Quantitative evaluation method for imbibition performance of oilfield imbibition agent

Abstract

The application provides a quantitative evaluation method for imbibition performance of an oilfield imbibition agent, and comprises the following steps: calculating emulsifying capacity E a , emulsion stability E s and core wettability improvement capacity value W i of the imbibition agent respectively, and calculating an imbibition comprehensive index I i of the imbibition agent according to the following formula: I i The larger I i is, the better the imbibition performance of the imbibition agent is, and the quantitative evaluation of the imbibition performance of the imbibition agent is completed. Compared with the prior art, the quantitative evaluation method for imbibition performance of the oilfield imbibition agent provided by the application determines the emulsifying capacity, emulsion stability and core wettability improvement of the imbibition agent in a quantitative way, comprehensively considers the influence of the three factors, and quantitatively evaluates the comprehensive performance of the imbibition agent. The method can overcome the defects of the prior art, greatly improves the accuracy of imbibition agent screening, and is more accurate in the evaluation result of the imbibition performance of the imbibition agent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of evaluation methods for the wicking performance of wicking agents, and more particularly to a quantitative evaluation method for the wicking performance of wicking agents used in oilfields. BACKGROUND

[0002] With the continuous deepening and development of oil and gas field development in China, the proportion of low-permeability oil and gas reservoirs in China is increasing, and gradually becoming an important field of energy supply in China. However, due to the characteristics of low-permeability oil and gas reservoirs, such as fracture development, small pore throat size, and serious heterogeneity, the development process usually faces problems such as water injection difficulty, injection-production imbalance, and injected water channeling, thus resulting in low recovery efficiency.

[0003] Wicking is one of the important mechanisms for oil recovery in low-permeability oil reservoirs. In the process of water injection development, if the reservoir rock is water-wet, the capillary force acts as a driving force, and the absorbed water displaces the oil from the low-permeability matrix rock. However, due to the high interfacial tension and wettability of the oil in the low-permeability oil reservoir, the oil is tightly adsorbed in the pore, and the wicking effect of the formation water is not obvious. By adding a wicking agent to the injected water system, it will be adsorbed in the reservoir after entering the matrix rock, greatly improving the rock wettability and reducing the oil-water interfacial tension, thereby reducing the adhesion work of the oil on the pore wall. At the same time, due to the emulsification and dispersion effect and the elastic deformation effect, the emulsified dispersion system has a reduced migration resistance during displacement, and is more easily displaced from the formation. The wicking performance of the wicking agent has an important influence on the oil displacement effect. The wicking effect of the wicking agent mainly reflects in three aspects: changing the rock wettability, emulsification capacity, and emulsion stability.

[0004] In the prior art, the determination of the emulsification capacity of the wicking agent is usually based on GB / T6367-2008 "Determination of Emulsifying Power of Surface-Active Agents by Colorimetry". The standard requires the use of marine diesel fuel oil as the oil, and distilled water with a pH of 7-8 as the water. The physicochemical properties of the fuel oil and distilled water are quite different from those of the oil and formation water in the oilfield, and cannot accurately reflect the emulsification capacity of the wicking agent. In the prior art, the determination of emulsion stability is usually based on visual grading method or water separation rate method. The visual grading method is a qualitative evaluation method, and lacks quantitative data representation. The water separation rate method has a large human factor, and the determination error of different people is large, which is not persuasive. The prior art only evaluates one of the three aspects of the emulsification capacity, emulsion stability, and improved rock wettability of the wicking agent, and ignores the synergistic effect of the three aspects, and cannot comprehensively consider and evaluate the strength of the wicking performance of the wicking agent. These lead to the fact that the existing evaluation method for the wicking performance of the wicking agent cannot correctly guide the oilfield production operation. SUMMARY

[0005] In order to solve the above-mentioned deficiencies and defects in the prior art, the present application provides a quantitative evaluation method for the imbibition performance of an oilfield imbibition agent, which determines the emulsification capacity, emulsion stability and rock wettability improvement of the imbibition agent in a quantitative manner, comprehensively considers the influence of the three factors, and quantitatively evaluates the comprehensive performance of the imbibition agent. The method can overcome the deficiencies of the prior art, greatly improve the accuracy of imbibition agent screening, and obtain more accurate evaluation results of the imbibition performance of the imbibition agent.

[0006] The present application provides a quantitative evaluation method for the imbibition performance of an oilfield imbibition agent, comprising the following steps:

[0007] The emulsification capacity E of the imbibition agent is calculated a , the emulsion stability E s and the rock wettability improvement capacity value W i of the imbibition agent are calculated, respectively, according to the following formula:

[0008]

[0009] The imbibition comprehensive index I of the imbibition agent is calculated i ; the larger the I i , the better the imbibition performance of the imbibition agent, and the quantitative evaluation of the imbibition performance of the imbibition agent is completed.

[0010] In the present application, the process for calculating the emulsification capacity E of the imbibition agent a is preferably specific as follows:

[0011] The imbibition agent is mixed with simulated formation water to prepare an imbibition agent solution, and then mixed with crude oil, stirred by a stirrer to form an emulsion. After standing and stratifying, the lower emulsion is taken out, extracted with an extractant, and the optical density value of the extract is determined. According to the standard curve, the corresponding emulsified oil amount is found, and then the emulsification capacity value E of the imbibition agent is calculated a ; the larger the value of the emulsification capacity E a , the stronger the emulsification capacity.

[0012] In the present application, the calculation formula of the emulsification capacity E a is as follows:

[0013] E a =(emulsion layer oil content / oil amount)×100%.

[0014] In the present application, the simulated formation water is prepared according to the composition of the oilfield water quality analysis table; the imbibition agent can be obtained from a commercially available source known to those skilled in the art, and the present application does not have special limitations thereon; the crude oil is preferably formation crude oil after dehydration and degassing; if necessary, the crude oil can be subjected to core filtration treatment to remove larger impurities in the crude oil.

[0015] In the present application, the stirring speed of the stirrer is preferably 800-1200 r / min, more preferably 1000 r / min, and the time is preferably 8-12 min, more preferably 10 min.

[0016] In the present application, the standing time is preferably 1-3 min, more preferably 2 min.

[0017] In the present application, the extractant is preferably carbon tetrachloride, with a density of 1.594 g / cm 3 .

[0018] In the present application, the standard curve is preferably obtained according to the following steps:

[0019] Carbon tetrachloride is mixed with crude oil to configure oil samples of different concentrations, the wavelength of the ultraviolet-visible spectrophotometer is adjusted, each concentration of oil sample is scanned, and the wavelength with the maximum absorbance is selected as the subsequent experimental wavelength; then the above wavelength is used to measure the absorbance of the above different concentrations of oil samples, and a standard curve is drawn to obtain a mathematical relationship between the absorbance of crude oil and the concentration of crude oil.

[0020] In the subsequent experiment, the absorbance of the extracted oil sample is measured, and the emulsified oil content is calculated according to the mathematical relationship between the absorbance and the concentration of crude oil.

[0021] In the present application, the concentration of the oil sample, i.e. the extracted oil sample, is not specifically specified, and only the absorbance value obtained by subsequent measurement is brought into the mathematical relationship after regression for calculation. In the preferred embodiment of the present application, the different concentrations of the oil sample are 50 mg / L, 1000 mg / L, 150 mg / L, 200 mg / L, 250 mg / L and 300 mg / L.

[0022] In the present application, the process for calculating the emulsification stability E s of the wicking agent is preferably as follows:

[0023] The wicking agent is mixed with simulated formation water to configure a wicking agent solution, which is then mixed with crude oil, stirred by a stirrer to form an emulsion, and after standing and separation, the lower emulsion is extracted with an extractant, and the absorbance A0 and A 12 of the extract before and after heat preservation are measured, and the emulsification stability E s of the wicking agent is calculated; the calculation formula of the emulsification stability E s is as follows:

[0024]

[0025] In the formula, A0 is the absorbance of the extract before heat preservation, and A 12 is the absorbance of the extract after heat preservation.

[0026] In the present application, the simulated formation water is configured according to the composition of oilfield water quality analysis table; the imbibition agent can be obtained from a commercially available source known to those skilled in the art, and the present application does not have special restrictions thereon; the crude oil is preferably formation crude oil after dehydration and degassing; if necessary, the crude oil can be subjected to core filtration treatment to remove larger impurities in the crude oil.

[0027] In the present application, the stirring speed of the stirrer is preferably 800 r / min to 1200 r / min, more preferably 1000 r / min, and the time is preferably 8 min to 12 min, more preferably 10 min.

[0028] In the present application, the standing time is preferably 1 min to 3 min, more preferably 2 min.

[0029] In the present application, the extractant is preferably carbon tetrachloride, and the density is 1.594 g / cm 3 .

[0030] In the present application, the heat preservation mode is preferably heat preservation in a constant temperature box, specifically: the capacity bottle of the core slice soaked in the imbibition agent solution is heat preserved in a constant temperature box; and the heat preservation temperature is preferably the reservoir temperature.

[0031] In the present application, the process for calculating the core wettability improvement capacity value W i of the imbibition agent is preferably specifically as follows:

[0032] The imbibition agent is mixed with the simulated formation water to configure an imbibition agent solution; the core slice is soaked in the capacity bottle containing the imbibition agent solution under heat preservation conditions for 24 h, then dried, the change range of the wetting contact angle of the core slice before and after soaking is measured, and then the core wettability improvement capacity value W i of the imbibition agent is calculated. i The calculation formula of the core wettability improvement value W i is as follows:

[0033] W i = (change in wetting contact angle / original wetting contact angle).

[0034] In the present application, the simulated formation water is configured according to the composition of oilfield water quality analysis table; the imbibition agent can be obtained from a commercially available source known to those skilled in the art, and the present application does not have special restrictions thereon.

[0035] In the present application, the heat preservation mode is preferably heat preservation in a constant temperature box, specifically: the capacity bottle of the core slice soaked in the imbibition agent solution is heat preserved in a constant temperature box; and the heat preservation temperature is preferably the reservoir temperature.

[0036] The oilfield imbibition agent imbibition performance quantitative evaluation method provided by the application gives a comprehensive parameter for quantitatively evaluating the imbibition performance of the imbibition agent, and to some extent, overcomes the defects and deficiencies of the prior art, and effectively solves the existing technical problems.

[0037] Emulsifying capacity: In the technical background above, the existing method for evaluating emulsifying capacity uses the method in GB GB / T6367-2008 ''Determination of Emulsifying Power of Surface-Active Agents - Colorimetric Method'', which has the following shortcomings: first, the distilled water and internal combustion engine fuel oil used in the national standard are far from the actual situation of the oil field (the salinity of the formation water in the oil field can reach tens of thousands of mg / L, which is far from the distilled water, and the viscosity and composition of the crude oil are very different from the fuel oil); second, the emulsification is closely related to mineral ions in water and certain polar components in crude oil, and the national standard does not consider these situations. In the emulsifying capacity determination of the application, the use of simulated formation water and crude oil can well reproduce the emulsification reaction that occurs in the original formation, and the measurement results are more accurate than the traditional method and closer to the actual situation of the oil field (in the case of the existing standard, replace the distilled water with simulated formation water and the fuel oil with crude oil, which is consistent with the actual situation of the oil field).

[0038] Emulsion stability: This method is commonly used in the food industry and has not been used in the petroleum industry. The original method requires a solvent with a volume fraction of 0.1% SDS (sodium dodecyl sulfate) and a scanning wavelength of 500 nm; because crude oil is not soluble in SDS, SDS cannot be used as a solvent, and carbon tetrachloride, which is commonly used in the petroleum industry, is selected as a solvent; the emulsion is scanned at a wavelength of 500 nm, and the absorbance obtained by scanning is unstable, with too much fluctuation, resulting in too much error in the calculation results. The wavelength scanning in the standard curve drawing step mentioned in the application is used to select the wavelength with the maximum absorbance as the experimental wavelength, and the experimental results are stable and accurate. In the emulsion stability determination, the absorbance of the emulsion before and after heat preservation is measured using a UV-visible spectrophotometer to quantitatively describe the emulsion stability of the emulsion, which greatly reduces the human error caused by the colorimetric method and the water separation rate method.

[0039] The application provides an oilfield imbibition agent imbibition performance quantitative evaluation method; the quantitative evaluation method mainly includes the following steps: configuring simulated formation water according to the water quality analysis table of the target oil field, configuring imbibition agent solutions with certain concentration gradients using the simulated formation water, mixing the configured imbibition agent solutions with crude oil, and then obtaining an emulsion after dispersion and emulsification, and respectively measuring the emulsifying capacity E a and the emulsion stability E s; the core slice is placed into a volumetric flask containing the imbibition agent solution at the reservoir temperature, and soaked for 24 hours, and then dried, the change range of the wetting contact angle of the core slice before and after soaking is measured, and the rock wetting improvement capacity value W of the imbibition agent is calculated i ; the imbibition comprehensive index I of the imbibition agent solution is obtained i , and the comprehensive evaluation of the imbibition performance of the imbibition agent solution is completed. The method for evaluating the imbibition performance of the imbibition agent can overcome the shortcomings of the prior art, and the evaluation of the imbibition performance of the imbibition agent is more objective and has good repeatability.

[0040] The method comprehensively considers the influence of the comprehensive action of the emulsification capacity, the emulsion stability and the rock wetting improvement of the imbibition agent on the imbibition performance of the imbibition agent, and has the following beneficial effects:

[0041] (1) Emulsification capacity: the limitation of the original method is improved, and the experimental precision is greatly improved; (2) Emulsion stability: the experimental steps and experimental materials are improved, so that the results are more accurate; (3) Rock wetting improvement capacity: the rock wetting improvement capacity value is proposed, and the capacity of the imbibition agent for improving the rock wetting is quantitatively evaluated; (4) Imbibition comprehensive index: for the first time, the imbibition comprehensive index is proposed, which quantitatively evaluates the imbibition performance of the imbibition agent by comprehensively considering the above three factors, and the experiment is simple and accurate; (5) Generally speaking, the strength of the imbibition performance of the imbibition agent needs to be evaluated by measuring the imbibition recovery rate through the imbibition experiment, and one set of imbibition experiment needs more than 2 days, which is time-consuming and the accuracy cannot be guaranteed and is easily affected by the external experimental environment. The experimental results show that: the comprehensive index proposed in the present application can well reflect the imbibition performance of the imbibition agent, and has a good guiding effect on the selection of the imbibition agent in the oil field, and is convenient, accurate and time-saving. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is the spectral scanning curve of the absorbance value of Changqing crude oil at different wavelengths;

[0043] Figure 2 is the curve of the absorbance of Changqing crude oil at 295 nm with the change of concentration. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0045] EMBODIMENT

[0046] (1) Draw the standard curve and the regression mathematical equation

[0047] The oil samples with concentrations of 50 mg / L, 1000 mg / L, 150 mg / L, 200 mg / L, 250 mg / L and 300 mg / L were prepared by mixing carbon tetrachloride and Changqing crude oil, and the absorbance values at different wavelengths were scanned by using a UV-visible spectrophotometer to obtain six curves.

[0048] Figure 1 The determination results of Changqing crude oil were as follows, the wavelength at the peak was selected as the optimal wavelength for subsequent measurement, and the wavelength of 295 nm was selected.

[0049] The above oil samples were scanned at the wavelength of 295 nm to obtain a standard curve, and the least square method was used to fit the data to obtain a mathematical relationship between the absorbance of crude oil and the concentration: Y=0.0015X, wherein Y is the absorbance value of crude oil, and X is the concentration of crude oil.

[0050] (2) Determination of emulsifying capacity

[0051] A 200 mL solution of DWS wicking agent (Dalian Davis Chemical Agent Co., Ltd., effective content: 35%) was prepared by mixing with simulated formation water at a concentration of 0.1%;

[0052] 20 mL of the DWS wicking agent solution was mixed with 20 mL of Changqing oil, and placed in a stirrer, the stirring speed was set to 1000 r / min, and the stirring time was 10 min. The prepared emulsion was poured into a separatory funnel and stood for 2 min, 10 mL of the lower emulsion was taken, extracted with 40 mL of carbon tetrachloride, and the oil content in the extract was measured by a UV-visible spectrophotometer, and then the emulsifying capacity value was calculated;

[0053] The above steps were repeated to measure the emulsifying capacity values of CW-2 (CNOOC Tianjin Branch, effective content: 100%), PO-FASD (CNOOC Oilfield Service Company, effective content: 35%) and BHS (Daqing Oilfield Company, effective content: 40%) three wicking agents, and the results are shown in Table 1.

[0054] Table 1 Emulsifying capacity values E of different wicking agent solutions a

[0055]

[0056]

[0057] As can be seen from Table 1, when the wicking agent is CW-2, the emulsifying capacity is the strongest, which indicates that under the same conditions, the CW-2 wicking agent can emulsify the most crude oil.

[0058] (3) Determination of emulsion stability

[0059] Using DWS (Dalian Davis Chemical Agent Co. Ltd, effective content: 35%) and simulated formation water, 200 mL of 0.1% DWS solution was prepared;

[0060] 20 mL of DWS solution was mixed with 20 mL of Changqing oil, and placed in a stirrer with a speed of 1000 r / min for 10 min. The prepared emulsion was poured into a separatory funnel and left for 2 min, and 10 mL of the lower emulsion was taken and extracted with 40 mL of carbon tetrachloride. One part of the extractant was measured for absorbance A0 by UV-visible spectrophotometer, and the other part was measured for absorbance A after 1 h of incubation in an incubator (reservoir temperature 60°C). 12 Then the emulsion stability value E was calculated s ;

[0061] The above steps were repeated to measure the emulsion stability values E of CW-2, PO-FASD and BHS respectively s , and the results are shown in Table 2.

[0062] Table 2 Emulsion stability values E of different DWS solutions s

[0063] Wicking agent solution (0.1%) E s (%)]] DWS 25.22 CW-2 25.00 PO-FASD 23.85 BHS 30.00

[0064] As can be seen from Table 2, when the DWS is BHS, the emulsion stability is the strongest, which indicates that under the same conditions, the emulsion formed by BHS is the most stable and is not easy to break.

[0065] (4) Measurement of the ability of DWS to improve rock wettability

[0066] Using DWS (Dalian Davis Chemical Agent Co. Ltd, effective content: 35%) and simulated formation water, 200 mL of 0.1% DWS solution was prepared;

[0067] At reservoir temperature (60°C), the core slice was soaked in a volumetric flask containing the DWS solution for 24 h and then dried. The change in wettability contact angle before and after soaking was measured, and then the value W of the ability of the DWS to improve the wettability of the core was calculated i ;

[0068] The above steps were repeated to measure the values W of the ability of CW-2, PO-FASD and BHS to improve the wettability of the rock respectively i , and the results are shown in Table 3.

[0069] Table 3 Values W of the ability of different DWS solutions to improve the wettability of the rock i

[0070] Wicking agent solution (0.1%) W i (%)]]> DWS 25.20 CW-2 33.52 PO-FASD 29.66 BHS 53.01

[0071] From Table 3, when the imbibition agent is BHS, the stronger the ability to improve the wettability of the core, the more likely the rock to exhibit water-wet characteristics, the greater the capillary force, and the greater the imbibition recovery.

[0072] (5) Calculation of the comprehensive imbibition index

[0073] According to the formula:

[0074]

[0075] The comprehensive imbibition index of different imbibition agents is calculated, and the results are shown in Table 4.

[0076] Table 4 Comprehensive imbibition index I of different imbibition agent solutions i

[0077] Wicking agent solution (0.1%) I i (%)]] DWS 19.36 CW-2 30.95 PO-FASD 26.39 BHS 42.17

[0078] From Table 4, when the imbibition agent is BHS, the comprehensive imbibition index is the largest, with a value of 0.4217. This indicates that under the same conditions, using BHS imbibition agent for imbibition oil recovery has the highest recovery rate.

[0079] (5) Verification of the applicability of the comprehensive imbibition index

[0080] In order to verify the applicability of the quantitative evaluation method of the imbibition performance of the imbibition agent proposed in the present application, a static imbibition experiment is performed, and the correctness and applicability of the comprehensive imbibition index are verified by comparing the correlation between the imbibition recovery and the comprehensive imbibition index. The experimental steps are as follows:

[0081] Prepare 200 mL of DWS imbibition agent solution with a concentration of 0.1%; first saturate the core with water, then saturate it with oil to obtain the volume of saturated oil, and finally place the core into an imbibition bottle; add the prepared imbibition agent solution into the imbibition bottle, place it into a constant temperature oven at 60°C (reservoir temperature), and record the volume of imbibition oil recovery; calculate the imbibition recovery.

[0082] Repeat the above steps to measure the imbibition recovery of CW-2, PO-FASD and BHS imbibition agents, respectively, as shown in Table 5.

[0083] Table 5 Imbibition recovery of different imbibition agent solutions

[0084] Wicking agent solution (0.1%) Wicking recovery (%) DWS 1.8 CW-2 3.4 PO-FASD 3.2 BHS 3.8

[0085] Combining Table 5 with Table 4, it can be seen that the comprehensive imbibition index of BHS imbibition agent is the highest, and the experimental results also show that the imbibition recovery of BHS imbibition agent is the highest, indicating that the quantitative evaluation method of the imbibition performance of the imbibition agent proposed in the present application is correct and effective, and has certain guiding significance for oilfield production.

[0086] (6) Repeatability verification of emulsion stability

[0087] Using DWS penetrant (Dalian Davis Chemical Agent Co., Ltd., effective content: 35%) and simulated formation water, 200 mL of penetrant solution with a concentration of 0.1% was prepared;

[0088] 20 mL of DWS penetrant was mixed with 20 mL of Changqing oil, and placed in a stirrer, the stirring speed was set to 1000 r / min, and the stirring time was 10 min. The prepared emulsion was poured into a separatory funnel and stood for 2 min, 10 mL of the lower emulsion was taken, and 40 mL of carbon tetrachloride was extracted. The extractant was divided into two parts, one part was measured by a UV-visible spectrophotometer to measure the absorbance A0 of the extractant, and the other part was measured after being kept in a thermostat (reservoir temperature 60°C) for 1 h to measure the absorbance A of the extractant after keeping. 12 Then the emulsion stability value E was calculated s ;

[0089] The above step was repeated three times to perform three groups of experiments DWS(1), DWS(2), and DWS(3), and the error was calculated, and the results are shown in Table 6.

[0090] Table 6 Error analysis of repeated experiments

[0091]

[0092] As shown in Table 6, the emulsion stability error of the three groups of experiments is within 5%, so the method for measuring the emulsion stability has good repeatability.

[0093] The above examples show that the penetrant penetration performance quantitative evaluation method of the present application eliminates human error and can well guide the selection of penetrant for oil penetration recovery in oil fields, which has great significance for oil field production.

[0094] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for quantitatively evaluating the wicking performance of an oil field wicking agent, characterized by, It comprises the following steps: The emulsifying capacity E of the imbibition agent is calculated respectively a , the emulsion stability E s and the core wettability improvement capacity value W i , according to the following formula: The calculation obtains the imbibition comprehensive index I of the imbibition agent i ; i The greater, the better the imbibition performance of the imbibition agent, and the quantitative evaluation of the imbibition performance of the imbibition agent is completed; The emulsifying capacity E of the wicking agent is calculated a The process is specified as follows: The imbibition agent is mixed with simulated formation water to configure an imbibition agent solution, and then mixed with crude oil to form an emulsion after stirring by a stirrer; after standing and stratification, the lower emulsion is taken out, extracted by an extractant, and the optical density value of the extract is measured to find the corresponding emulsified oil amount according to a standard curve, and then the emulsifying capacity value E of the imbibition agent is calculated a ; the calculation formula of the emulsifying capacity E a is as follows: E a = (emulsion layer oil content / added oil amount) x 100%; The emulsion stability E of the wicking agent is calculated s The process is in particular: The imbibition agent is mixed with simulated formation water to configure an imbibition agent solution, and then mixed with crude oil to form an emulsion after stirring by a stirrer; after standing and stratification, the lower emulsion is taken out, extracted by an extractant, and the absorbance A0 and A of the extract before and after heat preservation are measured 12 , and the emulsion stability E of the imbibition agent is calculated s ; the calculation formula of the emulsion stability E is s ​ In the formula, A0 is the absorbance of the extraction solution before heat preservation, A 12 is the absorbance of the extraction solution after heat preservation; Calculate the value W of the ability of the penetrant to improve the wettability of the core. i The process is as follows: The wicking agent is mixed with simulated formation water to configure a wicking agent solution; the core slice is soaked in the capacity bottle containing the wicking agent solution under a heat preservation condition for 24 hours, and then dried, the change range of the wetting contact angle before and after the core slice is soaked is measured, and then the wicking agent's ability value W of improving the wettability of the core is calculated i ; the calculation formula of the wettability improvement value W of the core is i ​ W i = (wetting contact angle change angle / original wetting contact angle angle).

2. The method for quantitatively evaluating the wicking performance of an oilfield wicking agent according to claim 1, characterized by, The standard curve is obtained according to the following steps: Carbon tetrachloride is mixed with crude oil to configure oil samples with different concentrations, the wavelength of the ultraviolet visible spectrophotometer is adjusted, each concentration of oil sample is scanned, the wavelength with the maximum absorbance is selected as the wavelength for subsequent experiments; the above wavelength is used to measure the absorbance of the above different concentrations of oil samples, a standard curve is drawn, and a mathematical relationship between the absorbance of crude oil and the concentration of crude oil is obtained.

3. The method for quantitatively evaluating the wicking performance of an oilfield wicking agent according to claim 1, characterized by, The crude oil is dehydrated and degassed crude oil.

4. The method for quantitatively evaluating the wicking performance of an oilfield wicking agent according to claim 1, characterized by, The stirring speed of the stirrer is 800r / min-1200r / min, and the time is 8min-12min.

5. The method for quantitatively evaluating the wicking performance of an oilfield wicking agent according to claim 1, characterized by, The standing time is 1min-3min.

6. The method for quantitatively evaluating the wicking performance of an oilfield wicking agent according to claim 1, characterized by, The extraction agent is carbon tetrachloride.

7. The method for quantitatively evaluating the wicking performance of an oilfield wicking agent according to claim 1, characterized by, The heat preservation mode is heat preservation in a constant temperature box; the heat preservation temperature is the reservoir temperature.

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