Compound demulsifier composition and demulsification method

Abstract

The invention belongs to the technical field of thin oil demulsification, and particularly relates to a compound demulsifier composition and a demulsification method. The demulsifying agent composition comprises a demulsifying agent component, the demulsifying agent composition comprises a demulsifying agent component, and the demulsifying agent component comprises an FW type demulsifying agent, an M-41T type demulsifying agent, an APE type demulsifying agent, an HC-1 type demulsifying agent and tetrakis hydroxymethyl phosphonium sulfate. According to the invention, the demulsification rate of high-emulsified crude oil is greater than 70%; the process integration degree is high, on-site treatment of the high-emulsification crude oil is achieved, tank cleaning and transportation are not needed, and the operation cost of an enterprise is reduced; the water content in the treated oil is less than 20%, the oil content in the water is less than 1000mg / L, the suspended matter content is less than 1000mg / L, and the mechanical impurity content is less than 0.4%.

Description

Technical Field

[0001] The invention belongs to the technical field of thin oil demulsification, and specifically relates to a compound demulsifier composition and a demulsification method. Background Art

[0002] The components such as colloid, asphaltene and paraffin contained in crude oil are natural high-performance emulsifiers. Crude oil in emulsion form brings difficulties to transportation, processing and sales. At the same time, the water contained in crude oil will react chemically with the salt to generate precipitated scaling substances that block pipelines and instruments and equipment. The salt will also form a catalyst with other impurities, which will seriously affect the stability of crude oil emulsion, destroy the original component structure and generate new impurity components. The presence of salt and water in crude oil will also cause considerable harm to the smooth operation of the constant pressure reduction device and subsequent devices, and equipment corrosion. Therefore, demulsification, desalination and dehydration of crude oil are essential links in the production process, and crude oil needs to be demulsified, usually using demulsifiers.

[0003] At present, the demulsifiers used in domestic oil fields are mainly polyether demulsifiers. However, when used alone, this type of demulsifier has an unsatisfactory demulsification effect, poor broad-spectrum adaptability to different crude oil products, and the demulsification effect does not meet the requirements. Moreover, as the oil field enters the medium-to-high water content period, a large amount of external fluids such as fracturing flowback fluid and acidizing operation waste fluid continue to enter the crude oil processing system, resulting in the phenomenon of gradually thickening stable emulsions in the sedimentation tank of the concentrated thin oil processing station. In addition, after the sedimentation tank is dehydrated, the emulsion in the tank has no separate treatment process, making the original treatment process unable to meet the current demulsification requirements. In order to maintain production, it can only be treated by simple tank cleaning or greatly increasing the temperature, and increasing the concentration of demulsifiers, resulting in a significant increase in treatment costs.

[0004] Chinese invention patent application CN101121898A discloses a rapid demulsification method, which includes microwave radiation, adding a demulsifier according to the mass ratio of water to demulsifier in the emulsified crude oil, and the mass ratio of water to demulsifier is 1:0.5×10 -4 -5×10 -4 , using microwaves for demulsification. The demulsifier is one or a mixture of two or more of polyamine polyoxypropylene polyoxyethylene ether, resin polyoxypropylene polyoxyethylene ether, high carbon alcohol initiator demulsifier or propylene glycol demulsifier. The microwave radiation has a microwave radiation frequency of 2450MHz or 915MHz. By utilizing the synergistic effect of demulsifier and microwave radiation, the oil-in-water emulsion can be demulsified in a shorter time, and a higher dehydration rate can be obtained, thereby improving the demulsification efficiency. However, the method is difficult to control the conditions, and different crude oils require different reaction conditions due to their different physical and chemical properties; many applications have only been completed in laboratories and have not been applied to industrial production on a large scale.

[0005] Chinese invention patent application CN104560127A discloses a method for treating crude oil wastewater. The method separates oil and water by passing water through a filter, a high-pressure pump, and a reverse osmosis membrane tube. When the wastewater passes through the membrane surface, the hydrophilicity and lipophilicity balance of various particles are destroyed. The wastewater is carried out in the membrane tube, and the emulsion particles are demulsified, and then aggregated and coarsened to achieve a separated state. However, the efficiency of this method needs to be improved, and it is not suitable for large-scale application in industrial production.

[0006] Take a certain oil field as an example. Its wells are currently entering a high water content period. A large amount of external fluids such as fracturing flowback fluids continue to enter the crude oil processing system, resulting in a gradually thickening stable emulsion phenomenon in the sedimentation tank of the centralized processing station. In order to maintain production, only passive treatment forms such as simple tank cleaning can be used, and the annual processing cost is as high as 3.2 million yuan. The highly emulsified crude oil was analyzed, and the results showed that the absolute value of the Zeta potential of the emulsion is very high, the density is close to that of water, the suspended matter content is high, and the colloid asphaltene content is high. It is a typical "Pickering" type emulsion. The temperature rises to 60°C and the demulsifier concentration reaches 200mg / L. It is still not demulsified, and the processing temperature and dosing concentration need to be further significantly increased.

[0007] The existing highly emulsified crude oil processing process still has the problems of large amount of demulsifier and high heating temperature, which leads to a significant increase in processing cost and energy consumption; therefore, providing an efficient demulsification method for highly emulsified crude oil to meet the normal operation of the thin oil processing station has become a technical problem that needs to be solved urgently. Summary of the invention

[0008] In view of the deficiencies in the prior art, the technical problem actually solved by the present invention is to provide a composite demulsifier composition and a demulsification method, which can reduce the demulsifier dosage and processing energy consumption while ensuring that the treated crude oil meets the processing index requirements.

[0009] In order to achieve the above-mentioned purpose of the present invention, the specific technical solution adopted by the present invention is:

[0010] A composite demulsifier composition comprises demulsifier components, wherein the demulsifier components comprise FW type demulsifier, M-41T type demulsifier, APE type demulsifier, HC-1 type demulsifier and tetrakis(hydroxymethyl)phosphonium sulfate.

[0011] Preferably, the weight percentage of the FW type demulsifier is 10-25% based on a solid content of 80%.

[0012] Preferably, the weight percentage of the M-41T demulsifier is 25-40% based on a solid content of 80%.

[0013] Preferably, the weight percentage of the APE type demulsifier is 10-35% based on a solid content of 80%.

[0014] Preferably, the weight percentage of the HC-1 type demulsifier is 15-30% based on a solid content of 80%.

[0015] Preferably, the weight percentage of tetrakis(hydroxymethyl)phosphonium sulfate is 10-25% based on a solid content of 75%.

[0016] Preferably, the FW type demulsifier is FW-135 demulsifier, and the APE type demulsifier is APE-8166 demulsifier.

[0017] Preferably, the M-41T is a polyoxyethylene polyoxypropylene block polyether with imidazoline as an initiator, and APE-8166 is a polyoxyethylene polyoxypropylene polyether with polyethylene polyamine as an initiator.

[0018] Preferably, the APE type demulsifier is prepared using polyethylene polyamine as an initiator, toluene-2,4-diisocyanate as a cross-linking agent, and methanol as a solvent.

[0019] Preferably, the composition further comprises an alcohol solvent, and the alcohol solvent is selected from one or more of methanol, ethanol and glycerol; the weight ratio of the demulsifier component to the alcohol solvent is 10:5-10:1, preferably 2:1-4:1.

[0020] Preferably, the composition further comprises water, and the weight percentage of the demulsifier component in the composition is 20-40%, preferably 25-30%.

[0021] The present invention also relates to a demulsification method, which comprises: adding the demulsifier composition into the produced fluid, heating, centrifuging and filtering.

[0022] Preferably, the concentration of the demulsifier composition in the produced fluid is 150-250 mg / L.

[0023] Preferably, the heating temperature is 50-70° C., and the heating time is 35-50 min.

[0024] Preferably, the centrifugal speed is 1800-2200 rpm; and the filtration is performed by a membrane filter device.

[0025] The purpose of the heating treatment is to accelerate the chemical demulsification reaction speed and achieve partial thermal demulsification at the same time.

[0026] The purpose of centrifugal treatment is to separate oil and water, and solid and liquid through centrifugation.

[0027] The purpose of filtration is to remove suspended solids in produced water for a second time and improve the quality of produced water so that the produced water meets the standards for oilfield reinjection water.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The demulsification rate of the present invention for highly emulsified crude oil reaches 90%;

[0030] (2) The process of the present invention has a high degree of integration, and realizes the on-site treatment of highly emulsified crude oil, without the need for tank cleaning and transportation, thus reducing the operating costs of the enterprise;

[0031] (3) After the treatment, the water content in the oil is less than 20%, the oil content in the water is less than 700 mg / L, the suspended matter content is less than 600 mg / L, and the mechanical impurity content is less than 0.4%, thereby realizing the recovery of crude oil and the back-mixing of water. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a process flow chart for treating thin oil and highly emulsified crude oil. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are further clearly described. The described embodiments are only a part of the present invention and are used to explain the present invention but not to limit the present invention. Therefore, other embodiments obtained by other technicians in the field without creative work all belong to the protection scope of the present invention.

[0034] FW-135 demulsifier and M-41T demulsifier were purchased from Akzo Nobel (Boxing);

[0035] APE-8166 demulsifier and HC-1 demulsifier were purchased from CNOOC Tianjin Oilfield Chemical Company;

[0036] Tetrakis hydroxymethyl phosphonium sulfate (THPS) was purchased from Jiangsu Kangxiang Industrial Co., Ltd.;

[0037] The reagents not particularly described in the present invention are all industrial products and are commercially available.

[0038] Example 1

[0039] Demulsifier composition: by weight percentage, 30% of demulsifier components (wherein, the mass ratio of FW-135 demulsifier, M-41T demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetrakis (hydroxymethyl) phosphonium sulfate is 1:1:1:1:1), 10% of methanol and 60% of water are mixed uniformly at 40° C. to obtain a demulsifier composition.

[0040] Demulsification method:

[0041] like Figure 1As shown in the process flow chart of thin oil highly emulsified crude oil demulsification, when the produced water treatment equipment is operating normally, the thin oil highly emulsified crude oil first enters the dosing unit to allow the chemical agent and emulsified oil to be fully mixed, and then the emulsified oil enters the heating furnace, where the temperature is increased for thermochemical demulsification to remove part of the emulsified oil and free water; the remaining emulsified oil is centrifuged, and the emulsified oil is further decomposed into oil and water, as well as impurities through centrifugal action. The water from the centrifuge enters the membrane filter, where the membrane filter is used to remove oil, suspended matter and other impurities in the water, and the filtered water enters the purified water tank for storage and use when it is reinjected into the oil field. The oil from the centrifuge is directly mixed back, and a very small amount of impurities is treated as solid waste.

[0042] (1) Dosing: Add the above-mentioned new demulsifier (200 mg / L);

[0043] (2) Heating device: The liquid from the dosing unit enters the heating unit and is heated to 60°C to accelerate the thermochemical demulsification rate. The reaction time is 40 minutes.

[0044] (3) Centrifugation: The remaining emulsion is lifted to the centrifugal unit by a lifting pump at a speed of 2000 rpm. The emulsion residence time is 20 min to separate oil, water and impurities.

[0045] (4) Filtration: The effluent is filtered through a membrane to remove suspended matter.

[0046] Example 2

[0047] Demulsifier composition: by weight percentage, 28% of demulsifier components (wherein, the mass ratio of FW-135 demulsifier, M-41T demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetrakis (hydroxymethyl) phosphonium sulfate is 2:3:1:2:2), 8% of ethanol and 64% of water are mixed uniformly at 40° C. to obtain the product.

[0048] Demulsification method:

[0049] (1) Dosing: Add the above-mentioned new demulsifier (150 mg / L);

[0050] (2) Heating device: The liquid from the dosing unit enters the heating unit and is heated to 70°C to accelerate the thermochemical demulsification rate. The reaction time is 35 minutes.

[0051] (3) Centrifugation: The remaining emulsion is lifted to the centrifugal unit by a lifting pump at a speed of 1800 rpm. The emulsion residence time is 25 min to separate oil, water and impurities.

[0052] (4) Filtration: The effluent is filtered through a membrane to remove suspended matter.

[0053] Example 3

[0054] Demulsifier composition: by weight percentage, 25% of demulsifier components (wherein, the mass ratio of FW-135 demulsifier, M-41T demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetrakis (hydroxymethyl) phosphonium sulfate is 2:1:2:3:2), 14% of glycerol and 58% of water are mixed uniformly at 40° C. to obtain a demulsifier composition.

[0055] Demulsification method:

[0056] (1) Dosing: Add the above-mentioned new demulsifier (250 mg / L);

[0057] (2) Heating device: The liquid from the dosing unit enters the heating unit and is heated to 50°C to accelerate the thermochemical demulsification rate. The reaction time is 50 minutes.

[0058] (3) Centrifugation: The remaining emulsion is lifted to the centrifugal unit by a lifting pump at a speed of 2200 rpm. The emulsion residence time is 15 min to separate oil, water and impurities.

[0059] (4) Filtration: The effluent is filtered through a membrane to remove suspended matter.

[0060] Comparative Example 1

[0061] Demulsifier composition: by weight percentage, 30% of demulsifier components (wherein the mass ratio of FW-135 demulsifier, M-41T demulsifier, HC-1 demulsifier and tetrakis(hydroxymethyl)phosphonium sulfate is 1:2:1:1), 10% of methanol and 60% of water are mixed uniformly at 40° C. to obtain the demulsifier composition.

[0062] The demulsification method is consistent with that in Example 1.

[0063] Comparative Example 2

[0064] Demulsifier composition: by weight percentage, 30% of demulsifier components (wherein the mass ratio of FW-135 demulsifier, APE-8166 demulsifier, HC-1 demulsifier and tetrakis(hydroxymethyl)phosphonium sulfate is 1:2:1:1), 10% of methanol and 60% of water are mixed uniformly at 40° C. to obtain the demulsifier composition.

[0065] The demulsification method is consistent with that in Example 1.

[0066] Comparative Example 3

[0067] Commercially available demulsifier, purchased from Xinkeao Company, model: SQ-A01;

[0068] The demulsification method is consistent with that in Example 1.

[0069] Comparative Example 4

[0070] The demulsifier composition and preparation method are consistent with those in Example 1;

[0071] The only difference between the demulsification method and Example 1 is that the centrifugal treatment in step (3) is not performed.

[0072] Comparative Example 5

[0073] The demulsifier composition and preparation method are consistent with those in Example 1;

[0074] The only difference between the demulsification method and Example 1 is that the drug addition treatment in step (1) is not performed.

[0075] Effect test

[0076] The composite demulsifiers of the embodiments and comparative examples were evaluated by SY / T5281-2000 to demulsify the produced liquid of the highly emulsified crude oil of the Shixi thin oil processing station in Xinjiang Oilfield. The test used Shixi highly emulsified crude oil with a water content of 36%, a dehydration temperature of 60°C, and a demulsifier concentration of 200 mg / L. The analysis results are shown in Table 1.

[0077] Table 1 Test results

[0078] Water content in oil (%) Oil content in water (mg / L) Suspended matter content (mg / L) Organic impurities content (%) Demulsification rate (%) Example 1 5 500 300 0.1 90 Example 2 14 600 400 0.3 72 Example 3 16 620 550 0.3 71 Comparative Example 1 21 770 780 0.4 55 Comparative Example 2 25 740 1030 0.4 61 Comparative Example 3 33 1100 1540 0.6 3 Comparative Example 4 28 810 1150 0.5 32 Comparative Example 5 25 800 1100 0.5 40

[0079] After being processed by this innovative achievement, the highly emulsified crude oil of Shixi Thin Oil Processing Station in Xinjiang Oilfield meets the requirements of less than 20% water content in oil, less than 700mg / L oil content in water, less than 600mg / L suspended matter content, less than 0.4% organic impurity content, and more than 70% demulsification rate, achieving the purpose of crude oil recovery and water back-mixing, and on-site treatment of highly emulsified crude oil. The equipment used in the device of the present invention is mature and reliable, has strong impact resistance, small footprint, and high degree of automation.

[0080] The above detailed description is a specific description of one feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A composite demulsifier composition, characterized in that: The demulsifier composition comprises a demulsifier component, and the demulsifier component comprises a FW type demulsifier, an M-41T type demulsifier, an APE type demulsifier, an HC-1 type demulsifier and tetrakis(hydroxymethyl)phosphonium sulfate.

2. The demulsifier composition according to claim 1, characterized in that In the demulsifier component, the weight percentage of the FW type demulsifier is 10-25% based on a solid content of 80%.

3. The demulsifier composition according to claim 1, characterized in that In the demulsifier component, the weight percentage of the M-41T demulsifier is 25-40% based on a solid content of 80%.

4. The demulsifier composition according to claim 1, characterized in that In the demulsifier component, the weight percentage of the APE type demulsifier is 10-35% based on a solid content of 80%.

5. The demulsifier composition according to claim 1, characterized in that In the demulsifier component, the weight percentage of the HC-1 type demulsifier is 15-30% based on a solid content of 80%.

6. The demulsifier composition according to claim 1, characterized in that In the demulsifier component, the weight percentage of the tetrakis(hydroxymethyl)phosphonium sulfate is 10-25% based on a solid content of 75%.

7. The demulsifier composition according to claim 1, characterized in that The M-41T demulsifier is formed by chain extension of polyoxyethylene polyoxypropylene block polyether with imidazoline as initiator; the APE demulsifier is formed by chain extension of polyoxyethylene polyoxypropylene polyether with polyethylene polyamine as initiator.

8. The demulsifier composition according to any one of claims 1 to 7, characterized in that The composition further comprises an alcohol solvent, which is selected from one or more of methanol, ethanol and glycerol; the weight ratio of the demulsifier component to the alcohol solvent is 10:5-10:

1.

9. The demulsifier composition according to claim 8, characterized in that The weight ratio of the demulsifier component to the alcohol solvent is 2:1-4:

1.

10. The demulsifier composition according to claim 1, characterized in that The composition further comprises water, and the weight percentage of the demulsifier component in the composition is 20-40%.

11. The demulsifier composition according to claim 10, characterized in that The weight percentage of the demulsifier component in the composition is 25-30%.

12. A demulsification method, characterized in that: The method comprises the following steps: adding the demulsifier composition according to any one of claims 1 to 11 into the produced fluid, heating, centrifuging and filtering.

13. The demulsification method according to claim 12, characterized in that: The concentration of the demulsifier composition in the produced fluid is 150-250 mg / L.

14. The demulsification method according to claim 12, characterized in that: The heating temperature is 50-70° C., and the heating time is 35-50 min.

15. The demulsification method according to claim 12, characterized in that: The centrifugal speed is 1800-2200 rpm; the filtration is performed by a membrane filter device.

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