on the top of the tank, the five-stage comprehensive water content (by mass) of the 8# tank is reduced from 0.75% to 0.25% within 4 hours, and the oil is qualified.

The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.

Claims (10)

1. The demulsifier for deep dehydration of crude oil in the settling tank of the combined station is characterized by comprising the following components in parts by mass: 30-50 parts by mass of polyoxyethylene polyoxypropylene block polyether; 1-10 parts by mass of a counterweight agent; 2-10 parts by mass of pH regulator; 1 part by mass of an acidification corrosion inhibitor; 23-62 parts by mass of a solvent.

2. The demulsifier for deep dehydration of crude oil in a settling tank of a combined station according to claim 1, wherein the polyoxyethylene polyoxypropylene block polyether is a phenolic amine resin polyoxyethylene polyoxypropylene block polyether.

3. A demulsifier for deep dewatering of crude oil in a settling tank of a co-station as claimed in claim 1, wherein the weighting agent is tetrakis hydroxymethyl phosphonium sulphate.

4. A demulsifier for deep dewatering of crude oil in a settling tank of a co-station as claimed in claim 1, wherein the pH adjuster is a mixture of citric acid and sulfamic acid.

5. The demulsifier for deep dewatering of crude oil in a settling tank of a co-station as claimed in claim 4, wherein the mass ratio of citric acid to sulfamic acid is 1:1.

6. A demulsifier for deep dehydration of crude oil in settling tanks of a combination station as claimed in claim 1, wherein the acidizing corrosion inhibitor is an imidazoline corrosion inhibitor.

7. The demulsifier for deep dehydration of crude oil in a settling tank of a combined station according to claim 1, wherein the mass ratio of any one of the solvents C1 to C2 alcohols to water is 1 (0.5 to 1.5).

8. A demulsifier for deep dewatering of crude oil in a settling tank of a co-station as claimed in claim 7, wherein the alcohol is methanol.

9. A method for preparing a demulsifier for deep dehydration of crude oil in a settling tank of a combined station, based on any one of claims 1 to 8, comprising the steps of:

(1) polymerizing phenolic amine resin and propylene oxide according to a mass ratio of 1 (25-199) to obtain an intermediate polymerization product, wherein the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, and the reaction temperature is kept between 130 and 140 ℃;

(2) Polymerizing the intermediate polymerization product with ethylene oxide to obtain phenolic resin polyoxyethylene polyoxypropylene block polyether, wherein the use amount of the ethylene oxide is 15-65 times of the mass of the phenolic amine resin in the step (1); the polymerization reaction needs to control the reaction pressure to be less than or equal to 0.4Mpa, the reaction temperature is kept between 130 and 140 ℃, and the polymerization reaction takes the reaction pressure not to drop as the end point;

(3) Adding the phenolic resin polyoxyethylene polyoxypropylene block polyether prepared in the step (2), a weighting agent, a pH regulator, an acidification corrosion inhibitor and a solvent into a reactor according to the mass parts, and stirring for 20-40 minutes at 40-50 ℃ to form a uniform mixture, namely the demulsifier.

10. Use of a demulsifier for deep dewatering of crude oil in a settling tank of a combination station according to any one of claims 1 to 8 in oil field development.