High-gas-content and high-wax-content emulsion crude oil viscosity reducer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of crude oil production, in particular to a high-gas-content and high-wax-content emulsion crude oil viscosity reducer and a preparation method and application thereof.The high-gas-content and high-wax-content emulsion crude oil viscosity reducer is prepared from 15%-30% of a density regulator, 0.5%-2% of a penetrating agent, 25%-35% of a surfactant, 1%-5% of a demulsifying agent, 2%-5% of a defoaming agent and the balance water, the density regulator is dissolved in the water, impurities and insoluble substances are removed after cooling sedimentation, and the viscosity reducer is prepared; obtaining a first solution; adding a surfactant, a penetrant and a demulsifier into the first solution, and stirring and mixing to obtain a second solution; and adding the defoaming agent into the second solution, stirring, dissolving and mixing to obtain the high-gas-content and high-wax-content emulsion crude oil viscosity reducer. The viscosity reducer can quickly settle and permeate into pasty foam oil, has the effects of reducing viscosity, defoaming and demulsifying, reduces the viscosity of crude oil, has good permeation and dehydration effects, is not influenced by field conditions and oil samples, is high in safety, and can be widely applied to viscosity reduction of return pressure reducing pipelines of oil wells.

Description

Technical Field

[0001] This invention relates to the field of crude oil production technology, specifically to a high-gas-content and high-wax-content emulsion crude oil viscosity reducer, its preparation method, and its application. Background Technology

[0002] During crude oil production, some wells have high gas content, and the crude oil also has high wax content, high viscosity, and strong emulsification ability. Under suitable temperature and pressure conditions, the crude oil emerges from the wellhead as a stable emulsion-like bubble oil. In a closed environment, degassing and dehydration are difficult, resulting in poor flowability of the bubble oil during extraction and transportation. Furthermore, on-site construction techniques are limited, and adding defoamers, viscosity reducers, and demulsifiers on-site is ineffective. After performing circulating hot washing degassing, the pressure rises rapidly and exceeds that before hot washing, causing the well to be unable to produce normally and affecting output. To solve the problem of stable bubble oil extraction and transportation, a viscosity reducer product that can quickly penetrate and has defoaming, degassing, and viscosity-reducing effects is formulated using current on-site construction techniques.

[0003] High-volume, high-wax emulsified crude oil undergoes significant gas release during extraction as pressure and temperature change. However, due to the crude oil's viscosity and emulsification properties, dense gas bubbles (oil-in-water, oil-in-gas) form, which are difficult to dissipate, increasing the crude oil's viscosity and making transportation difficult. Circulating hot washing for degassing and viscosity reduction is ineffective; the pressure drops during hot washing but rises rapidly afterward, far exceeding the original pressure. Chemical dosing (adding viscosity reducers, demulsifiers, defoamers, etc.) is also problematic due to on-site limitations. Adding chemicals through the casing results in the chemicals being lifted by the crude oil, rendering them ineffective. Adding chemicals through surface pipelines also fails to penetrate the crude oil, instead flowing away along the inner wall of the tubing, similarly failing to achieve the desired effect.

[0004] Chinese patent document CN102604618B discloses a viscosity reducer for heavy oil cold production of formation crude oil. The weight percentages of the components are as follows: sodium N,N-oleoyl bis-taurate: 10.2–11.5%; sodium lauroyl methyl taurate: 18.6–19.0%; sodium secondary alkyl sulfate: 15.3–15.8%; emulsifier OPE-12: 3.5–4.5%; sodium oleate: 0.1–0.15%; sodium hydroxide: 0.1–0.15%; the remainder is water, and the sum of the weight percentages of all components is 100%. Its main purpose is to address the issue of how formation crude oil flows into the wellbore during heavy oil cold production.

[0005] Chinese patent document CN1093099A discloses a viscosity reducer for heavy crude oil used in high-viscosity oilfield extraction, as well as its preparation and application methods. This viscosity reducer is formulated from oleic acid polyoxyethylene ester, polyoxyethylene alkylphenyl ether, polyphenols, and water in a specific ratio. In use, the viscosity reducer is diluted into an aqueous solution, then mixed with heavy oil in a certain proportion. The heavy oil is emulsified using suction or slight stirring. Its main function is to effectively reduce the viscosity of heavy oil, improving its fluidity and extraction efficiency.

[0006] Therefore, there is an urgent need for a viscosity reducer that increases the permeability of the agent and solves the above problems by reducing crude oil viscosity, defoaming, degassing, and demulsifying. Summary of the Invention

[0007] This invention provides a high-gas-content and high-wax-content emulsion crude oil viscosity reducer, its preparation method, and its application. It overcomes the shortcomings of the prior art and can effectively solve the problems of increased crude oil viscosity caused by factors such as high gas content, high wax content, high viscosity, and crude oil emulsification in existing crude oil viscosity reducers, as well as the difficulties in crude oil well extraction and transportation due to various construction conditions.

[0008] One of the technical solutions of the present invention is achieved through the following measures: a high gas content and high wax content emulsion crude oil viscosity reducer, wherein the raw materials, by mass percentage, are 15% to 30% density regulator, 0.5% to 2% penetrant, 25% to 35% surfactant, 1% to 5% demulsifier, 2% to 5% defoamer, and the remainder is water.

[0009] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The density regulator mentioned above is calcium chloride.

[0010] The aforementioned penetrant is dodecylbenzenesulfonic acid.

[0011] The surfactants mentioned above are polyether surfactants.

[0012] The demulsifier mentioned above is allyl polyoxyethylene polyoxypropylene ether.

[0013] The defoamer mentioned above is a high-carbon alcohol defoamer.

[0014] The following steps were used to prepare the following: The first step is to fully dissolve the required density regulator in water, cool and allow it to settle to remove impurities and insoluble matter, thus obtaining the first solution; The second step is to add the required amounts of surfactant, penetrant, and demulsifier to the first solution, stir and mix thoroughly to obtain the second solution; The third step is to add the required amount of defoamer to the second solution and stir until it is completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

[0015] The second technical solution of the present invention is achieved through the following measures: a method for preparing a high-gas-content and high-wax-content emulsion crude oil viscosity reducer, which is prepared according to the following steps: The first step is to fully dissolve the required density regulator in water, cool and allow it to settle to remove impurities and insoluble matter, thus obtaining the first solution; The second step is to add the required amounts of surfactant, penetrant, and demulsifier to the first solution, stir and mix thoroughly to obtain the second solution; The third step is to add the required amount of defoamer to the second solution and stir until it is completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

[0016] The following are further optimizations and / or improvements to the second technical solution of the above invention: The density regulator mentioned above is calcium chloride.

[0017] The aforementioned penetrant is dodecylbenzenesulfonic acid.

[0018] The surfactants mentioned above are polyether surfactants.

[0019] The demulsifier mentioned above is allyl polyoxyethylene polyoxypropylene ether.

[0020] The defoamer mentioned above is a high-carbon alcohol defoamer.

[0021] The third technical solution of the present invention is achieved through the following measures: the application of a high-gas-content and high-wax-content emulsion crude oil viscosity reducer in viscosity reduction of oil well backpressure pipelines.

[0022] This invention can quickly settle and penetrate into paste-like foam oil, playing a role in viscosity reduction, defoaming, and demulsification, thereby reducing crude oil viscosity. It also has good penetration and dehydration effects, is not limited by site conditions and oil sample, has high safety, and can be widely used in viscosity reduction of oil well backpressure pipelines. Detailed Implementation

[0023] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of this invention. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are well-known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, generally defined as 25°C.

[0024] The present invention will be further described below with reference to embodiments: Example 1: The high gas and high wax emulsion crude oil viscosity reducer contains the following raw materials by mass percentage: 15% to 30% density modifier (also known as rheology modifier), 0.5% to 2% penetrant, 25% to 35% surfactant, 1% to 5% demulsifier, 2% to 5% defoamer, and the remainder is water.

[0025] In existing processes for extracting and transporting high-gas-content and high-wax-content emulsion crude oil, the use of hot washing for degassing leads to a rapid pressure increase after hot washing, far exceeding the pre-wash pressure, resulting in high back pressure and difficult extraction. Furthermore, due to limitations in on-site construction conditions, adding reagents through the casing results in the reagents being lifted by the crude oil, preventing them from mixing evenly and achieving the desired effect. Adding reagents through surface pipelines also fails to penetrate the crude oil, instead flowing away along the inner wall of the tubing, similarly ineffective. This invention, through the use of chemical dosing (adding viscosity reducers, demulsifiers, defoamers, etc.), not only reduces back pressure and facilitates extraction during the extraction and transportation of high-gas-content and high-wax-content emulsion crude oil, but also utilizes density modifiers (rheology modifiers) in the reagents, enabling them to quickly enter the produced fluid through sedimentation. This allows the reagents to effectively contact the crude oil, achieving the corresponding defoaming, demulsifying, and viscosity-reducing effects. When using conventional on-site processes, it is not limited by on-site conditions or oil sample requirements.

[0026] Example 2: As an optimization of the above example, the density regulator is calcium chloride.

[0027] Example 3: As an optimization of the above examples, the penetrant is dodecylbenzenesulfonic acid.

[0028] Example 4: As an optimization of the above examples, the surfactant is a polyether surfactant.

[0029] Example 5: As an optimization of the above examples, the demulsifier is allyl polyoxyethylene polyoxypropylene ether.

[0030] Example 6: As an optimization of the above examples, the defoamer is a high-carbon alcohol defoamer.

[0031] Example 7: As an optimization of the above examples, the following steps were followed to prepare the following: The first step is to fully dissolve the required density regulator in water, cool and allow it to settle to remove impurities and insoluble matter, thus obtaining the first solution; The second step is to add the required amounts of surfactant, penetrant, and demulsifier to the first solution, stir and mix thoroughly to obtain the second solution; The third step is to add the required amount of defoamer to the second solution and stir until it is completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

[0032] Example 8: The preparation method of this high-gas-content and high-wax-content emulsion crude oil viscosity reducer is carried out according to the following steps: The first step is to fully dissolve the required density regulator in water, cool and allow it to settle to remove impurities and insoluble matter, thus obtaining the first solution; The second step is to add the required amounts of surfactant, penetrant, and demulsifier to the first solution, stir and mix thoroughly to obtain the second solution; The third step is to add the required amount of defoamer to the second solution and stir until it is completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

[0033] Example 9: Application of this high-gas-content and high-wax-content emulsion crude oil viscosity reducer in viscosity reduction of oil well backpressure pipelines.

[0034] Example 10: This high-gas-content and high-wax-content emulsion crude oil viscosity reducer was prepared according to the following steps: The first step is to fully dissolve 15% density regulator in water by mass percentage, and remove impurities and insoluble matter after cooling and settling to obtain the first solution; The second step involves adding 35% surfactant, 0.5% penetrant, and 5% demulsifier to the first solution and stirring until fully mixed to obtain the second solution. The third step is to add 5% defoamer to the second solution and stir until completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

[0035] Example 11: This high-gas-content and high-wax-content emulsion crude oil viscosity reducer was prepared according to the following steps: The first step is to fully dissolve 30% density regulator in water by mass percentage, cool and settle the solution to remove impurities and insoluble matter, and obtain the first solution. The second step involves adding 25% surfactant, 2% penetrant, and 1% demulsifier to the first solution and stirring to mix thoroughly to obtain the second solution. The third step is to add 2% defoamer to the second solution and stir until completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

[0036] Example 12: This high-gas-content and high-wax-content emulsion crude oil viscosity reducer was prepared according to the following steps: The first step is to fully dissolve 15% density regulator in water by mass percentage, and remove impurities and insoluble matter after cooling and settling to obtain the first solution; The second step involves adding 25% surfactant, 2% penetrant, and 1% demulsifier to the first solution and stirring to mix thoroughly to obtain the second solution. The third step is to add 2% defoamer to the second solution and stir until completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

[0037] Example 13: This high-gas-content and high-wax-content emulsion crude oil viscosity reducer was prepared according to the following steps: The first step is to fully dissolve 30% density regulator in water by mass percentage, cool and settle the solution to remove impurities and insoluble matter, and obtain the first solution. The second step involves adding 35% surfactant, 0.5% penetrant, and 5% demulsifier to the first solution and stirring until fully mixed to obtain the second solution. The third step is to add 5% defoamer to the second solution and stir until completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

[0038] Comparative Example 1: The crude oil viscosity reducer used was a commercially available anionic surfactant (sodium dodecylbenzenesulfonate).

[0039] Comparative Example 2: Commercially available polyether surfactants were used as crude oil viscosity reducers.

[0040] Comparative Example 3: The crude oil viscosity reducer consists of 5% penetrant, 25% surfactant, 5% demulsifier, 2% defoamer, and the remainder is water. The penetrant, surfactant, demulsifier, and defoamer are the same as those in Example 13 of this invention.

[0041] Comparative Example 4: The crude oil viscosity reducer consists of 0.5% penetrant, 35% surfactant, 2% demulsifier, 5% defoamer, and the remainder is water. The penetrant, surfactant, demulsifier, and defoamer are the same as those in Example 13 of this invention.

[0042] In Examples 10 to 13 above, the present invention (high gas and high wax emulsion crude oil viscosity reducer) and Comparative Examples 1 to 4 (crude oil viscosity reducer) were tested on the viscosity reduction effect of a certain high gas and high wax emulsion crude oil well. A total of 8 equal weight test samples were used (4 samples of the present invention and 4 samples of the comparative examples).

[0043] First, the density (g / mL) of each sample was tested, as shown in Table 1. Then, the samples from the same oil well were divided into 8 equal portions, and 300g of each portion was weighed as experimental oil samples (water content ≥30%). Under the same experimental temperature conditions (other experimental conditions were the same), 0.42g of the experimental sample was added to each of the 8 weighed experimental oil samples. After being kept at a constant temperature for 10 minutes, the mixture was stirred at a speed of 400r / min for 1 minute. The viscosity of the crude oil was measured to calculate the viscosity reduction rate. Finally, the 8 samples were tested in the field at a high-gas-content and high-wax-content emulsion crude oil well (dosage and experimental time were the same) to observe the change in well back pressure after the addition of the agent and to judge the effect of the viscosity reducer, as shown in Table 1.

[0044] As shown in Table 1, the oil samples after adding the high gas and high wax emulsion crude oil viscosity reducer of the present invention had significantly lower field back pressures than those in Comparative Examples 1 to 4. This indicates that the high gas and high wax emulsion crude oil viscosity reducer of the present invention can meet field requirements while ensuring a high viscosity reduction rate. Compared with the comparative examples, the present invention can effectively solve the problem caused by uneven mixing of the agent in the field, and can reduce the back pressure of the oil well to below 1.5 MPa, thus solving the production restriction problem.

[0045] In summary, this invention can quickly settle and penetrate into paste-like foam oil, thereby reducing viscosity, defoaming, and demulsifying, thus lowering the viscosity of crude oil. It also has good penetration and dehydration effects, is not affected by site conditions or oil samples, has high safety, and can be widely used in viscosity reduction in oil well backpressure pipelines.

[0046] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A viscosity reducer for high-gas-content and high-wax-content emulsion crude oil, characterized in that... The raw materials, by mass percentage, consist of 15% to 30% density regulator, 0.5% to 2% penetrant, 25% to 35% surfactant, 1% to 5% demulsifier, 2% to 5% defoamer, and the remainder is water.

2. The high-gas-content and high-wax-content emulsion crude oil viscosity reducer according to claim 1, characterized in that... The density regulator is calcium chloride.

3. The high-gas-content and high-wax-content emulsion crude oil viscosity reducer according to claim 1 or 2, characterized in that... The penetrant is dodecylbenzenesulfonic acid.

4. The high-gas-content and high-wax-content emulsion crude oil viscosity reducer according to any one of claims 1 to 3, characterized in that... The surfactant is a polyether surfactant.

5. The high-gas-content and high-wax-content emulsion crude oil viscosity reducer according to any one of claims 1 to 4, characterized in that... The demulsifier is allyl polyoxyethylene polyoxypropylene ether.

6. The high-gas-content and high-wax-content emulsion crude oil viscosity reducer according to any one of claims 1 to 5, characterized in that... The defoamer is a high-carbon alcohol defoamer.

7. The high-gas-content and high-wax-content emulsion crude oil viscosity reducer according to any one of claims 1 to 6, characterized in that... It is prepared according to the following steps: The first step is to fully dissolve the required density regulator in water, cool and allow it to settle to remove impurities and insoluble matter, thus obtaining the first solution; The second step is to add the required amounts of surfactant, penetrant, and demulsifier to the first solution, stir and mix thoroughly to obtain the second solution; The third step is to add the required amount of defoamer to the second solution and stir until it is completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

8. A method for preparing a high-gas-content, high-wax-content emulsion crude oil viscosity reducer according to claim 1, characterized in that... Prepare according to the following steps: The first step is to fully dissolve the required density regulator in water, cool and allow it to settle to remove impurities and insoluble matter, thus obtaining the first solution; The second step is to add the required amounts of surfactant, penetrant, and demulsifier to the first solution, stir and mix thoroughly to obtain the second solution; The third step is to add the required amount of defoamer to the second solution and stir until it is completely dissolved and mixed to obtain a high-gas-content and high-wax-content emulsion crude oil viscosity reducer.

9. The preparation method of the high-gas-content and high-wax-content emulsion crude oil viscosity reducer according to claim 8, characterized in that the density... The regulator is calcium chloride; and / or the penetrant is dodecylbenzenesulfonic acid; and / or the surfactant is a polyether surfactant; and / or the demulsifier is allyl polyoxyethylene polyoxypropylene ether; and / or the defoamer is a high-carbon alcohol defoamer.

10. The application of a high-gas-content and high-wax-content emulsion crude oil viscosity reducer according to any one of claims 1 to 7 in viscosity reduction of oil well backpressure pipelines.

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