A method for drawing a ternary phase diagram of heavy oil emulsion

Abstract

The present invention relates to a method for drawing a ternary phase diagram of heavy oil emulsion, belonging to the technical field of oil and gas field development, including: preparing a viscosity reducer and a mineralized aqueous solution; taking points to calculate the relative volume of each component of the heavy oil emulsion and the mass concentration of the viscosity reducer; carrying out an emulsification experiment according to the relative volume; determining the liquid-liquid phase equilibrium state; calculating the concentration of the oil-water dispersed phase; determining the phase state partition boundary line; drawing a ternary phase diagram of the heavy oil emulsion; and determining the phase state and the concentration of the dispersed phase under given conditions. The present invention obtains the influence of the mass concentration of the viscosity reducer, the water-oil ratio and the salinity on the phase state of the emulsion system through experiments, so as to qualitatively and quantitatively characterize the phase state change of the emulsion. The present invention reveals the influence mechanism of the mass concentration of the viscosity reducer, mineralized water and heavy oil on the liquid-liquid phase equilibrium state, constructs a ternary phase diagram of the heavy oil emulsion system, and realizes the convenient judgment of the phase state of the emulsion under the relative volume of different chemical agents.

Description

Technical Field

[0001] The present invention relates to a method for drawing a ternary phase diagram of heavy oil emulsion, belonging to the technical field of oil and gas field development. Background Art

[0002] The key to the development of heavy oil reservoirs is to reduce the viscosity of crude oil. The cold production development method by chemical emulsification to reduce viscosity is an important research direction for the efficient development of heavy oil. In the chemical composite cold production development of heavy oil, different phase states such as water, oil, water-in-oil emulsion, and oil-in-water emulsion will appear under the influence of reservoir conditions and fluid conditions. The phase equilibrium characteristics are relatively complex, which has an important impact on the development effect.

[0003] At present, the research on emulsion phase states mainly focuses on microemulsion systems with nanometer-sized particle diameters. However, the particle diameter of the emulsion system is in the micron range, and this system is a thermodynamically unstable system, and its phase state changes are extremely complex. Therefore, carrying out experimental research on the phase equilibrium of heavy oil emulsions and drawing the ternary phase diagram of heavy oil emulsions has become the key to guiding the optimization of field development.

[0004] At present, there is a method for drawing a pseudo-ternary phase diagram of microemulsions, which can determine the range of different emulsion types according to the phase diagram, intuitively reflect the influence of the concentration of each phase on the phase state at phase equilibrium, and determine the composition of the single-phase emulsion. However, the existing drawing method lacks an emulsion state equation when judging the emulsion phase state, and cannot accurately predict the emulsion type; and due to the instability of the emulsion, there are few methods for studying the emulsion phase equilibrium model. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a method for drawing a ternary phase diagram of heavy oil emulsion.

[0006] The present invention conducts phase equilibrium characteristic experiments on the heavy oil / viscosity reducer / water emulsion system, and studies the microscopic characteristics of the emulsion system through a microfluidic test system, a laser particle size analyzer, and a conductivity meter. It reveals the influence mechanism of the mass concentrations of the viscosity reducer, mineralized water, and heavy oil on the phase equilibrium of the emulsion, constructs the ternary phase diagram of the heavy oil emulsion system, and proposes a method for drawing the ternary phase diagram of the heavy oil emulsion. It overcomes the disadvantages of difficult measurement and hard drawing by traditional means.

[0007] The technical solution of the present invention is as follows:

[0008] A method for drawing a ternary phase diagram of heavy oil emulsion, comprising:

[0009] Preparing a viscosity reducer and a mineralized water solution;

[0010] Taking points to calculate the relative volume of each component of the heavy oil emulsion and the mass concentration of the viscosity reducer;

[0011] Conducting an emulsification experiment according to the relative volume;

[0012] Determine the equilibrium state of the emulsion phase;

[0013] Calculate the concentration of the oil and water dispersed phases;

[0014] Determine the phase state partition boundary line;

[0015] Draw the ternary phase diagram of the heavy oil emulsion;

[0016] Determine the phase state and the concentration of the dispersed phase under given conditions.

[0017] Preferably according to the present invention, prepare a viscosity reducer and a mineralized aqueous solution; including:

[0018] Mix the viscosity reducer and distilled water in a ratio of 100:1 to 1000:1, and stir well with a stirrer to prepare a viscosity reducer solution with a mass concentration of 0.01 wt% to 1.0 wt% and place it in measuring cylinder A;

[0019] Take distilled water with a volume of a, take sodium chloride with a mass of x, and prepare mineralized water with a salinity of ω and place it in measuring cylinder B; take heavy oil with a volume of a / 2 and place it in measuring cylinder C, where a ranges from 20 to 100 mL, x ranges from 0.1 to 2.0 g, and ω ranges from 1000 to 100000 mg / L.

[0020] Preferably according to the present invention, calculate the relative volumes of the components of the heavy oil emulsion and the mass concentration of the viscosity reducer by taking points; including:

[0021] Draw a triangle with heavy oil, mineralized water, and viscosity reducer as vertices, add scale lines from 0 to 1 between every two vertices, take points evenly in the triangle, and calculate the relative volumes of heavy oil and mineralized water and the mass concentration of the viscosity reducer according to the positions of the taken points.

[0022] Preferably according to the present invention, the calculation method for the relative volumes of the components of the heavy oil emulsion and the mass concentration of the viscosity reducer is as follows: draw a line parallel to the bottom edge of the triangle through the selected point, the corresponding value of the intersection point with the left side is the relative volume of water, the corresponding value of the intersection point with the right side is the relative volume of heavy oil, and their sum is 1; at the same time, draw an extension line through the vertex of the triangle and the selected point, and the value corresponding to the intersection point with the bottom edge of the triangle multiplied by 1.0% is the mass concentration of the viscosity reducer.

[0023] Preferably according to the present invention, the number of taken points is not less than 50.

[0024] Preferably according to the present invention, carry out an emulsification experiment based on the relative volume; including:

[0025] Select a point in the triangular diagram. Take a viscosity reducer solution with a volume of a' in graduated cylinders A and B, and mix it with mineralized water with a volume of b' in graduated cylinder C to obtain an oil-water mixture with a volume of c'. Calculate the sampling volume of each liquid according to the relative volumes of heavy oil and aqueous solution. Among them, the sampling volume of heavy oil is: c'×e; the relative volume of the aqueous solution is: c'×(1 - e), where e refers to the relative volume of heavy oil. The value range of a' is 10 - 50 mL; the value range of b' is 10 - 150 mL, and the value range of c' is 20 - 200 mL;

[0026] Use an emulsifier to emulsify the water mixture at a constant speed, and finally obtain a homogeneous emulsion system. Seal and let graduated cylinder C stand for 7 - 21 days, and the emulsion system in the graduated cylinder shows a layered state. Change the sampling point position and repeat the emulsification experiment.

[0027] According to the preference of the present invention, determine the emulsion liquid phase equilibrium state; including:

[0028] Take samples of each equilibrium phase of the emulsion, use a conductivity meter to test the conductivity at the liquid phase equilibrium of the emulsion, distinguish between water-in-oil emulsions and oil-in-water emulsions, and use an electron microscope to microscopically observe the emulsion samples to further distinguish the emulsion liquid phase equilibrium state.

[0029] According to the preference of the present invention, calculate the oil-water dispersed phase concentration; including:

[0030] Calculate the volume differences of the oil and water phases before and after emulsification of heavy oil, viscosity reducer, and mineralized water respectively, calculate the volume concentration of the dispersed substance in the dispersed phase in the emulsion, and mark them on the triangular diagram respectively to obtain the oil-water dispersed phase concentration;

[0031] f = g / h×100%; where f refers to the oil dispersed phase concentration, g refers to the volume of the oil phase in the water-in-oil emulsion, and h refers to the total volume of the emulsion;

[0032] i = j / h×100%; where i refers to the water dispersed phase concentration, and j refers to the volume of the water phase in the oil-in-water emulsion.

[0033] According to the preference of the present invention, determine the phase state partition boundary line; including:

[0034] According to the experimental results, use different symbols to represent different emulsion types, mark their positions on the triangular diagram, and draw the phase state partition boundary line by taking the points at the boundaries of different symbol aggregation areas.

[0035] According to the preference of the present invention, determine the phase state partition boundary line; including:

[0036] In the triangular diagram, if the upper part is the oil phase and the lower part is the water-in-oil emulsion, it is the water-in-water emulsion - oil phase equilibrium state, recorded as area one, and the points in it are marked with circular marks in the triangular diagram;

[0037] If the upper part is an oil-in-water emulsion and the lower part is a water-in-oil emulsion, it is a water-in-oil - oil-in-water emulsion phase equilibrium state, recorded as Zone 2, and the points therein are marked with triangle symbols in the triangular diagram;

[0038] If the upper part is an oil-in-water emulsion and the lower part is an aqueous phase, it is an oil-in-water emulsion - aqueous phase equilibrium state, recorded as Zone 3, and the points therein are marked with square symbols in the triangular diagram;

[0039] If the upper part is an oil phase and the lower part is an aqueous phase, it is an aqueous phase - oil phase equilibrium state, recorded as Zone 4, and the points therein are marked with diamond symbols in the triangular diagram.

[0040] Preferably according to the present invention, a ternary phase diagram of the heavy oil emulsion is drawn; including:

[0041] For a certain phase of the emulsion, the corresponding contour map is drawn for the dispersed phase concentration inside the triangle, and the established phase partition and the contour map of the dispersed phase concentration are the ternary phase diagram of the heavy oil emulsion.

[0042] Preferably according to the present invention, the steps for drawing the ternary phase diagram of the heavy oil emulsion are as follows:

[0043] (1) Taking the vertex where the viscosity reducer is located in the triangular diagram as the origin, and extending to the right along the bottom edge of the triangle as the X-axis to establish a rectangular coordinate system, so that the ternary phase diagram is located in the first quadrant of the coordinate system. Place the phase boundary line in the ternary phase diagram in the rectangular coordinate system, determine the (x, y) rectangular coordinates of each point on the phase boundary line and perform regression fitting; the (x, y) rectangular coordinates are converted into the component ratios of each point on the corresponding ternary phase diagram as follows:

[0044]

[0045] Wherein, o represents the oil component, v represents the viscosity reducer component, w represents the water component, and x and y respectively represent the abscissa and ordinate of the established rectangular coordinate system;

[0046] (2) Establish a function for the phase partition boundary of the ternary phase diagram of the heavy oil emulsion system, perform fitting calculations on the different phase boundary lines drawn in the ternary phase diagram, and establish a mathematical model for characterizing the phase partition of the ternary phase diagram of the heavy oil emulsion system, that is, the boundary line mathematical model, as shown below:

[0047]

[0048] Wherein, y1 represents the boundary function between Zone 1 and Zone 2 on the ternary phase diagram of the heavy oil emulsion system, and is represented by a solid line in the ternary phase diagram; y2 represents the boundary function between Zone 2 and Zone 3 of the heavy oil emulsion system, and is represented by a dashed line in the ternary phase diagram; y3 represents the boundary function between Zone 3 and Zone 4 of the heavy oil emulsion system, and is represented by a dashed line combined with dots in the ternary phase diagram.

[0049] Preferably according to the present invention, the data processing software includes Excel and Origin.

[0050] Preferably according to the present invention, given conditions determine the phase state and the concentration of the dispersed phase; including:

[0051] Given the ratio of heavy oil to mineralized water and the mass concentration of the viscosity reducer, the point corresponding to this condition in the plane coordinate system is added to the ternary phase diagram of the heavy oil emulsion. According to the region where the point is located, the corresponding phase state is determined, and the emulsion concentration value is obtained by interpolating the isoconcentration line of the dispersed phase concentration.

[0052] The beneficial effects of the present invention are as follows:

[0053] 1. Through experiments, the present invention obtains the influence of the mass concentration of the viscosity reducer, the water-oil ratio, and the salinity on the phase state of the emulsion system, enabling qualitative and quantitative characterization of the phase state change of the emulsion.

[0054] 2. By revealing the influence mechanism of the mass concentration of the viscosity reducer, mineralized water, and heavy oil on the phase equilibrium state of the emulsion, the present invention constructs a ternary phase diagram of the heavy oil emulsion system, realizing convenient judgment of the phase state of the emulsion under different relative volumes of chemical agents. Description of the Drawings

[0055] Figure 1 is a flow schematic diagram of a method for drawing a ternary phase diagram of a heavy oil emulsion according to the present invention;

[0056] Figure 2 is a graph showing the relationship between the mass concentration of different viscosity reducers and the equilibrium phase volume fraction of the heavy oil emulsion;

[0057] Figure 3 is a ternary phase diagram of the heavy oil emulsion system;

[0058] Figure 4 is an isoconcentration line diagram of the oil-water dispersed phase concentration;

[0059] Figure 5 is a calculation chart plate for the boundary line of the heavy oil emulsion phase state partition. Detailed Embodiments

[0060] The present invention will be further described below in conjunction with the drawings of the specification and embodiments, but is not limited thereto.

[0061] Example 1

[0062] A method for drawing a ternary phase diagram of a heavy oil emulsion, as Figure 1 shown, includes:

[0063] Prepare a viscosity reducer and a mineralized water solution;

[0064] Take points to calculate the relative volumes of each component of the heavy oil emulsion and the mass concentration of the viscosity reducer;

[0065] Carry out emulsification experiments based on relative volume;

[0066] Determine the equilibrium state of the emulsion phase; Phase equilibrium refers to the limit state reached by the changes in each phase in a multiphase system. At this time, macroscopically, no substance is transferred between phases, but microscopically, there are still substances transferring between phases in opposite directions with equal speeds.

[0067] Calculate the concentration of the oil and water dispersed phases; Dispersed phase concentration: It refers to the volume fraction of the oil phase in an oil-in-water emulsion or the volume fraction of the water phase in a water-in-oil emulsion.

[0068] Determine the phase state partition boundary line;

[0069] Draw the ternary phase diagram of the heavy oil emulsion;

[0070] Determine the phase state and the concentration of the dispersed phase under given conditions.

[0071] Example 2

[0072] A method for drawing the ternary phase diagram of a heavy oil emulsion according to Example 1, characterized in that:

[0073] Prepare a viscosity reducer and a mineralized aqueous solution; including:

[0074] Mix the viscosity reducer and distilled water in a ratio of 100:1 to 1000:1, and stir well with a stirrer to prepare a viscosity reducer solution with a mass concentration of 0.01wt% to 1.0wt% and place it in measuring cylinder A;

[0075] Take distilled water with a volume of a, take sodium chloride with a mass of x, and prepare mineralized water with a salinity of ω and place it in measuring cylinder B; Take heavy oil with a volume of a / 2 and place it in measuring cylinder C, where the value range of a is 20 - 100 mL, the value range of x is 0.1 - 2.0 g, and the value range of ω is 1000 - 100000 mg / L.

[0076] The viscosity reducer used is a water-soluble viscosity reducer.

[0077] Take points to calculate the relative volume of each component of the heavy oil emulsion and the mass concentration of the viscosity reducer; including:

[0078] Draw a triangle with heavy oil, mineralized water, and viscosity reducer as vertices, add scale lines from 0 to 1 (to determine the composition ratio of each component) between every two vertices, evenly take points in the triangle, and calculate the relative volume of heavy oil and mineralized water and the mass concentration of the viscosity reducer according to the positions of the taken points.

[0079] The calculation method for the relative volume of each component of the heavy oil emulsion and the mass concentration of the viscosity reducer is as follows: draw a line parallel to the bottom edge of the triangle through the selected point. The value corresponding to the intersection with the left side is the relative volume of water, and the value corresponding to the intersection with the right side is the relative volume of heavy oil. The sum of the two is 1. At the same time, extend the line through the vertex of the triangle and the selected point, and the value corresponding to the intersection with the bottom edge of the triangle multiplied by 1.0% is the mass concentration of the viscosity reducer.

[0080] The number of selected points is not less than 50.

[0081] Carry out emulsification experiments based on the relative volume, including:

[0082] Select a certain point in the triangular diagram. Take the viscosity reducer solution with a volume of a’ and the mineralized water with a volume of b’ in measuring cylinders A and B respectively, and mix them in measuring cylinder C to obtain an oil-water mixture with a volume of c’. Calculate the sampling volume of each liquid according to the relative volume of heavy oil and aqueous solution. Among them, the sampling volume of heavy oil is: c’×e; the relative volume of the aqueous solution is: c’×(1 - e), where e refers to the relative volume of heavy oil. The value range of a’ is 10 - 50 mL; the value range of b’ is 10 - 150 mL, and the value range of c’ is 20 - 200 mL;

[0083] Use an emulsifier to emulsify the water mixture at a constant speed under a certain shear rate to finally obtain a uniform emulsion system. Seal and let the measuring cylinder C stand still for 7 - 21 days, and the emulsion system in the measuring cylinder shows a layered state. Change the position of the selected point and repeat the emulsification experiment.

[0084] Determine the emulsion phase equilibrium state, including:

[0085] Take samples of each equilibrium phase of the emulsion, use a conductivity meter to measure the conductivity of the emulsion at phase equilibrium, and distinguish between water-in-oil emulsions and oil-in-water emulsions. The conductivity of water-in-oil emulsions is much greater than that of oil-in-water emulsions. Use an electron microscope to conduct microscopic observations on the emulsion samples to further distinguish the emulsion phase equilibrium state. In water-in-oil emulsions, oil droplets are dispersed in a bright aqueous solution, while in oil-in-water emulsions, bright water droplets are dispersed in a continuous oil phase.

[0086] Calculate the concentration of the oil-water dispersed phase, including:

[0087] Calculate the volume difference of the oil-water phases before and after emulsification of heavy oil, viscosity reducer, and mineralized water respectively, calculate the volume concentration of the dispersed substance in the dispersed phase in the emulsion, and mark them on the triangular diagram respectively to obtain the oil-water dispersed phase concentration;

[0088] f = g / h×100%; where f refers to the concentration of the oil dispersed phase, g refers to the volume of the oil phase in the water-in-oil emulsion, and h refers to the total volume of the emulsion;

[0089] i = j / h × 100%; where i refers to the concentration of the aqueous dispersed phase, and j refers to the volume of the aqueous phase in the water-in-oil emulsion.

[0090] Determine the phase state partition boundary; including:

[0091] According to the experimental results, different emulsion types are represented by different symbols and marked on the triangular diagram. Points at the boundaries of different symbol aggregation areas are taken to draw the phase state partition boundary.

[0092] Determine the phase state partition boundary; including:

[0093] In the triangular diagram, if the upper part is the oil phase and the lower part is the water-in-oil emulsion, it is the water-in-water emulsion - oil phase equilibrium state, recorded as zone 1, and the points in it are marked with circular symbols on the triangular diagram;

[0094] If the upper part is the water-in-oil emulsion and the lower part is the oil-in-water emulsion, it is the oil-in-water - water-in-oil emulsion phase equilibrium state, recorded as zone 2, and the points in it are marked with triangular symbols on the triangular diagram;

[0095] If the upper part is the water-in-oil emulsion and the lower part is the aqueous phase, it is the water-in-oil emulsion - aqueous phase equilibrium state, recorded as zone 3, and the points in it are marked with square symbols on the triangular diagram;

[0096] If the upper part is the oil phase and the lower part is the aqueous phase, it is the aqueous phase - oil phase equilibrium state, recorded as zone 4, and the points in it are marked with diamond symbols on the triangular diagram.

[0097] Draw the ternary phase diagram of the heavy oil emulsion; including:

[0098] Using data processing software, draw the corresponding contour map of the dispersed phase concentration of a certain phase state emulsion inside the triangle. The established phase state partition and the contour map of the dispersed phase concentration are the ternary phase diagram of the heavy oil emulsion.

[0099] When drawing the contour map of the dispersed phase concentration, the contour lines of the oil dispersed phase concentration are represented by dots, and the concentration of the aqueous dispersed phase is represented by thin solid lines.

[0100] The steps for drawing the ternary phase diagram of the heavy oil emulsion are as follows:

[0101] (1) Taking the vertex where the viscosity reducer is located in the triangular diagram as the origin, extending to the right along the bottom edge of the triangle as the X-axis to establish a rectangular coordinate system, so that the ternary phase diagram is located in the first quadrant of the coordinate system. Place the phase state boundary line in the ternary phase diagram in the rectangular coordinate system, determine the (x, y) rectangular coordinates of each point on the phase state boundary line and perform regression fitting; the (x, y) rectangular coordinates are converted into the component ratios corresponding to each point on the ternary phase diagram as follows:

[0102]

[0103] Among them, o represents the oil component, v represents the viscosity reducer component, w represents the water component, and x and y respectively represent the abscissa and ordinate of the established rectangular coordinate system;

[0104] (2) Establish a function for the phase state partition boundary of the ternary phase diagram of the heavy oil emulsion system, perform fitting calculations on the different phase state boundary lines drawn in the ternary phase diagram, and establish a mathematical model for characterizing the phase state partition of the ternary phase diagram of the heavy oil emulsion system, that is, the boundary line mathematical model, as follows:

[0105]

[0106] Among them, y1 represents the boundary function between the first and second regions of the ternary phase diagram of the heavy oil emulsion system, which is represented by a solid line in the ternary phase diagram; y2 represents the boundary function between the second and third regions of the heavy oil emulsion system, which is represented by a dotted line in the ternary phase diagram; y3 represents the boundary function between the third and fourth regions of the heavy oil emulsion system, which is represented by a dotted line combined with dots in the ternary phase diagram.

[0107] The data processing software includes Excel and Origin.

[0108] Determine the phase state and the concentration of the dispersed phase under given conditions; including:

[0109] Given the ratio of heavy oil to mineralized water and the mass concentration condition of the viscosity reducer, add the point corresponding to this condition in the plane coordinate system to the ternary phase diagram of the heavy oil emulsion, determine the corresponding phase state according to the region where the point is located, and obtain the emulsion concentration value by interpolating the isoconcentration line of the dispersed phase concentration.

[0110] Example 3

[0111] According to the method for drawing the ternary phase diagram of a heavy oil emulsion described in Example 2, the difference is that:

[0112] Mix the viscosity reducer and distilled water in a certain ratio, and stir well with a stirrer to prepare a viscosity reducer solution with a mass concentration of 0.3 wt% and place it in graduated cylinder A;

[0113] Take 100 mL of distilled water, take 1.0 g of sodium chloride, and prepare mineralized water with a salinity of 10,000 mg / L and place it in graduated cylinder B. Take a certain volume of heavy oil and place it in graduated cylinder C;

[0114] Take points evenly in the triangle. According to the position of the points taken as Figure 2 shown, calculate the relative volumes of the three liquids and the mass concentration of the viscosity reducer.

[0115] Take 12.5 mL of the viscosity reducer solution, 12.5 mL of the mineralized water, and 25 mL of the heavy oil from graduated cylinders A, B, and C respectively, and mix them in graduated cylinder D to obtain a total of 50 mL of the oil-water mixture, and calculate the sampling volume of each liquid.

[0116] Seal the graduated cylinder C and let it stand still for 14 days.

[0117] Example 4

[0118] A method for drawing a ternary phase diagram of a heavy oil emulsion, according to Example 2, is characterized in that:

[0119] Mix the viscosity reducer and distilled water in a certain proportion and stir well with a stirrer to prepare a viscosity reducer solution with a certain mass concentration;

[0120] Take a certain volume of distilled water and a certain mass of sodium chloride, configure mineralized water with a salinity of ω and place it in graduated cylinder B, and take a certain volume of heavy oil and place it in graduated cylinder C;

[0121] Draw a triangle with heavy oil, viscosity reducer, and mineralized water as vertices, add scale lines from 0 to 1 between every two vertices, evenly take points in the triangle, and calculate the relative volumes of the three liquids according to the positions of the taken points;

[0122] Take a viscosity reducer solution with a volume of a, mineralized water with a volume of b, and heavy oil with a volume of c in graduated cylinders A, B, and C respectively, mix them in graduated cylinder D to obtain a total of 50 mL of oil-water mixture, and calculate the sampling volumes of each liquid.

[0123] Use an emulsifier to emulsify it at a constant speed under a certain shear rate, and finally obtain a uniform emulsion system. Seal the experimental graduated cylinder and let it stand still for 14 days. The emulsion system in the graduated cylinder shows a layered state. Change the position of the taken points and repeat this step;

[0124] Take samples of each equilibrium phase of the emulsion, use a conductivity meter to measure the conductivity of the emulsion at phase equilibrium, and use an electron microscope to microscopically observe the emulsion samples to determine the phase equilibrium state of the emulsion;

[0125] Calculate the volume difference between the oil and water phases before and after emulsification of heavy oil / viscosity reducer / water, calculate the volume concentration of the dispersed substance in the dispersed phase in the emulsion, and mark them on the triangle diagram respectively to obtain the oil-water dispersed phase concentration;

[0126] According to the experimental results, represent different emulsion types with different symbols and mark their positions on the triangle diagram. Take the points at the boundaries of the aggregation areas of different symbols to draw the phase state partition boundary line;

[0127] Use data processing software to draw the corresponding contour map of the dispersed phase concentration of a certain phase state emulsion inside the triangle, as Figure 4 shown. The established phase state partition and the contour map of the dispersed phase concentration are the ternary phase diagram of the heavy oil emulsion;

[0128] A function for establishing the phase state partition boundary of the ternary phase diagram of the heavy oil emulsion system is used to perform fitting calculations on the different phase state boundary lines drawn in the ternary phase diagram. Figure 5 It is a calculation chart for the phase state partition boundary line of the heavy oil emulsion. A mathematical model for characterizing the phase state partition of the ternary phase diagram of the heavy oil emulsion system, that is, the demarcation line mathematical model, is as follows:

[0129]

[0130] Figure 3 It is the ternary phase diagram of the heavy oil emulsion system. Among them, y1 represents the boundary function between region 1 and region 2 on the ternary phase diagram of the heavy oil emulsion system, which is represented by a solid line in the figure; y2 represents the boundary function between region 2 and region 3 of the heavy oil emulsion system, which is represented by a dashed line in the figure; y3 represents the boundary function between region 3 and region 4 of the heavy oil emulsion system, which is represented by a dashed line combined with dots in the figure.

[0131] Given that the mass concentrations of heavy oil, viscosity reducer, and mineralized water are 0.25, 0.3, and 0.45 respectively, this point is added to the ternary phase diagram of the heavy oil emulsion. According to the region where this point is located, the corresponding phase state is determined to be the phase equilibrium state of water-in-oil emulsion - water phase. According to the interpolation of the isoconcentration line of the dispersed phase concentration, the oil dispersed phase concentration can be obtained as 37 and the water dispersed phase concentration can be obtained as 22.

[0132] The above embodiments are only used to illustrate the present invention. Any equivalent transformation and improvement made on the basis of the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A method for drawing a ternary phase diagram of a heavy oil emulsion, characterized in that Including: Preparing a viscosity reducer and a mineralized aqueous solution; Taking points to calculate the relative volumes of each component of the heavy oil emulsion and the mass concentration of the viscosity reducer; Conducting an emulsification experiment based on the relative volumes; Determining the phase equilibrium state of the emulsion; Calculating the concentration of the oil and water dispersed phases; Determining the phase state partition boundary line; Drawing the ternary phase diagram of the heavy oil emulsion; Given conditions to determine the phase state and the concentration of the dispersed phase; The steps for drawing the ternary phase diagram of the heavy oil emulsion are as follows: (1) Taking the vertex where the viscosity reducer is located in the triangular diagram as the origin, extending to the right along the base of the triangle as the X-axis to establish a rectangular coordinate system, so that the ternary phase diagram is located in the first quadrant of the coordinate system. Placing the phase state boundary line in the ternary phase diagram in the rectangular coordinate system, determining the (x, y) rectangular coordinates of each point on the phase state boundary line and performing regression fitting; the (x, y) rectangular coordinates are converted into the component ratios corresponding to each point on the ternary phase diagram as follows: Where, o represents the oil component, v represents the viscosity reducer component, w represents the water component, and x and y respectively represent the horizontal and vertical coordinates of the established rectangular coordinate system; (2) Establishing a function for the phase state partition boundary of the ternary phase diagram of the heavy oil emulsion system, performing fitting calculations on the different phase state boundary lines drawn in the ternary phase diagram, and establishing a mathematical model for characterizing the phase state partition of the ternary phase diagram of the heavy oil emulsion system, that is, the boundary line mathematical model, as shown below: Where, y1 represents the boundary function between the first and second regions on the ternary phase diagram of the heavy oil emulsion system, represented by a solid line in the ternary phase diagram; y2 represents the boundary function between the second and third regions of the heavy oil emulsion system, represented by a dashed line in the ternary phase diagram; y3 represents the boundary function between the third and fourth regions of the heavy oil emulsion system, represented by a dashed line combined with dots in the ternary phase diagram.

2. The method for drawing a ternary phase diagram of a heavy oil emulsion according to claim 1, characterized in that, Preparing a viscosity reducer and a mineralized aqueous solution; Including: Mixing the viscosity reducer and distilled water in a ratio of 100:1 to 1000:1, fully stirring with a stirrer, and preparing a viscosity reducer solution with a mass concentration of 0.01wt% to 1.0wt% and placing it in measuring cylinder A; Taking a volume of a of distilled water, taking a mass of x of sodium chloride, and preparing mineralized water with a salinity of ω and placing it in measuring cylinder B; taking a volume of a / 2 of heavy oil and placing it in measuring cylinder C, where the value range of a is 20 to 100 mL, the value range of x is 0.1 to 2.0 g, and the value range of ω is 1000 to 100000 mg / L.

3. A method for drawing a ternary phase diagram of a heavy oil emulsion according to claim 1, characterized in that, Taking points to calculate the relative volumes of each component of the heavy oil emulsion and the mass concentration of the viscosity reducer; including: Drawing a triangle with heavy oil, mineralized water, and viscosity reducer as vertices, adding scale lines from 0 to 1 between every two vertices, evenly taking points in the triangle, and calculating the relative volumes of heavy oil and mineralized water and the mass concentration of the viscosity reducer according to the positions of the taken points.

4. A method for drawing a ternary phase diagram of a heavy oil emulsion according to claim 3, characterized in that The calculation method for the relative volumes of each component of the heavy oil emulsion and the mass concentration of the viscosity reducer is: drawing a straight line parallel to the base of the triangle through the selected point, the corresponding value of the intersection point with the left side is the relative volume of water, the corresponding value of the intersection point with the right side is the relative volume of heavy oil, and the sum of the two is 1; at the same time, drawing an extension line through the vertex of the triangle and the selected point, and multiplying the corresponding value of the intersection point with the base of the triangle by 1.0% to obtain the mass concentration of the viscosity reducer; the number of taken points is not less than 50.

5. A method for drawing a ternary phase diagram of a heavy oil emulsion according to claim 3, characterized in that, Conducting an emulsification experiment based on the relative volumes; including: Select a point in the triangular diagram. Take a viscosity reducer solution with a volume of a' in measuring cylinders A and B, and mineralized water with a volume of b'. Mix them in measuring cylinder C to obtain an oil-water mixture with a volume of c'. Calculate the sampling volume of each liquid according to the relative volumes of heavy oil and aqueous solution. Among them, the sampling volume of heavy oil is: c'×e; the relative volume of the aqueous solution is: c'×(1 - e), where e refers to the relative volume of heavy oil. The value range of a' is 10 - 50 mL; the value range of b' is 10 - 150 mL, and the value range of c' is 20 - 200 mL; Use an emulsifier to emulsify the water mixture at a constant speed, and finally obtain a uniform emulsion system. Seal and let the measuring cylinder C stand still for 7 - 21 days, and the emulsion system in the measuring cylinder shows a layered state. Change the sampling point position and repeat the emulsification experiment.

6. A method for drawing a ternary phase diagram of a heavy oil emulsion according to claim 1, characterized in that, Determine the emulsion liquid-liquid equilibrium state; including: Take samples of each equilibrium phase of the emulsion, use a conductivity meter to measure the conductivity at the liquid-liquid equilibrium of the emulsion, distinguish between oil-in-water emulsions and water-in-oil emulsions, and use an electron microscope to microscopically observe the emulsion samples to further distinguish the liquid-liquid equilibrium state; Calculate the oil-water dispersed phase concentration; including: Calculate the volume difference of the oil-water phases before and after emulsification of heavy oil, viscosity reducer, and mineralized water respectively, calculate the volume concentration of the dispersed substance in the dispersed phase in the emulsion, and mark them on the triangular diagram respectively to obtain the oil-water dispersed phase concentration; f = g / h×100%; where f refers to the oil dispersed phase concentration, g refers to the volume of the oil phase in the oil-in-water emulsion, and h refers to the total volume of the emulsion; i = j / h×100%; where i refers to the water dispersed phase concentration, and j refers to the volume of the water phase in the water-in-oil emulsion.

7. A method for drawing a ternary phase diagram of a heavy oil emulsion according to claim 3, characterized in that Determine the phase state partition boundary; including: In the triangular diagram, if the upper part is the oil phase and the lower part is the oil-in-water emulsion, it is the water-in-water emulsion - oil phase liquid-liquid equilibrium state, recorded as zone 1, and the points in it are marked with circular symbols in the triangular diagram; If the upper part is the water-in-oil emulsion and the lower part is the oil-in-water emulsion, it is the oil-in-water - water-in-oil emulsion liquid-liquid equilibrium state, recorded as zone 2, and the points in it are marked with triangular symbols in the triangular diagram; If the upper part is the water-in-oil emulsion and the lower part is the water phase, it is the water-in-oil emulsion - water phase liquid-liquid equilibrium state, recorded as zone 3, and the points in it are marked with square symbols in the triangular diagram; If the upper part is the oil phase and the lower part is the water phase, it is the water phase - oil phase liquid-liquid equilibrium state, recorded as zone 4, and the points in it are marked with diamond symbols in the triangular diagram.

8. A method for drawing a ternary phase diagram of a heavy oil emulsion according to claim 1, characterized in that, Draw the ternary phase diagram of heavy oil emulsion; including: Draw the corresponding contour map of the dispersed phase concentration of a certain phase state emulsion inside the triangle. The established phase state partition and the contour map of the dispersed phase concentration are the ternary phase diagram of heavy oil emulsion.

9. A method for drawing a ternary phase diagram of a heavy oil emulsion according to any one of claims 1-8, characterized in that, Determine the phase state and dispersed phase concentration under given conditions; including: Given the ratio of heavy oil and mineralized water and the mass concentration of the viscosity reducer, add the point corresponding to this condition in the plane coordinate system to the ternary phase diagram of heavy oil emulsion. Determine the corresponding phase state according to the area where the point is located, and obtain the emulsion concentration value by interpolating according to the contour line of the dispersed phase concentration.

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