Method for detecting concentration of polymer and viscoelastic particle oil displacement agent in heterogeneous system

Abstract

The invention discloses a method for detecting the concentration of a polymer and a viscoelastic particle oil-displacing agent in a heterogeneous system. The method comprises the following specific steps: (1) respectively preparing a polymer standard solution and a viscoelastic particle oil-displacing agent standard solution with different concentrations; (2) carrying out liquid chromatography determination; and (3) respectively obtaining the content of the polymer and the content of the viscoelastic particle oil-displacing agent according to results measured by the liquid chromatography. The method for detecting the concentration of the polymer and the viscoelastic particle oil-displacing agent in the heterogeneous system, disclosed by the invention, is rapid, simple and convenient, good in linear relation, wide in linear range, sensitive in detection and high in accuracy, and has obvious mine field application potential.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield chemical analysis, and in particular relates to a method for detecting the concentration of polymer and viscoelastic particle oil displacement agent in a heterogeneous system. Background Art

[0002] Generally, the use of oil layer energy to extract oil is called primary oil recovery. Injecting water and gas into the oil layer to replenish the energy of the oil layer to extract oil is called secondary oil recovery. Using chemical substances to improve the performance of oil, gas, water and rocks to extract more oil is called tertiary oil recovery. There are many methods to improve oil recovery in tertiary oil recovery, mainly including the following: injection of surfactants; injection of polymer thickened water; injection of alkaline water flooding; injection of CO2 flooding; polymer flooding; injection of inert gas flooding; injection of hydrocarbon miscible flooding; burning of oil layer; injection of steam flooding, etc. For example, Chinese patent application CN 1587341A discloses a new method for improving crude oil recovery by high-concentration polymer flooding, which is to improve crude oil recovery by injecting high-concentration polymer solution directly into the formation after water flooding, or injecting it into the formation after different stages of conventional polymer flooding (polymer concentration is less than 1500mg / l). For example, Chinese invention patent application CN 107448179A discloses a method for driving gas by alternating CO2-water injection and its application, the method comprising: injecting CO2 into the injection well, shutting down the production well, and increasing the reservoir pressure; when the production well returns to the original formation pressure, the well is opened for production, and gas is driven out by alternating CO2-water injection.

[0003] Normally, the overall recovery rate of oil reservoirs after polymer flooding is only about 50%, and about 50% of crude oil may be further mined. However, after polymer flooding, the heterogeneity of the reservoir becomes more serious, the coefficient of variation increases significantly, and the distribution of remaining oil becomes more dispersed. It is difficult to further improve the recovery rate with existing oil flooding methods.

[0004] Viscoelastic particle oil-displacing agent is a novel heterogeneous polymer oil-displacing agent with a partially cross-linked and partially branched structure. Its linear branched part is soluble in water, which increases the fluid mechanics volume and can provide excellent suspension performance and migration capacity. Its cross-linked network structure partially absorbs water and swells to form a strong and temperature-resistant and salt-resistant hydrogel skeleton. Through the plasticized cross-linked network within the branched chain, the water absorption capacity, shear resistance and deformation-recovery capacity of the particles are significantly improved. For example, Chinese patent application CN 114213594A proposes a preparation method and application of a heterogeneous oil-displacing system based on a temperature-resistant and salt-resistant viscoelastic particle oil-displacing agent, which belongs to the field of oil extraction, transportation and chemical technology. The heterogeneous oil-displacing system provided by the present invention is prepared step by step by a certain concentration of temperature-resistant and salt-resistant viscoelastic particle oil-displacing agent, a polyacrylamide emulsion and a nano oil-washing agent, wherein the temperature-resistant and salt-resistant viscoelastic particle oil-displacing agent is polymerized step by step with acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide as monomer molecules. The heterogeneous oil displacement system based on the temperature-resistant and salt-resistant viscoelastic granular oil displacement agent can still synergistically exert an excellent deep flooding effect in high-temperature and high-salt reservoirs, heterogeneous reservoirs and polymer flooding reservoirs with temperatures ≤90°C and total mineralization ≤32848 mg / L.

[0005] The structural characteristics of viscoelastic particle oil displacement agent make it have the dual advantages of linear polymer and cross-linked polymer in performance: it has the viscosity-increasing ability and migration ability in the formation of linear polymer, and the excellent temperature and salt resistance, aging resistance and ability to adjust the formation permeability of cross-linked polymer.

[0006] Under the guidance of the theory of additive synergistic effect of oil displacement agents, Shengli Oilfield carried out field tests on a heterogeneous composite oil displacement system of viscoelastic particle oil displacement agents, polymers and surfactants in response to reservoir conditions after polymer flooding. In order to accurately grasp the field application effect of heterogeneous composite flooding, it is necessary to conduct separate dynamic tracking and monitoring of the viscoelastic particle oil displacement agent and polymer concentrations in the on-site heterogeneous system.

[0007] However, the simplest method currently used to detect polymers in complex oil field systems is liquid chromatography. This method uses the principle of exclusion chromatography to separate polymers with ultra-large molecular weights from other small molecular interferences in the oil field system, such as salt, residual oil, surfactants, etc., and then detect the polymer. However, under the chromatographic conditions of this method, the chromatographic peaks of the viscoelastic particle oil displacement agent and the polymer are superimposed together, and only the total amount of the two in the heterogeneous system can be detected, but the viscoelastic particle oil displacement agent and the polymer cannot be detected separately, and the separate dynamic tracking and monitoring of the concentration of the viscoelastic particle oil displacement agent and the polymer in the heterogeneous system cannot be achieved. In addition, under the chromatographic conditions of this method, a customized chromatographic column is required, and a commercial chromatographic column cannot be used.

[0008] To this end, Zhu Yangwen published an article in Oilfield Chemistry in 2017 titled "A New Method for Detecting Viscoelastic Particle Displacement Agent PPG in Oilfield Produced Fluids" that proposed a sample pretreatment method, adding a crosslinker and a degelling agent to a heterogeneous system to precipitate the polymer from the solution, in order to eliminate the interference of the polymer when detecting viscoelastic particle displacement agents by liquid chromatography. However, this method still has the following shortcomings: 1. The operation process is cumbersome and time-consuming; 2. The amount of crosslinker and degelling agent added is difficult to accurately control, which poses a great obstacle to the practical application of the method, especially when detecting large quantities of samples.

[0009] Therefore, it is necessary to find a method that is easy to operate and can quickly detect the concentration of polymer and viscoelastic particle oil displacement agents in heterogeneous systems. This method has important guiding significance for further improving the accuracy and stability of dynamic monitoring data of heterogeneous systems in mines and ensuring the injection effect of mines. Summary of the invention

[0010] Purpose of the invention: In order to solve the problems existing in the above-mentioned prior art, the present invention provides a method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system. The method has fast analysis speed, simple operation, safety and reliability, and is particularly suitable for simultaneously detecting the concentration of viscoelastic particle oil-displacing agent and polymer in a heterogeneous system.

[0011] The present invention first adopts liquid chromatography, uses a C18 chromatographic column, sets mobile phase conditions, makes the chromatographic peaks of the viscoelastic particle oil-displacing agent and the polymer appear at the same time, detects the total concentration of the viscoelastic particle oil-displacing agent and the polymer in the heterogeneous system, and then uses a specific mobile phase ratio to make the chromatographic peaks of the linear part of the polymer and the viscoelastic particle oil-displacing agent not appear, and only the chromatographic peak of the cross-linked part of the viscoelastic particle oil-displacing agent appears, and according to the linear relationship between the chromatographic peak area of ​​the cross-linked part of the viscoelastic particle oil-displacing agent and the concentration of the viscoelastic particle oil-displacing agent, the concentration of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained, and the total concentration minus the concentration of the viscoelastic particle oil-displacing agent is the polymer concentration. In this way, the concentrations of the viscoelastic particle oil-displacing agent and the polymer in the heterogeneous system can be obtained respectively.

[0012] Technical solution: A method for detecting the concentration of polymer and viscoelastic particle oil displacement agent in a heterogeneous system, the specific steps are:

[0013] (1) respectively preparing polymer standard solutions and viscoelastic particle oil displacement agent standard solutions of different concentrations;

[0014] (2) Liquid chromatography determination:

[0015] (21) Drawing of standard working straight lines

[0016] (211), under chromatographic conditions i, the standard working straight line 1 of the viscoelastic particle oil displacement agent and the standard working straight line 2 of the polymer are drawn:

[0017] According to the chromatographic condition i, all the viscoelastic particle oil displacement agent standard solutions and polymer standard solutions of different concentrations obtained in step (1) are sampled respectively, and the standard working straight line 1 of the viscoelastic particle oil displacement agent is obtained with the corresponding chromatographic peak area as the ordinate and the viscoelastic particle oil displacement agent concentration as the abscissa, and

[0018] The corresponding chromatographic peak area is used as the ordinate and the polymer concentration is used as the abscissa to obtain the standard working straight line 2 of the polymer, where:

[0019] Under chromatographic conditions, the viscoelastic particle displacement agent and the polymer elute simultaneously;

[0020] The chromatographic analysis conditions i are:

[0021] Chromatographic column: commercial C18 column;

[0022] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 85 / 15 (v / v);

[0023] Mobile phase flow rate: 0.9~1.2mL / min;

[0024] Injection volume: 10-20 μL;

[0025] Column temperature: 20-25°C;

[0026] Detector: UV detector with a wavelength of 200nm to 205nm.

[0027] (212) Drawing of the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil displacement agent under chromatographic analysis condition ii:

[0028] According to the chromatographic condition ii, all the viscoelastic particle oil-displacing agent standard solutions of different concentrations obtained in step (1) are sampled, and the chromatographic peak area of ​​the cross-linked part of the viscoelastic particle oil-displacing agent is used as the ordinate, and the concentration of the viscoelastic particle oil-displacing agent is used as the abscissa to obtain the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent, wherein:

[0029] Under chromatographic condition ii, the viscoelastic particle oil-displacing agent emits a peak while the polymer does not, that is, the peak emitted by the viscoelastic particle oil-displacing agent is the chromatographic peak of the cross-linked part of the viscoelastic particle oil-displacing agent;

[0030] Chromatographic conditions ii are:

[0031] Chromatographic column: commercial C18 column;

[0032] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 92 / 8 (v / v);

[0033] Mobile phase flow rate: 0.9~1.2mL / min;

[0034] Injection volume: 10-20 μL;

[0035] Column temperature: 20-25°C;

[0036] Detector: UV detector with a wavelength of 200nm to 205nm.

[0037] (22) Heterogeneous system sample detection

[0038] (221), according to the above chromatographic condition i, the heterogeneous system sample enters the liquid chromatography detection to obtain the total chromatographic peak area Ai of the viscoelastic particle oil displacement agent and the polymer;

[0039] (222), according to the above chromatographic condition ii, the heterogeneous system sample is again subjected to liquid chromatography detection to obtain the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil displacement agent;

[0040] (3) The contents of the polymer and the viscoelastic particle oil-displacing agent are obtained according to the results of the liquid chromatography:

[0041] (31), the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil-displacing agent is brought into the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent under chromatographic condition ii, and the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained;

[0042] (32), the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is brought into the standard working straight line 1 of the viscoelastic particle oil-displacing agent under the chromatographic condition i, and the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained;

[0043] (33) subtracting the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system from the total chromatographic peak area Ai of the viscoelastic particle oil-displacing agent and the polymer in the heterogeneous system to obtain the chromatographic peak area A2 of the polymer in the heterogeneous system;

[0044] (34) The chromatographic peak area A2 of the polymer in the heterogeneous system is substituted into the standard working line 2 of the polymer under chromatographic condition i to obtain the concentration C2 of the polymer in the heterogeneous system sample.

[0045] Furthermore, the polymer in step (1) is polyacrylamide.

[0046] Furthermore, step (1) comprises the following steps:

[0047] (11) Prepare a polymer standard solution with a concentration of 250 mg / L;

[0048] (12) preparing a standard solution of viscoelastic particle oil displacement agent with a concentration of 250 mg / L;

[0049] (13) The polymer standard solution obtained in step (11) and the viscoelastic particle oil displacement agent standard solution obtained in step (12) are broken up by a homogenizer, and then the broken polymer standard solution and the viscoelastic particle oil displacement agent standard solution are diluted with simulated formation water to form polymer standard solutions of different concentrations and viscoelastic particle oil displacement agent standard solutions of different concentrations, respectively.

[0050] Furthermore, the specific steps of step (11) are:

[0051] (111), weigh 150 mL of simulated formation water into a container;

[0052] (112) Place the container on the stirrer, insert a magnetic stirring bar, and adjust the speed to 1500±250rpm;

[0053] (113) Weigh 0.0375 g of polymer, then add all the polymer into the container and stir continuously for at least 20 h to obtain a polymer standard solution with a concentration of 250 mg / L.

[0054] Furthermore, the specific steps of step (12) are:

[0055] (121), weigh 150 mL of simulated formation water into a container;

[0056] (122) Place the container on the stirrer, insert a magnetic stirring bar, and adjust the speed to 1500±250rpm;

[0057] (123) Weigh 0.0375 g of the viscoelastic particle oil-displacing agent, then add all of the viscoelastic particle oil-displacing agent into a container, and stir continuously for at least 20 h to obtain a viscoelastic particle oil-displacing agent standard solution with a concentration of 250 mg / L.

[0058] Furthermore, the homogenizer used in step (13) is an Aika homogenizer;

[0059] The polymer standard solution obtained in step (11) is crushed using an Aika homogenizer under the following conditions: crushing for 25 to 30 minutes at a rotation speed of 20,000 to 25,000 rpm;

[0060] The viscoelastic particle oil displacement agent standard solution obtained in step (12) is crushed using an Aika homogenizer at 20,000 to 25,000 revolutions per minute for 60 to 70 minutes.

[0061] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively;

[0062] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively.

[0063] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively;

[0064] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively.

[0065] Furthermore, in step (2), the chromatographic column model is Agilent ZORBAX Extend-C18, with a length of 250 mm, an inner diameter of 4.6 mm, a chromatographic column filler particle diameter of 5 μm, and a pore size of

[0066] Furthermore, in step (2), the mobile phase adopts isocratic elution.

[0067] The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system disclosed in the present invention has the following beneficial effects:

[0068] Taking advantage of the difference in the adsorption capacity of a standard commercial C18 column for polymer and viscoelastic particulate oil-displacing agents under different mobile phase conditions, a liquid chromatography method for the simultaneous separation and detection of polymer and viscoelastic particulate oil-displacing agents in a heterogeneous system was established by adjusting the ratio of acetonitrile / brine in 250 mM NaH2PO4 as the mobile phase.

[0069] The method is rapid and simple, has good linear relationship, wide linear range, sensitive detection, high accuracy, and has particularly obvious potential for practical application. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is a liquid chromatogram of a standard solution of a viscoelastic particle oil-displacing agent with a concentration of 50 mg / L under chromatographic condition i in Example 1 of the present invention.

[0071] Figure 2 This is a liquid chromatogram of a polymer standard solution with a concentration of 50 mg / L under chromatographic condition i in Example 1 of the present invention.

[0072] Figure 3It is the standard working straight line 1 of the viscoelastic particle oil-displacing agent under the chromatographic condition i in Example 1 of the present invention.

[0073] Figure 4 It is the standard working straight line 2 of the polymer under the chromatographic condition i in Example 1 of the present invention.

[0074] Figure 5 This is a liquid chromatogram of a standard solution of a viscoelastic particle oil-displacing agent with a concentration of 50 mg / L under chromatographic condition ii in Example 1 of the present invention.

[0075] Figure 6 It is the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent under the chromatographic condition ii in Example 1 of the present invention.

[0076] Figure 7 This is the liquid chromatogram of the heterogeneous system sample 1 under the chromatographic condition i in Example 1 of the present invention.

[0077] Figure 8 This is the liquid chromatogram of the heterogeneous system sample 2 under the chromatographic condition i in Example 1 of the present invention.

[0078] Fig. 9 This is the liquid chromatogram of the heterogeneous system sample 3 under the chromatographic condition i in Example 1 of the present invention.

[0079] Fig.10 This is the liquid chromatogram of the heterogeneous system sample 1 under the chromatographic condition ii in Example 1 of the present invention.

[0080] Fig.11 This is the liquid chromatogram of the heterogeneous system sample 2 under the chromatographic condition ii in Example 1 of the present invention.

[0081] Fig.12 This is the liquid chromatogram of the heterogeneous system sample 3 under the chromatographic condition ii in Example 1 of the present invention.

[0082] Fig.13 The present invention is a schematic flow chart of a method for detecting the concentration of polymer and viscoelastic particle oil displacement agent in a heterogeneous system. Specific implementation method:

[0083] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0084] In this application:

[0085] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 85 / 15 (v / v) means:

[0086] 85 parts by volume of a 250 mM NaH2PO4 aqueous solution and 15 parts by volume of acetonitrile were mixed as the mobile phase.

[0087] Example 1

[0088] The method for detecting the concentration of polymer and viscoelastic particle oil displacement agent in a heterogeneous system comprises the following specific steps:

[0089] (1) Prepare polymer standard solutions and viscoelastic particle oil displacement agent standard solutions of different concentrations respectively.

[0090] (11) Prepare a polymer standard solution with a concentration of 250 mg / L;

[0091] (12) preparing a standard solution of viscoelastic particle oil displacement agent with a concentration of 250 mg / L;

[0092] (13) The polymer standard solution obtained in step (11) and the viscoelastic particle oil displacement agent standard solution obtained in step (12) are broken up by a homogenizer, and then the broken polymer standard solution and the viscoelastic particle oil displacement agent standard solution are diluted with simulated formation water to form polymer standard solutions of different concentrations and viscoelastic particle oil displacement agent standard solutions of different concentrations, respectively.

[0093] Wherein: the specific steps of step (11) are:

[0094] (111), weigh 150 mL of simulated formation water into a container;

[0095] (112) Place the container on a stirrer, insert a magnetic stirring bar, and adjust the speed to 1500 rpm;

[0096] (113) Weigh 0.0375 g of polymer, then add all the polymer into the container and stir continuously for 24 h to obtain a polymer standard solution with a concentration of 250 mg / L.

[0097] Furthermore, the specific steps of step (12) are:

[0098] (121), weigh 150 mL of simulated formation water into a container;

[0099] (122) Place the container on a stirrer, insert a magnetic stirring bar, and adjust the speed to 1500 rpm;

[0100] (123) Weigh 0.0375 g of viscoelastic particle oil-displacing agent, then add all of the viscoelastic particle oil-displacing agent into a container, and stir continuously for 24 h to obtain a viscoelastic particle oil-displacing agent standard solution with a concentration of 250 mg / L.

[0101] Furthermore, the homogenizer used in step (13) is an Aika homogenizer;

[0102] The polymer standard solution obtained in step (11) is crushed using an Aika homogenizer under the following conditions: crushing for 25 minutes at a rotation speed of 20,000 rpm;

[0103] The viscoelastic particle oil displacement agent standard solution obtained in step (12) is crushed using an Aika homogenizer at 20,000 rpm for 60 minutes.

[0104] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively;

[0105] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively.

[0106] (2) Liquid chromatography determination

[0107] (21) Drawing of standard working straight lines

[0108] (211) Drawing of the standard working straight line 1 of the viscoelastic particle oil displacement agent and the standard working straight line 2 of the polymer under chromatographic conditions i:

[0109] Chromatographic analysis conditions i: Agilent 1100 liquid chromatograph, Agilent ZORBAX Extend-C18 (4.6 mm × 250 mm, 5 μm, );

[0110] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 85 / 15 (v / v), isocratic elution;

[0111] Flow rate: 1.0 mL / min;

[0112] Detector: UV detector 200nm; injection volume: 20μL; column temperature: 25℃;

[0113] According to the above chromatographic condition i, all viscoelastic particle oil displacement agent standard solutions and polymer standard solutions of different concentrations were injected respectively, and the standard working straight line 1 of the viscoelastic particle oil displacement agent was obtained with the corresponding chromatographic peak area as the ordinate and the viscoelastic particle oil displacement agent concentration as the abscissa (such as Figure 3 shown), and

[0114] The corresponding chromatographic peak area is used as the ordinate and the polymer concentration is used as the abscissa to obtain the standard working straight line 2 of the polymer (such as Figure 4 ), where:

[0115] Under the chromatographic conditions, the viscoelastic particle displacement agent and the polymer elute simultaneously.

[0116] Figure 1 This is a liquid chromatogram of a standard solution of a viscoelastic particle oil-displacing agent with a concentration of 50 mg / L under chromatographic condition i in Example 1 of the present invention. Figure 2 This is a liquid chromatogram of a polymer standard solution with a concentration of 50 mg / L under chromatographic condition i in Example 1 of the present invention. (The chromatographic peak with a retention time of 1.6 min is the quantitative chromatographic peak of the polymer).

[0117] (212) Drawing of the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil displacement agent under chromatographic analysis condition ii:

[0118] Chromatographic analysis conditions ii: Agilent 1100 liquid chromatograph, Agilent ZORBAX Extend-C18 (4.6 mm × 250 mm, 5 μm, ); mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 92 / 8 (v / v), isocratic elution; flow rate: 1.0 mL / min; detection wavelength: 200 nm; injection volume: 20 μL; detector: UV detector; column temperature: 25°C.

[0119] According to the above chromatographic condition ii, all the viscoelastic particle oil-displacing agent standard solutions of different concentrations obtained in step (1) were sampled, and the chromatographic peak area of ​​the cross-linked part of the viscoelastic particle oil-displacing agent was used as the ordinate, and the concentration of the viscoelastic particle oil-displacing agent was used as the abscissa to obtain the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent (such as Figure 6 (shown)

[0120] Figure 5 The liquid chromatogram of a standard solution of a viscoelastic particle oil-displacing agent with a concentration of 50 mg / L under chromatographic condition ii in Example 1 of the present invention (wherein the chromatographic peak with a retention time of 1.6 min is the quantitative chromatographic peak of the cross-linked portion of the viscoelastic particle oil-displacing agent).

[0121] (22) Heterogeneous system sample detection

[0122] According to the above chromatographic condition i, heterogeneous system sample 1, heterogeneous system sample 2, and heterogeneous system sample 3 were injected respectively. The specific results are as follows Figures 7 to 9 shown. Figure 7 , Figure 8 , Fig. 9They are the liquid chromatograms of heterogeneous system sample 1, heterogeneous system sample 2, and heterogeneous system sample 3, respectively, wherein the chromatographic peak with a retention time of 1.6 min is the quantitative chromatographic peak of the polymer, and the peak areas are 578.9, 1217, and 566.6, respectively.

[0123] According to the above chromatographic condition ii, heterogeneous system sample 1, heterogeneous system sample 2, and heterogeneous system sample 3 were injected respectively. The specific results are as follows Figures 10-12 shown. Fig.10 , Fig.11 , Fig.12 They are the liquid chromatograms of heterogeneous system sample 1, heterogeneous system sample 2, and heterogeneous system sample 3, respectively, wherein the chromatographic peak with a retention time of 1.6 min is the quantitative chromatographic peak of the cross-linked part of the viscoelastic particle oil displacement agent, and the peak areas are 10.2, 116.4, and 20.3, respectively.

[0124] (3) The contents of the polymer and the viscoelastic particle oil-displacing agent are obtained according to the results of the liquid chromatography:

[0125] The chromatographic peak areas of the cross-linked structure of the viscoelastic particle oil-displacing agent of heterogeneous system sample 1, heterogeneous system sample 2, and heterogeneous system sample 3 are 10.2, 116.4, and 20.3, respectively, and are respectively brought into the working straight line of the cross-linked structure of the viscoelastic particle oil-displacing agent under chromatographic condition ii, Y=3.5496X-19.205, and the concentrations of the viscoelastic particle oil-displacing agent in the heterogeneous system sample 1, the heterogeneous system sample 2, and the heterogeneous system sample 3 are obtained to be 8.3 mg / L, 38.2 mg / L, and 11.1 mg / L, respectively;

[0126] When 8.3 mg / L, 38.2 mg / L and 11.1 mg / L are respectively introduced into the working straight line Y=11.903X+55.707 of the viscoelastic particle oil displacement agent standard solution under chromatographic condition i, the chromatographic peak areas corresponding to the viscoelastic particle oil displacement agent in heterogeneous system sample 1, heterogeneous system sample 2 and heterogeneous system sample 3 are obtained as 154.3, 510.4 and 187.8;

[0127] The total chromatographic peak areas of the viscoelastic particle displacement agent and the polymer in the heterogeneous system sample are 578.9, 1217, and 566.6, respectively, minus 154.3, 510.4, and 187.8, to obtain the chromatographic peak areas of the polymer in the heterogeneous system sample 1, the heterogeneous system sample 2, and the heterogeneous system sample 3, which are 198.2, 706.6, and 378.8;

[0128] When 198.2, 706.6, and 378.8 are substituted into the chromatographic condition i, the working straight line of the polymer standard solution is Y=12.185X+9.8139, and the concentrations of the polymers in the heterogeneous system sample 1, the heterogeneous system sample 2, and the heterogeneous system sample 3 are obtained as 15.5 mg / L, 57.2 mg / L, and 30.3 mg / L, respectively.

[0129] Example 2

[0130] The method for detecting the concentration of polymer and viscoelastic particle oil displacement agent in a heterogeneous system comprises the following specific steps:

[0131] (1) respectively preparing polymer standard solutions and viscoelastic particle oil displacement agent standard solutions of different concentrations;

[0132] (2) Liquid chromatography determination:

[0133] (21) Drawing of standard working straight lines

[0134] (211), under chromatographic conditions i, the standard working straight line 1 of the viscoelastic particle oil displacement agent and the standard working straight line 2 of the polymer are drawn:

[0135] According to the chromatographic condition i, all the viscoelastic particle oil displacement agent standard solutions and polymer standard solutions of different concentrations obtained in step (1) are sampled respectively, and the standard working straight line 1 of the viscoelastic particle oil displacement agent is obtained with the corresponding chromatographic peak area as the ordinate and the viscoelastic particle oil displacement agent concentration as the abscissa, and

[0136] The corresponding chromatographic peak area is used as the ordinate and the polymer concentration is used as the abscissa to obtain the standard working straight line 2 of the polymer, where:

[0137] Under chromatographic conditions, the viscoelastic particle displacement agent and the polymer elute simultaneously;

[0138] The chromatographic analysis conditions i are:

[0139] Chromatographic column: commercial C18 column;

[0140] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 85 / 15 (v / v);

[0141] Mobile phase flow rate: 0.9 mL / min;

[0142] Injection volume: 10 μL;

[0143] Column temperature: 20°C;

[0144] Detector: UV detector with a wavelength of 200 nm.

[0145] (212) Drawing of the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil displacement agent under chromatographic analysis condition ii:

[0146] According to the chromatographic condition ii, all the viscoelastic particle oil-displacing agent standard solutions of different concentrations obtained in step (1) are sampled, and the chromatographic peak area of ​​the cross-linked part of the viscoelastic particle oil-displacing agent is used as the ordinate, and the concentration of the viscoelastic particle oil-displacing agent is used as the abscissa to obtain the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent, wherein:

[0147] Under chromatographic condition ii, the viscoelastic particle oil-displacing agent emits a peak while the polymer does not, that is, the peak emitted by the viscoelastic particle oil-displacing agent is the chromatographic peak of the cross-linked part of the viscoelastic particle oil-displacing agent;

[0148] Chromatographic conditions ii are:

[0149] Chromatographic column: commercial C18 column;

[0150] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 92 / 8 (v / v);

[0151] Mobile phase flow rate: 0.9 mL / min;

[0152] Injection volume: 10 μL;

[0153] Column temperature: 20°C;

[0154] Detector: UV detector with a wavelength of 200 nm.

[0155] (22) Heterogeneous system sample detection

[0156] (221), according to the above chromatographic condition i, the heterogeneous system sample enters the liquid chromatography detection to obtain the total chromatographic peak area Ai of the viscoelastic particle oil displacement agent and the polymer;

[0157] (222), according to the above chromatographic condition ii, the heterogeneous system sample is again subjected to liquid chromatography detection to obtain the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil displacement agent;

[0158] (3) The contents of the polymer and the viscoelastic particle oil-displacing agent are obtained according to the results of the liquid chromatography:

[0159] (31), the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil-displacing agent is brought into the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent under chromatographic condition ii, and the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained;

[0160] (32), the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is brought into the standard working straight line 1 of the viscoelastic particle oil-displacing agent under the chromatographic condition i, and the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained;

[0161] (33) subtracting the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system from the total chromatographic peak area Ai of the viscoelastic particle oil-displacing agent and the polymer in the heterogeneous system to obtain the chromatographic peak area A2 of the polymer in the heterogeneous system;

[0162] (34) The chromatographic peak area A2 of the polymer in the heterogeneous system is substituted into the standard working line 2 of the polymer under chromatographic condition i to obtain the concentration C2 of the polymer in the heterogeneous system sample.

[0163] Furthermore, the polymer in step (1) is polyacrylamide.

[0164] Furthermore, step (1) comprises the following steps:

[0165] (11) Prepare a polymer standard solution with a concentration of 250 mg / L;

[0166] (12) preparing a standard solution of viscoelastic particle oil displacement agent with a concentration of 250 mg / L;

[0167] (13) The polymer standard solution obtained in step (11) and the viscoelastic particle oil displacement agent standard solution obtained in step (12) are broken up by a homogenizer, and then the broken polymer standard solution and the viscoelastic particle oil displacement agent standard solution are diluted with simulated formation water to form polymer standard solutions of different concentrations and viscoelastic particle oil displacement agent standard solutions of different concentrations, respectively.

[0168] Furthermore, the specific steps of step (11) are:

[0169] (111), weigh 150 mL of simulated formation water into a container;

[0170] (112), place the container on the stirrer, insert a magnetic stirring bar, and adjust the speed to 1250 rpm;

[0171] (113) Weigh 0.0375 g of polymer, then add all the polymer into the container and stir continuously for 20 h to obtain a polymer standard solution with a concentration of 250 mg / L.

[0172] Furthermore, the specific steps of step (12) are:

[0173] (121), weigh 150 mL of simulated formation water into a container;

[0174] (122), place the container on the stirrer, insert a magnetic stirring bar, and adjust the speed to 1250 rpm;

[0175] (123) Weigh 0.0375 g of viscoelastic particle oil-displacing agent, then add all of the viscoelastic particle oil-displacing agent into a container, and stir continuously for 20 h to obtain a viscoelastic particle oil-displacing agent standard solution with a concentration of 250 mg / L.

[0176] Furthermore, the homogenizer used in step (13) is an Aika homogenizer;

[0177] The polymer standard solution obtained in step (11) is crushed using an Aika homogenizer under the following conditions: crushing for 30 minutes at a speed of 20,000 rpm;

[0178] The viscoelastic particle oil displacement agent standard solution obtained in step (12) is crushed using an Aika homogenizer at 20,000 rpm for 70 minutes.

[0179] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively;

[0180] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively.

[0181] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively;

[0182] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively.

[0183] Furthermore, in step (2), the chromatographic column model is Agilent ZORBAX Extend-C18, with a length of 250 mm, an inner diameter of 4.6 mm, a chromatographic column filler particle diameter of 5 μm, and a pore size of

[0184] Furthermore, in step (2), the mobile phase adopts isocratic elution.

[0185] Example 3

[0186] The method for detecting the concentration of polymer and viscoelastic particle oil displacement agent in a heterogeneous system comprises the following specific steps:

[0187] (1) respectively preparing polymer standard solutions and viscoelastic particle oil displacement agent standard solutions of different concentrations;

[0188] (2) Liquid chromatography determination:

[0189] (21) Drawing of standard working straight lines

[0190] (211), under chromatographic conditions i, the standard working straight line 1 of the viscoelastic particle oil displacement agent and the standard working straight line 2 of the polymer are drawn:

[0191] According to the chromatographic condition i, all the viscoelastic particle oil displacement agent standard solutions and polymer standard solutions of different concentrations obtained in step (1) are sampled respectively, and the standard working straight line 1 of the viscoelastic particle oil displacement agent is obtained with the corresponding chromatographic peak area as the ordinate and the viscoelastic particle oil displacement agent concentration as the abscissa, and

[0192] The corresponding chromatographic peak area is used as the ordinate and the polymer concentration is used as the abscissa to obtain the standard working straight line 2 of the polymer, where:

[0193] Under chromatographic conditions, the viscoelastic particle displacement agent and the polymer elute simultaneously;

[0194] The chromatographic analysis conditions i are:

[0195] Chromatographic column: commercial C18 column;

[0196] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 85 / 15 (v / v);

[0197] Mobile phase flow rate: 1.2 mL / min;

[0198] Injection volume: 20 μL;

[0199] Column temperature: 25°C;

[0200] Detector: UV detector with a wavelength of 205 nm.

[0201] (212) Drawing of the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil displacement agent under chromatographic analysis condition ii:

[0202] According to the chromatographic condition ii, all the viscoelastic particle oil-displacing agent standard solutions of different concentrations obtained in step (1) are sampled, and the chromatographic peak area of ​​the cross-linked part of the viscoelastic particle oil-displacing agent is used as the ordinate, and the concentration of the viscoelastic particle oil-displacing agent is used as the abscissa to obtain the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent, wherein:

[0203] Under chromatographic condition ii, the viscoelastic particle oil-displacing agent emits a peak while the polymer does not, that is, the peak emitted by the viscoelastic particle oil-displacing agent is the chromatographic peak of the cross-linked part of the viscoelastic particle oil-displacing agent;

[0204] Chromatographic conditions ii are:

[0205] Chromatographic column: commercial C18 column;

[0206] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 92 / 8 (v / v);

[0207] Mobile phase flow rate: 1.2 mL / min;

[0208] Injection volume: 20 μL;

[0209] Column temperature: 25°C;

[0210] Detector: UV detector with a wavelength of 205 nm.

[0211] (22) Heterogeneous system sample detection

[0212] (221), according to the above chromatographic condition i, the heterogeneous system sample enters the liquid chromatography detection to obtain the total chromatographic peak area Ai of the viscoelastic particle oil displacement agent and the polymer;

[0213] (222), according to the above chromatographic condition ii, the heterogeneous system sample is again subjected to liquid chromatography detection to obtain the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil displacement agent;

[0214] (3) The contents of the polymer and the viscoelastic particle oil-displacing agent are obtained according to the results of the liquid chromatography:

[0215] (31), the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil-displacing agent is brought into the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent under chromatographic condition ii, and the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained;

[0216] (32), the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is brought into the standard working straight line 1 of the viscoelastic particle oil-displacing agent under the chromatographic condition i, and the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained;

[0217] (33) subtracting the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system from the total chromatographic peak area Ai of the viscoelastic particle oil-displacing agent and the polymer in the heterogeneous system to obtain the chromatographic peak area A2 of the polymer in the heterogeneous system;

[0218] (34) The chromatographic peak area A2 of the polymer in the heterogeneous system is substituted into the standard working line 2 of the polymer under chromatographic condition i to obtain the concentration C2 of the polymer in the heterogeneous system sample.

[0219] Furthermore, the polymer in step (1) is polyacrylamide.

[0220] Furthermore, step (1) comprises the following steps:

[0221] (11) Prepare a polymer standard solution with a concentration of 250 mg / L;

[0222] (12) preparing a standard solution of viscoelastic particle oil displacement agent with a concentration of 250 mg / L;

[0223] (13) The polymer standard solution obtained in step (11) and the viscoelastic particle oil displacement agent standard solution obtained in step (12) are broken up by a homogenizer, and then the broken polymer standard solution and the viscoelastic particle oil displacement agent standard solution are diluted with simulated formation water to form polymer standard solutions of different concentrations and viscoelastic particle oil displacement agent standard solutions of different concentrations, respectively.

[0224] Furthermore, the specific steps of step (11) are:

[0225] (111), weigh 150 mL of simulated formation water into a container;

[0226] (112) Place the container on a stirrer, insert a magnetic stirring bar, and adjust the speed to 1750 rpm;

[0227] (113) Weigh 0.0375 g of polymer, then add all the polymer into the container and stir continuously for 24 h to obtain a polymer standard solution with a concentration of 250 mg / L.

[0228] Furthermore, the specific steps of step (12) are:

[0229] (121), weigh 150 mL of simulated formation water into a container;

[0230] (122) Place the container on a stirrer, insert a magnetic stirring bar, and adjust the speed to 1750 rpm;

[0231] (123) Weigh 0.0375 g of viscoelastic particle oil-displacing agent, then add all of the viscoelastic particle oil-displacing agent into a container, and stir continuously for 24 h to obtain a viscoelastic particle oil-displacing agent standard solution with a concentration of 250 mg / L.

[0232] Furthermore, the homogenizer used in step (13) is an Aika homogenizer;

[0233] The polymer standard solution obtained in step (11) is crushed using an Aika homogenizer under the following conditions: crushing for 25 minutes at a rotation speed of 25,000 rpm;

[0234] The viscoelastic particle oil displacement agent standard solution obtained in step (12) is crushed using an Aika homogenizer at 25,000 rpm for 60 minutes.

[0235] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively;

[0236] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively.

[0237] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively;

[0238] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively.

[0239] Furthermore, in step (2), the chromatographic column model is Agilent ZORBAX Extend-C18, with a length of 250 mm, an inner diameter of 4.6 mm, a chromatographic column filler particle diameter of 5 μm, and a pore size of

[0240] Furthermore, in step (2), the mobile phase adopts isocratic elution.

[0241] Example 4

[0242] The method for detecting the concentration of polymer and viscoelastic particle oil displacement agent in a heterogeneous system comprises the following specific steps:

[0243] (1) respectively preparing polymer standard solutions and viscoelastic particle oil displacement agent standard solutions of different concentrations;

[0244] (2) Liquid chromatography determination:

[0245] (21) Drawing of standard working straight lines

[0246] (211), under chromatographic conditions i, the standard working straight line 1 of the viscoelastic particle oil displacement agent and the standard working straight line 2 of the polymer are drawn:

[0247] According to the chromatographic condition i, all the viscoelastic particle oil displacement agent standard solutions and polymer standard solutions of different concentrations obtained in step (1) are sampled respectively, and the standard working straight line 1 of the viscoelastic particle oil displacement agent is obtained with the corresponding chromatographic peak area as the ordinate and the viscoelastic particle oil displacement agent concentration as the abscissa, and

[0248] The corresponding chromatographic peak area is used as the ordinate and the polymer concentration is used as the abscissa to obtain the standard working straight line 2 of the polymer, where:

[0249] Under chromatographic conditions, the viscoelastic particle displacement agent and the polymer elute simultaneously;

[0250] The chromatographic analysis conditions i are:

[0251] Chromatographic column: commercial C18 column;

[0252] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 85 / 15 (v / v);

[0253] Mobile phase flow rate: 1 mL / min;

[0254] Injection volume: 15 μL;

[0255] Column temperature: 22°C;

[0256] Detector: UV detector with a wavelength of 203 nm.

[0257] (212) Drawing of the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil displacement agent under chromatographic analysis condition ii:

[0258] According to the chromatographic condition ii, all the viscoelastic particle oil-displacing agent standard solutions of different concentrations obtained in step (1) are sampled, and the chromatographic peak area of ​​the cross-linked part of the viscoelastic particle oil-displacing agent is used as the ordinate, and the concentration of the viscoelastic particle oil-displacing agent is used as the abscissa to obtain the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent, wherein:

[0259] Under chromatographic condition ii, the viscoelastic particle oil-displacing agent emits a peak while the polymer does not, that is, the peak emitted by the viscoelastic particle oil-displacing agent is the chromatographic peak of the cross-linked part of the viscoelastic particle oil-displacing agent;

[0260] Chromatographic conditions ii are:

[0261] Chromatographic column: commercial C18 column;

[0262] Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 92 / 8 (v / v);

[0263] Mobile phase flow rate: 1 mL / min;

[0264] Injection volume: 15 μL;

[0265] Column temperature: 22°C;

[0266] Detector: UV detector with a wavelength of 203 nm.

[0267] (22) Heterogeneous system sample detection

[0268] (221), according to the above chromatographic condition i, the heterogeneous system sample enters the liquid chromatography detection to obtain the total chromatographic peak area Ai of the viscoelastic particle oil displacement agent and the polymer;

[0269] (222), according to the above chromatographic condition ii, the heterogeneous system sample is again subjected to liquid chromatography detection to obtain the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil displacement agent;

[0270] (3) The contents of the polymer and the viscoelastic particle oil-displacing agent are obtained according to the results of the liquid chromatography:

[0271] (31), the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil-displacing agent is brought into the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent under chromatographic condition ii, and the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained;

[0272] (32), the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is brought into the standard working straight line 1 of the viscoelastic particle oil-displacing agent under the chromatographic condition i, and the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained;

[0273] (33) subtracting the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system from the total chromatographic peak area Ai of the viscoelastic particle oil-displacing agent and the polymer in the heterogeneous system to obtain the chromatographic peak area A2 of the polymer in the heterogeneous system;

[0274] (34) The chromatographic peak area A2 of the polymer in the heterogeneous system is substituted into the standard working line 2 of the polymer under chromatographic condition i to obtain the concentration C2 of the polymer in the heterogeneous system sample.

[0275] Furthermore, the polymer in step (1) is polyacrylamide.

[0276] Furthermore, step (1) comprises the following steps:

[0277] (11) Prepare a polymer standard solution with a concentration of 250 mg / L;

[0278] (12) preparing a standard solution of viscoelastic particle oil displacement agent with a concentration of 250 mg / L;

[0279] (13) The polymer standard solution obtained in step (11) and the viscoelastic particle oil displacement agent standard solution obtained in step (12) are broken up by a homogenizer, and then the broken polymer standard solution and the viscoelastic particle oil displacement agent standard solution are diluted with simulated formation water to form polymer standard solutions of different concentrations and viscoelastic particle oil displacement agent standard solutions of different concentrations, respectively.

[0280] Furthermore, the specific steps of step (11) are:

[0281] (111), weigh 150 mL of simulated formation water into a container;

[0282] (112) Place the container on a stirrer, insert a magnetic stirring bar, and adjust the speed to 1500 rpm;

[0283] (113) Weigh 0.0375 g of polymer, then add all the polymer into the container and stir continuously for 36 h to obtain a polymer standard solution with a concentration of 250 mg / L.

[0284] Furthermore, the specific steps of step (12) are:

[0285] (121), weigh 150 mL of simulated formation water into a container;

[0286] (122) Place the container on a stirrer, insert a magnetic stirring bar, and adjust the speed to 1500 rpm;

[0287] (123) Weigh 0.0375 g of viscoelastic particle oil-displacing agent, then add all of the viscoelastic particle oil-displacing agent into a container, and stir continuously for 36 h to obtain a viscoelastic particle oil-displacing agent standard solution with a concentration of 250 mg / L.

[0288] Furthermore, the homogenizer used in step (13) is an Aika homogenizer;

[0289] The polymer standard solution obtained in step (11) is crushed using an Aika homogenizer under the following conditions: crushing for 27 minutes at a speed of 22,000 rpm;

[0290] The viscoelastic particle oil displacement agent standard solution obtained in step (12) is crushed using an Aika homogenizer at 22,000 rpm for 65 minutes.

[0291] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively;

[0292] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively.

[0293] Further, the concentrations of the polymer standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively;

[0294] The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively.

[0295] Furthermore, in step (2), the chromatographic column model is Agilent ZORBAX Extend-C18, with a length of 250 mm, an inner diameter of 4.6 mm, a chromatographic column filler particle diameter of 5 μm, and a pore size of

[0296] Furthermore, in step (2), the mobile phase adopts isocratic elution.

[0297] The above describes the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A method for detecting the concentration of polymer and viscoelastic particle oil displacement agent in a heterogeneous system, characterized in that: The specific steps are: (1) respectively preparing polymer standard solutions and viscoelastic particle oil displacement agent standard solutions of different concentrations; (2) Liquid chromatography determination: (21) Drawing of standard working straight lines; (22) Heterogeneous system sample detection; (3) The contents of the polymer and the viscoelastic particle oil-displacing agent are respectively obtained according to the results of the liquid chromatography.

2. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system as claimed in claim 1, characterized in that: Step (21) comprises the following steps: (211), under chromatographic conditions i, the standard working straight line 1 of the viscoelastic particle oil displacement agent and the standard working straight line 2 of the polymer are drawn: According to the chromatographic condition i, all the viscoelastic particle oil displacement agent standard solutions and polymer standard solutions of different concentrations obtained in step (1) are sampled respectively, and the standard working straight line 1 of the viscoelastic particle oil displacement agent is obtained with the corresponding chromatographic peak area as the ordinate and the viscoelastic particle oil displacement agent concentration as the abscissa, and The corresponding chromatographic peak area is used as the ordinate and the polymer concentration is used as the abscissa to obtain the standard working straight line 2 of the polymer, where: Under chromatographic conditions, the viscoelastic particle displacement agent and the polymer elute simultaneously; The chromatographic analysis conditions i are: Chromatographic column: commercial C18 column; Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 85 / 15 (v / v); Mobile phase flow rate: 0.9~1.2mL / min; Injection volume: 10-20 μL; Column temperature: 20-25°C; Detector: UV detector with wavelength of 200nm~205nm; (212) Drawing of the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil displacement agent under chromatographic analysis condition ii: According to the chromatographic condition ii, all the viscoelastic particle oil-displacing agent standard solutions of different concentrations obtained in step (1) are sampled, and the chromatographic peak area of ​​the cross-linked part of the viscoelastic particle oil-displacing agent is used as the ordinate, and the concentration of the viscoelastic particle oil-displacing agent is used as the abscissa to obtain the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent, wherein: Under chromatographic condition ii, the viscoelastic particle oil-displacing agent emits a peak while the polymer does not, that is, the peak emitted by the viscoelastic particle oil-displacing agent is the chromatographic peak of the cross-linked part of the viscoelastic particle oil-displacing agent; Chromatographic conditions ii are: Chromatographic column: commercial C18 column; Mobile phase: 250 mM NaH2PO4 solution / acetonitrile = 92 / 8 (v / v); Mobile phase flow rate: 0.9~1.2mL / min; Injection volume: 10-20 μL; Column temperature: 20-25°C; Detector: UV detector with a wavelength of 200nm to 205nm.

3. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system as claimed in claim 2, characterized in that: Step (22) comprises the following steps: (221), according to the above chromatographic condition i, the heterogeneous system sample enters the liquid chromatography detection to obtain the total chromatographic peak area Ai of the viscoelastic particle oil displacement agent and the polymer; (222) According to the above chromatographic condition ii, the heterogeneous system sample is again subjected to liquid chromatography detection to obtain the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil displacement agent.

4. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system as claimed in claim 3, characterized in that: Step (3) comprises the following steps: (31), the chromatographic peak area Aii of the cross-linked structure of the viscoelastic particle oil-displacing agent is brought into the standard working straight line 3 of the cross-linked part of the viscoelastic particle oil-displacing agent under chromatographic condition ii, and the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained; (32), the concentration C1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is brought into the standard working straight line 1 of the viscoelastic particle oil-displacing agent under the chromatographic condition i, and the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system is obtained; (33) subtracting the chromatographic peak area A1 of the viscoelastic particle oil-displacing agent in the heterogeneous system from the total chromatographic peak area Ai of the viscoelastic particle oil-displacing agent and the polymer in the heterogeneous system to obtain the chromatographic peak area A2 of the polymer in the heterogeneous system; (34) The chromatographic peak area A2 of the polymer in the heterogeneous system is substituted into the standard working line 2 of the polymer under chromatographic condition i to obtain the concentration C2 of the polymer in the heterogeneous system sample.

5. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system as claimed in claim 1, characterized in that: The polymer in step (1) is polyacrylamide.

6. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system according to claim 1, characterized in that: Step (1) comprises the following steps: (11) Prepare a polymer standard solution with a concentration of 250 mg / L; (12) preparing a standard solution of viscoelastic particle oil displacement agent with a concentration of 250 mg / L; (13) The polymer standard solution obtained in step (11) and the viscoelastic particle oil displacement agent standard solution obtained in step (12) are broken up by a homogenizer, and then the broken polymer standard solution and the viscoelastic particle oil displacement agent standard solution are diluted with simulated formation water to form polymer standard solutions of different concentrations and viscoelastic particle oil displacement agent standard solutions of different concentrations, respectively.

7. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system as claimed in claim 6, characterized in that: The specific steps of step (11) are: (111), weigh 150 mL of simulated formation water into a container; (112) Place the container on the stirrer, insert a magnetic stirring bar, and adjust the speed to 1500±250rpm; (113) Weigh 0.0375 g of polymer, then add all the polymer into the container and stir continuously for at least 20 h to obtain a polymer standard solution with a concentration of 250 mg / L.

8. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system as claimed in claim 6, characterized in that: The specific steps of step (12) are: (121), weigh 150 mL of simulated formation water into a container; (122) Place the container on the stirrer, insert a magnetic stirring bar, and adjust the speed to 1500±250rpm; (123) Weigh 0.0375 g of the viscoelastic particle oil-displacing agent, then add all of the viscoelastic particle oil-displacing agent into a container, and stir continuously for at least 20 h to obtain a viscoelastic particle oil-displacing agent standard solution with a concentration of 250 mg / L.

9. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system as claimed in claim 6, characterized in that: The homogenizer used in step (13) is an Aika homogenizer; The polymer standard solution obtained in step (11) is crushed using an Aika homogenizer under the following conditions: crushing for 25 to 30 minutes at a rotation speed of 20,000 to 25,000 rpm; The viscoelastic particle oil displacement agent standard solution obtained in step (12) is crushed using an Aika homogenizer at 20,000 to 25,000 revolutions per minute for 60 to 70 minutes.

10. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system according to claim 6, characterized in that: The concentrations of the polymer standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively; The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, and 250 mg / L, respectively.

11. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system according to claim 6, characterized in that: The concentrations of the polymer standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively; The concentrations of the viscoelastic particle oil-displacing agent standard solutions of different concentrations in step (13) are 4 mg / L, 8 mg / L, 16 mg / L, 32 mg / L, 62.5 mg / L, 125 mg / L, and 250 mg / L, respectively.

12. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system as claimed in claim 2, characterized in that: In step (2), the chromatographic column model is Agilent ZORBAX Extend-C18, with a length of 250 mm, an inner diameter of 4.6 mm, a chromatographic column filler particle diameter of 5 μm, and a pore size of 13. The method for detecting the concentration of polymer and viscoelastic particle oil-displacing agent in a heterogeneous system according to claim 2, characterized in that: In step (2), the mobile phase is isocratic elution.

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