Application of acid sophorolipid hydrate anti-agglomerant in oil-gas-water three-phase mixed transportation pipeline

Abstract

The application discloses application of an acid-type sophorolipid hydrate anti-agglomerant in an oil-gas-water three-phase mixed pipeline, and comprises the following steps: step one, hydrate anti-agglomerant concentration is a wt%, a is 1-8, initial flow rate in the pipeline and real-time flow rate after pumping for 12-16 hours are respectively measured, and the hydrate anti-agglomerant is an acid-type sophorolipid; step two, if the anti-agglomerant is effective, the anti-agglomerant concentration is set as (a-0.5) wt%; step one is repeated to carry out the i+1th experiment, if the i+1th experiment result is, the anti-agglomerant is determined to be ineffective, and the anti-agglomerant concentration is (a-0.5i) wt%. The acid-type sophorolipid is used as the hydrate anti-agglomerant, excellent water solubility, foaming property, pH sensitivity and self-polymerization of the acid-type sophorolipid can ensure that hydrate particles in the oil-gas-water three-phase mixed pipeline keep a flowing state at all times, and the phenomenon of agglomeration into blocks and deposition on a pipe wall does not occur.

Description

TECHNICAL FIELD

[0001] The application relates to application of an anti-agglomerant in an oil-gas-water three-phase mixed pipeline, in particular to application of an acid-type sophorolipid hydrate anti-agglomerant in an oil-gas-water three-phase mixed pipeline. BACKGROUND

[0002] With the continuous progress of deep water (500-1500 m) and ultra-deep water (>1500 m) drilling technology, the current offshore oil and gas production has accounted for more than 30% of the global oil and gas production, and the offshore oil and gas resources have become an important part of the global resource increase and production. Since the offshore oil and gas gathering pipelines are mostly used in the mixed transportation mode, due to the low-temperature deep water environment and long-distance submarine pipeline transportation, the hydrate blockage problem in the oil-gas mixed pipeline has become a great threat to long-term oil and gas production.

[0003] The traditional prevention and treatment generation method aims to change the hydrate generation condition, and the main means include injection of thermodynamic inhibitors, installation of heat insulation layer, heating and pressure reduction, etc. Among them, the injection of thermodynamic inhibitors has been the only choice for preventing blockage in the field. The method changes the hydrate phase equilibrium condition by adding a large amount of thermodynamic inhibitors (such as methanol, ethylene glycol, etc.) to prevent hydrate generation. However, with the increasing depth of offshore oil and gas development, the traditional prevention and treatment generation method has become increasingly prominent in technical limitations such as high cost, difficult operation and environmental pollution.

[0004] With the continuous deepening of the research on the nucleation and aggregation mechanism of natural gas hydrate, the method for solving the hydrate blockage problem gradually transits to the hydrate risk management based on hydrate dynamics. The hydrate risk management does not emphasize the complete inhibition of hydrate, but focuses more on controlling the development degree of hydrate within an effective time, and ensuring that the fluid is transported to the destination within a given time without hydrate blockage, so the hydrate anti-agglomerant emerges as the times require.

[0005] The hydrate anti-agglomerant is divided into anionic, cationic and non-ionic types according to the difference of hydrophilic groups. At present, the most widely used hydrate anti-agglomerant in the world industry is mainly a quaternary ammonium salt cationic surfactant. In the prior art, there are hydrate anti-agglomerants with head group structures of quaternary ammonium salt and quaternary phosphonium salt with three or four alkyl groups; single-tail quaternary ammonium salt anti-agglomerants with strong water solubility and double-tail quaternary ammonium salt anti-agglomerants with strong oil solubility. The supercooling degree of these quaternary ammonium salts can exceed 20℃; there are alkyl benzene sulfonate anti-agglomerants, which can maintain flow and not be blocked after hydrate crystals are generated in the system when the amount is 0.1-3wt%. Non-ionic hydrate anti-agglomerants such as fatty alcohol polyoxyethylene ether.

[0006] When the existing anionic, cationic and non-ionic hydrate anti-agglomerants are used to solve the hydrate blockage problem in the oil and gas mixed transportation pipeline, the sewage containing a large amount of hydrate anti-agglomerants is generated at the oil and gas gathering terminal, the subsequent degradation of the anti-agglomerants is difficult, the treatment cost is high, and the operation is complex. SUMMARY

[0007] The present application aims at providing an effective judgment method for hydrate anti-agglomerants in oil and gas mixed transportation pipelines, which is low in sewage treatment cost, environmentally friendly, simple and convenient.

[0008] Technical scheme: The application relates to an acid-type sophorolipid hydrate anti-agglomerant applied in an oil and gas water three-phase mixed transportation pipeline, and comprises the following steps:

[0009] Step one, the concentration of the hydrate anti-agglomerant is a wt%, a is 1-8, and the initial flow rate in the pipeline is measured and the real-time flow rate after the pump is started for 12-16 hours The hydrate anti-agglomerant is an acid-type sophorolipid.

[0010] Step two, if the anti-agglomerant is determined to be effective, the concentration of the anti-agglomerant is set as (a-0.5) wt%, the step one is repeated to perform the i+1th experiment, if the i+1th experiment result is the anti-agglomerant is determined to be ineffective, and the concentration of the anti-agglomerant is (a-0.5i) wt%.

[0011] Further, the purity of the acid-type sophorolipid hydrate anti-agglomerant is 95-99%, and the BOD / COD value is 0.3-0.5. The molecular structure of the sophorolipid synthesized by yeast fermentation contains a hydrophilic end and a hydrophobic end, which are connected by a glycosidic bond. The hydrophilic part is sophorose, and the hydrophobic part is a hydroxylated fatty acid tail of 16 or 18 carbon atoms. According to whether the sophorolipid molecule contains a free hydroxyl fatty acid tail, the sophorolipid can be divided into two categories, namely lactone-type sophorolipid (LSL) and acid-type sophorolipid (ASL).

[0012] The acid sophorolipid has excellent water solubility, foaming property, pH sensitivity and self-polymerization, and can realize the hydrate drag reduction effect in the pipeline. The commercially available sophorolipid is mostly a mixture, and the yield and proportion of the lactone type and acid type sophorolipid synthesized by fermentation of different substrates are different, so that the product uniformity of different manufacturers or different batches of the same manufacturer cannot be guaranteed, thereby the experimental results are difficult to repeat in the actual application of the oil field. Therefore, the sophorolipid needs to be separated and purified to obtain high-purity acid sophorolipid. The purification method of the acid sophorolipid is as follows: the mixture of acid sophorolipid and lactone sophorolipid is added into a single-necked flask, excessive anhydrous ethanol is added, and then the temperature is increased to 80-85 DEG C, and the mixture is stirred for 30-40 minutes under the magnetic force, and then the solid is obtained by vacuum filtration, and the acid sophorolipid hydrate anti-agglomerating agent is obtained after constant temperature drying. The temperature of constant temperature drying is 70-80 DEG C, and the time is 20-24 h.

[0013] Further, the initial flow rate is obtained by averaging the flow rates at three different positions of the pipeline. The real-time flow rate is measured by an online flow meter.

[0014] Further, the volume ratio of the water in the pipeline to the total volume of the oil-water two-phase is less than or equal to 50.0%, preferably 10.0-45.0%. When the volume ratio of the water to the total volume of the oil-water two-phase is greater than 50.0%, the anti-agglomerating effect of the acid sophorolipid hydrate anti-agglomerating agent will be reduced or even completely lost.

[0015] Further, the pressure in the pipeline is 6-20 MPa, and the temperature is 2-8 DEG C. a is 1-4.

[0016] Further, the chemical oxygen demand and the biochemical oxygen demand of the acid sophorolipid hydrate anti-agglomerating agent are 1123 mg / L and 474 mg / L respectively, the BOD / COD value is 0.42, which is higher than 0.3, and is suitable for biological treatment.

[0017] Beneficial effects: compared with the prior art, the present application has the following remarkable features:

[0018] 1. The acid sophorolipid is used as a hydrate anti-agglomerating agent, and the excellent water solubility, foaming property, pH sensitivity and self-polymerization of the acid sophorolipid can ensure that the hydrate particles in the oil-gas-water three-phase mixed transportation pipeline always maintain a flowing state and do not agglomerate into blocks or deposit on the pipeline wall, thereby effectively solving the flow safety guarantee problem of the multiphase mixed transportation pipeline.

[0019] 2. Whether the acid sophorolipid hydrate anti-agglomerating agent is invalid can be determined in time, so that the working concentration thereof can be adjusted.

[0020] 3. The BOD / COD value of the acid sophorolipid hydrate anti-agglomerant is higher than 0.3, which is suitable for the biological treatment method to treat wastewater containing the anti-agglomerant. The sophorolipid as the anti-agglomerant has good anti-agglomerating effect, mild performance, low toxicity, and is easy to degrade in the later stage, and has low wastewater treatment cost and is environmentally friendly.

[0021] 4. The acid sophorolipid hydrate anti-agglomerant can effectively separate commercially available sophorolipids, and improve the purity of the acid sophorolipid, which is suitable for large-scale popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural general formula of the lactone sophorolipid;

[0023] Figure 2 is a structural general formula of the acid sophorolipid. DETAILED DESCRIPTION

[0024] In the following examples, the experimental material is an oil-gas-water three-phase mixed transportation system, deionized water is used for the water phase, -20# diesel oil is used for the oil phase, and high-purity methane is used for the gas phase. Figures 1-2 The sophorolipid is divided into two categories: lactone sophorolipid (LSL) and acid sophorolipid (ASL). The chemical oxygen demand and biochemical oxygen demand of the acid sophorolipid hydrate anti-agglomerant are 1123 mg / L and 474 mg / L respectively, and the BOD / COD value is 0.42, which is higher than 0.3 and is suitable for biological treatment method.

[0025] Example 1

[0026] The application of the acid sophorolipid hydrate anti-agglomerant in the oil-gas-water three-phase mixed transportation pipeline includes the following steps:

[0027] (1) Purification of acid sophorolipid: A mixture of commercially available acid sophorolipid and lactone sophorolipid is added to a single-necked flask, and then excess anhydrous ethanol is added and heated to 81°C. The mixture is magnetically stirred for 38 minutes, and then vacuum filtration is performed to obtain a solid. The solid is dried at 72°C for 23 hours to obtain the acid sophorolipid hydrate anti-agglomerant.

[0028] (2) Using a continuous circulation pipeline device equipped with a high-precision online flowmeter, the initial flow rate and the real-time flow rate after pumping for 12 hours are measured under the conditions of acid sophorolipid hydrate anti-agglomerant concentration 2wt% (water mass as reference amount), water content 30%, temperature 3°C, pressure 7MPa and salinity 3%. The values are measured by the online flowmeter at three different positions in the pipeline, and the average value is taken, and the results are as shown in Table 1.

[0029] Table 1 Pipeline flow rate table of Example 1

[0030]

[0031] The experimental results show that the acid sophorolipid hydrate anti-aggregation agent concentration is 2wt%, The acid sophorolipid hydrate anti-aggregation agent concentration is adjusted to 1.5wt% and the above experiment is repeated, and it is found that It is proved that the acid sophorolipid hydrate anti-aggregation agent with a concentration of 2wt% still has excellent anti-aggregation effect after 12h under the pipeline conditions of water content 30%, temperature 3℃, pressure 7MPa and salinity 3%.

[0032] Example 2

[0033] The application of acid sophorolipid hydrate anti-aggregation agent in oil-gas-water three-phase mixed pipeline includes the following steps:

[0034] (1) Purification of acidic sophorolipid: A mixture of commercially available acid sophorolipid and lactone sophorolipid is added to a single-necked flask, and then excess anhydrous ethanol is added and heated to 84℃. Stirring for 31 minutes under magnetic field, vacuum filtration, and then drying at 79℃ for 21h to obtain acid sophorolipid hydrate anti-aggregation agent.

[0035] (2) Using a continuous circulation pipeline device equipped with a high-precision online viscometer and a flowmeter, the initial flow rate and the real-time flow rate after pumping for 12h and The values are obtained by averaging the values at three different positions in the pipeline. The results are shown in Table 2.

[0036] Table 2 Pipeline flow table of Example 2

[0037]

[0038]

[0039] The experimental results show that the acid sophorolipid hydrate anti-aggregation agent concentration is 4wt%, The acid sophorolipid hydrate anti-aggregation agent concentration is adjusted to 3.5wt% and the above experiment is repeated, and it is found that It is proved that the acid sophorolipid hydrate anti-aggregation agent with a concentration of 4wt% still has excellent anti-aggregation effect after 12h under the pipeline conditions of water content 40%, temperature 5℃, pressure 12MPa and salinity 5%.

[0040] Example 3

[0041] Application of the acid sophorolipid hydrate anti-agglomerant in the oil-gas-water three-phase mixed transportation pipeline, comprising the following steps:

[0042] (1) Purification of acid sophorolipid: A mixture of commercially available acid sophorolipid and lactone sophorolipid is added to a single-necked flask, and then excess anhydrous ethanol is added and heated to 80°C. The mixture is stirred magnetically for 40 minutes, and then filtered under vacuum to obtain a solid. The solid is dried at a constant temperature of 70°C for 24 hours to obtain the acid sophorolipid hydrate anti-agglomerant.

[0043] (2) Using a continuous circulation pipeline device equipped with a high-precision online flow meter, the initial flow rate in the pipeline is measured under the following conditions: acid sophorolipid hydrate anti-agglomerant concentration 1wt% (water mass as reference amount), water content 10.0%, temperature 4°C, pressure 6MPa, and salinity 4%. The real-time flow rate after 16 hours of pumping is measured. The values are measured by the online flow meter at three different positions in the pipeline, and the average value is taken. The results are shown in Table 3.

[0044] Table 3 Pipeline flow rate of Example 3

[0045]

[0046] The experimental results show that when the concentration of acid sophorolipid hydrate anti-agglomerant is 1wt% After adjusting the concentration of acid sophorolipid hydrate anti-agglomerant to 0.5wt%, the above experiment is repeated, and it is found that It is confirmed that the acid sophorolipid hydrate anti-agglomerant with a concentration of 1wt% still has excellent anti-agglomeration effect after 16 hours under the conditions of water content 10.0%, temperature 4°C, pressure 6MPa, and salinity 4% in the pipeline.

[0047] Example 4

[0048] Application of the acid sophorolipid hydrate anti-agglomerant in the oil-gas-water three-phase mixed transportation pipeline, comprising the following steps:

[0049] (1) Purification of acid sophorolipid: A mixture of commercially available acid sophorolipid and lactone sophorolipid is added to a single-necked flask, and then excess anhydrous ethanol is added and heated to 85°C. The mixture is stirred magnetically for 30 minutes, and then filtered under vacuum to obtain a solid. The solid is dried at a constant temperature of 80°C for 20 hours to obtain the acid sophorolipid hydrate anti-agglomerant.

[0050] (2) Using a continuous circulation pipeline device equipped with a high-precision online flow meter, the initial flow rate in the pipeline is measured under the following conditions: acid sophorolipid hydrate anti-agglomerant concentration 7wt% (water mass as reference amount), water content 45.0%, temperature 2°C, pressure 20MPa, and salinity 5%. The real-time flow rate after 13 hours of pumping is measured. and The values were measured by online flow meters at three different positions of the pipeline, and the average value was taken, as shown in Table 4.

[0051] Table 4 Pipeline flow table of Example 4

[0052]

[0053] The experimental results found that the concentration of the acid sophorolipid hydrate anti-aggregation agent was 7wt% After adjusting the concentration of the acid sophorolipid hydrate anti-aggregation agent to 6.5wt%, the above experiment was repeated, and it was found that Therefore, it is determined that the acid sophorolipid hydrate anti-aggregation agent with a concentration of 7wt% still has excellent anti-aggregation effect after 13h under the conditions of a water content of 45.0%, a temperature of 2℃, a pressure of 20MPa, and a salinity of 5% in the pipeline.

[0054] Example 5

[0055] The application of the acid sophorolipid hydrate anti-aggregation agent in the oil-gas-water three-phase mixed pipeline includes the following steps:

[0056] (1) Purification of acid sophorolipid: A mixture of commercially available acid sophorolipid and lactone sophorolipid is added to a single-necked flask, and after adding excess anhydrous ethanol, it is heated to 83℃, magnetically stirred for 35 minutes, vacuum filtered to obtain a solid, and dried at a constant temperature of 75℃ for 22h to obtain the acid sophorolipid hydrate anti-aggregation agent.

[0057] (2) Using a continuous circulation pipeline device equipped with a high-precision online flow meter, under the conditions of an acid sophorolipid hydrate anti-aggregation agent concentration of 4.5wt% (water mass as the reference amount), a water content of 25.0%, a temperature of 8℃, a pressure of 15MPa, and a salinity of 3%, the initial flow rate in the pipeline and the real-time flow rate after pumping for 15h and The values were measured by online flow meters at three different positions of the pipeline, and the average value was taken, as shown in Table 5.

[0058] Table 5 Pipeline flow table of Example 5

[0059]

[0060] The experimental results found that the concentration of the acid sophorolipid hydrate anti-aggregation agent was 4.5wt% After adjusting the concentration of the acid sophorolipid hydrate anti-aggregation agent to 4wt%, the above experiment was repeated, and it was found that It is proved that 4.5wt% of acid sophorolipid hydrate anti-agglomerant still has excellent anti-agglomerating effect after 15h under the pipeline conditions of 25.0% of water cut, 8℃ of temperature, 15MPa of pressure and 3% of salinity.

[0061] Comparative Example 1

[0062] The chemical oxygen demand and biochemical oxygen demand of common cationic, anionic and nonionic hydrate anti-agglomerants are tested by using multi-parameter water quality tester, and it is found that the BOD / COD value of each of them is less than 0.3, which is not suitable for biological treatment method.

[0063] Table 6 Chemical oxygen demand and biochemical oxygen demand of different surfactants

[0064] Surfactant COD (mg / L) BOD5 (mg / L) BOD5 / COD CTAC 1902 337 0.18 SDBS 1782 493 0.28 AEO-5 1502 425 0.28

[0065] CTAC is cetyltrimethylammonium chloride; SDBS is sodium dodecyl benzene sulfonate; and AEO-5 is fatty alcohol polyoxyethylene ether.

Claims

1. The application of an acidic sophorolipid hydrate anti-polymerization agent in a three-phase oil-gas-water mixed-transmission pipeline, characterized in that: Includes the following steps: Step 1: The concentration of the hydrate anti-polymerization agent is a wt%, where a ranges from 1 to 8. The initial flow rate in the pipeline is then measured. Real-time flow rate 12-16 hours after pump start-up The hydrate anti-agglomeration agent is an acidic sophorolipid that ensures that hydrate particles in the three-phase oil-gas-water pipeline remain in a fluid state at all times. Step two, if If the result is positive, the anti-polymerization agent is deemed effective, and its concentration is set to (a-0.5) wt%. Step one is repeated for the (i+1)th experiment. If the result of the (i+1)th experiment is... If the anti-polymerization agent fails, its concentration is determined to be (a-0.5i) wt%; The purity of the hydrate anti-polymerization agent is 95-99%, and the BOD / COD value is 0.3-0.5; The pressure inside the pipeline is 6~20MPa, and the temperature is 2~8℃; The purification method of the acidic sophorolipid is as follows: a mixture of acidic sophorolipid and lactone sophorolipid is added to a single-necked flask, excess anhydrous ethanol is added, the temperature is raised to 80~85℃, magnetically stirred for 30~40 minutes, vacuum filtered to obtain a solid, and dried at a constant temperature to obtain an acidic sophorolipid hydrate anti-polymerization agent. The constant temperature drying temperature is 70~80℃, and the time is 20~24h.

2. The application of the acidic sophorolipid hydrate anti-polymerization agent according to claim 1 in a three-phase oil-gas-water mixed transportation pipeline, characterized in that: The initial flow rate is obtained by averaging the flow rates at three different locations in the pipeline.

3. The application of the acidic sophorolipid hydrate anti-polymerization agent according to claim 1 in a three-phase oil-gas-water mixed transportation pipeline, characterized in that: The real-time flow rate is obtained by measuring an online flow meter.

4. The application of the acidic sophorolipid hydrate anti-polymerization agent according to claim 1 in a three-phase oil-gas-water mixed transportation pipeline, characterized in that: The water volume in the pipeline accounts for less than or equal to 50.0% of the total volume of the oil and water phases.

5. The application of the acidic sophorolipid hydrate anti-polymerization agent according to claim 4 in a three-phase oil-gas-water mixed transportation pipeline, characterized in that: The water volume in the pipeline accounts for 10.0% to 45.0% of the total volume of the oil and water two phases.

6. The application of the acidic sophorolipid hydrate anti-polymerization agent according to claim 1 in a three-phase oil-gas-water mixed transportation pipeline, characterized in that: The value of 'a' is 1 to 4.

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