Method for predicting thick oil chemical viscosity reduction effect of oil-soluble viscosity reducer

Abstract

The invention provides a thick oil chemical viscosity reduction effect prediction method of an oil-soluble viscosity reducer. The method comprises the following steps: acquiring the viscosity and actual viscosity reduction rate of various oil-soluble viscosity reducers; constructing a relation curve between the viscosity of the oil-soluble viscosity reducers and the actual viscosity reduction rate; performing data fitting on the relation curve to obtain a thick oil chemical viscosity reduction effect prediction formula of the oil-soluble viscosity reducer; and substituting the viscosity of the oil-soluble viscosity reducer to be evaluated into the thick oil chemical viscosity reduction effect prediction formula of the oil-soluble viscosity reducer to obtain a corresponding predicted viscosity reduction rate. Based on the viscosity and the viscosity reduction effect of a common oil-soluble viscosity reducer, the viscosity reduction effect relation curve of the oil-soluble viscosity reducer is constructed, so that the viscosity reduction effect of the oil-soluble viscosity reducer is accurately predicted, and the operation is simple and convenient.

Description

Technical Field

[0001] The present application relates to the field of petroleum analytical chemistry, and in particular to a method for predicting the chemical viscosity reduction effect of a heavy oil using an oil-soluble viscosity reducer. Background Art

[0002] Heavy oil accounts for a large proportion of the world's oil and gas resources. Heavy oil has the characteristics of high viscosity, high density, high freezing point, and difficulty in flowing. Therefore, reducing the viscosity of heavy oil and increasing its fluidity are the key to improving the recovery rate of heavy oil. At present, the methods for heavy oil production at home and abroad include: thermal recovery, thin oil blending and viscosity reduction, chemical viscosity reduction, etc. Among them, thermal recovery is the most widely used and can effectively reduce viscosity, but the energy consumption is huge and the cost is too high; thin oil blending and viscosity reduction has a good viscosity reduction effect, but it is greatly limited by thin oil resources; and chemical viscosity reduction has the characteristics of low cost and easy implementation. Commonly used chemical viscosity reducers include water-soluble emulsified viscosity reducers, modified catalytic viscosity reducers and oil-soluble viscosity reducers.

[0003] Oil-soluble viscosity reducers can not only effectively reduce the pour point and viscosity of heavy oil, loosen the structure of heavy oil and improve its fluidity, but also avoid the post-processing problems caused by emulsification viscosity reduction. Therefore, using oil-soluble viscosity reducers to reduce viscosity is an effective way to solve the problems of heavy oil mining and transportation. For different heavy oils, due to their different initial viscosities, the types and amounts of oil-soluble viscosity reducers required are also different. Therefore, when chemically reducing the viscosity of heavy oil, it is particularly important to choose a suitable oil-soluble viscosity reducer. Therefore, the evaluation of the viscosity reduction effect of different oil-soluble viscosity reducers has become increasingly important. Summary of the invention

[0004] The present application provides a method for predicting the chemical viscosity reduction effect of heavy oil using an oil-soluble viscosity reducer, and adopts the following technical scheme:

[0005] A method for predicting the chemical viscosity reduction effect of heavy oil using an oil-soluble viscosity reducer, comprising:

[0006] Obtain the viscosity and actual viscosity reduction rate of various oil-soluble viscosity reducers;

[0007] Constructing relationship curves between the viscosity of the plurality of oil-soluble viscosity reducers and the actual viscosity reduction rate;

[0008] The relationship curve is fitted with data to obtain a prediction formula for the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer;

[0009] Substitute the viscosity of the oil-soluble viscosity reducer to be evaluated into the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer to obtain the corresponding predicted viscosity reduction rate.

[0010] By adopting the above technical solution, based on the viscosity and actual viscosity reduction rate of common oil-soluble viscosity reducers, a relationship curve between the viscosity of oil-soluble viscosity reducers and the actual viscosity reduction rate is constructed, and the relationship curve is fitted by software to output a fitting formula. Based on the fitting formula, for oil-soluble viscosity reducers with known viscosity, its predicted viscosity reduction rate can be directly calculated by the fitting formula, so as to accurately predict the viscosity reduction effect of the oil-soluble viscosity reducer, and the operation is simple and convenient. At the same time, according to the initial viscosity of the heavy oil, the viscosity of the viscosity reducer and the predicted viscosity reduction rate, a suitable viscosity reducer can be selected for viscosity reduction, thereby improving the comprehensive efficiency of the selection of the viscosity reducer.

[0011] Optionally, the step of obtaining the viscosity and actual viscosity reduction rate of a plurality of oil-soluble viscosity reducers includes:

[0012] Measuring and obtaining the initial viscosity of the heavy oil and the viscosity of the various oil-soluble viscosity reducers;

[0013] Mixing each of the oil-soluble viscosity reducers with the heavy oil according to a preset mass ratio to obtain a mixed system;

[0014] Measuring and obtaining the mixed system viscosity of the mixed system corresponding to each oil-soluble viscosity reducer;

[0015] According to the initial viscosity of the heavy oil, the viscosity of each oil-soluble viscosity reducer and the corresponding mixed system viscosity of the mixed system, the actual viscosity reduction rate of each oil-soluble viscosity reducer is calculated.

[0016] Optionally, the actual viscosity reduction rate of each oil-soluble viscosity reducer is calculated based on the initial viscosity of the heavy oil, the viscosity of each oil-soluble viscosity reducer and the corresponding mixed system viscosity of the mixed system, including:

[0017] According to the initial viscosity of the heavy oil, the viscosity of the oil-soluble viscosity reducer and the corresponding mixed system viscosity of the mixed system, the actual viscosity reduction rate of the oil-soluble viscosity reducer is calculated based on the following formula:

[0018] s = (ab) / a*100%;

[0019] Among them, s is the actual viscosity reduction rate of the oil-soluble viscosity reducer, a is the initial viscosity of the heavy oil, and b is the mixed system viscosity of the mixed system corresponding to the oil-soluble viscosity reducer.

[0020] By adopting the above technical solution, the actual viscosity reduction rate s is calculated by the initial viscosity a of the heavy oil and the viscosity b of the mixed system, so as to construct a relationship curve between the viscosity of the oil-soluble viscosity reducer and the actual viscosity reduction rate.

[0021] Optionally, before each of the oil-soluble viscosity reducers is mixed with the heavy oil in a preset mass ratio to obtain a mixed system, the method further comprises:

[0022] The plurality of oil-soluble viscosity reducers are screened to obtain a plurality of oil-soluble viscosity reducers with a viscosity range of 0.1 mPa·s to 100 mPa·s.

[0023] By adopting the above technical solution, when selecting an oil-soluble viscosity reducer, based on a larger viscosity range, the obtained relationship curve has wider applicability and improves the prediction accuracy of the relationship curve.

[0024] Optionally, the screening of the plurality of oil-soluble viscosity reducers further comprises: screening the plurality of oil-soluble viscosity reducers according to the following conditions:

[0025] Select at least one group of oil-soluble viscosity reducers within the viscosity range of 0.1 mPa·s to 20 mPa·s;

[0026] Selecting at least one group of oil-soluble viscosity reducers within the viscosity range of 20 mPa·s to 50 mPa·s;

[0027] At least one group of oil-soluble viscosity reducers is selected within the viscosity range of 50 mPa·s to 100 mPa·s.

[0028] By adopting the above technical solution, when selecting the fitting points, the fitting points are evenly distributed in three small intervals, which increases the applicable range of the relationship curve and is beneficial to improving the fitting accuracy of the viscosity and viscosity reduction effect of the oil-soluble viscosity reducer.

[0029] Optionally, a rotational rheometer is used to measure the initial viscosity of the heavy oil, the viscosity of the oil-soluble viscosity reducer and the corresponding viscosity of the mixed system.

[0030] By adopting the above technical solution, the rotational rheometer can obtain multiple indicators such as yield stress, viscosity, shear modulus, etc., which can more accurately describe the properties of the sample and ensure the accuracy of the experimental data.

[0031] Optionally, the viscosity of the oil-soluble viscosity reducer to be evaluated is substituted into the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer to obtain the corresponding predicted viscosity reduction rate, including:

[0032] Substitute the viscosity of the oil-soluble viscosity reducer to be evaluated into the following heavy oil chemical viscosity reduction effect prediction formula to obtain the predicted viscosity reduction rate:

[0033] y=0.009x 2 -1.1948x+96.887;

[0034] Among them, the fitting correlation coefficient R 2 =0.9918, y is the predicted viscosity reduction rate, and x is the viscosity of the oil-soluble viscosity reducer to be evaluated.

[0035] By adopting the above technical solution, the above prediction formula is fitted, which facilitates the direct prediction of the viscosity reducing effect of the oil-soluble viscosity reducer.

[0036] Optionally, after performing data fitting on the relationship curve to obtain a prediction formula for the chemical viscosity reduction effect of the oil-soluble viscosity reducer on heavy oil, the method further includes verifying the prediction formula for the chemical viscosity reduction effect of the oil-soluble viscosity reducer on heavy oil.

[0037] Optionally, the verification of the prediction formula for the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer includes:

[0038] Substituting the viscosity of the oil-soluble viscosity reducer into the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer to calculate the predicted viscosity reduction rate;

[0039] The relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate is calculated.

[0040] Optionally, the calculating the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate includes:

[0041] According to the predicted viscosity reduction rate and the actual viscosity reduction rate, the relative deviation is calculated based on the following formula:

[0042] r=|st| / s*100%;

[0043] Among them, r is the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate, s is the actual viscosity reduction rate, and t is the predicted viscosity reduction rate.

[0044] By adopting the above technical solution, the fitting formula is verified, that is, the predicted viscosity reduction rate calculated by the fitting formula is compared with the actual viscosity reduction rate of the oil-soluble viscosity reducer, and the relative deviation is calculated, which is conducive to improving the accuracy of the fitting.

[0045] Optionally, before obtaining the viscosity and actual viscosity reduction rate of various oil-soluble viscosity reducers, the following is also included:

[0046] A variety of oil-soluble viscosity reducers are obtained, including non-polar molecule oil-soluble viscosity reducers and polar molecule oil-soluble viscosity reducers.

[0047] By adopting the above technical scheme, when selecting oil-soluble viscosity reducers, polar molecule oil-soluble viscosity reducers and non-polar molecule oil-soluble viscosity reducers should be included at the same time to increase the applicability of the relationship curve between the viscosity of the oil-soluble viscosity reducer and the actual viscosity reduction rate, and eliminate the influence of the molecular properties of different viscosity reducers on the evaluation of the oil-soluble viscosity reduction effect.

[0048] Optionally, the step of obtaining a plurality of oil-soluble viscosity reducing agents including non-polar molecule oil-soluble viscosity reducing agents and polar molecule oil-soluble viscosity reducing agents comprises:

[0049] Obtaining an oil-soluble viscosity reducer of the type of non-polar aliphatic hydrocarbons and / or non-polar aromatic hydrocarbons, and,

[0050] Obtain at least one type of oil-soluble viscosity reducer selected from the group consisting of polar ester-based, polar phenol-based, and polar alcohol-based.

[0051] Based on the above technical solution, the beneficial effects of this application compared with the prior art are as follows:

[0052] 1. The method for predicting the chemical viscosity reduction effect of heavy oil of the oil-soluble viscosity reducer in the embodiment of the present application selects commonly used oil-soluble viscosity reducers, obtains the viscosity of each viscosity reducer and the viscosity reduction rate after mixing with heavy oil under the same conditions, and then fits the viscosity and viscosity reduction rate of each oil-soluble viscosity reducer to construct a fitting formula for the viscosity and viscosity reduction effect of the oil-soluble viscosity reducer. Through the fitting formula, after obtaining the viscosity of the oil-soluble viscosity reducer to be tested, it is substituted into the fitting formula to predict the viscosity reduction rate of the oil-soluble viscosity reducer to be tested, thereby being able to accurately predict the viscosity reduction effect of the oil-soluble viscosity reducer, and the operation method is simple.

[0053] 2. The viscosity reduction effect prediction method in the embodiment of the present application selects the viscosity and viscosity reduction rate of viscosity reducers with different molecular properties and molecular weights to construct a relationship curve, so that the relationship curve can be applied to non-polar molecules and polar molecules with different molecular weights, and has a wide range of applications.

[0054] 3. The method for predicting the chemical viscosity reduction effect of the oil-soluble viscosity reducer on heavy oil in the embodiment of the present application is based on the relationship curve between the viscosity of the oil-soluble viscosity reducer and the viscosity reduction effect. According to the initial viscosity of the heavy oil and the viscosity of the viscosity reducer, a suitable viscosity reducer can be selected for viscosity reduction, thereby improving the overall efficiency of the viscosity reducer selection.

[0055] 4. The method for predicting the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer in the examples of the present application provides strong support for further research on the viscosity reduction mechanism of the oil-soluble viscosity reducer and optimization of the viscosity reduction conditions of the oil-soluble viscosity reducer.

[0056] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a first flow chart of the method for predicting the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer in the embodiment of the present application;

[0058] Figure 2 is a second flow chart of the method for predicting the heavy oil chemical viscosity reducing effect of the oil-soluble viscosity reducing agent in the embodiment of the present application;

[0059] Figure 3 It is a curve diagram showing the relationship between the viscosity of the oil-soluble viscosity reducer and the actual viscosity reduction rate in the embodiment of the present application. DETAILED DESCRIPTION

[0060] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0061] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0062] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0063] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0064] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0065] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0066] It should be understood that the size of the serial numbers of the steps in the following embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0067] When considering the factors affecting the viscosity reduction effect of oil-soluble viscosity reducers, the molecular properties, molecular weight and viscosity of oil-soluble viscosity reducers may all be factors affecting their viscosity reduction effect, but it is difficult to evaluate the effect of one or more of them on the viscosity reduction effect of oil-soluble viscosity reducers through a relatively definite model. Therefore, how to simply and quickly evaluate the viscosity reduction effect of oil-soluble viscosity reducers and provide a basis for the selection of oil-soluble viscosity reducers has become a difficult problem that needs to be solved in this field.

[0068] The inventors found that when a variety of non-polar molecule oil-soluble viscosity reducers and polar molecule oil-soluble viscosity reducers are selected at the same time to reduce the viscosity of heavy oil, the molecular properties and molecular weight and other properties have little effect on the viscosity reduction effect of the viscosity reducer, and the correlation is small. However, the actual viscosity reduction rate of the oil-soluble viscosity reducer on the heavy oil has an obvious negative correlation with the viscosity of the corresponding oil-soluble viscosity reducer. Based on this change rule, the present invention provides a method for predicting the chemical viscosity reduction effect of the heavy oil of the oil-soluble viscosity reducer, so as to solve the technical problem of evaluating the viscosity reduction effect of the oil-soluble viscosity reducer that the technicians in this field have always wanted to solve but have never successfully solved.

[0069] The present application provides a method for predicting the chemical viscosity reduction effect of a heavy oil using an oil-soluble viscosity reducer, referring to Figure 1 The method for predicting the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer in the embodiment of the present application comprises the following steps:

[0070] Step S101: Obtain the viscosity and viscosity reduction rate of multiple oil-soluble viscosity reducers. Specifically, it includes:

[0071] The viscosity of various oil-soluble viscosity reducers was measured by rotational rheometer.

[0072] The initial viscosity of heavy oil is measured by a rotational rheometer. The initial viscosity of heavy oil can be measured by a paddle rotor rheometer.

[0073] A variety of oil-soluble viscosity reducers were screened, and several oil-soluble viscosity reducers with a viscosity range of 0.1 mPa·s to 100 mPa·s were screened. Specifically, a variety of oil-soluble viscosity reducers were screened according to the following conditions:

[0074] Select at least one group of oil-soluble viscosity reducers within the viscosity range of 0.1 mPa·s to 20 mPa·s;

[0075] Selecting at least one group of oil-soluble viscosity reducers within the viscosity range of 20 mPa·s to 50 mPa·s;

[0076] At least one group of oil-soluble viscosity reducers is selected within the viscosity range of 50 mPa·s to 100 mPa·s.

[0077] Each oil-soluble viscosity reducer is mixed with heavy oil according to a preset mass ratio to obtain a mixed system.

[0078] The viscosity of the mixed system formed by mixing each oil-soluble viscosity reducer with heavy oil was measured using a rotational rheometer.

[0079] According to the initial viscosity of the heavy oil, the viscosity of the oil-soluble viscosity reducer and the viscosity of the corresponding mixed system, the actual viscosity reduction rate of the oil-soluble viscosity reducer is calculated based on the following formula:

[0080] s = (ab) / a*100%;

[0081] Among them, s is the actual viscosity reduction rate of the oil-soluble viscosity reducer, a is the initial viscosity of the heavy oil, and b is the mixed system viscosity of the mixed system corresponding to the oil-soluble viscosity reducer.

[0082] Step S102: Constructing a relationship curve between the viscosity of the various oil-soluble viscosity reducers and the actual viscosity reduction rate. Based on the correlation between the viscosity of the oil-soluble viscosity reducer and the actual viscosity reduction rate, the relationship graph between the viscosity of the oil-soluble viscosity reducer and the actual viscosity reduction rate is constructed using EXCELL software, with the viscosity of the oil-soluble viscosity reducer as the abscissa and the actual viscosity reduction rate as the ordinate, and a trend line is added to obtain a relationship curve between the viscosity of the oil-soluble viscosity reducer and the actual viscosity reduction rate.

[0083] Step S103: Refer to Figure 3 , the relationship curve is fitted with data to obtain the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer. Specifically, the relationship curve can be fitted with data using a polynomial fitting method to obtain the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer.

[0084] Step S104: Substituting the viscosity of the oil-soluble viscosity reducer to be evaluated into the heavy oil chemical viscosity reduction effect prediction formula of the oil-soluble viscosity reducer to predict the viscosity reduction effect.

[0085] After obtaining the viscosity of the oil-soluble viscosity reducer to be tested, substituting it into the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer can predict the viscosity reduction rate of the oil-soluble viscosity reducer to be tested, and the operation method is simple.

[0086] It should be noted that, in this embodiment, the viscosity reduction effect is characterized by the viscosity reduction rate. When the viscosity reduction rate is larger, the viscosity reduction effect is better, and when the viscosity reduction rate is smaller, the viscosity reduction effect is worse.

[0087] In the embodiment of the present application, in order to ensure the accuracy of the formula, after obtaining the prediction formula for the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer, it can also be verified first. Only when the formula meets the requirements after verification can it be used to predict the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer.

[0088] Reference Figure 2 As shown, after obtaining the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer based on steps S101 to S103, the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer is verified by the following step S1031. The specific implementation process of step S1031 may include:

[0089] Substituting the viscosity of the oil-soluble viscosity reducer into the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer, the predicted viscosity reduction rate is calculated;

[0090] Calculate the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate.

[0091] Specifically, the relative deviation may be calculated based on the following formula according to the predicted viscosity reduction rate and the actual viscosity reduction rate:

[0092] r=|st| / s*100%;

[0093] Among them, r is the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate, s is the actual viscosity reduction rate, and t is the predicted viscosity reduction rate.

[0094] In order to more clearly describe the embodiments of the present application, the present application is described in detail through a specific embodiment.

[0095] First, the correlation analysis between the viscosity of the oil-soluble viscosity reducer and its viscosity reduction effect was carried out:

[0096] A variety of oil-soluble viscosity reducers including non-polar molecule oil-soluble viscosity reducers and polar molecule oil-soluble viscosity reducers are obtained. That is, the selected oil-soluble viscosity reducers should include both non-polar molecule oil-soluble viscosity reducers and polar molecule oil-soluble viscosity reducers. In order to improve the universality and accuracy of correlation analysis, in the selection process of non-polar molecule oil-soluble viscosity reducers, oil-soluble viscosity reducers of non-polar aliphatic alkanes and / or non-polar aromatic hydrocarbons are obtained; in the selection process of polar molecule oil-soluble viscosity reducers, oil-soluble viscosity reducers of at least one type of polar ester group, polar phenol group, and polar alcohol group are obtained. In other embodiments, the selection of oil-soluble viscosity reducers may also be other types, as long as their molecular properties and molecular weights are different.

[0097] When screening a variety of oil-soluble viscosity reducers in the range of 0.1mPa·s to 100mPa·s, five oil-soluble viscosity reducers were selected, including n-heptane (non-polar aliphatic alkane), toluene (non-polar aromatic hydrocarbon), n-pentylbenzene (non-polar aliphatic alkane), hexadecane (non-polar aliphatic alkane), and diisononyl phthalate (polar molecule) in the viscosity range of 0.1mPa·s to 20mPa·s; two oil-soluble viscosity reducers, including dodecyl rosin acid ester (polar molecule) and long-chain alkyl anthracene (non-polar aromatic hydrocarbon) were selected in the viscosity range of 20mPa·s to 50mPa·s; and one oil-soluble viscosity reducer, nonylphenol (polar molecule), was selected in the viscosity range of 50mPa·s to 100mPa·s. The corresponding molecular weights of n-heptane, toluene, n-pentylbenzene, hexadecane, diisononyl phthalate, long-chain alkyl anthracene, dodecyl rosin acid and nonylphenol are 100, 92, 148, 226, 418, 656, 456 and 220, respectively.

[0098] In this embodiment, each oil-soluble viscosity reducer is mixed with the same heavy oil. After measurement, the initial viscosity of the heavy oil used in this embodiment is 37260mPa·s. Of course, in other embodiments, due to the change of the type of heavy oil selected, its viscosity value also changes accordingly. It should be noted that when the viscosity of the heavy oil changes, the obtained prediction formula will also change. Therefore, for heavy oils with different viscosity values, the prediction formula needs to be obtained again through the above steps S101-S103. It should be noted that when different types of heavy oils are used for viscosity reduction experiments, the obtained prediction formula fitting correlation coefficients all meet greater than 0.99, which has a good correlation.

[0099] In this embodiment, when measuring the viscosity, since the viscosity is negatively correlated with the shear rate, the higher the shear rate, the smaller the viscosity measurement value. The viscosity of the commonly used oil-soluble viscosity reducer is generally low, so the measurement condition is a low shear rate of 7.34s -1 To avoid the viscosity value being too low, which would affect the accuracy of the measurement. When measuring heavy oil with a large viscosity value, a higher shear rate of 50s is selected. -1 .

[0100] When the heavy oil and the oil-soluble viscosity reducer are mixed, in this embodiment, the mass ratio of the oil-soluble viscosity reducer to the heavy oil is set to 1:10.

[0101] In this embodiment, according to the initial viscosity of the heavy oil, the viscosity of the oil-soluble viscosity reducer and the viscosity of the mixed system of the corresponding mixed system, the actual viscosity reduction rate of the oil-soluble viscosity reducer is calculated based on the following formula:

[0102] s = (ab) / a*100%;

[0103] Among them, s is the actual viscosity reduction rate of the oil-soluble viscosity reducer, a is the initial viscosity of the heavy oil, and b is the mixed system viscosity of the mixed system corresponding to the oil-soluble viscosity reducer.

[0104] Specifically, the measurement results of molecular weight, viscosity, heavy oil viscosity, mixed system viscosity and actual viscosity reduction rate are shown in the following table:

[0105] Table 1- Effect of different types of viscosity reducers on viscosity reduction of heavy oil

[0106]

[0107] According to the variation law of the actual viscosity reduction rate s in the table, the inventors found that when a variety of non-polar molecule oil-soluble viscosity reducers and polar molecule oil-soluble viscosity reducers are selected at the same time to reduce the viscosity of heavy oil, the molecular properties and molecular weight and other properties have little effect on the viscosity reduction effect of the viscosity reducer, and the correlation is small. However, the actual viscosity reduction rate of the oil-soluble viscosity reducer on the heavy oil has an obvious negative correlation with the viscosity of the corresponding oil-soluble viscosity reducer. Based on this variation law, the present invention provides a method for predicting the chemical viscosity reduction effect of heavy oil of an oil-soluble viscosity reducer, so as to solve the technical problem of evaluating the viscosity reduction effect of an oil-soluble viscosity reducer that those skilled in the art have always wanted to solve but have never successfully solved.

[0108] In the embodiment of the present invention, in order to obtain the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer, firstly, according to the viscosity and actual viscosity reduction rate of the eight oil-soluble viscosity reducers in Table 1, the relationship curves between the viscosity and the actual viscosity reduction rate of the various oil-soluble viscosity reducers are constructed; the relationship curves are fitted by the polynomial fitting method to obtain the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer:

[0109] y=0.009x 2 -1.1948x+96.887;

[0110] Among them, the fitting correlation coefficient R 2 =0.9918, greater than 0.99, with good correlation. y is the predicted viscosity reduction rate, and x is the viscosity of the oil-soluble viscosity reducer to be evaluated.

[0111] Next, the viscosities of the eight oil-soluble viscosity reducers in Table 1 were substituted into the prediction formula to obtain the predicted viscosity reduction rate, and then the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate was calculated to verify the accuracy of the prediction formula. It should be noted that the relative deviation was calculated based on the following formula according to the predicted viscosity reduction rate and the actual viscosity reduction rate of the oil-soluble viscosity reducer:

[0112] r=|st| / s*100%;

[0113] Among them, r is the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate of the oil-soluble viscosity reducer, s is the actual viscosity reduction rate of the oil-soluble viscosity reducer, and t is the predicted viscosity reduction rate of the oil-soluble viscosity reducer.

[0114] Specifically, the predicted viscosity reduction rate, actual viscosity reduction rate and relative deviation of each oil-soluble viscosity reducer are shown in the following table:

[0115] Table 2 - Actual viscosity reduction rate, predicted viscosity reduction rate and relative deviation of oil-soluble viscosity reducers for heavy oil

[0116]

[0117]

[0118] According to the contents of Table 2, the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate of each oil-soluble viscosity reducer is within 5%, indicating that the test data and the fitting formula are highly consistent.

[0119] Furthermore, this embodiment predicts the viscosity reduction rate of kerosene and a commercially available oil-soluble viscosity reducer based on the above-mentioned heavy oil chemical viscosity reduction effect prediction formula of the oil-soluble viscosity reducer.

[0120] First, the viscosity of kerosene and a commercially available oil-soluble viscosity reducer was measured, which were 1.14 mPa·s and 2.33 mPa·s respectively; then they were substituted into the prediction formula as x values:

[0121] y=0.009x 2 -1.1948x+96.887;

[0122] It is calculated that when the mass ratio of viscosity reducer to heavy oil is 1:10, the predicted viscosity reduction rates of the viscosity reducer are 95.54% and 94.15% respectively.

[0123] The two oil-soluble viscosity reducers were mixed with heavy oil at a preset mass ratio of 1:10, and the viscosity of the corresponding mixed systems was measured respectively; then, according to the viscosity of each oil-soluble viscosity reducer and the viscosity of the corresponding mixed system, the actual viscosity reduction rate was calculated according to the formula;

[0124] s = (ab) / a*100%;

[0125] The actual viscosity reduction rate of kerosene and a commercially available oil-soluble viscosity reducer was calculated; finally, the relative deviation was calculated using the formula:

[0126] r=|st| / s*100%;

[0127] The calculated relative deviations of the two oil-soluble viscosity reducers are 0.26% and 0.63%, respectively. See Table 3 for details:

[0128] Table 3- Prediction of viscosity reduction effect of two oil-soluble viscosity reducers on heavy oil

[0129]

[0130]

[0131] The results show that the predicted viscosity reduction rates of the two oil-soluble viscosity reducers are close to the actual viscosity reduction rates, and the relative standard deviation is less than 1%. This further verifies the accuracy of the above fitting equation in predicting the viscosity reduction effect of the oil-soluble viscosity reducer, which facilitates relevant personnel to select suitable viscosity reducers for viscosity reduction and improves the overall efficiency of viscosity reducer selection. In addition, the correlation between the viscosity and the viscosity reduction effect of the oil-soluble viscosity reducer in this application has guiding significance for further research on the viscosity reduction mechanism of the oil-soluble viscosity reducer and the optimization research on the viscosity reduction conditions of the oil-soluble viscosity reducer.

[0132] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", as explained by "including" used as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

Claims

1. A method for predicting the chemical viscosity reduction effect of heavy oil using an oil-soluble viscosity reducer, characterized in that: include: Obtain the viscosity and actual viscosity reduction rate of various oil-soluble viscosity reducers; Constructing relationship curves between the viscosity of the plurality of oil-soluble viscosity reducers and the actual viscosity reduction rate; The relationship curve is fitted with data to obtain a prediction formula for the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer; Substitute the viscosity of the oil-soluble viscosity reducer to be evaluated into the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer to obtain the corresponding predicted viscosity reduction rate.

2. The method for predicting the heavy oil chemical viscosity reducing effect of the oil-soluble viscosity reducer according to claim 1, characterized in that: The method of obtaining the viscosity and actual viscosity reduction rate of various oil-soluble viscosity reducers includes: Measuring and obtaining the initial viscosity of the heavy oil and the viscosity of the various oil-soluble viscosity reducers; Mixing each of the oil-soluble viscosity reducers with the heavy oil according to a preset mass ratio to obtain a mixed system; Measuring and obtaining the mixed system viscosity of the mixed system corresponding to each oil-soluble viscosity reducer; According to the initial viscosity of the heavy oil, the viscosity of each oil-soluble viscosity reducer and the corresponding mixed system viscosity of the mixed system, the actual viscosity reduction rate of each oil-soluble viscosity reducer is calculated.

3. The method for predicting the heavy oil chemical viscosity reducing effect of the oil-soluble viscosity reducer according to claim 2, characterized in that: The actual viscosity reduction rate of each oil-soluble viscosity reducer is calculated based on the initial viscosity of the heavy oil, the viscosity of each oil-soluble viscosity reducer and the corresponding mixed system viscosity of the mixed system, including: According to the initial viscosity of the heavy oil, the viscosity of the oil-soluble viscosity reducer and the viscosity of the corresponding mixed system, the actual viscosity reduction rate of the oil-soluble viscosity reducer is calculated based on the following formula: s = (ab) / a*100%; Among them, s is the actual viscosity reduction rate of the oil-soluble viscosity reducer, a is the initial viscosity of the heavy oil, and b is the mixed system viscosity of the mixed system corresponding to the oil-soluble viscosity reducer.

4. The method for predicting the heavy oil chemical viscosity reducing effect of the oil-soluble viscosity reducer according to claim 2, characterized in that: Before each of the oil-soluble viscosity reducers is mixed with the heavy oil in a preset mass ratio to obtain a mixed system, the method further includes: The plurality of oil-soluble viscosity reducers are screened to obtain a plurality of oil-soluble viscosity reducers with a viscosity range of 0.1 mPa·s to 100 mPa·s.

5. The method for predicting the heavy oil chemical viscosity reducing effect of the oil-soluble viscosity reducer according to claim 4, characterized in that: The method further comprises: screening the plurality of oil-soluble viscosity reducers according to the following conditions: Select at least one group of oil-soluble viscosity reducers within the viscosity range of 0.1 mPa·s to 20 mPa·s; Selecting at least one group of oil-soluble viscosity reducers within the viscosity range of 20 mPa·s to 50 mPa·s; At least one group of oil-soluble viscosity reducers is selected within the viscosity range of 50 mPa·s to 100 mPa·s.

6. The method for predicting the heavy oil chemical viscosity reducing effect of the oil-soluble viscosity reducer according to claim 2, characterized in that: Also includes: The initial viscosity of the heavy oil, the viscosity of the oil-soluble viscosity reducer and the corresponding viscosity of the mixed system are measured by a rotational rheometer.

7. The method for predicting the heavy oil chemical viscosity reducing effect of the oil-soluble viscosity reducer according to claim 1, characterized in that: Substituting the viscosity of the oil-soluble viscosity reducer to be evaluated into the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer to obtain the corresponding predicted viscosity reduction rate includes: Substitute the viscosity of the oil-soluble viscosity reducer to be evaluated into the following heavy oil chemical viscosity reduction effect prediction formula to obtain the predicted viscosity reduction rate: y=0.009x 2 -1.1948x+96.887; Among them, the fitting correlation coefficient R 2 =0.9918, y is the predicted viscosity reduction rate, and x is the viscosity of the oil-soluble viscosity reducer to be evaluated.

8. The method for predicting the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer according to claim 2, characterized in that: After performing data fitting on the relationship curve to obtain a prediction formula for the chemical viscosity reduction effect of the oil-soluble viscosity reducer on heavy oil, the method further includes verifying the prediction formula for the chemical viscosity reduction effect of the oil-soluble viscosity reducer on heavy oil.

9. The method for predicting the heavy oil chemical viscosity reducing effect of the oil-soluble viscosity reducer according to claim 8, characterized in that: The verification of the prediction formula for the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer includes: Substituting the viscosity of the oil-soluble viscosity reducer into the prediction formula of the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer to calculate the predicted viscosity reduction rate; The relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate is calculated.

10. The method for predicting the heavy oil chemical viscosity reduction effect of an oil-soluble viscosity reducer according to claim 9, characterized in that: The calculating of the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate includes: According to the predicted viscosity reduction rate and the actual viscosity reduction rate, the relative deviation is calculated based on the following formula: r=|st| / s*100%; Among them, r is the relative deviation between the predicted viscosity reduction rate and the actual viscosity reduction rate, s is the actual viscosity reduction rate, and t is the predicted viscosity reduction rate.

11. The method for predicting the heavy oil chemical viscosity reducing effect of an oil-soluble viscosity reducing agent according to claim 1, characterized in that: Before obtaining the viscosity and actual viscosity reduction rate of various oil-soluble viscosity reducers, it also includes: A variety of oil-soluble viscosity reducers are obtained, including non-polar molecule oil-soluble viscosity reducers and polar molecule oil-soluble viscosity reducers.

12. The method for predicting the heavy oil chemical viscosity reduction effect of the oil-soluble viscosity reducer according to claim 11, characterized in that: The method of obtaining a plurality of oil-soluble viscosity reducers including non-polar molecule oil-soluble viscosity reducers and polar molecule oil-soluble viscosity reducers includes: Obtaining an oil-soluble viscosity reducer of the type of non-polar aliphatic hydrocarbons and / or non-polar aromatic hydrocarbons, and, Obtain at least one type of oil-soluble viscosity reducer selected from the group consisting of polar ester-based, polar phenol-based, and polar alcohol-based.

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