Temporary plugging agent composition, temporary plugging agent, and preparation method and application thereof

Abstract

This invention relates to the field of oilfield chemical technology, and discloses a temporary plugging agent composition, a temporary plugging agent, its preparation method, and its application. Based on the total weight of the temporary plugging agent composition, the composition comprises: 0.3-0.5 wt% thermosensitive copolymer, 0.01-0.015 wt% biosurfactant, 0.8-1.5 wt% polyphenol crosslinking agent, 0.5-0.8 wt% curing agent, 0.5-1 wt% nano-zirconia, 0.01-0.015 wt% initiator, 0.1-0.5 wt% cobalt chloride, and 95.67-97.78 wt% water. This invention forms a gel system by combining a temperature-sensitive copolymer with a polyphenol crosslinking agent and a curing agent, and simultaneously adds a certain amount of nano-zirconia and cobalt chloride to form a composite temporary plugging system. The gel system is a non-rigid structure that is easily destroyed by bacteria and ammonium persulfate. The nano-zirconia and cobalt chloride are dissolved by dilute oil. Therefore, this temporary plugging system can break down the gel immediately without blocking the oil well, and the broken gel fragments will not cause pump jamming accidents. It also has the advantages of being pollution-free, harmless to the reservoir, and low in cost.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, specifically to temporary plugging agent compositions, temporary plugging agents, their preparation methods, and applications. Background Technology

[0002] Thermal recovery technology, as a primary means of heavy oil development, has been widely applied in the development of heavy oil reservoirs both domestically and internationally. Commonly used thermal recovery methods include steam injection, steam drive, hot water drive, reservoir combustion, electromagnetic heating, and thermochemical methods. Among these, steam injection and steam drive are the most widely used and produce the largest oil yields. However, with the advancement of development, factors such as inter-layer permeability differences and steam / gas overlap can cause injected steam to surge along high-permeability zones. When high-permeability zones between two wells connect, inter-well steam channeling occurs, affecting the normal production of adjacent wells and reducing the effectiveness of thermal recovery. For example, in the Qi 40 block steam drive, the temperature of 105 wells in the injection group exceeded 70°C, resulting in severe steam channeling problems. In the SAGD block, during operations, the near-wellbore zone suffered from high-temperature rock dissolution and depletion, making it impossible to establish circulation for well control. The best solution to this problem is to inject chemical agents with a certain sealing strength into the reservoir to ensure the consistency of reservoir permeability.

[0003] Liquid-phase hydrogels have proven to be one of the most effective methods for reservoir consistency control. Currently, polymer gel systems offer the best performance and are the most widely used. This system consists of polymers, cross-linking systems, and additives. The prepared gel solution is injected into the formation and aged for a period to form a gel. The viscosity of the gel system increases significantly after gelation, achieving the purpose of sealing the formation. Commonly used polymer systems mainly include polyacrylamide (PAM) and partially hydrolyzed polyacrylamide (HPAM). However, these systems are not suitable for steam flooding and SAGD, where temperatures exceed 150°C. Currently, the most widely used high-temperature plugging agents in the industry are cement-based solid materials. While cement-based plugging agents have good temperature resistance and high compressive strength, the curing time at high temperatures is difficult to control. Flash solidification during the sealing process can pose risks to the operation. Therefore, existing plugging agents are insufficient to meet the requirements of measures under extreme well conditions. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of poor temperature resistance of temporary plugging agents and difficulty in controlling curing time at high temperatures in the prior art, and to provide temporary plugging agent compositions, temporary plugging agents and their preparation methods and applications. The temporary plugging agent obtained by this invention is a gel system with temperature sensing function and high temperature resistance.

[0005] To achieve the above objectives, a first aspect of the present invention provides a temporary plugging agent composition, which, based on the total weight of the temporary plugging agent composition, comprises: 0.3-0.5 wt% of a thermosensitive copolymer, 0.01-0.015 wt% of a biosurfactant, 0.8-1.5 wt% of a polyphenol crosslinking agent, 0.5-0.8 wt% of a curing agent, 0.5-1 wt% of nano-zirconia, 0.01-0.015 wt% of an initiator, 0.1-0.5 wt% of cobalt chloride, and 95.67-97.78 wt% of water.

[0006] A second aspect of the present invention provides a method for preparing a temporary plugging agent, the method comprising:

[0007] (1) Dissolve the biosurfactant in water to form a biosurfactant dispersion; dissolve the thermosensitive copolymer in the biosurfactant dispersion and perform a first treatment; after the copolymer is completely dissolved, obtain the copolymer mother liquor.

[0008] (2) Add polyphenol crosslinking agent, curing agent, nano-zirconia and initiator to the copolymer mother liquor to obtain a gel system;

[0009] (3) Cobalt chloride is added to the gel system for a second treatment to obtain a temporary plugging agent.

[0010] A third aspect of the present invention provides a temporary plugging agent prepared by the aforementioned preparation method.

[0011] The fourth aspect of this invention provides the application of the aforementioned temporary plugging agent in heavy oil extraction.

[0012] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0013] 1) This invention forms a gel system by combining a temperature-sensitive copolymer with a polyphenol crosslinking agent and a curing agent, and simultaneously adds a certain amount of nano-zirconia and cobalt chloride to form a composite temporary plugging system. The gel system is a non-rigid structure that is easily destroyed by bacteria and ammonium persulfate. The nano-zirconia and cobalt chloride are dissolved by dilute oil. Therefore, the temporary plugging system can break the gel immediately without blocking the oil well, and the broken gel fragments will not cause pump jamming accidents. It also has the advantages of being pollution-free, harmless to the reservoir, and low cost.

[0014] 2) The temporary plugging agent of this invention is a nano-polymer gel system. It utilizes a crosslinking agent with a special structure to crosslink with stable copolymer molecules, forming a nano-network structure with an average size of approximately 500 nm. The embedded nanoparticles further reduce the network structure size of the high-strength nanogel, improving gel stability. The nano- and micro-structures exhibit significant steric hindrance effects on water molecules, and the copolymer and crosslinking agent themselves possess good stability and high chemical bond energy, ensuring the high strength, temperature resistance, salt resistance, and shear resistance of the high-strength nanogel. Attached Figure Description

[0015] Figure 1 This is an electron microscope image of the nano-thermosensitive gel prepared in this invention;

[0016] Figure 2 This is an electron micrograph of a common gel;

[0017] Figure 3 This is a schematic diagram of the network structure of conventional heat-resistant gels, heat-resistant copolymer systems, and the nano-copolymer gel of this invention. Detailed Implementation

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] The first aspect of the present invention provides a temporary plugging agent composition, which, based on the total weight of the temporary plugging agent composition, comprises: 0.3-0.5 wt% of a thermosensitive copolymer, 0.01-0.015 wt% of a biosurfactant, 0.8-1.5 wt% of a polyphenol crosslinking agent, 0.5-0.8 wt% of a curing agent, 0.5-1 wt% of nano-zirconia, 0.01-0.015 wt% of an initiator, 0.1-0.5 wt% of cobalt chloride, and 95.67-97.78 wt% of water.

[0020] According to this invention, the thermosensitive copolymer in the system forms a three-dimensional network gel with the polyphenol crosslinking agent and the curing agent. The polyphenol crosslinking agent molecule has multiple reactive phenolic hydroxyl groups, which can form additional crosslinking sites by coupling with free radicals in the curing agent. The crosslinking density of the material increases significantly with the increase of polyphenol content, increasing the temperature stability of the system. The curing agent reacts with the polyphenol crosslinking agent to cure, improving the toughness and viscosity of the gel. The biosurfactant plays a role in solubilizing, emulsifying, wetting, foaming, dispersing, and reducing surface tension in the system, while also being degradable, destroying the gel structure after a period of time. This agent mainly controls the gelation time; the larger the amount added, the shorter the gelation time. Nano-zirconia can increase the temperature stability of the system. Cobalt chloride is a structural support agent for the gel system, preventing gel dehydration.

[0021] According to this embodiment, the temporary plugging agent composition has better temperature resistance, salt resistance and shear resistance.

[0022] In some embodiments of the present invention, the thermosensitive copolymer is obtained by polymerization of acrylamide, N-vinyl-2-pyrrolidone and 2-acrylamide-2-methacrylic acid as monomers.

[0023] In some preferred embodiments of the present invention, the weight ratio of acrylamide, N-vinyl-2-pyrrolidone and 2-acrylamide-2-methacrylic acid is 1.5-2:1-1.25:1-1.25.

[0024] The relative density of the thermosensitive copolymer of the present invention is 1.1-1.3.

[0025] In some embodiments of the present invention, the polyphenol crosslinking agent is p-bromophenol, 2-bromo-4-methylphenol, or 2,4,6-tribromophenol.

[0026] In some embodiments of the present invention, the biosurfactant is rhamnolipid or sophorolipid.

[0027] In some embodiments of the present invention, the curing agent is 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, m-phenylenediamine, or diaminodiphenylmethane.

[0028] In some embodiments of the present invention, the initiator is a persulfate.

[0029] Preferably, the initiator is potassium persulfate, sodium persulfate, or ammonium persulfate.

[0030] In some embodiments of the present invention, the particle size of the nano-zirconia is 10-50 nm, such as 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, and any value in the range of any two values, preferably 20-40 nm.

[0031] In this invention, nano-zirconia can also be added in the form of a nano-zirconia dispersion. The main preparation method includes: dispersing nano-zirconia powder in an aqueous medium to form a highly dispersed, homogenized, and stable nano-zirconia aqueous slurry. Commercially available nano-zirconia dispersions can also be used, as they have good stability, eliminating the need for a pre-dispersion step and allowing for direct mixing and addition to the system. Preferably, the concentration of the nano-zirconia dispersion is 20-40%, more preferably 30%.

[0032] A second aspect of the present invention provides a method for preparing a temporary plugging agent, the method comprising:

[0033] (1) Dissolve the biosurfactant in water to form a biosurfactant dispersion; dissolve the thermosensitive copolymer in the biosurfactant dispersion and perform a first treatment; after the copolymer is completely dissolved, obtain the copolymer mother liquor.

[0034] (2) Add polyphenol crosslinking agent, curing agent, nano-zirconia and initiator to the copolymer mother liquor to obtain a gel system;

[0035] (3) Cobalt chloride is added to the gel system for a second treatment to obtain a temporary plugging agent.

[0036] The temporary plugging agent of the present invention is a gel system with temperature sensing function, high temperature resistance and recoverability (with gel breaking function).

[0037] The temperature-sensitive material of this invention is a low-viscosity fluid at low temperatures. Once the temperature exceeds the phase transition point, it can form a semi-solid, water-insoluble gel in a short time. Since its thickening temperature is controllable, the curing time can be adjusted in real time according to the temperature of the formation to be sealed. This ensures construction safety and allows selective sealing using the formation temperature field, expanding the heating radius of subsequent steam injection and improving the thermal recovery effect of heavy oil.

[0038] like Figure 1 The image shown is an electron microscope image of the nano-thermosensitive gel prepared according to the present invention. Figure 2 The image shown is an electron microscope image of a conventional gel. The schematic diagram of the network structure of the nanopolymer gel of this invention is shown below. Figure 3 As shown. The nanopolymer solution of this invention utilizes nanoparticles with special structures to crosslink with stable copolymer molecules, forming a nano-network structure with an average size of approximately 500 nm. The embedded nanoparticles can further reduce the network structure size of the high-strength nanogel and improve its stability. The nano- and micro-structures have a significant steric hindrance effect on water molecules, and the copolymers have good stability and high chemical bond energy, ensuring high strength and resistance to temperature, salt, and shear.

[0039] In some embodiments of the present invention, the concentration of the biosurfactant in the biosurfactant dispersion is 0.01-0.015 wt%.

[0040] In some embodiments of the present invention, the weight ratio of the biosurfactant to the thermosensitive copolymer, polyphenol crosslinking agent, curing agent, nano-zirconia, initiator and cobalt chloride is 0.01-0.015:0.3-0.5:0.8-1.5:0.5-0.8:0.5-1:0.01-0.015:0.1-0.5.

[0041] In some embodiments of the present invention, the thermosensitive copolymer is obtained by polymerization of acrylamide, N-vinyl-2-pyrrolidone and 2-acrylamide-2-methacrylic acid as monomers.

[0042] In some preferred embodiments of the present invention, the weight ratio of acrylamide, N-vinyl-2-pyrrolidone and 2-acrylamide-2-methacrylic acid is 1.5-2:1-1.25:1-1.25.

[0043] In some embodiments of the present invention, the polyphenol crosslinking agent is p-bromophenol, 2-bromo-4-methylphenol, or 2,4,6-tribromophenol.

[0044] In some embodiments of the present invention, the biosurfactant is rhamnolipid or sophorolipid.

[0045] In some embodiments of the present invention, the curing agent is 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, m-phenylenediamine, or diaminodiphenylmethane.

[0046] In some embodiments of the present invention, the initiator is a persulfate.

[0047] Preferably, the initiator is a persulfate, preferably potassium persulfate, sodium persulfate, or ammonium persulfate.

[0048] In some embodiments of the present invention, the particle size of the nano-zirconia is 10-50 nm, such as 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, and any value in the range of any two values, preferably 20-40 nm.

[0049] In this invention, nano-zirconia can also be added in the form of a nano-zirconia dispersion. The main preparation method includes: dispersing nano-zirconia powder in an aqueous medium to form a highly dispersed, homogenized, and stable nano-zirconia aqueous slurry. Commercially available nano-zirconia dispersions can also be used, as they have good stability, eliminating the need for a pre-dispersion step and allowing for direct mixing and addition to the system. Preferably, the concentration of the nano-zirconia dispersion is 20-40%, more preferably 30%.

[0050] In some embodiments of the present invention, in step (1), the conditions for the first treatment include: a stirring speed of 100-200 rpm, a temperature of 50-60°C, a pressure of 1-1.5 MPa, and a time of 10-15 min.

[0051] In some embodiments of the present invention, step (2) specifically includes: adding polyphenol crosslinking agent and curing agent to the copolymer mother liquor in sequence at a stirring speed of 100-200 rpm, stirring for 5-10 min, and then adding nano-zirconia and initiator.

[0052] In some embodiments of the present invention, in step (3), the second treatment includes: first stirring at 200-250 rpm at 50-60°C and 1.5-2 MPa, and then aging at 60-80°C for 6-8 hours.

[0053] The third aspect of the present invention provides a temporary plugging agent prepared by the preparation method of the second aspect described above.

[0054] The temporary plugging agent of this invention is a nano-temperature-sensitive gel. By using different concentrations of nano-temperature-sensitive gel, high-strength nano-gels with different properties and uses can be prepared (three systems: low viscosity, medium viscosity, and high viscosity). The high-temperature curing time of 4-48 hours can also be controlled by changing the system formulation, and can be adjusted according to the needs of the site.

[0055] The temporary plugging agent of the present invention can be used for temporary plugging, profile modification, leakage plugging and well control in high-temperature and high-salinity oil and gas reservoirs.

[0056] The temporary plugging agent composition provided in the first aspect of the present invention undergoes a cross-linking reaction in a high-temperature reactor at 120°C to generate a temporary plugging agent gel. After 24 hours, the viscosity of the temporary plugging agent gel is measured and can reach 20,000-30,000 mPa·s. Then, the temperature is raised to 180°C, and after 48 hours, the viscosity of the temporary plugging agent gel is measured and can reach 15,000-18,000 mPa·s.

[0057] Taking the following temporary plugging agent composition as an example, the composition includes: 0.3 wt% thermosensitive copolymer, 0.01 wt% biosurfactant, 0.8 wt% polyphenol crosslinking agent, 0.5 wt% curing agent, 0.5 wt% nano-zirconia, 0.01 wt% initiator, 0.5 wt% cobalt chloride, and 97.38 wt% water. Based on this, by changing the amount of thermosensitive copolymer added, crosslinking reactions were carried out in a high-temperature reactor, and viscosity-temperature data of nano-thermosensitive gels with different concentration formulations after gelation were obtained. The results are shown in Table 1.

[0058] This invention employs a HAAKE MARSIII modular rheometer (equipped with a closed measurement system), heating the instrument to the desired temperature range, and using a magnetic rotor to measure the viscosity and viscoelasticity of the fluid in a closed container. The shear rate for measuring the system viscosity is 5 s. -1 The shear rate range for the system rheological curve test was 0.01 s⁻¹. -1 -10s -1 .

[0059] Table 1. Viscosity and temperature data of nano-thermosensitive gels with different concentrations after gelation.

[0060]

[0061] As shown in Table 1, when the polymer addition is 0.3-0.5 wt%, it has a better viscosity range and is more suitable for plugging gas channeling in heavy oil extraction.

[0062] Table 2 shows the comparative data between the temperature-sensitive temporary plugging agent nanogel obtained in this invention and existing colloidal types. Schematic diagrams of the network structures of conventional temperature-resistant gels, temperature-resistant copolymer systems, and the nanopolymer gel of this invention are shown below. Figure 3 As shown.

[0063] Table 2

[0064]

[0065] As shown in Table 2, the nanogel of this invention utilizes nanoparticles with special structures to crosslink with stable copolymer molecules, forming a nano-network structure with an average size of approximately 500 nm. The embedded nanoparticles further reduce the size of the high-strength nanogel network structure and improve its stability. The nano- and micro-structures exhibit significant steric hindrance effects on water molecules, and the copolymers possess good stability and high chemical bond energy, ensuring high strength and resistance to temperature, salt, and shear. In commonly used polymer-based organic crosslinked gels, the average size of the network structure formed by linear crosslinking of polymer molecules and crosslinking agents is generally tens of micrometers. The intermolecular forces between water and polymer molecules in the gel system are mainly weak intermolecular forces between polar groups in the polymer molecules and water molecules. Under high temperatures (120℃-150℃) or high shear rates, water loss is likely, and polymer molecules shrink or even degrade, causing phase separation between water and the gel network structure, leading to gel failure.

[0066] The temporary plugging agent of the present invention has the following effects:

[0067] (1) Good injection performance: low viscosity before gelation (5-1000 mPa·s);

[0068] (2) Temperature-sensitive properties: The gelation temperature is adjustable: 50℃-180℃, and the gelation can be controlled at different temperatures;

[0069] (3) Stable viscosity after gelation: 200 mPa·s-100000 mPa·s, which can be increased to hundreds of thousands of mPa·s with the addition of a curing agent;

[0070] (4) Good temperature resistance (up to 180-250℃): Low temperature sensitivity; the gelling state and viscosity decrease slowly as the temperature increases. The viscosity of the nanogel, which was 18500 mPa·s, decreased to 8700 mPa·s after aging at 250℃ for 10 days.

[0071] (5) Good shear resistance: 10s -1 After stirring for 1 hour, the viscosity retention rate is above 70wt%, and the gel depth after formation pore shearing is more than 3 times that of conventional gels.

[0072] (6) Good salt resistance: After contact with water with a mineralization of 100,000, the viscosity retention rate is 70wt%-80wt%; when mixed with water with a mineralization of 100,000, the viscosity retention rate is 30wt%-40wt%.

[0073] (7) Good temporary plugging effect: Different temporary plugging processes are designed according to different well temperatures and well conditions, and the plugging effectiveness is >95%.

[0074] Viscosity parameters (mPa·s) were measured using a HAAKE MARSIII modular rheometer (the HAAKE MARSIII rheometer is equipped with a closed measurement system; the instrument is heated to the required temperature range, and a magnetic rotor is used to measure the viscosity and viscoelasticity of the fluid in the closed container).

[0075] Viscosity retention rate = viscosity of the temporary plugging agent after aging / viscosity of the temporary plugging agent before aging × 100wt%.

[0076] The fourth aspect of this invention provides the application of the temporary plugging agent described in the third aspect in heavy oil extraction.

[0077] According to this invention, during field use, the concentration, dosage, and injection parameters of the temporary plugging agent should be adjusted according to different well conditions and well temperatures.

[0078] The specific application method of the temporary plugging agent provided by the present invention is as follows: First, design the temporary plugging agent composition and prepare the temporary plugging agent according to the well temperature. Then, calculate the required amount and injection rate of the temporary plugging agent according to the leakage rate and formation thickness of the well. Then, carry out on-site construction, record the end pressure and the wellhead pressure 3 days later, and evaluate whether the temporary plugging is successful.

[0079] In some embodiments of the present invention, the ground leakage velocity is 1-5 m / s. 3 / h but not including 5m 3 At a rate of / h, the dosage of the temporary plugging agent is 5-9m. 3 / m, injection rate is 0.5-0.6m 3 / min.

[0080] In some embodiments of the present invention, the ground leakage velocity is 5-10 m / s. 3 At a rate of / h, the dosage of the temporary plugging agent is 10-15m. 3 / m, injection rate is 1-1.2m 3 / min.

[0081] In some embodiments of the present invention, when the formation leakage velocity is >10m 3 At a rate of / h, the dosage of the temporary plugging agent is 20-25m. 3 / m, injection rate is 2-2.5m 3 / min.

[0082] According to this invention, three well conditions are classified based on the target temporary plugging temperature:

[0083] The first type, when the formation temperature is 120-150℃ but not including 150℃, the temporary plugging agent composition, based on a total weight of 100wt%, comprises: 0.3-0.4wt% of a thermosensitive copolymer, 0.01-0.015wt% of a surfactant, 0.8-1.0wt% of a polyphenol crosslinking agent, 0.5-0.6wt% of a curing agent, 0.5-0.8wt% of nano-zirconia, 0.01-0.015wt% of an initiator, 0.1-0.3wt% of cobalt chloride, and the balance being water.

[0084] The second method, when the stratum temperature is 150-200℃, the temporary plugging agent composition, based on a total weight of 100wt%, includes: 0.4-0.5wt% thermosensitive copolymer, 0.01-0.015wt% surfactant, 1.0-1.5wt% polyphenol crosslinking agent, 0.6-0.8wt% curing agent, 0.8-1.0wt% nano-zirconia, 0.01-0.015wt% initiator, 0.3-0.5wt% cobalt chloride, and the balance being water.

[0085] The third type, when the stratum temperature is greater than 200°C, the temporary plugging agent composition comprises, based on a total weight of 100 wt%, 0.5 wt% of a thermosensitive copolymer, 0.01 wt% of a surfactant, 1.5 wt% of a polyphenol crosslinking agent, 0.8 wt% of a curing agent, 1 wt% of nano-zirconia, 0.01 wt% of an initiator, 0.5 wt% of cobalt chloride, and the balance being water.

[0086] The present invention will be described in detail below through examples, but the scope of protection of the present invention is not limited to the following description. Unless otherwise specified in the following examples and comparative examples, conditions were performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0087] In the following embodiments:

[0088] Acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer, purchased from Aisen (China) Flocculant Co., Ltd., with a molecular weight of 3-5 million.

[0089] The nano-zirconia dispersion was purchased from Hangzhou Zhitai Purification Technology Co., Ltd. The nano-zirconia particle size is 30nm, the concentration of nano-zirconia is 20-40%, and the dispersion medium is water.

[0090] The cobalt chloride is anhydrous cobalt chloride, a blue crystalline powder, purchased from Baoding Fusai Cobalt & Nickel New Materials Co., Ltd., with the molecular formula CoCl and molecular weight 129.839.

[0091] Rhamnose glycolipid, purchased from Sichuan Sansen Biotechnology Co., Ltd., model number R5L.

[0092] Viscosity parameters (mPa·s): A HAAKE MARSIII modular rheometer (equipped with a closed measurement system) was used. The instrument was heated to the required measurement temperature range, and a magnetic rotor was used to measure the viscosity and viscoelasticity of the fluid in the closed container. The shear rate during viscosity measurement was 5 s. -1 The shear rate range for the system rheological curve test was 0.01 s⁻¹. -1 -10s -1 .

[0093] Example 1

[0094] Well Du 84-46-62 requires temporary plugging. Before plugging, the target formation temperature was tested at 135℃. Water injection tests showed that the formation leakage rate was 6.7 m / s². 3 / h, the target sealing layer is 12.8m.

[0095] Step 1: Based on the well temperature design and the concentration of the temporary plugging agent, with a well temperature of 135℃, the specific composition of the temporary plugging agent is as follows:

[0096]

[0097] The second step is to calculate the required amount of temporary plugging agent based on the well's leakage rate and formation thickness. At this leakage rate, the required amount of plugging agent is 10m³. 3 / m, the oil layer thickness is 12.8m, then the plugging agent dosage V = 10 × 12.8 = 128m 3 .

[0098] The third step is to prepare the following specific materials based on the total amount of temporary plugging agent needed:

[0099] Acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer weight W1 = 0.3wt% × 128m 3 =384kg;

[0100] Rhamnose lipid W2 = 0.01 wt% × 128 m 3 =12.8kg;

[0101] p-Bromophenol W3 = 1.5wt% × 128m 3 =1920kg;

[0102] 3,3'-Dimethyl-4,4-diaminodicyclohexylmethane W4 = 0.5wt% × 128m 3 =640kg;

[0103] Nano-zirconia W5 = 0.5wt% × 128m 3 =640kg;

[0104] Initiator potassium persulfate W6 = 0.01wt% × 128m 3 =12.8kg;

[0105] Anhydrous cobalt chloride W7 = 0.1 wt% × 128 m 3 =128kg;

[0106] Water W8≈124,000kg.

[0107] ① Preparation of copolymer mother liquor: Dissolve 12.8 kg of rhamnolipid in 124,000 kg of water, and at the same time add 384 kg of thermosensitive copolymer acrylamide (AM)-N-vinyl-2-pyrrolidone (NVP)-2-acrylamide-2-methacrylic acid (AMPS) to the solution. Stir at 100 rpm and at 50 °C.

[0108] ② Preparation of gel system: After the thermosensitive copolymer is completely dissolved, while keeping the stirring speed constant, add 1920 kg of p-bromophenol and 640 kg of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in sequence. After stirring for 5 min, add 640 kg of nano-zirconia and 12.8 kg of potassium persulfate.

[0109] ③ Insertion of cobalt chloride: Increase the stirring speed to 200 rpm, add 128 kg of anhydrous cobalt chloride, and pressurize the reactor to 2 MPa.

[0110] ④ Preparation of temporary plugging agent: Adjust the temperature of the reactor to 80℃, and complete the preparation of the temporary plugging agent after 6 hours. The viscosity of the temporary plugging agent is tested to be 280 mPa·s.

[0111] Step 4, on-site construction: The temporary plugging agent prepared above is added to a tanker truck and transported to the site. A 700-type pump truck is used for injection on-site. Based on the formation leakage situation, the injection rate is designed to be 1m / s². 3 / min.

[0112] Step 5, construction completed: The final pressure was 9.1 MPa, and the wellhead pressure was observed to be 8.9 MPa after 3 days, indicating that the temporary plugging was successful.

[0113] Example 2

[0114] Well Qi 40-21-54 requires temporary plugging. Before plugging, the target formation temperature was tested at 186℃. Water injection tests showed that the formation leakage rate was 3.4m / s. 3 / h, the target sealing layer is 24.2m.

[0115] Step 1: Based on the well temperature design and the concentration of the temporary plugging agent, with a well temperature of 186℃, the specific composition of the temporary plugging agent is as follows:

[0116]

[0117] The second step is to calculate the required amount of temporary plugging agent based on the well's leakage rate and formation thickness. At this leakage rate, the required amount of plugging agent is 5m³. 3 / m, the oil layer thickness is 24.2m, then the plugging agent dosage V=5×24.2=121m 3 .

[0118] The third step is to prepare the following specific materials based on the total amount of temporary plugging agent needed:

[0119] Acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer weight W1 = 0.4wt% × 121m 3 =484kg;

[0120] Rhamnose lipid W2 = 0.01 wt% × 121 m 3 =12.1kg;

[0121] p-Bromophenol W3 = 1.0 wt% × 121 m 3 =1210kg;

[0122] 3,3'-Dimethyl-4,4-diaminodicyclohexylmethane W4 = 0.6wt% × 121m 3 =726kg;

[0123] Nano-zirconia W5 = 0.8wt% × 121m 3 =968kg;

[0124] Initiator ammonium persulfate W6 = 0.01 wt% × 121 m 3 =12.1kg;

[0125] Anhydrous cobalt chloride W7 = 0.3 wt% × 121 m 3 =384kg;

[0126] Water W8≈117,000kg.

[0127] ① Preparation of copolymer mother liquor: 12.1 kg of rhamnolipid was dissolved in 117,000 kg of water, and 484 kg of acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer was added to the solution. The stirring speed was 150 rpm and the temperature was 50℃.

[0128] ② Preparation of gel system: After the thermosensitive copolymer is completely dissolved, while keeping the stirring speed constant, add 1210 kg of p-bromophenol and 726 kg of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in sequence. After stirring for 5 min, add 968 kg of nano-zirconia and 12.1 kg of ammonium persulfate.

[0129] ③ Embedding cobalt chloride: Increase the stirring speed to 200 rpm, add 384 kg of anhydrous cobalt chloride, and pressurize the reactor to 2 MPa.

[0130] ④ Preparation of temporary plugging agent: Adjust the temperature of the reactor to 80℃, and complete the preparation of the temporary plugging agent after 7 hours. The viscosity of the temporary plugging agent is tested to be 549 mPa·s.

[0131] Step 4, on-site construction: The temporary plugging agent prepared above is added to tanker trucks and transported to the site. Two 700-type pump trucks are used for injection on-site. Based on the formation leakage situation, the injection rate is designed to be 0.5m / s. 3 / min.

[0132] Step 5, construction completed: The final pressure was 8.2 MPa. After 3 days, the wellhead pressure was observed to be 8.1 MPa, indicating that the temporary plugging was successful.

[0133] Example 3

[0134] Well Du 84-56-152 requires temporary plugging. Before plugging, the target formation temperature was tested at 251℃. Water injection tests showed that the formation leakage rate was 16.9 m / s². 3 / h, the target sealing layer is 46.7m.

[0135] Step 1: Based on the well temperature design and the concentration of the temporary plugging agent, with a well temperature of 251℃, the specific composition of the temporary plugging agent is as follows:

[0136]

[0137] The second step is to calculate the required amount of temporary plugging agent based on the well's leakage rate and formation thickness. At this leakage rate, the required amount of plugging agent is 20m³. 3 / m, the oil layer thickness is 46.7m, then the plugging agent dosage V = 20 × 46.7 = 934m 3 .

[0138] The third step is to prepare the following specific materials based on the total amount of temporary plugging agent needed:

[0139] Acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer weight W1 = 0.5wt% × 934m 3 =4670kg;

[0140] Rhamnose lipid W2 = 0.01wt% × 934m 3 = 93.4 kg;

[0141] p-Bromophenol W3 = 0.8wt% × 934m 3 =7472kg;

[0142] 3,3'-Dimethyl-4,4-diaminodicyclohexylmethane W4 = 0.8wt% × 934m 3 =7472kg;

[0143] Nano-zirconia W5 = 1 wt% × 934 m 3 =9340kg;

[0144] Initiator ammonium persulfate W6 = 0.01wt% × 934m 3 = 93.4 kg;

[0145] Anhydrous cobalt chloride W7 = 0.5 wt% × 934 m 3 =4670kg;

[0146] Water W8≈900,000kg.

[0147] ① Preparation of copolymer mother liquor: Dissolve 93.4 kg of rhamnolipid in 900,000 kg of water, and simultaneously add 4670 kg of acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer to the solution. Stir at 150 rpm and at 50 °C.

[0148] ② Preparation of gel system: After the thermosensitive copolymer is completely dissolved, while keeping the stirring speed constant, add 7472 kg of p-bromophenol and 7472 kg of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in sequence. After stirring for 5 min, add 9340 kg of nano-zirconia and 93.4 kg of ammonium persulfate.

[0149] ③ Embedding cobalt chloride: Increase the stirring speed to 200 rpm, add 4670 kg of anhydrous cobalt chloride, and pressurize the reactor to 2 MPa.

[0150] ④ Preparation of temporary plugging agent: Adjust the temperature of the reactor to 80℃, and complete the preparation of the temporary plugging agent after 8 hours. The viscosity of the temporary plugging agent is tested to be 962 mPa·s.

[0151] Step 4, on-site construction: The temporary plugging agent prepared above is added to tanker trucks and transported to the site. Two 1000-type pump trucks are used for injection on-site. Based on the formation leakage situation, the injection rate is designed to be 2m / s. 3 / min.

[0152] The fifth step of the construction was completed, with a final pressure of 7.9 MPa. Three days later, the wellhead pressure was observed to be 7.4 MPa, indicating that the temporary plugging was successful.

[0153] Example 4

[0154] Well Du 84-46-62 requires temporary plugging. Before plugging, the target formation temperature was tested at 135℃. Water injection tests showed that the formation leakage rate was 6.7 m / s². 3 / h, the target sealing layer is 12.8m.

[0155] Step 1: Based on the well temperature design and the concentration of the temporary plugging agent, with a well temperature of 135℃, the specific composition of the temporary plugging agent is as follows:

[0156]

[0157] The second step is to calculate the required amount of temporary plugging agent based on the well's leakage rate and formation thickness. At this leakage rate, the required amount of plugging agent is 10m³. 3 / m, the oil layer thickness is 12.8m, then the plugging agent dosage V = 10 × 12.8 = 128m 3 .

[0158] The third step is to prepare the following specific materials based on the total amount of temporary plugging agent needed:

[0159] Acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer weight W1 = 0.4wt% × 128m 3 =512kg;

[0160] Rhamnose lipid W2 = 0.01 wt% × 128 m 3 =12.8kg;

[0161] p-Bromophenol W3 = 0.8wt% × 128m 3 =1920kg;

[0162] 3,3'-Dimethyl-4,4-diaminodicyclohexylmethane W4 = 0.5wt% × 128m 3 =640kg;

[0163] Nano-zirconia W5 = 0.5wt% × 128m 3 =640kg;

[0164] Initiator potassium persulfate W6 = 0.01wt% × 128m 3 =12.8kg;

[0165] Anhydrous cobalt chloride W7 = 0.1 wt% × 128 m 3 =128kg;

[0166] Water W8≈124,000kg.

[0167] ① Preparation of copolymer mother liquor: Dissolve 12.8 kg of rhamnolipid in 124,000 kg of water, and at the same time add 512 kg of acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer to the solution. Stir at 100 rpm and at 50 °C.

[0168] ② Preparation of gel system: After the copolymer is completely dissolved, while keeping the stirring speed constant, add 1920 kg of p-bromophenol and 640 kg of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in sequence. After stirring for 5 min, add 640 kg of nano-zirconia and 12.8 kg of potassium persulfate.

[0169] ③ Insertion of cobalt chloride: Increase the stirring speed to 200 rpm, add 128 kg of anhydrous cobalt chloride, and pressurize the reactor to 2 MPa.

[0170] ④ Preparation of temporary plugging agent: Adjust the temperature of the reactor to 80℃, and complete the preparation of the temporary plugging agent after 6 hours. The viscosity of the temporary plugging agent is tested to be 502 mPa·s.

[0171] Step 4, on-site construction: The temporary plugging agent prepared above is added to a tanker truck and transported to the site. A 700-type pump truck is used for injection on-site. Based on the formation leakage situation, the injection rate is designed to be 1m / s². 3 / min.

[0172] Step 5: Construction completed, pressure reduced to 11.9 MPa, temporary plugging successful.

[0173] Unlike Example 1, when the weight of the acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer was changed, the viscosity of the temporary plugging agent increased to 502 mPa·s, and the final actual injected temporary plugging dosage was 86 m. 3 To complete the construction, the final pressure was 11.9 MPa, and the temporary plugging was successful.

[0174] Example 5

[0175] Well Du 84-46-62 requires temporary plugging. Before plugging, the target formation temperature was tested at 135℃. Water injection tests showed that the formation leakage rate was 6.7 m / s². 3 / h, the target sealing layer is 12.8m.

[0176] Step 1: Based on the well temperature design and the concentration of the temporary plugging agent, with a well temperature of 135℃, the specific composition of the temporary plugging agent is as follows:

[0177]

[0178]

[0179] The second step is to calculate the required amount of temporary plugging agent based on the well's leakage rate and formation thickness. At this leakage rate, the required amount of plugging agent is 10m³. 3 / m, the oil layer thickness is 12.8m, then the plugging agent dosage V = 10 × 12.8 = 128m 3 .

[0180] The third step is to prepare the following specific materials based on the total amount of temporary plugging agent needed:

[0181] Acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer weight W1 = 0.3wt% × 128m 3 =384kg;

[0182] Rhamnose lipid W2 = 0.01 wt% × 128 m 3 =12.8kg;

[0183] p-Bromophenol W3 = 0.8wt% × 128m 3 =1024kg;

[0184] 3,3'-Dimethyl-4,4-diaminodicyclohexylmethane W4 = 0.5wt% × 128m 3 =640kg;

[0185] Nano-zirconia W5 = 0.5wt% × 128m 3 =640kg;

[0186] Initiator potassium persulfate W6 = 0.01wt% × 128m 3 =12.8kg;

[0187] Anhydrous cobalt chloride W7 = 0.1 wt% × 128 m 3 =128kg;

[0188] Water W8≈124,000kg.

[0189] ① Preparation of copolymer mother liquor: Dissolve 12.8 kg of rhamnolipid in 124,000 kg of water, and at the same time add 384 kg of acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer to the solution. Stir at 100 rpm and at 50 °C.

[0190] ② Preparation of gel system: After the thermosensitive copolymer is completely dissolved, while keeping the stirring speed constant, add 1024 kg of p-bromophenol and 640 kg of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in sequence. After stirring for 5 min, add 640 kg of nano-zirconia and 12.8 kg of potassium persulfate.

[0191] ③ Insertion of cobalt chloride: Increase the stirring speed to 200 rpm, add 128 kg of anhydrous cobalt chloride, and pressurize the reactor to 2 MPa.

[0192] ④ Preparation of temporary plugging agent: Adjust the temperature of the reactor to 80℃, and complete the preparation of the temporary plugging agent after 6 hours. The viscosity of the temporary plugging agent is tested to be 294 mPa·s.

[0193] Step 4, on-site construction: The temporary plugging agent prepared above is added to a tanker truck and transported to the site. A 700-type pump truck is used for injection on-site. Based on the formation leakage situation, the injection rate is designed to be 1m / s². 3 / min.

[0194] Step 5: Construction completed, pressure reduced to 9.1 MPa, temporary plugging successful.

[0195] Example 6

[0196] Well Du 84-46-62 requires temporary plugging. Before plugging, the target formation temperature was tested at 135℃. Water injection tests showed that the formation leakage rate was 6.7 m / s². 3 / h, the target sealing layer is 12.8m.

[0197] Step 1: Based on the well temperature design and the concentration of the temporary plugging agent, with a well temperature of 135℃, the specific composition of the temporary plugging agent is as follows:

[0198]

[0199] The second step is to calculate the required amount of temporary plugging agent based on the well's leakage rate and formation thickness. At this leakage rate, the required amount of plugging agent is 10m³. 3 / m, the oil layer thickness is 12.8m, then the plugging agent dosage V = 10 × 12.8 = 128m 3 .

[0200] The third step is to prepare the following specific materials based on the total amount of temporary plugging agent needed:

[0201] Acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer weight W1 = 0.3wt% × 128m 3 =384kg;

[0202] Rhamnose lipid W2 = 0.01 wt% × 128 m3 =12.8kg;

[0203] p-Bromophenol W3 = 1.5wt% × 128m 3 =1920kg;

[0204] 3,3'-Dimethyl-4,4-diaminodicyclohexylmethane W4 = 0.5wt% × 128m 3 =640kg;

[0205] Nano-zirconia W5 = 1 wt% × 128 m 3 =1280kg;

[0206] Initiator potassium persulfate W6 = 0.01wt% × 128m 3 =12.8kg;

[0207] Anhydrous cobalt chloride W7 = 0.1 wt% × 128 m 3 =128kg;

[0208] Water W8≈124,000kg.

[0209] ① Preparation of copolymer mother liquor: Dissolve 12.8 kg of rhamnolipid in 124,000 kg of water, and at the same time add 384 kg of acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer to the solution. Stir at 100 rpm and at 50 °C.

[0210] ② Preparation of gel system: After the copolymer is completely dissolved, while keeping the stirring speed constant, add 1920 kg of p-bromophenol and 640 kg of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in sequence. After stirring for 5 min, add 640 kg of nano-zirconia and 12.8 kg of potassium persulfate.

[0211] ③ Insertion of cobalt chloride: Increase the stirring speed to 200 rpm, add 128 kg of anhydrous cobalt chloride, and pressurize the reactor to 2 MPa.

[0212] ④ Preparation of temporary plugging agent: Adjust the temperature of the reactor to 80℃, and complete the preparation of the temporary plugging agent after 6 hours. The viscosity of the temporary plugging agent is tested to be 412 mPa·s.

[0213] Step 4, on-site construction: The temporary plugging agent prepared above is added to a tanker truck and transported to the site. A 700-type pump truck is used for injection on-site. Based on the formation leakage situation, the injection rate is designed to be 1m / s². 3 / min.

[0214] Step 5, construction completed: The final pressure was 10.1 MPa. After 3 days, the wellhead pressure was observed to be 10.1 MPa, indicating that the temporary plugging was successful.

[0215] Unlike Example 1, the amount of nano-zirconia used was increased, resulting in better construction results.

[0216] Comparative Example 1

[0217] Well Du 84-46-62 requires temporary plugging. Before plugging, the target formation temperature was tested at 135℃. Water injection tests showed that the formation leakage rate was 6.7 m / s². 3 / h, the target sealing layer is 12.8m.

[0218] Step 1: Based on the well temperature design and the concentration of the temporary plugging agent, with a well temperature of 135℃, the specific composition of the temporary plugging agent is as follows:

[0219]

[0220] The second step is to calculate the required amount of temporary plugging agent based on the well's leakage rate and formation thickness. At this leakage rate, the required amount of plugging agent is 10m³. 3 / m, the oil layer thickness is 12.8m, then the plugging agent dosage V = 10 × 12.8 = 128m 3 .

[0221] The third step is to prepare the following specific materials based on the total amount of temporary plugging agent needed:

[0222] Acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer weight W1 = 0.1wt% × 128m 3 =128kg;

[0223] Rhamnose lipid W2 = 0.005 wt% × 128 m 3 =6.4kg;

[0224] p-Bromophenol W3 = 0.2wt% × 128m 3 =256kg;

[0225] 3,3'-Dimethyl-4,4-diaminodicyclohexylmethane W4 = 0.1wt% × 128m 3 =128kg;

[0226] Nano-zirconia W5 = 0.1wt% × 128m 3 =128kg;

[0227] Initiator potassium persulfate W6 = 0.005 wt% × 128 m 3 =6.4kg;

[0228] Anhydrous cobalt chloride W7 = 0.05 wt% × 128 m 3 =64kg;

[0229] Water W8≈127,000kg.

[0230] ① Preparation of copolymer mother liquor: Dissolve 6.4 kg of rhamnolipid in 127,000 kg of water, and at the same time add 128 kg of acrylamide (AM) / N-vinyl-2-pyrrolidone (NVP) / 2-acrylamide-2-methacrylic acid (AMPS) thermosensitive copolymer to the solution. Stir at 100 rpm and at 50 °C.

[0231] ② Preparation of gel system: After the copolymer is completely dissolved, while keeping the stirring speed constant, add 256 kg of p-bromophenol and 128 kg of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in sequence. After stirring for 5 min, add 128 kg of nano-zirconia and 6.4 kg of potassium persulfate.

[0232] ③ Insertion of cobalt chloride: Increase the stirring speed to 200 rpm, add 64 kg of anhydrous cobalt chloride, and pressurize the reactor to 2 MPa.

[0233] ④ Preparation of temporary plugging agent: Adjust the temperature of the reactor to 80℃, and complete the preparation of the temporary plugging agent after 6 hours. The viscosity of the temporary plugging agent is tested to be 91 mPa·s.

[0234] Step 4, on-site construction: The temporary plugging agent prepared above is added to a tanker truck and transported to the site. A 700-type pump truck is used for injection on-site. Based on the formation leakage situation, the injection rate is designed to be 1m / s². 3 / min.

[0235] Step 5: Construction completed, pressure 0 MPa, temporary plugging failed.

[0236] Unlike Example 1, Comparative Example 1 is not within the scope of protection. Therefore, the temporary plugging agent did not undergo a solidification reaction during the injection process, and the temporary plugging failed.

[0237] Comparative Example 2

[0238] Well Du 84-46-62 requires temporary plugging. Before plugging, the target formation temperature was tested at 135℃. Water injection tests showed that the formation leakage rate was 6.7 m / s². 3 / h, the target sealing layer is 12.8m.

[0239] Step 1: Based on the well temperature design and the concentration of the temporary plugging agent, with a well temperature of 135℃, the specific composition of the temporary plugging agent is as follows:

[0240]

[0241] The second step is to calculate the required amount of temporary plugging agent based on the well's leakage rate and formation thickness. At this leakage rate, the required amount of plugging agent is 10m³. 3 / m, the oil layer thickness is 12.8m, then the plugging agent dosage V = 10 × 12.8 = 128m 3 .

[0242] The third step is to prepare the following specific materials based on the total amount of temporary plugging agent needed:

[0243] Rhamnose lipid W2 = 0.01 wt% × 128 m 3 =12.8kg;

[0244] p-Bromophenol W3 = 1.5wt% × 128m 3 =1920kg;

[0245] 3,3'-Dimethyl-4,4-diaminodicyclohexylmethane W4 = 0.5wt% × 128m 3 =640kg;

[0246] Nano-zirconia W5 = 0.5wt% × 128m 3 =640kg;

[0247] Potassium persulfate W6 = 0.01 wt% × 128 m 3 =12.8kg;

[0248] Anhydrous cobalt chloride W7 = 0.1 wt% × 128 m 3 =128kg;

[0249] Water W8≈124,000kg.

[0250] ① Preparation of mother liquor: Dissolve 12.8 kg of rhamnolipin in 124,000 kg of water, stirring at 100 rpm and at 50 °C;

[0251] ② Preparation of gel system: After the copolymer is completely dissolved, while keeping the stirring speed constant, add 1920 kg of p-bromophenol and 640 kg of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane in sequence. After stirring for 5 min, add 640 kg of nano-zirconia and 12.8 kg of potassium persulfate.

[0252] ③ Insertion of cobalt chloride: Increase the stirring speed to 200 rpm, add 128 kg of anhydrous cobalt chloride, and pressurize the reactor to 2 MPa.

[0253] ④ Preparation of temporary plugging agent: Adjust the temperature of the reactor to 80℃, and complete the preparation of the temporary plugging agent after 6 hours. The viscosity of the temporary plugging agent is tested to be 15 mPa·s.

[0254] Step 4, on-site construction: The temporary plugging agent prepared above is added to a tanker truck and transported to the site. A 700-type pump truck is used for injection on-site. Based on the formation leakage situation, the injection rate is designed to be 1m / s². 3 / min.

[0255] Step 5: Construction completed, pressure 0 MPa, temporary plugging failed.

[0256] Unlike Example 1, no temperature-sensitive copolymer was added in Comparative Example 2, so a temporary plugging agent could not be prepared at all, and the effect of temporarily plugging the oil layer could not be achieved.

[0257] Comparative Example 3

[0258] Well Du 84-46-62 requires temporary plugging. Before plugging, the target formation temperature was tested at 135℃. Water injection tests showed that the formation leakage rate was 6.7 m / s². 3 / h, the target sealing layer is 12.8m.

[0259] This comparative example uses a conventional temporary plugging formulation:

[0260]

[0261] Based on the total amount of temporary plugging agent needed, prepare the following specific materials:

[0262] Polyacrylamide weight W1 = 0.3wt% × 128m 3 =384kg;

[0263] Phenol W2 = 0.4 wt% × 128 m 3 =512kg;

[0264] Formaldehyde W3 = 0.4wt% × 128m 3 =512kg;

[0265] Bark powder W4 = 0.5wt% × 128m 3 =640kg;

[0266] Water W8≈126,000kg.

[0267] ① Preparation of copolymer mother liquor: Dissolve 384 kg of polyacrylamide in 126,000 kg of water, stirring at 100 rpm and at 50 °C.

[0268] ② Preparation of the gel system: After the polyacrylamide was completely dissolved, 512 kg of phenol and 512 kg of formaldehyde were added sequentially while maintaining the stirring speed. After stirring for 5 minutes, 640 kg of bark powder was added. The viscosity of the temporary plugging agent was tested to be 563 mPa·s.

[0269] On-site construction: The temporary plugging agent prepared above was added to a tanker truck and transported to the site. A 700-type pump truck was used for injection on-site. Based on the formation leakage situation, the injection rate was designed to be 1m / s². 3 / min.

[0270] Step 5: Construction completed, pressure 0 MPa, temporary plugging failed.

[0271] Unlike Example 1, Comparative Example 3 used a polyacrylamide temporary plugging system, which is only resistant to temperatures up to 95°C and therefore rapidly hydrates in formations at 135°C.

[0272] The performance results of the temporary plugging agents obtained in Examples 1-6 and Comparative Examples 1-3 are shown in Table 3.

[0273] Table 3

[0274]

[0275] As can be seen from the results in Table 3, Embodiments 1, 2, and 3 within the scope of protection of this invention have significantly better effects.

[0276] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A temporary plugging agent composition, characterized in that, Based on the total weight of the temporary plugging agent composition, the temporary plugging agent composition comprises: 0.3-0.5 wt% thermosensitive copolymer, 0.01-0.015 wt% biosurfactant, 0.8-1.5 wt% crosslinking agent, 0.5-0.8 wt% curing agent, 0.5-1 wt% nano-zirconia, 0.01-0.015 wt% initiator, 0.1-0.5 wt% cobalt chloride, and 95.67-97.78 wt% water; The crosslinking agent is p-bromophenol, 2-bromo-4-methylphenol, or 2,4,6-tribromophenol, and the thermosensitive copolymer is obtained by polymerization of acrylamide, N-vinyl-2-pyrrolidone, and 2-acrylamido-2-methylpropanesulfonic acid as monomers.

2. The temporary plugging agent composition according to claim 1, wherein the weight ratio of acrylamide, N-vinyl-2-pyrrolidone and 2-acrylamido-2-methylpropanesulfonic acid is 1.5-2:1-1.25:1-1.

25.

3. The temporary plugging agent composition according to claim 1 or 2, wherein, The biosurfactant is rhamnolipin or sophorolipid.

4. The temporary plugging agent composition according to claim 1 or 2, wherein, The curing agent is 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, m-phenylenediamine, or diaminodiphenylmethane.

5. The temporary plugging agent composition according to claim 1 or 2, wherein, The initiator is a persulfate.

6. The temporary plugging agent composition according to claim 1 or 2, wherein, The initiator is potassium persulfate, sodium persulfate, or ammonium persulfate.

7. The temporary plugging agent composition according to claim 1 or 2, wherein, The nano-zirconia has a particle size of 10-50 nm.

8. A method for preparing a temporary plugging agent, characterized in that, The temporary plugging agent is prepared using the temporary plugging agent composition according to any one of claims 1-7, wherein the preparation method comprises: (1) Dissolve the biosurfactant in water to form a biosurfactant dispersion; dissolve the thermosensitive copolymer in the biosurfactant dispersion and perform a first treatment. After the copolymer is completely dissolved, a copolymer mother liquor is obtained. (2) Add a crosslinking agent, a curing agent, nano-zirconia and an initiator to the copolymer mother liquor to obtain a gel system, wherein the crosslinking agent is p-bromophenol, 2-bromo-4-methylphenol or 2,4,6-tribromophenol; (3) Add cobalt chloride to the gel system and perform a second treatment to obtain a temporary plugging agent; The thermosensitive copolymer is obtained by polymerization of acrylamide, N-vinyl-2-pyrrolidone and 2-acrylamido-2-methylpropanesulfonic acid as monomers.

9. The preparation method according to claim 8, wherein, The concentration of the biosurfactant in the biosurfactant dispersion is 0.01-0.015 wt%.

10. The preparation method according to claim 8, wherein, The weight ratio of the biosurfactant to the thermosensitive copolymer, crosslinking agent, curing agent, nano-zirconia, initiator and cobalt chloride is 0.01-0.015:0.3-0.5:0.8-1.5:0.5-0.8:0.5-1:0.01-0.015:0.1-0.

5.

11. The preparation method according to claim 8, wherein, The weight ratio of acrylamide, N-vinyl-2-pyrrolidone and 2-acrylamide-2-methylpropanesulfonic acid is 1.5-2:1-1.25:1-1.

25.

12. The preparation method according to any one of claims 8-11, wherein, The biosurfactant is rhamnolipin or sophorolipin; And / or, the curing agent is 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, m-phenylenediamine, or diaminodiphenylmethane; And / or, the initiator is a persulfate; And / or, the particle size of the nano-zirconia is 10-50 nm.

13. The preparation method according to claim 12, wherein, The initiator is potassium persulfate, sodium persulfate, or ammonium persulfate.

14. The preparation method according to any one of claims 8-11, wherein, In step (1), the conditions for the first treatment include: a stirring speed of 100-200 rpm, a temperature of 50-60℃, a pressure of 1-1.5 MPa, and a time of 10-15 min.

15. The preparation method according to any one of claims 8-11, wherein, Step (2) specifically includes: at a stirring speed of 100-200 rpm, first add the crosslinking agent and curing agent to the copolymer mother liquor in sequence, stir for 5-10 min, and then add nano-zirconia and initiator.

16. The preparation method according to any one of claims 8-11, wherein, In step (3), the second treatment includes: first stirring at 200-250 rpm at 50-60℃ and 1.5-2 MPa, and then aging at 60-80℃ for 6-8 hours.

17. A temporary plugging agent prepared by any one of claims 8-16.

18. The application of the temporary plugging agent according to claim 17 in heavy oil extraction.

19. The application according to claim 18, wherein, When the stratum leakage velocity is 1-5m 3 / h but not including 5m 3 At a rate of / h, the dosage of the temporary plugging agent is 5-9m. 3 / m, injection rate is 0.5-0.6m 3 / min; Alternatively, when the stratum leakage velocity is 5-10m 3 At a rate of / h, the dosage of the temporary plugging agent is 10-15m. 3 / m, injection rate is 1-1.2m 3 / min; Or, when the formation leakage velocity is >10m 3 At a rate of / h, the dosage of the temporary plugging agent is 20-25m. 3 / m, injection rate is 2-2.5m 3 / min.

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