Preparation method of simulated emulsion for evaluating demulsifier

Abstract

The invention belongs to the field of oil reservoir exploitation, and discloses a preparation method of a simulated emulsion for demulsifier evaluation, and the preparation method comprises the following steps: obtaining the emulsion type, oil content, viscosity data and particle size distribution data of a target emulsion; preparing a simulated emulsion under different emulsification conditions based on the emulsion type and the oil content of the target emulsion, and measuring viscosity data and particle size distribution data of the simulated emulsion; and determining a matching relationship between the simulated emulsion and the target emulsion based on the viscosity data and the particle size distribution data of the simulated emulsion and the target emulsion. The raw material ratio is preset based on the emulsion type and the oil content of the target emulsion, the shearing condition and the ultrasonic condition of emulsification are determined based on the matching effect of the liquid viscosity data and the particle size distribution data of the simulated emulsion and the target emulsion, and the problems that the viscosity of a polymer-containing system is high, the oscillation and stirring frequency and speed uncertainty are large, and the stability is poor are solved. The method solves the problem that when the method is used for evaluating the effect of the demulsifier, the demulsifier is greatly different from a field sample, and the applicability of the demulsifier or a reverse demulsifier to the field emulsion can be evaluated more accurately.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of oil reservoir exploitation, and particularly relates to a preparation method of a simulated emulsion for evaluation of a demulsifier. BACKGROUND

[0002] With further exploitation of oil fields, most of the oil fields in China have entered the high water cut period. With the continuous expansion of the polymer flooding scale, the presence of polyacrylamide greatly improves the emulsion stability, and the emulsion type is more complex. The produced fluid of the oil well changes from the original water-in-oil emulsion to the oil-in-water emulsion, and the complex system of multiple emulsions coexists. In the existing evaluation standard methods of demulsifiers and reverse demulsifiers, methods such as oscillation, mechanical stirring, and high-speed shear dispersion are used to prepare water-in-oil or oil-in-water emulsions. However, due to the high viscosity of the polymer-containing system, the uncertainty of the oscillation, stirring frequency, and speed is large, which leads to large differences in the properties of different batches of emulsions, and it is difficult to simulate multiple emulsion systems. When used for demulsifier effect evaluation, there is often a large difference with the field sample. Therefore, it is necessary to provide a preparation method of a simulated emulsion for evaluation of a demulsifier, which has stable performance and simulates a complex emulsion system. SUMMARY

[0003] In order to overcome the defects of the prior art, the purpose of the present application is to provide a preparation method of a simulated emulsion for evaluation of a demulsifier, so as to meet the evaluation requirements of the demulsifier.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0005] A preparation method of a simulated emulsion for evaluation of a demulsifier, comprising:

[0006] obtaining emulsion type, oil content, viscosity data, and particle size distribution data of a target emulsion;

[0007] preparing a simulated emulsion under different emulsification conditions based on the emulsion type and oil content of the target emulsion, and measuring the viscosity data and particle size distribution data of the simulated emulsion;

[0008] determining the matching relationship between the simulated emulsion and the target emulsion based on the viscosity data and particle size distribution data of the simulated emulsion and the target emulsion.

[0009] Further, obtaining the emulsion type, oil content, viscosity data, and particle size distribution data of the target emulsion comprises:

[0010] determining the emulsion type of the target emulsion by using a dispersion method or a microscope method;

[0011] detecting the target emulsion to obtain the oil content, viscosity data, and particle size distribution data of the target emulsion.

[0012] Further, based on the emulsion type and oil content of the target emulsion, simulate emulsions are prepared under different emulsification conditions, including:

[0013] Based on the emulsion type and oil content of the target emulsion, the ratio of raw materials is preset;

[0014] With polymer solution, simulate oil and surfactant as raw materials, emulsification is carried out under different emulsification conditions with preset raw material ratio, and the viscosity data of each simulate emulsion and the corresponding emulsification conditions are recorded.

[0015] Further, the emulsion type of the target emulsion includes water-in-oil, oil-in-water and water-in-oil-in-water.

[0016] Further, emulsification is carried out under different emulsification conditions with preset raw material ratio, including:

[0017] When the target emulsion is water-in-oil or oil-in-water, the polymer solution with preset raw material ratio is mixed with simulate oil and surfactant, and then shear stirring is carried out to obtain simulate emulsion.

[0018] Further, the shear speed of shear stirring is 5000-8000 rpm, and the shear time is 5-90 min.

[0019] Further, emulsification is carried out under different emulsification conditions with preset raw material ratio, including:

[0020] When the target emulsion is water-in-oil-in-water, the polymer solution is mixed with simulate oil and surfactant, and then shear stirring is carried out to obtain primary emulsion;

[0021] The viscosity data of the primary emulsion is measured, and the primary emulsion with matched viscosity is selected based on the viscosity data of the primary emulsion and the target emulsion to carry out ultrasonic, and the water-in-oil-in-water target emulsion is obtained.

[0022] Further, the shear speed of shear stirring is 5000-8000 rpm, and the shear time is 5-90 min.

[0023] Further, the ultrasonic is continuous ultrasonic or pulse ultrasonic, the power of ultrasonic is 100-250 W, the frequency is 20-30 Hz, and the effective ultrasonic time is 0.5-5 min.

[0024] Further, based on the viscosity data and particle size distribution data of the simulate emulsion and the target emulsion, the matching relationship between the simulate emulsion and the target emulsion is determined, including:

[0025] The viscosity data of the simulate emulsion and the target emulsion are compared, and when the viscosity difference is ≤10%, it is determined that the viscosity of the simulate emulsion and the target emulsion is matched;

[0026] The particle size distribution data of the simulated emulsion and the target emulsion are compared, and when the difference between the median particle size and the average particle size is not more than 75%, it is determined that the particle size distribution of the simulated emulsion matches that of the target emulsion.

[0027] The application also discloses an application of the preparation method of the simulated emulsion, and the performance of the demulsifier and the reverse demulsifier is evaluated based on the above method.

[0028] Technical effects and advantages of the application:

[0029] The application preconfigures the raw material ratio based on the emulsion type and the oil content of the target emulsion, and determines the shearing condition and the ultrasonic condition of emulsification based on the matching effect of the viscosity data and the particle size distribution data of the simulated emulsion and the target emulsion, thereby solving the problems of high viscosity of the polymer-containing system, large uncertainty of oscillation, stirring frequency and speed, large difference in properties of different batches of emulsions, difficulty in simulating multiple emulsion systems, and large difference between the simulated emulsion and the field sample when the demulsifier effect is evaluated, and the applicability of the demulsifier or the reverse demulsifier to the field emulsion can be more accurately evaluated.

[0030] Other features and advantages of the application will be described in the following description, and some will become apparent from the description, or will be understood through implementation of the application. The purpose and other advantages of the application can be achieved and obtained through the structures indicated in the specification, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A flowchart of the preparation method of the simulated emulsion for demulsifier evaluation of the application. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0033] As shown in the drawings, Figure 1 The application provides a preparation method of a simulated emulsion for demulsifier evaluation, which comprises the following steps:

[0034] acquiring the emulsion type, oil content, viscosity data and particle size distribution data of a target emulsion;

[0035] preparing simulated emulsions under different emulsification conditions based on the emulsion type and the oil content of the target emulsion, and measuring the viscosity data and the particle size distribution data of the simulated emulsions;

[0036] The matching relationship between the simulation emulsion and the target emulsion is determined based on viscosity data and particle size distribution data of the simulation emulsion and the target emulsion.

[0037] In some embodiments of the present application, the emulsion type, oil content, viscosity data and particle size distribution data of the target emulsion are obtained, including:

[0038] The emulsification type of the target emulsion is determined by dispersion method or microscopy method.

[0039] The target emulsion is detected to obtain the oil content, viscosity data and particle size distribution data of the target emulsion.

[0040] In some embodiments of the present application, the simulation emulsion is prepared based on the emulsion type and oil content of the target emulsion under different emulsification conditions, including:

[0041] The raw material ratio is preset based on the emulsion type and oil content of the target emulsion.

[0042] The polymer solution, simulation oil and surfactant are used as raw materials to emulsify under the preset raw material ratio and different emulsification conditions to obtain a plurality of simulation emulsions, and the viscosity data and corresponding emulsification conditions of each simulation emulsion are recorded.

[0043] In some embodiments of the present application, the emulsion type of the target emulsion includes water-in-oil, oil-in-water and water-in-oil-in-water.

[0044] In some embodiments of the present application, the emulsification is carried out under the preset raw material ratio and different emulsification conditions, including:

[0045] When the target emulsion is water-in-oil or oil-in-water, the polymer solution, simulation oil and surfactant with the preset raw material ratio are mixed and then sheared and stirred to obtain the simulation emulsion. The shearing speed of shearing and stirring is 5000-8000 rpm, and the shearing time is 5-90 min.

[0046] When the target emulsion is water-in-oil-in-water, the polymer solution, simulation oil and surfactant are mixed and then sheared and stirred to obtain a primary emulsion, wherein the shearing speed of shearing and stirring is 5000-8000 rpm, and the shearing time is 5-90 min. Then, the viscosity data of the primary emulsion is measured, the primary emulsion with matched viscosity is selected based on the viscosity data of the primary emulsion and the target emulsion, and ultrasonic is performed on the primary emulsion with matched viscosity. The ultrasonic mode is continuous ultrasonic or pulse ultrasonic, the power of ultrasonic is 100-250 W, the frequency is 20-30 Hz, and the effective ultrasonic time is 0.5-5 min to obtain the target emulsion of water-in-oil-in-water.

[0047] In some embodiments of the present application, the matching relationship between the simulation emulsion and the target emulsion is determined based on the viscosity data and particle size distribution data of the simulation emulsion and the target emulsion, including:

[0048] Comparing the viscosity data of the simulated emulsion and the target emulsion, when the viscosity difference is ≤10%, it is determined that the viscosity of the simulated emulsion matches that of the target emulsion;

[0049] Comparing the particle size distribution data of the simulated emulsion and the target emulsion, when the difference between the median particle size and the average particle size is not more than 75%, it is determined that the particle size distribution of the simulated emulsion matches that of the target emulsion.

[0050] The application also provides an application of the preparation method of the simulated emulsion, and the performance of the demulsifier and the reverse demulsifier is evaluated based on the above method.

[0051] In order to better illustrate the present scheme, the following examples are provided.

[0052] Example 1

[0053] Taking the target emulsion collected after a three-phase separator of a certain polymer flooding combination station in an oilfield as an example:

[0054] Step one: using the dispersion method, it is confirmed that the emulsification type of the target emulsion is oil-in-water (O / W) emulsion; the oil content is 526 mg / L, the polymer content is 355 mg / L, the viscosity is 1.91 mPa·s, the median particle size is 2.257 μm, and the average particle size is 2.377 μm.

[0055] Step two: configuring a 350 mg / L polymer solution (partially hydrolyzed polyacrylamide, molecular weight 1200-1600 million), adding 500 mg / L simulated oil to the polymer solution, using Tween 80 as an emulsifier, mixing and stirring by a high-speed shearing machine at a shearing speed of 5000-18000 rpm and a shearing time of 5-90 min, and emulsifying under the corresponding conditions to obtain multiple simulated emulsions; after the emulsification is completed, the viscosity distribution of each simulated emulsion is determined.

[0056] Step three: comparing the viscosity data of the simulated emulsion obtained in step two with the detection results of the target emulsion in step one, obtaining the shearing condition-viscosity matching relationship of the simulated emulsion and the target emulsion, as shown in Table 1, the viscosity of the target emulsion is 1.91 mPa·s, and the shearing condition is determined to be 18000 rpm and 90 min.

[0057] Table 1 Shearing condition-viscosity matching relationship of simulated emulsion and target emulsion

[0058]

[0059]

[0060] Step four: measure the particle size distribution of the simulated emulsion obtained under the shear condition of 18000 rpm for 90 min, and the median particle size is 2.015 pm, and the average particle size is 2.792 pm, which meets the requirement that the difference between the particle size distribution data of the target emulsion and the simulated emulsion is not more than 75%, and the particle size data meets the target emulsion.

[0061] Example 2

[0062] Taking the target emulsion of the inlet valve group of a certain polymer flooding combination station in an oilfield as an example, the shear condition-viscosity matching relationship of the simulated emulsion and the target emulsion in this example is the same as that in Example 1.

[0063] Step one: use microscopy to confirm that the emulsion type of the target emulsion is water-in-oil-in-water (W / O / W) emulsion; the oil content is 4759 mg / L, the polymer content is 368 mg / L, the viscosity is 5.77 mPa·s, the median particle size is 1.375 pm, and the average particle size is 2.059 pm.

[0064] Step two: according to the viscosity of the target emulsion in step one, and combining the shear condition-viscosity matching relationship of the simulated emulsion and the target emulsion, the shear condition is determined as 12000 rpm for 90 min to prepare a primary emulsion.

[0065] Step three: ultrasonic preparation of water-in-oil-in-water type simulated emulsion for the primary emulsion, ultrasonic power 100-250 W, ultrasonic frequency 20-30 Hz, effective ultrasonic time 0.5-5 min, and the median particle size of the simulated emulsion is measured after ultrasonic emulsification.

[0066] Step four: compare the median particle size of the simulated emulsion obtained in step three with the detection results of the target emulsion in step one, and obtain the ultrasonic condition-particle size matching relationship of the simulated emulsion and the target emulsion, as shown in Table 2. As shown in Table 2, the ultrasonic conditions with the closest median particle size to the target emulsion are 100 W / 5 min or 150 W / 1 min, wherein the average particle size corresponding to the condition of 100 W / 5 min is 1.277 pm, and the average particle size corresponding to the condition of 150 W / 1 min is 1.954 pm, which is closer to the target emulsion.

[0067] In summary, based on the emulsion type and oil content of the target emulsion, the raw material ratio is preset, and based on the matching effect of the viscosity data and the particle size distribution data of the simulated emulsion and the target emulsion, the shear condition and the ultrasonic condition of emulsification are determined, which solves the problems of high viscosity of the polymer-containing system, large uncertainty of oscillation and stirring frequency and speed, large difference in properties of different batches of emulsions, difficulty in simulating multiple emulsion systems, and large difference between the simulated emulsion and the field sample when evaluating the effect of the demulsifier, and can more accurately evaluate the applicability of the demulsifier or reverse demulsifier to the field emulsion.

[0068] Table 2 Ultrasonic condition-particle size matching relationship of simulated emulsion and target emulsion

[0069]

[0070] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for the preparation of simulated emulsions for the evaluation of demulsifiers, characterized in that, The application relates to a method for evaluating the performance of demulsifiers and reverse demulsifiers. The method comprises the following steps: acquiring emulsion type, oil content, viscosity data and particle size distribution data of a target emulsion; preparing simulation emulsions under different emulsification conditions based on the emulsion type and oil content of the target emulsion, and measuring the viscosity data and particle size distribution data of the simulation emulsions; 2. A method for preparing simulated emulsions for evaluation of demulsifiers according to claim 1, characterized in that, determining the matching relationship between the simulation emulsions and the target emulsion based on the viscosity data and particle size distribution data of the simulation emulsions and the target emulsion. The method for acquiring the emulsion type, oil content, viscosity data and particle size distribution data of the target emulsion comprises the following steps: determining the emulsion type of the target emulsion by using a dispersion method or a microscope method; 3. A method for preparing simulated emulsions for evaluation of demulsifiers according to claim 1, characterized in that, detecting the target emulsion to acquire the oil content, viscosity data and particle size distribution data of the target emulsion. The method for preparing the simulation emulsions under different emulsification conditions based on the emulsion type and oil content of the target emulsion comprises the following steps: presetting the raw material ratio based on the emulsion type and oil content of the target emulsion; 4. A method for preparing simulated emulsions for evaluation of demulsifiers according to claim 3, characterized in that, using a polymer solution, simulation oil and a surfactant as raw materials to emulsify under the preset raw material ratio and different emulsification conditions, so as to obtain a plurality of simulation emulsions, and record the viscosity data and corresponding emulsification conditions of each simulation emulsion.

5. A method for preparing simulated emulsions for evaluation of demulsifiers according to claim 4, characterized in that, The emulsion type of the target emulsion comprises water-in-oil type, oil-in-water type and water-in-oil-in-water type. The method for emulsifying under the preset raw material ratio and different emulsification conditions comprises the following steps:

6. A method for preparing a simulated emulsion for evaluation of a demulsifier according to claim 5, characterized in that, when the target emulsion is of the water-in-oil type or the oil-in-water type, the polymer solution, the simulation oil and the surfactant in the preset raw material ratio are mixed and then sheared and stirred to obtain the simulation emulsion.

7. A method for preparing simulated emulsions for evaluation of demulsifiers according to claim 4, characterized in that, The shearing speed of the shearing and stirring is 5000-8000 rpm, and the shearing time is 5-90 min. The method for emulsifying under the preset raw material ratio and different emulsification conditions further comprises the following steps: when the target emulsion is of the water-in-oil-in-water type, the polymer solution, the simulation oil and the surfactant are mixed and then sheared and stirred to obtain a primary emulsion; 8. A method of preparing a simulated emulsion for evaluation of a demulsifier according to claim 7, characterized in that, the viscosity data of the primary emulsion are measured, the primary emulsion with matched viscosity is selected based on the viscosity data of the primary emulsion and the target emulsion, and the selected primary emulsion is subjected to ultrasonic treatment to obtain the target emulsion of the water-in-oil-in-water type.

9. A method for preparing a simulated emulsion for evaluation of a demulsifier according to claim 7, characterized in that, The shearing speed of the shearing and stirring is 5000-8000 rpm, and the shearing time is 5-90 min.

10. A method for preparing simulated emulsions for evaluation of demulsifiers according to claim 1, characterized in that, The ultrasonic treatment is continuous ultrasonic treatment or pulse ultrasonic treatment, the power of the ultrasonic treatment is 100-250 W, the frequency of the ultrasonic treatment is 20-30 Hz, and the effective ultrasonic treatment time is 0.5-5 min. The method for determining the matching relationship between the simulation emulsions and the target emulsion based on the viscosity data and particle size distribution data of the simulation emulsions and the target emulsion comprises the following steps: comparing the viscosity data of the simulation emulsions and the target emulsion, and determining that the viscosity of the simulation emulsion is matched with that of the target emulsion when the viscosity difference is less than or equal to 10%; 11. Use of a method of preparing an emulsion to simulate a method of preparing a milk, characterized in that, comparing the particle size distribution data of the simulation emulsions and the target emulsion, and determining that the particle size distribution of the simulation emulsion is matched with that of the target emulsion when the difference between the median particle size and the average particle size is less than or equal to 75%. The application can be applied to the evaluation of the performance of demulsifiers and reverse demulsifiers based on the method.

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