A method for determining the time to break and the time to onset of a targeted thickening polymer

Abstract

The application discloses a kind of targeted thickening polymer shell breaking and effect time test determination methods, comprising the following steps: S1 preparation targeted thickening polymer solution;S2 targeted thickening polymer solution oxygen removal;S3 test different time point sample viscosity;S4 draw sample different aging time and viscosity curve, determine targeted thickening oil displacement agent initial shell breaking time point and effect time point, the application is applicable to oil and gas field development technical field, by simulating formation environment to test shell breaking and effect time, for different types of reservoirs to provide strong basis for optimum polymer, monitor the performance of targeted thickening polymer, ensure the injection quality of polymer in the field, simple to operate, short time, high efficiency, for improving chemical oil displacement precision, more significantly improve recovery, with great research value and application prospect.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, specifically a method for testing and determining the shell breaking and onset time of targeted thickening polymers. Background Technology

[0002] Chemical flooding is the main focus of my country's tertiary oil recovery efforts. Among them, polymer flooding, with its relatively simple technology and low cost, is an important method for significantly improving oil recovery in ultra-high water-cut oilfields. The principle of polymer flooding is to add high molecular weight partially hydrolyzed polyacrylamide to the injected water, increasing the viscosity of the displaced phase, reducing the oil-water mobility ratio, and expanding the swept volume of the oil reservoir, thereby achieving the goal of improving crude oil recovery.

[0003] Currently, the polymers used in field applications are mainly linear polymeric hydrolyzed polyacrylamide. During surface preparation, the polymer needs to be completely dissolved before being injected into the formation. Therefore, the following problems still exist in field applications:

[0004] (1) Conventional dry powder partially hydrolyzed polyacrylamide takes more than 2 hours to dissolve and mature, requiring corresponding dispersion, dissolution and maturation equipment, resulting in a long dispensing process, large floor space and high ground investment.

[0005] (2) The dissolved polymer has a high molecular weight. During the injection process, after being sheared at high speed through the injection pipeline and the borehole, the polymer molecular chain is cut off, the molecular aggregation morphology changes, and the viscosity is lost by 40-50%, which leads to waste of reagents and affects the chemical flooding effect.

[0006] (3) Currently, most chemical flooding involves the injection of produced water, which contains reducing Fe. 2+ S 2- It reacts with oxygen to form free radicals, which leads to polymer chain scission and a significant decrease in viscosity.

[0007] Microencapsulation technology offers advantages such as core material protection, controlled release, and ease of storage, leading to its widespread application in industries like medicine, textiles, and coatings. In petroleum engineering, it primarily relates to tubing corrosion resistance and fracturing fluid technology. However, its application in enhancing oil recovery in oilfields remains relatively unexplored. Based on this technology, we propose the concept of targeted viscosity-enhancing polymers: conventional polymers are encapsulated within physicochemically inert microcapsules to form nano-suspension emulsions. These emulsions are then directly injected into the formation after mixing, eliminating the need for surface curing and improving injection efficiency. During perforation, the internal polymer viscosity remains unaffected due to the protective shell. Once in the formation, the encapsulated polymer is slowly released under the high-temperature environment of the reservoir, achieving targeted release into the target layer. This technology requires the polymer to be stable during storage and capable of rapid release under formation conditions, thus ensuring the controllability of the targeted viscosity-enhancing polymer. Therefore, researching the release time of targeted viscosity-enhancing polymers is crucial for targeted polymer design optimization, product performance testing, and in-situ oil displacement effects.

[0008] The literature "Research Progress on the Application of Polyurethane Microcapsules" covers the preparation method, raw materials, and application research progress of polyurethane (PU) microcapsules. It reviews the application effects of commonly used monomers and different emulsifiers, focusing on the characteristics of single-shell and multi-shell microcapsules and their development prospects in pharmaceuticals, fragrances, and materials. However, this article does not cover the testing methods for microcapsule rupture time.

[0009] Patent CN114316919A discloses a polymer / graphene oxide composite microcapsule for encapsulating phase change energy storage materials and its preparation method. The prepared microcapsules encapsulate phase change materials; the inner shell is a polymer, and the outer shell is a modified graphene oxide particle layer. This double-shell structure significantly enhances the barrier properties and thermal stability of the microcapsules, making it a potential candidate material for encapsulating gas-sensitive or moisture-sensitive substances, especially volatile substances requiring long-term storage. The paper mainly describes the raw materials and preparation stages, without covering the subsequent microcapsule breaking process.

[0010] The master's thesis, "Preparation and Performance Study of Green Targeted Microcapsule Oil Enhancement System," involves microcapsule encapsulation of surfactants. It investigates the effects of wall material structure and core / wall material mass ratio on microcapsule size distribution, characterizes the microcapsule structure, and examines the targeted controlled release characteristics of polymers in the oil phase, providing a new technology for enhancing oil recovery in conventional reservoirs and high-temperature, high-salinity reservoirs. However, the thesis does not cover methods for testing microcapsule rupture time.

[0011] Based on the above research, the focus of microcapsule polymer research is mainly on materials, preparation, and application effects. Currently, there is no corresponding testing method to determine the release and onset time of targeted thickening polymers. Summary of the Invention

[0012] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for testing and determining the shell breakage and onset time of targeted thickening polymers.

[0013] To achieve the above objectives, the present invention adopts the following technical solution:

[0014] A method for determining the shell breakage and onset time of a targeted thickening polymer includes the following steps:

[0015] S1 is used to prepare a targeted thickening polymer solution;

[0016] S2 targeted thickening polymer solution for oxygen removal;

[0017] S3 tests the viscosity of samples at different time points;

[0018] S4 plots curves of different aging times and viscosities for the samples to determine the initial break-out time and the effective time of the targeted viscosity-enhancing and oil displacement agent.

[0019] Preferably, step S1 specifically includes:

[0020] Preparation of S11 sodium bicarbonate brine;

[0021] Weighing the S12 targeted thickening polymer stock solution;

[0022] Dispersion of S13 targeted thickening polymer solution.

[0023] Preferably, step S11 specifically includes:

[0024] Take 500-600 parts of experimental water, stir it on a magnetic stirrer at a speed of 280-320 r / min, and add 0.3443-0.4131 parts of sodium bicarbonate to obtain sodium bicarbonate brine.

[0025] Preferably, in step S11, the mineralization of the experimental water is 5000-30000 mg / L.

[0026] Preferably, in step S11, the prepared sodium bicarbonate salt solution is homogeneous and transparent, without precipitation, and has a shelf life of 5-7 days.

[0027] Preferably, in step S12, the weighing device is taken, rinsed with the original liquid, dried on the outside of the weighing device, placed on the balance and zeroed, and then the mass of the original liquid is weighed.

[0028] Preferably, in step S12, the weighing device is a disposable sterile syringe with a capacity of 1ml to 5ml.

[0029] Preferably, in step S13, a certain amount of sodium bicarbonate brine is weighed, heated and stirred, and then the targeted thickening polymer stock solution weighed in step S12 is added to the brine along the vortex wall. After stirring for a certain period of time again, an unbroken targeted thickening polymer solution is obtained with a concentration ρ.

[0030] Preferably, in step S13, the concentration of the unbroken-shell targeted thickening polymer solution is:

[0031] ρ=m 原液 / (m 盐水+ m 原液 )×100%(1-1);

[0032] Wherein, ρ is the concentration of the unbroken-shell targeted thickening polymer solution;

[0033] m 原液 The mass of the targeted thickening polymer stock solution to be weighed;

[0034] m 盐水 The mass of the sodium bicarbonate salt solution weighed is [value missing].

[0035] Preferably, in step S12, the mass percentage concentration of the targeted thickening polymer stock solution is 4000–6000 mg / L.

[0036] Preferably, in step S13, heating is performed in a constant temperature water bath, and stirring is performed using a paddle mixer.

[0037] Preferably, in step S13, when adding the targeted thickening polymer, the speed of the paddle stirrer is 480-520 r / min, and the water bath temperature is 40-55℃.

[0038] Preferably, in step S13, after adding the targeted thickening polymer, the speed of the paddle mixer is 680-720 r / min, and the stirring time is 20-30 min.

[0039] Preferably, step S2 specifically includes:

[0040] After evacuating the targeted thickening polymer solution under vacuum for a period of time, it is then heated and stored.

[0041] Preferably, in step S2, the targeted thickening polymer solution is evenly packed into ampoules, the ampoules are then connected to the vacuum manifold, and the vacuum is evacuated to 13.1-13.3 Pa using the deoxygenation system. The ampoules are then evacuated for 1-1.5 hours under shaking conditions and stored in an oven.

[0042] Preferably, in step S2, the oven temperature is set to simulate the formation temperature.

[0043] Preferably, in step S3, the viscosity of the sample at different time points is tested using a rheometer.

[0044] Preferably, in step S3, the time points are 2h, 4h, 6h, 12h, 24h, 48h, 72h, and 96h.

[0045] Preferably, in step S4, 2-3 mPa·s is used as the initial breaking viscosity of the targeted thickening polymer, and the corresponding time point is the initial breaking time point.

[0046] Preferably, step S4 specifically includes:

[0047] S41 uses a flow rate testing device to monitor and record the time per milliliter of experimental water and samples of different viscosities passing through a porous medium made of sintered quartz sand of different mesh sizes under certain pressure conditions, and converts it into flow rate.

[0048] S42 dimensionlessly transforms the collected water injection flow rate and polymer injection flow rate, and plots the relationship curve between viscosity and dimensionless flow rate.

[0049] S43 determines that the viscosity corresponding to the inflection point of the curve slope is the effective viscosity of the targeted thickening polymer.

[0050] Preferably, in step S41, the porous medium has a diameter of 3.8–4 cm, a thickness of 2–3 cm, and a permeability of 0.5–10 μm. 2 .

[0051] Preferably, in step S43, the method for determining the slope inflection point A is as follows:

[0052] Draw the tangent line to the initial viscosity point on the curve and the tangent line to the corresponding point after the flow rate ratio stabilizes. The two tangent lines intersect after being extended. The viscosity at the intersection point is the effective viscosity of the targeted thickening polymer, and the corresponding time point is the effective time point.

[0053] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0054] In this invention, the shell breaking and onset time are tested by simulating the formation environment, providing a strong basis for selecting the best polymers for different types of reservoirs. The performance of targeted thickening polymers is monitored to ensure the quality of polymer injection in the field. The operation is simple and easy to understand, takes little time, and is highly efficient. It has great research value and application prospects for improving the accuracy of chemical flooding and significantly increasing the recovery rate. Attached Figure Description

[0055] Figure 1 This is a flowchart of the present invention;

[0056] Figure 2 This is a graph showing the sustained-release thickening and time curve of the targeted thickening polymer of the present invention;

[0057] Figure 3 This is a diagram of the flow rate testing device of the present invention;

[0058] Figure 4 This is a dimensionless flow velocity curve for different viscosities according to the present invention;

[0059] Figure 5 This is a graph showing the relationship between the broken-shell viscosity and time in Example 7 of this invention;

[0060] Figure 6 This is a graph showing the relationship between the broken-shell viscosity and time in Example 8 of this invention;

[0061] Figure 7 This is a graph showing the relationship between the broken-shell viscosity and time in Example 9 of this invention;

[0062] Figure 8 This is a graph showing the relationship between the broken-shell viscosity and time in Example 10 of this invention. Detailed Implementation

[0063] The following embodiments further illustrate specific implementations of the method for determining the shell breakage and onset time of a targeted adhesive polymer according to the present invention. The method for determining the shell breakage and onset time of a targeted adhesive polymer according to the present invention is not limited to the descriptions in the following embodiments.

[0064] This invention provides a method for testing and determining the shell breakage and onset time of targeted thickening polymers. Targeted thickening polymers differ from conventional polymers in both morphology and composition, therefore, it is necessary to establish targeted evaluation methods and technical requirements, among which the initial shell breakage time and onset time are important performance indicators.

[0065] Example 1:

[0066] A method for determining the shell breakage and onset time of targeted thickening polymers, such as Figure 1 As shown, it includes the following steps:

[0067] Step 1: Prepare the targeted thickening polymer solution;

[0068] Step 2: Deoxygenation of the targeted thickening polymer solution;

[0069] Step 3: Test the viscosity of the sample at different time points.

[0070] Furthermore, the preparation of the targeted thickening polymer solution includes: preparation of sodium bicarbonate brine, weighing of the targeted thickening polymer stock solution, and dispersion of the targeted thickening polymer solution.

[0071] Furthermore, the preparation method of sodium bicarbonate saline is as follows: take 500g of experimental water (mineralization 5000mg / L), stir it on a magnetic stirrer at a speed of 280r / min, and add 0.3443g of sodium bicarbonate.

[0072] Furthermore, the prepared sodium bicarbonate salt solution should be homogeneous and transparent, without any precipitation, and have a shelf life of 5 days.

[0073] Furthermore, the method for weighing the targeted viscosity-enhancing polymer stock solution is as follows: Take a 1ml disposable sterile syringe, rinse it with the stock solution, dry the outside of the syringe, zero the balance, and then weigh the stock solution (m). 原液 .

[0074] Furthermore, the dispersion method of the targeted thickening polymer solution is as follows: Use a beaker to weigh out m tons of sodium bicarbonate saline solution. 盐水 The sample was placed in a constant temperature water bath and heated. A paddle stirrer was turned on, and the sample was slowly added from the syringe to the brine along the vortex wall at a certain speed. After high-speed stirring for a certain period, an unbroken-shell targeted thickening polymer solution was obtained, with a concentration ρ.

[0075] ρ=m 原液 / (m 盐水+ m 原液)×100%(1-1);

[0076] Furthermore, a targeted thickening polymer solution is prepared, with a concentration of mass percentage, i.e., the mass of the targeted thickening polymer accounts for the total mass of the solution, ranging from 4000 mg / L.

[0077] Furthermore, when adding the targeted thickening polymer, the paddle stirrer speed is 480 r / min and the water bath temperature is 40℃.

[0078] Furthermore, after adding the targeted thickening polymer, the paddle mixer speed was set to 680 r / min, and the stirring time was 20 min.

[0079] Furthermore, the method for deoxygenating the targeted thickening polymer solution is as follows: the targeted thickening polymer solution is evenly distributed into ampoules, the ampoules are then connected to the vacuum manifold, the vacuum is evacuated to 13.1 Pa using the deoxygenation system, the evacuation is carried out under shaking conditions for 1 hour, and then the solution is stored in an oven.

[0080] Furthermore, the oven temperature should be set to simulate the formation temperature.

[0081] Furthermore, the time points for testing viscosity using a rheometer can be 2h, 4h, 6h, 12h, 24h, 48h, 72h, and 96h.

[0082] Example 2:

[0083] A method for determining the shell breakage and onset time of targeted thickening polymers, such as Figure 1 As shown, it includes the following steps:

[0084] Step 1: Prepare the targeted thickening polymer solution;

[0085] Step 2: Deoxygenation of the targeted thickening polymer solution;

[0086] Step 3: Test the viscosity of the sample at different time points.

[0087] Furthermore, the preparation of the targeted thickening polymer solution includes: preparation of sodium bicarbonate brine, weighing of the targeted thickening polymer stock solution, and dispersion of the targeted thickening polymer solution.

[0088] Furthermore, the preparation method of sodium bicarbonate saline is as follows: take 550g of experimental water (mineralization 20000mg / L), stir it on a magnetic stirrer at a speed of 300r / min, and add 0.3842g of sodium bicarbonate.

[0089] Furthermore, the prepared sodium bicarbonate salt solution should be homogeneous and transparent, without any precipitation, and have a shelf life of 6 days.

[0090] Furthermore, the method for weighing the targeted thickening polymer stock solution is as follows: Take a 3ml disposable sterile syringe, rinse it with the stock solution, dry the outside of the syringe, zero the balance, and then weigh the stock solution (m). 原液 .

[0091] Furthermore, the dispersion method of the targeted thickening polymer solution is as follows: Use a beaker to weigh out m tons of sodium bicarbonate saline solution. 盐水 The sample was placed in a constant temperature water bath and heated. A paddle stirrer was turned on, and the sample was slowly added from the syringe to the brine along the vortex wall at a certain speed. After high-speed stirring for a certain period, an unbroken-shell targeted thickening polymer solution was obtained, with a concentration ρ.

[0092] ρ=m 原液 / (m 盐水+ m 原液 )×100%(1-1);

[0093] Furthermore, a targeted thickening polymer solution is prepared, with a concentration of mass percentage, i.e., the mass of the targeted thickening polymer accounts for the total mass of the solution, ranging from 5000 mg / L.

[0094] Furthermore, when adding the targeted thickening polymer, the paddle mixer speed is 500 r / min and the water bath temperature is 50℃.

[0095] Furthermore, after adding the targeted thickening polymer, the paddle mixer speed was set to 700 r / min, and the stirring time was 25 min.

[0096] Furthermore, the method for deoxygenating the targeted thickening polymer solution is as follows: the targeted thickening polymer solution is evenly distributed into ampoules, the ampoules are then connected to the vacuum manifold, the vacuum is evacuated to 13.2 Pa using the deoxygenation system, and the solution is evacuated for 1.3 hours under shaking conditions before being stored in an oven.

[0097] Furthermore, the oven temperature should be set to simulate the formation temperature.

[0098] Furthermore, the time points for testing viscosity using a rheometer can be 2h, 4h, 6h, 12h, 24h, 48h, 72h, and 96h.

[0099] Example 3:

[0100] A method for determining the shell breakage and onset time of targeted thickening polymers, such as Figure 1 As shown, it includes the following steps:

[0101] Step 1: Prepare the targeted thickening polymer solution;

[0102] Step 2: Deoxygenation of the targeted thickening polymer solution;

[0103] Step 3: Test the viscosity of the sample at different time points.

[0104] Furthermore, the preparation of the targeted thickening polymer solution includes: preparation of sodium bicarbonate brine, weighing of the targeted thickening polymer stock solution, and dispersion of the targeted thickening polymer solution.

[0105] Furthermore, the preparation method of sodium bicarbonate saline is as follows: take 600g of experimental water (mineralization 30000mg / L), stir it on a magnetic stirrer at a speed of 320r / min, and add 0.4131g of sodium bicarbonate.

[0106] Furthermore, the prepared sodium bicarbonate salt solution should be homogeneous and transparent, without any precipitation, and have a shelf life of 7 days.

[0107] Furthermore, the method for weighing the targeted viscosity-enhancing polymer stock solution is as follows: Take a 5ml disposable sterile syringe, rinse it with the stock solution, dry the outside of the syringe, zero the balance, and then weigh the stock solution (m). 原液 .

[0108] Furthermore, the dispersion method of the targeted thickening polymer solution is as follows: Use a beaker to weigh out m tons of sodium bicarbonate saline solution. 盐水 The sample was placed in a constant temperature water bath and heated. A paddle stirrer was turned on, and the sample was slowly added from the syringe to the brine along the vortex wall at a certain speed. After high-speed stirring for a certain period, an unbroken-shell targeted thickening polymer solution was obtained, with a concentration ρ.

[0109] ρ=m 原液 / (m 盐水+ m 原液 )×100%(1-1);

[0110] Furthermore, a targeted thickening polymer solution is prepared, with a concentration of mass percentage, i.e., the mass of the targeted thickening polymer accounts for the total mass of the solution, ranging from 6000 mg / L.

[0111] Furthermore, when adding the targeted thickening polymer, the paddle stirrer speed is 520 r / min and the water bath temperature is 55℃.

[0112] Furthermore, after adding the targeted thickening polymer, the paddle mixer speed was set to 720 r / min, and the stirring time was 30 min.

[0113] Furthermore, the method for deoxygenating the targeted thickening polymer solution is as follows: the targeted thickening polymer solution is evenly distributed into ampoules, the ampoules are then connected to the vacuum manifold, the vacuum system is used to evacuate to 13.3 Pa, the evacuation is carried out for 1.5 hours under shaking conditions, and then the solution is stored in an oven.

[0114] Furthermore, the oven temperature should be set to simulate the formation temperature.

[0115] Furthermore, the time points for testing viscosity using a rheometer can be 2h, 4h, 6h, 12h, 24h, 48h, 72h, and 96h.

[0116] Example 4:

[0117] A method for determining the shell breakage and onset time of targeted thickening polymers, such as Figure 2 As shown, the determination method is as follows: plot the curves of different aging times and viscosities of the sample, and determine the initial shell breaking time point t1 and the effective time point t2 of the targeted viscosity-enhancing and oil displacement agent.

[0118] Furthermore, 2 mPa·s is taken as the initial breaking viscosity of the targeted thickening polymer, and the corresponding time point is the initial breaking time point t1.

[0119] Furthermore, the methods for determining the effective viscosity and the effective time point t2 of the targeted thickening polymer are as follows:

[0120] Step 1, such as Figure 3 As shown, A is a storage cup; B is a porous medium; C is an electronic balance. Using a flow rate testing device, under certain pressure conditions, experimental water and samples of different viscosities were passed through a porous medium (diameter 3.8 cm, thickness 2 cm, permeability 0.5 μm) sintered from quartz sand of different mesh sizes. 2 The time taken per milliliter is monitored and recorded, and then converted into flow rate.

[0121] Step Two, as follows Figure 4 As shown, the collected water injection flow rate and polymer injection flow rate were dimensionless, and the relationship curve between viscosity and dimensionless flow rate was plotted.

[0122] Step 3: Determine the viscosity corresponding to the inflection point A of the curve slope as the effective viscosity of the targeted thickening polymer.

[0123] Furthermore, the method for determining the slope inflection point A is as follows: draw the tangent line at the initial viscosity point B on the curve and the tangent line at the corresponding point C after the flow rate ratio stabilizes. The two tangent lines intersect after being extended. The viscosity corresponding to the intersection point is the effective viscosity of the targeted thickening polymer, and the corresponding time point is the effective time point t2.

[0124] Example 5:

[0125] A method for determining the shell breakage and onset time of targeted thickening polymers, such as Figure 2 As shown, the determination method is as follows: plot the curves of different aging times and viscosities of the sample, and determine the initial shell breaking time point t1 and the effective time point t2 of the targeted viscosity-enhancing and oil displacement agent.

[0126] Furthermore, 2.5 mPa·s was taken as the initial breaking viscosity of the targeted thickening polymer, and the corresponding time point was the initial breaking time point t1.

[0127] Furthermore, the methods for determining the effective viscosity and the effective time point t2 of the targeted thickening polymer are as follows:

[0128] Step 1, such as Figure 3 As shown, using a flow rate testing device, under certain pressure conditions, experimental water and samples of different viscosities were passed through a porous medium (diameter 3.9 cm, thickness 2.5 cm, permeability 5 μm) sintered from quartz sand of different mesh sizes. 2 The time taken per milliliter is monitored and recorded, and then converted into flow rate.

[0129] Step Two, as follows Figure 4 As shown, the collected water injection flow rate and polymer injection flow rate were dimensionless, and the relationship curve between viscosity and dimensionless flow rate was plotted.

[0130] Step 3: Determine the viscosity corresponding to the inflection point A of the curve slope as the effective viscosity of the targeted thickening polymer.

[0131] Furthermore, the method for determining the slope inflection point A is as follows: draw the tangent line at the initial viscosity point B on the curve and the tangent line at the corresponding point C after the flow rate ratio stabilizes. The two tangent lines intersect after being extended. The viscosity corresponding to the intersection point is the effective viscosity of the targeted thickening polymer, and the corresponding time point is the effective time point t2.

[0132] Example 6:

[0133] A method for determining the shell breakage and onset time of targeted thickening polymers, such as Figure 2 As shown, the determination method is as follows: plot the curves of different aging times and viscosities of the sample, and determine the initial shell breaking time point t1 and the effective time point t2 of the targeted viscosity-enhancing and oil displacement agent.

[0134] Furthermore, 3 mPa·s was taken as the initial breaking viscosity of the targeted thickening polymer, and the corresponding time point was the initial breaking time point t1.

[0135] Furthermore, the methods for determining the effective viscosity and the effective time point t2 of the targeted thickening polymer are as follows:

[0136] Step 1, such as Figure 3 As shown, using a flow rate testing device, under certain pressure conditions, experimental water and samples of different viscosities were passed through a porous medium (4 cm in diameter, 3 cm thick, 10 μm permeability) sintered from quartz sand of different mesh sizes. 2 The time taken per milliliter is monitored and recorded, and then converted into flow rate.

[0137] Step Two, as follows Figure 4 As shown, the collected water injection flow rate and polymer injection flow rate were dimensionless, and the relationship curve between viscosity and dimensionless flow rate was plotted.

[0138] Step 3: Determine the viscosity corresponding to the inflection point A of the curve slope as the effective viscosity of the targeted thickening polymer.

[0139] Furthermore, the method for determining the slope inflection point A is as follows: draw the tangent line at the initial viscosity point B on the curve and the tangent line at the corresponding point C after the flow rate ratio stabilizes. The two tangent lines intersect after being extended. The viscosity corresponding to the intersection point is the effective viscosity of the targeted thickening polymer, and the corresponding time point is the effective time point t2.

[0140] Example 7:

[0141] The specific steps for testing the breakout time of targeted thickening polymers are as follows:

[0142] (1) Preparation of sodium bicarbonate salt water: Weigh 500g of experimental water (mineralization 19334mg / L), add 0.3443g of sodium bicarbonate on a magnetic stirrer at a speed of (500±20)r / min, and stir for 20min;

[0143] (2) Weigh the targeted thickening polymer stock solution: First, rinse the disposable sterile syringe with the stock solution, wipe the outside of the syringe dry, place it on the balance and zero it, then weigh 1.8g of the polymer stock solution.

[0144] (3) Preparation of targeted thickening polymer solution: Weigh 298.2g of sodium bicarbonate saline solution into a beaker, place it in a constant temperature water bath at 50℃, and turn on the paddle stirrer at a speed of (500±20)r / min. Slowly add the targeted thickening polymer stock solution weighed in the syringe along the vortex wall to the sodium bicarbonate saline solution, then adjust the speed of the paddle stirrer to (700±20)r / min and stir for 0.5h to prepare an unbroken targeted thickening polymer solution (concentration of 6000mg / L).

[0145] (4) Deoxygenation of targeted thickening polymer: The unbroken targeted thickening polymer solution is evenly filled into ampoules and then connected to the vacuum manifold. The vacuum is evacuated to 13.3 Pa using the deoxygenation system. After evacuation for 1 hour under shaking conditions, the ampoules are sealed and stored in a 75°C high-temperature oven.

[0146] (5) Viscosity test: A rheometer was used at a temperature of 66℃ and a shear rate of 7.34s. -1 The viscosity of samples with different aging times was tested, and the results are shown in Table 1. Figure 5 As shown.

[0147] (6) Plot the viscosity versus dimensionless flow rate curve to determine the effective time point (permeability is 1 μm). 2 ).

[0148] Table 1. Example 7: Shell Breaking Viscosity Test

[0149]

[0150] At the given mineralization, aging temperature, and concentration, the initial breaking viscosity of the targeted thickening polymer was 2 mPa·s, and the effective viscosity was 5 mPa·s. The initial breaking time t1 was 4 h, and the effective time t2 was 9 h.

[0151] Example 8:

[0152] Weigh out the experimental water (mineralization 19334 mg / L), solution concentration 5000 mg / L, aging temperature 75℃, permeability 2.0 μm. 2 The preparation process, deoxygenation, and testing procedures followed Example 7, and the results are shown in Table 2. Figure 6 As shown.

[0153] Table 2 Example 8 Shell Breaking Viscosity Test

[0154]

[0155] At the given mineralization, aging temperature, and concentration, the initial breaking viscosity of the targeted thickening polymer was 2 mPa·s, and the effective viscosity was 6 mPa·s. The initial breaking time t1 was 6 h, and the effective time t2 was 17 h.

[0156] Example 9:

[0157] Weigh out the experimental water (mineralization 8689 mg / L), solution concentration 6000 mg / L, aging temperature 75℃, permeability 3.0 μm. 2 The preparation process, deoxygenation, and testing procedures followed Example 7, and the results are shown in Table 3. Figure 7 As shown.

[0158] Table 3 Example 9 Shell Breaking Viscosity Test

[0159]

[0160] At the given mineralization, aging temperature, and concentration, the initial breaking viscosity of the targeted thickening polymer was 2 mPa·s, and the effective viscosity was 8 mPa·s. The initial breaking time t1 was 2 h, and the effective time t2 was 7 h.

[0161] Example 10:

[0162] Weigh out the experimental water (mineralization 8689 mg / L), the solution concentration is 6000 mg / L, the aging temperature is 95℃, and the permeability is 3.5 μm. 2 The preparation process, deoxygenation, and testing procedures followed those of Example 7, and the results are shown in Table 4. Figure 8 As shown.

[0163] Table 4 Example 8 Shell Breaking Viscosity Test

[0164]

[0165] At the given mineralization, aging temperature, and concentration, the initial breaking viscosity of the targeted thickening polymer was 2 mPa·s, and the effective viscosity was 9 mPa·s. The initial breaking time t1 was 1 h, and the effective time t2 was 4 h.

[0166] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for determining the shell breakage and onset time of a targeted thickening polymer, characterized in that, Includes the following steps: S1 is used to prepare a targeted thickening polymer solution; S2 targeted thickening polymer solution for oxygen removal; S3 tests the viscosity of samples at different time points; S4 plots curves of different aging times and viscosities for the samples to determine the initial break-out time and the effective time of the targeted viscosity-enhancing and oil displacement agent.

2. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 1, characterized in that, Step S1 specifically includes: Preparation of S11 sodium bicarbonate brine; Weighing the S12 targeted thickening polymer stock solution; Dispersion of S13 targeted thickening polymer solution.

3. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 2, characterized in that, Step S11 specifically includes: Take 500-600 parts of experimental water, stir it on a magnetic stirrer at a speed of 280-320 r / min, and add 0.3443-0.4131 parts of sodium bicarbonate to obtain sodium bicarbonate brine.

4. The method for determining the shell breakage and onset time of a targeted thickening polymer as described in claim 3, characterized in that, In step S11, the mineralization of the experimental water is 5000–30000 mg / L.

5. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 3, characterized in that, In step S11, the prepared sodium bicarbonate salt solution is homogeneous and transparent, without any precipitation, and has a shelf life of 5-7 days.

6. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 2, characterized in that, In step S12, the weighing device is taken, rinsed with the original liquid, dried on the outside of the weighing device, placed on the balance and zeroed, and then the mass of the original liquid is weighed.

7. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 6, characterized in that, In step S12, the weighing device is a disposable sterile syringe with a capacity of 1ml to 5ml.

8. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 2, characterized in that, In step S13, a certain amount of sodium bicarbonate brine is weighed, heated and stirred, and then the targeted thickening polymer stock solution weighed in step S12 is added to the brine along the vortex wall. After stirring for a certain period of time again, an unbroken targeted thickening polymer solution is obtained with a concentration ρ.

9. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 1, characterized in that, In step S13, the concentration of the unbroken-shell targeted thickening polymer solution is: ρ=m 原液 / (m 盐水+ m 原液 )×100%(1-1); Wherein, ρ is the concentration of the unbroken-shell targeted thickening polymer solution; m 原液 The mass of the targeted thickening polymer stock solution to be weighed; m 盐水 The mass of the sodium bicarbonate salt solution weighed is [value missing].

10. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 2, characterized in that, In step S12, the mass percentage concentration of the targeted thickening polymer stock solution is 4000–6000 mg / L.

11. The method for determining the shell breakage and onset time of a targeted thickening polymer as described in claim 8, characterized in that, In step S13, the mixture is heated in a constant temperature water bath and stirred using a paddle mixer.

12. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 11, characterized in that, In step S13, when adding the targeted thickening polymer, the speed of the paddle stirrer is 480-520 r / min, and the water bath temperature is 40-55℃.

13. The method for determining the shell breakage and onset time of a targeted thickening polymer as described in claim 11, characterized in that, In step S13, after adding the targeted thickening polymer, the speed of the paddle mixer is 680-720 r / min, and the stirring time is 20-30 min.

14. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 1, characterized in that, Step S2 specifically includes: After evacuating the targeted thickening polymer solution under vacuum for a period of time, it is then heated and stored.

15. The method for determining the shell breakage and onset time of a targeted thickening polymer as described in claim 14, characterized in that, In step S2, the targeted thickening polymer solution is evenly packed into ampoules, which are then connected to the vacuum manifold. The vacuum is then evacuated to 13.1–13.3 Pa using the deoxygenation system. The ampoules are then evacuated for 1–1.5 hours under shaking conditions and stored in an oven.

16. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 15, characterized in that, In step S2, the oven temperature is set to simulate the formation temperature.

17. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 1, characterized in that, In step S3, the viscosity of the sample at different time points is tested using a rheometer.

18. The method for determining the shell breakage and onset time of a targeted thickening polymer as described in claim 17, characterized in that, In step S3, the time points are 2h, 4h, 6h, 12h, 24h, 48h, 72h, and 96h.

19. The method for determining the shell breakage and onset time of a targeted thickening polymer as described in claim 1, characterized in that, In step S4, 2-3 mPa·s is used as the initial breaking viscosity of the targeted thickening polymer, and the corresponding time point is the initial breaking time point.

20. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 1, characterized in that, Step S4 specifically includes: S41 uses a flow rate testing device to monitor and record the time per milliliter of experimental water and samples of different viscosities passing through a porous medium made of sintered quartz sand of different mesh sizes under certain pressure conditions, and converts it into flow rate. S42 dimensionlessly transforms the collected water injection flow rate and polymer injection flow rate, and plots the relationship curve between viscosity and dimensionless flow rate. S43 determines that the viscosity corresponding to the inflection point of the curve slope is the effective viscosity of the targeted thickening polymer.

21. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 20, characterized in that, In step S41, the porous medium has a diameter of 3.8–4 cm, a thickness of 2–3 cm, and a permeability of 0.5–10 μm. 2 .

22. The method for determining the shell breakage and onset time of a targeted adhesive polymer as described in claim 20, characterized in that, In step S43, the method for determining the slope inflection point A is as follows: Draw the tangent line to the initial viscosity point on the curve and the tangent line to the corresponding point after the flow rate ratio stabilizes. The two tangent lines intersect after being extended. The viscosity at the intersection point is the effective viscosity of the targeted thickening polymer, and the corresponding time point is the effective time point.

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