Composition for composite dual-network polymer gel plugging agent, composite dual-network polymer gel plugging agent, and preparation method therefor and use thereof
Patent Information
- Application Number
- PCT/CN2026/085156
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-28
- Filing Date
- 2026-03-23
- Publication Date
- 2026-10-01
Smart Images
Figure CN2026085156_01102026_PF_FP_ABST
Abstract
Description
Compositions for composite dual-network polymer gel plugging agents, composite dual-network polymer gel plugging agents, their preparation methods and applications
[0001] Cross-reference to related applications
[0002] This application claims the benefit of Chinese Patent Application No. 202510384706.0, filed on March 28, 2025, the contents of which are incorporated herein by reference. Technical Field
[0003] This invention relates to the field of oilfield chemistry, specifically to a composition for a composite dual-network polymer gel plugging agent, the composite dual-network polymer gel plugging agent, its preparation method, and its application. Background Technology
[0004] Profile control and water shut-off are among the important technologies for improving reservoir heterogeneity and enhancing reservoir recovery.
[0005] During water injection development of fractured and porous reservoirs, due to reservoir heterogeneity and the presence of natural fractures, injected water is prone to severe water channeling along high-permeability layers or fractures, reducing water drive sweep efficiency, increasing well water cut, exacerbating ineffective water injection, and seriously restricting the development benefits of the oilfield.
[0006] Polymer gels, as one of the most effective profile control and plugging agents, have been widely studied and applied in oilfield development.
[0007] Currently, the technology for deep profile control in medium- and high-temperature reservoirs is relatively mature. However, the contradiction between low-temperature gelation and high-salinity stability has led to the slow development of profile control systems for low-temperature and high-salinity reservoirs.
[0008] In low-temperature environments, polyacrylamide polymer (HPAM) / organic acid chromium system and HPAM / phenolic system are more commonly used. HPAM / organic acid chromium system has a relatively short gelation time (<1 day) in low-temperature environments and poor long-term stability under high salt and high divalent metal ion conditions. HPAM and phenolic crosslinking system has low crosslinking reactivity in low-temperature environments. Generally, the gelation time of the system is controlled by controlling the amount of crosslinking agent, polymer and crosslinking accelerator. Under suitable gelation time conditions, the system has problems such as poor injection, weak gel strength or poor stability.
[0009] For example, CN113913168A discloses a low-temperature, high-salt-resistant deep-penetration crosslinking system, its preparation method, and its application. This system is a gel system formed by a combination of a polymeric flocculant and a phenolic crosslinking agent under the catalysis of an organic acid. The combined crosslinking agent consists of hexamethylenetetramine and resorcinol. The gelation time of this system is controllable at 20-40℃ for 36-96 hours, but the amount of reagents used is relatively high, the viscosity of the gel is high, and the deep-penetration ability is limited.
[0010] For example, CN106916249A discloses a plugging agent suitable for water shut-off and profile control in low-temperature, high-salinity oil reservoirs. This plugging agent is produced by in-situ polymerization of acrylamide with a mass concentration of 5.00-7.00%, N,N-methylenebisacrylamide with a mass concentration of 0.50-0.70%, ammonium persulfate with a mass concentration of 0.40-0.60%, and sodium ferricyanide with a mass concentration of 0.06-0.10%. Acrylamide is known to be highly toxic and is not suitable for direct injection into oil fields.
[0011] Besides in-situ cross-linked polymer gels, organic gel particulate plugging agents are also the most widely used type of polymer gel plugging agents in oilfields, such as pre-cross-linked gel particles, polymer microspheres, and gel dispersions. CN210085365U discloses a pre-cross-linked polyacrylamide particle for deep plugging, which has good injectability and a certain plugging effect. However, particulate plugging agents cannot effectively improve the water injection pressure in layers containing high-permeability channels or fractures, and the particles are easily extracted from adjacent production wells during field operations.
[0012] In response to the severe water channeling in fractured and porous reservoirs, and the problem of deep migration blockage in current deep regulation and driving agents for low-temperature and high-salinity reservoirs, there is an urgent need to provide a new deep regulation and driving agent and its application. Summary of the Invention
[0013] The purpose of this invention is to provide a low-temperature, high-salinity oil reservoir composite dual-network polymer gel plugging agent that can migrate deep into the formation and effectively seal high-permeability layers.
[0014] To achieve the above objectives, a first aspect of the present invention provides a composition for a composite dual-network polymer gel plugging agent, the composition comprising a main agent and auxiliary agents, wherein the main agent is an AM / AMPS binary copolymer, and the auxiliary agents include a metal ion crosslinking agent, a non-metal ion organic crosslinking agent, and an accelerator; based on the total weight of the composition, the content of the AM / AMPS binary copolymer in the composition is 0.4wt%-1.0wt%, the content of the metal ion crosslinking agent is 0.01wt%-0.02wt%, the content of the non-metal ion organic crosslinking agent is 0.4wt%-1.0wt%, and the content of the accelerator is 0.2wt%-0.6wt%.
[0015] In the AM / AMPS binary copolymer, the content of AMPS as a structural unit is 5-10 mol%.
[0016] The non-metallic ionic organic crosslinking agent is a phenolic prepolymer crosslinking agent.
[0017] A second aspect of the present invention provides a method for preparing a composite dual-network polymer gel plugging agent, the method being carried out using the composite dual-network polymer gel plugging agent composition described in the first aspect above, comprising: mixing and contacting the main agent and the components of the auxiliary agent in the composite dual-network polymer gel plugging agent composition in the presence of water.
[0018] A third aspect of the present invention provides a composite dual-network polymer gel plugging agent prepared by the method described in the second aspect above.
[0019] The fourth aspect of this invention provides the application of the composite dual-network polymer gel plugging agent described in the third aspect above in deep profile control and plugging of low-temperature, high-salinity oil reservoirs.
[0020] Through the above technical solution, the present invention has at least the following beneficial technical effects:
[0021] (1) The composite dual-network polymer gel plugging agent provided by the present invention is composed of two composite crosslinking agents with different crosslinking effects, and has a dual network structure.
[0022] Specifically, the metal ion crosslinking agent undergoes a crosslinking reaction with the polymer under low-temperature conditions through coordination bonds, forming a certain weak network structure. This weak network structure has good ductility and self-healing properties. During reservoir injection, the gel plugging agent can be stretched and deformed to penetrate deep into the formation. The structure that is sheared and damaged in the formation can be crosslinked again through coordination bonds. As the aging time increases, the non-metal ion organic crosslinking agent further interacts with the polymer through covalent bonds to form a dense network structure, giving the gel high strength and good salt resistance.
[0023] (2) The composite dual-network polymer gel plugging agent provided by the present invention has a long gelation time for the non-metallic ion organic crosslinking system at low temperature. The rapid gelation of the metal ion crosslinking agent can reduce the chromatographic separation and dilution of the system during the formation injection process and reduce the impact of dilution on the gelation performance of the non-metallic ion organic crosslinking system. The composite crosslinking agent has a good synergistic effect in the polymer gel system.
[0024] (3) In the composite dual-network polymer gel plugging agent provided by the present invention, the low-temperature pre-crosslinked network system can reduce the damage to medium and low permeability oil layers during formation migration. The non-metallic ion organic crosslinking system has a gelation time of more than 30 days at low temperature. Without affecting the injectability, it can gel in the deep formation to form a high-strength gel. The composite dual-network polymer gel can achieve deep formation migration and effectively plug high permeability layers. Attached Figure Description
[0025] Figure 1 is a graph showing the change in gel viscosity of the composite dual-network polymer gel plugger-A1 prepared in Example 1;
[0026] Figure 2 shows the viscosity variation of the composite dual-network polymer gel plugger-DA5 prepared in Comparative Example 5. Detailed Implementation
[0027] 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.
[0028] In this invention, AM stands for acrylamide, AMPS stands for 2-acrylamido-2-methylpropanesulfonic acid, and AM / AMPS binary copolymer represents a binary copolymer prepared using acrylamide and 2-acrylamido-2-methylpropanesulfonic acid as reactive monomers.
[0029] As previously described, the first aspect of the present invention provides a composition for a composite dual-network polymer gel plugging agent, the composition comprising a main agent and auxiliary agents, wherein the main agent is an AM / AMPS binary copolymer, and the auxiliary agents include a metal ion crosslinking agent, a non-metal ion organic crosslinking agent, and an accelerator; based on the total weight of the composition, the content of the AM / AMPS binary copolymer in the composition is 0.4wt%-1.0wt%, the content of the metal ion crosslinking agent is 0.01wt%-0.02wt%, the content of the non-metal ion organic crosslinking agent is 0.4wt%-1.0wt%, and the content of the accelerator is 0.2wt%-0.6wt%.
[0030] In the AM / AMPS binary copolymer, the content of AMPS as a structural unit is 5-10 mol%.
[0031] The non-metallic ionic organic crosslinking agent is a phenolic prepolymer crosslinking agent.
[0032] According to a preferred embodiment, based on the total weight of the composition, the content of the AM / AMPS binary copolymer in the composition is 0.4wt%-0.6wt%, the content of the metal ion crosslinking agent is 0.01wt%-0.02wt%, the content of the non-metal ion organic crosslinking agent is 0.5wt%-0.8wt%, and the content of the accelerator is 0.4wt%-0.6wt%.
[0033] According to a preferred embodiment, the phenolic molar ratio of the phenolic prepolymer crosslinking agent is 1:2-3.
[0034] According to a preferred embodiment, the phenolic substance in the phenolic prepolymer crosslinking agent is phenol, and the aldehyde substance is formaldehyde.
[0035] According to a more preferred embodiment, the phenolic prepolymer crosslinking agent has a degree of polymerization of 2-8 and a solid content of 30-35 wt%. The inventors of this invention have discovered that, under this preferred embodiment, the composite dual-network polymer gel plugging agent provided by this invention exhibits superior long-term stability and gel strength.
[0036] Preferably, the relative molecular mass of the AM / AMPS binary copolymer is between 6 million and 8 million.
[0037] More preferably, the adjuvant in the composition further includes water, the water having a mineralization of 80,000 mg / L-120,000 mg / L, and the water containing Ca... 2+ and Mg 2+ The sum of their concentrations is 5000mg / L-10000mg / L.
[0038] More preferably, the water has a mineralization of 80,000 mg / L to 100,000 mg / L, and the Ca in the water... 2+ and Mg 2+ The sum of their concentrations is 6000 mg / L - 8000 mg / L.
[0039] More preferably, the water is the balance based on the total weight of the composition.
[0040] In a preferred embodiment, the metal ion crosslinking agent is selected from at least one of aluminum citrate crosslinking agent, chromium acetate crosslinking agent, and organozirconium crosslinking agent.
[0041] Particularly preferably, the metal ion crosslinking agent is a chromium acetate crosslinking agent. The inventors of this invention have discovered that, under this preferred embodiment, the composite dual-network polymer gel plugging agent provided by this invention has a controllable initial gelling viscosity.
[0042] Preferably, the accelerator is ammonium chloride.
[0043] As previously stated, a second aspect of the present invention provides a method for preparing a composite dual-network polymer gel plugging agent, the method being carried out using the composite dual-network polymer gel plugging agent composition described in the first aspect, comprising: mixing and contacting the main agent and the components of the auxiliary agent in the composite dual-network polymer gel plugging agent composition in the presence of water.
[0044] Preferably, the method further includes: before performing the mixing contact, first mixing the main agent with a portion of water to obtain a main agent stock solution I with a concentration of 0.5-1.5 wt%; second mixing the main agent stock solution I with another portion of water to obtain a main agent stock solution II with a concentration of 0.4-1.0 wt%; and then performing the mixing contact between the main agent stock solution II and the remaining components in the composite dual-network polymer gel plugging agent composition.
[0045] Preferably, the first mixing is carried out under stirring condition I, wherein the stirring speed of stirring condition I is 300-400 rpm.
[0046] More preferably, the first mixing time is 3-4 hours.
[0047] Preferably, the second mixing is carried out under stirring condition II, wherein the stirring speed of stirring condition II is 200-400 rpm.
[0048] More preferably, the second mixing time is 5-60 minutes.
[0049] According to a preferred embodiment, a method for preparing the composite dual-network polymer gel plugging agent includes:
[0050] (1) Under the condition of a rotation speed of 300-400 rpm, the main agent is mixed with a portion of water for 3-4 hours to obtain a main agent mother liquor I with a concentration of 0.5-1.5 wt%;
[0051] (2) Under the condition of a rotation speed of 200-400 rpm, the main agent mother liquor I is mixed with another part of water for 5-60 min to obtain the main agent mother liquor II with a concentration of 0.4-1.0 wt%;
[0052] (3) Under the condition of a rotation speed of 200-400 rpm, the metal ion crosslinking agent and the main agent mother liquor II are stirred and mixed to obtain solution III;
[0053] (4) Under the condition of a rotation speed of 200-300 rpm, the non-metallic ion organic crosslinking agent and the accelerator are stirred and mixed with the solution III for 15-25 min to obtain the composite dual network polymer gel plugging agent.
[0054] As previously stated, the third aspect of the present invention provides a composite dual-network polymer gel plugging agent prepared by the method described in the second aspect above.
[0055] As mentioned above, the fourth aspect of the present invention provides the application of the composite dual-network polymer gel plugging agent described in the third aspect above in deep profile modification and plugging of low-temperature, high-salinity oil reservoirs.
[0056] Preferably, the temperature of the low-temperature, high-salinity oil reservoir is 30℃-50℃.
[0057] More preferably, the temperature of the low-temperature, high-salinity reservoir is 40°C-50°C.
[0058] More preferably, the formation water salinity of the low-temperature, high-salinity oil reservoir is 80,000 mg / L-120,000 mg / L, and the Ca in the formation water is... 2+ and Mg 2+ The sum of their concentrations is 5000mg / L-10000mg / L.
[0059] More preferably, the formation water salinity of the low-temperature, high-salinity reservoir is 80,000 mg / L-100,000 mg / L, and the Ca in the formation water is... 2+ and Mg 2+ The sum of their concentrations is 6000 mg / L - 8000 mg / L.
[0060] In this invention, the elastic modulus of the prepared composite dual-network polymer gel plug is measured using a rheometer to assess its gelation strength; the long-term stability of the composite dual-network polymer gel plug is assessed by the dehydration rate; in addition, the gelation viscosity of the composite dual-network polymer gel plug is measured using a rheometer.
[0061] 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. In the following examples, unless otherwise specified, all raw materials and reagents used are common commercially available products, and all are of analytical grade.
[0062] The following examples include some of the raw materials used and their sources:
[0063] AM / AMPS binary copolymer:
[0064] AM / AMPS binary copolymer-I: The content of the structural units provided by AMPS is 5 mol%, grade AN105, purchased from Aisen (China) Flocculant Co., Ltd.
[0065] AM / AMPS binary copolymer-II: The content of the structural units provided by AMPS is 15 mol%, grade AN113, purchased from Aisen (China) Flocculant Co., Ltd.
[0066] Polyacrylamide polymer (HPAM): degree of hydrolysis 5%, grade AN905, purchased from Aisen (China) Flocculant Co., Ltd.
[0067] Metal ion crosslinking agent:
[0068] Metal ion crosslinking agent-I: Chromium acetate crosslinking agent, grade Cr(Ⅲ)-45, purchased from Shandong Chemical Co., Ltd.;
[0069] Metal ion crosslinking agent-II: Aluminum citrate crosslinking agent, brand name Al-65, purchased from Shandong Chemical Co., Ltd.;
[0070] Non-metallic ionic organic crosslinking agents:
[0071] Phenolic prepolymer crosslinking agent-I: phenolic molar ratio is 1:2.2, degree of polymerization is 2-8, solid content is 32wt%, grade is WSPF-30, purchased from Jinan Shengquan Group Co., Ltd.
[0072] Phenolic prepolymer crosslinking agent-II: phenol and formaldehyde molar ratio is 1:3.5, degree of polymerization is 10-15, solid content is 35wt%, grade WSPF-G30, purchased from Jinan Shengquan Group Co., Ltd.
[0073] Phenolic crosslinking agent: A mixture of resorcinol and paraformaldehyde in a 1:1 mass ratio, wherein...
[0074] Hydroquinone: purchased from Shanghai Guoyao; Paraformaldehyde: purchased from Shanghai Guoyao.
[0075] Accelerator: Ammonium chloride;
[0076] Water: mineralization is 100,000 mg / L, Ca 2+ and Mg 2+ The sum of the concentrations is 6000 mg / L.
[0077] Example 1
[0078] This embodiment provides a preparation method for a composite dual-network polymer gel plugging agent, comprising the following steps:
[0079] (1) Weigh 1g of AM / AMPS binary copolymer-I and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of chromium acetate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% chromium acetate crosslinking agent mother liquor; weigh 1g of phenolic prepolymer crosslinking agent-I and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0080] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0081] (2) Weigh 40g of AM / AMPS binary copolymer mother liquor I and add it to 50g of water. Stir at 300rpm until homogeneous to obtain AM / AMPS binary copolymer mother liquor II.
[0082] (3) Add 1g of chromium acetate crosslinking agent mother liquor, 5g of phenolic prepolymer crosslinking agent mother liquor and 4g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor II in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-A1.
[0083] Example 2
[0084] This embodiment provides a preparation method for a composite dual-network polymer gel plugging agent, comprising the following steps:
[0085] (1) Weigh 1g of AM / AMPS binary copolymer-I and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of chromium acetate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% chromium acetate crosslinking agent mother liquor; weigh 1g of phenolic prepolymer crosslinking agent-I and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0086] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0087] (2) Weigh 50g of AM / AMPS binary copolymer mother liquor I and add it to 36.5g of water. Stir at 300rpm until homogeneous to obtain AM / AMPS binary copolymer mother liquor II.
[0088] (3) Add 1.5g of chromium acetate crosslinking agent mother liquor, 7g of phenolic prepolymer crosslinking agent mother liquor and 5g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor II in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-A2.
[0089] Example 3
[0090] This embodiment provides a preparation method for a composite dual-network polymer gel plugging agent, comprising the following steps:
[0091] (1) Weigh 1g of AM / AMPS binary copolymer-I and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of chromium acetate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% chromium acetate crosslinking agent mother liquor; weigh 1g of phenolic prepolymer crosslinking agent-I and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0092] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0093] (2) Weigh 40g of AM / AMPS binary copolymer mother liquor I and add it to 44g of water. Stir at 300rpm until homogeneous to obtain AM / AMPS binary copolymer mother liquor II.
[0094] (3) Add 2g of chromium acetate crosslinking agent mother liquor, 8g of phenolic prepolymer crosslinking agent mother liquor and 6g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor II in sequence, and stir at 200 rpm for 20 min to obtain composite double network polymer gel blocker-A3.
[0095] Example 4
[0096] This embodiment uses a method similar to that of Example 1, except that an equal amount of phenolic prepolymer crosslinking agent II is used instead of phenolic prepolymer crosslinking agent I. The specific steps include:
[0097] (1) Weigh 1g of AM / AMPS binary copolymer-I and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of chromium acetate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% chromium acetate crosslinking agent mother liquor; weigh 1g of phenolic prepolymer crosslinking agent-II and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0098] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0099] (2) Weigh 40g of AM / AMPS binary copolymer mother liquor I and add it to 50g of water. Stir at 300rpm until homogeneous to obtain AM / AMPS binary copolymer mother liquor II.
[0100] (3) Add 1g of chromium acetate crosslinking agent mother liquor, 5g of phenolic prepolymer crosslinking agent mother liquor and 4g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor II in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-A4.
[0101] Example 5
[0102] This embodiment uses a method similar to that of Example 1, except that an equal amount of aluminum citrate crosslinking agent is used instead of chromium acetate crosslinking agent. The specific steps include:
[0103] (1) Weigh 1g of AM / AMPS binary copolymer-I and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of aluminum citrate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% aluminum citrate crosslinking agent mother liquor; weigh 1g of phenolic prepolymer crosslinking agent-I and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0104] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0105] (2) Weigh 40g of AM / AMPS binary copolymer mother liquor I and add it to 50g of water. Stir at 300rpm until homogeneous to obtain AM / AMPS binary copolymer mother liquor II.
[0106] (3) Add 1g of aluminum citrate crosslinking agent, 5g of phenolic prepolymer crosslinking agent mother liquor and 4g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-A5.
[0107] Comparative Example 1
[0108] This comparative example was conducted using a method similar to that of Example 1, except that an equal amount of the phenolic composite crosslinking agent was used to replace the phenolic prepolymer crosslinking agent-I. The specific steps included:
[0109] (1) Weigh 1g of AM / AMPS binary copolymer-I and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of chromium acetate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% chromium acetate crosslinking agent mother liquor; weigh 1g of phenolic compound crosslinking agent and add it to 9g of water, stir and mix to prepare 10wt% phenolic compound crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0110] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0111] (2) Weigh 40g of AM / AMPS binary copolymer mother liquor I and add it to 50g of water. Stir at 300rpm until homogeneous to obtain AM / AMPS binary copolymer mother liquor II.
[0112] (3) Add 1g of chromium acetate crosslinking agent mother liquor, 5g of phenolic composite crosslinking agent mother liquor and 4g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor II in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-DA1.
[0113] Comparative Example 2
[0114] This comparative example was conducted using a method similar to that of Example 1, except that an equal amount of polyacrylamide polymer (HPAM) was used instead of AM / AMPS binary copolymer-I. The specific steps included:
[0115] (1) Weigh 1g of polyacrylamide polymer (HPAM) and add it to 99g of water, stir and mix to prepare 1wt% HPAM polymer mother liquor I; weigh 1g of chromium acetate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% chromium acetate crosslinking agent mother liquor; weigh 1g of phenolic prepolymer crosslinking agent-I and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0116] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0117] (2) Weigh 40g of HPAM polymer mother liquor I and add it to 50g of water. Stir at 300rpm until homogeneous to obtain HPAM polymer mother liquor II.
[0118] (3) Add 1g of chromium acetate crosslinking agent mother liquor, 5g of phenolic prepolymer crosslinking agent mother liquor and 4g of ammonium chloride mother liquor to HPAM polymer mother liquor II in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-DA2.
[0119] Comparative Example 3
[0120] This comparative example was conducted using a method similar to that of Example 1, except that an equal amount of AM / AMPS binary copolymer-II was used instead of AM / AMPS binary copolymer-I. The specific steps included:
[0121] This comparative example provides a method for preparing a composite dual-network polymer gel plugging agent, comprising the following steps:
[0122] (1) Weigh 1g of AM / AMPS binary copolymer-II and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of chromium acetate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% chromium acetate crosslinking agent mother liquor; weigh 1g of phenolic prepolymer crosslinking agent-I and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0123] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0124] (2) Weigh 40g of AM / AMPS binary copolymer mother liquor I and add it to 50g of water. Stir at 300rpm until homogeneous to obtain AM / AMPS binary copolymer mother liquor II.
[0125] (3) Add 1g of chromium acetate crosslinking agent mother liquor, 5g of phenolic prepolymer crosslinking agent mother liquor and 4g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor II in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-DA3.
[0126] Comparative Example 4
[0127] This comparative example was conducted using a method similar to that of Example 1, except that the amount of accelerator was adjusted to 0.8 wt%. The specific steps included:
[0128] (1) Weigh 1g of AM / AMPS binary copolymer-I and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of chromium acetate crosslinking agent and add it to 99g of water, stir and mix to prepare 1wt% chromium acetate crosslinking agent mother liquor; weigh 1g of phenolic prepolymer crosslinking agent-I and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0129] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0130] (2) Weigh 40g of AM / AMPS binary copolymer mother liquor I and add it to 46g of water. Stir at 300rpm to obtain AM / AMPS binary copolymer mother liquor II.
[0131] (3) Add 1g of chromium acetate crosslinking agent mother liquor, 5g of phenolic prepolymer crosslinking agent mother liquor and 8g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor II in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-DA4.
[0132] Comparative Example 5
[0133] This comparative example was conducted using a method similar to that of Example 1, except that no metal ion crosslinking agent was added. The specific steps included:
[0134] (1) Weigh 1g of AM / AMPS binary copolymer-I and add it to 99g of water, stir and mix to prepare 1wt% AM / AMPS binary copolymer mother liquor I; weigh 1g of phenolic prepolymer crosslinking agent-I and add it to 9g of water, stir and mix to prepare 10wt% phenolic prepolymer crosslinking agent mother liquor; weigh 1g of ammonium chloride and add it to 9g of water, stir and mix to prepare 10wt% ammonium chloride mother liquor;
[0135] Control the speed of all the above stirring and mixing processes to 300 rpm;
[0136] (2) Weigh 40g of AM / AMPS binary copolymer mother liquor I and add it to 51g of water. Stir at 300rpm to obtain AM / AMPS binary copolymer mother liquor II.
[0137] (3) Add 5g of phenolic prepolymer crosslinking agent mother liquor and 4g of ammonium chloride mother liquor to AM / AMPS binary copolymer mother liquor II in sequence, and stir at 200rpm for 20min to obtain composite double network polymer gel blocker-DA5.
[0138] Test case
[0139] This test example illustrates the performance testing of the composite dual-network polymer gel plugging agents prepared in the above examples.
[0140] Gel strength: The elastic modulus of each material was tested using a rheometer;
[0141] Long-term stability: After 100 days of aging, observe whether each material undergoes dehydration and degradation, and evaluate the long-term stability of each material based on the dehydration rate.
[0142] Test Example 1
[0143] Take 20 mL of the composite dual-network polymer gel plugging agent obtained in each of the above examples and place it in an ampoule. Place the ampoule in a constant temperature water bath at 40°C.
[0144] The specific test results are shown in Table 1.
[0145] In Table 1, the formula for calculating the dehydration rate is:
[0146] In the formula, M is the initial mass of the gel, in g; m w The mass of water removed from the gel is expressed in grams.
[0147] Table 1
[0148] Figure 1 shows the viscosity change of the composite dual-network polymer gel plugger-A1 prepared in Example 1 over a period of 0-1000 hours. Based on the data in Table 1 and Figure 1, it can be concluded that the composite dual-network polymer gel plugger prepared in this invention exhibits typical two-stage gelation and thickening characteristics. The metal ion crosslinking agent undergoes initial crosslinking with the polymer, forming a weak gel. With increasing aging time, the non-metal ion organic crosslinking agent further crosslinks with the polymer, further increasing the viscosity of the gel system. The formed polymer gels did not exhibit dehydration or degradation after 100 days of aging.
[0149] Compared with Example 1, when the non-metallic ionic organic crosslinking agent in Comparative Example 1 uses a phenolic combination system, the salt-resistant gelation time is greatly shortened, the two crosslinking agents fail to produce a synergistic effect, and the dehydration rate reaches 10% after aging for 100 days.
[0150] In Comparative Example 2, when HPAM polymer was used instead of AM / AMPS binary copolymer, the results showed that the low-temperature gelation time of the polymer was shortened under the action of metal ion crosslinking agent. However, after aging for 100 days, dehydration occurred with a dehydration rate of 5%, indicating that the gelation stability of the composite dual-network polymer gel blocker was poor.
[0151] In Comparative Example 3, when an AM / AMPS binary copolymer with an AMPS structural unit content of 15 mol% was used, the results showed that the low-temperature metal ion crosslinking agent failed to crosslink with the polymer. The crosslinking system formed by the non-metal ion organic crosslinking agent and the polymer had a gelation time of up to 52 days, and after aging for 100 days, the elastic modulus of the polymer gel was as low as 11.2 Pa. The gelation strength of this gel system was weak.
[0152] In Comparative Example 4, as the amount of accelerator increased, the cross-linking time between the metal-organic cross-linking agent and the polymer at low temperature was greatly shortened. However, after aging for 100 days, the stability of the gel system was greatly reduced, and the dehydration rate reached 20%.
[0153] Figure 2 shows the viscosity change of the composite dual-network polymer gel plugger-DA5 prepared in Comparative Example 5. According to Figure 2 and the data in Table 1, it can be concluded that when no metal-organic crosslinking agent is added, the gel system begins to show viscosity increase after 30 days of aging. In actual use, this gel plugger is prone to chromatographic separation and dilution by formation water, and therefore is not suitable for deep reservoir regulation and flooding.
[0154] Test Example 2
[0155] This test example illustrates the performance of the composite dual-network polymer gel plugger-A1 at different water bath temperatures. The specific test results are shown in Table 2.
[0156] Table 2
[0157] As can be seen from the data in Table 2, the gelation time is greatly shortened as the aging temperature increases. When the aging temperature reaches 60℃, the gel system becomes a high-strength gel after only 4 days of aging, which is difficult to achieve deep migration and cannot effectively block the high-permeability layer in practical applications.
[0158] In summary, the composite dual-network polymer gel plugger provided by this invention can undergo a preliminary cross-linking reaction with the polymer at low temperatures to form a weak gel with a certain network structure. As the aging time increases, the non-metallic ion organic cross-linking agent further undergoes a cross-linking reaction with the polymer through covalent bonds to form a dense network structure, giving the gel high strength and good salt resistance.
[0159] 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 composition for a composite dual-network polymer gel plugging agent, characterized in that, The composition comprises a main agent and auxiliary agents. The main agent is an AM / AMPS binary copolymer, and the auxiliary agents include a metal ion crosslinking agent, a non-metal ion organic crosslinking agent, and an accelerator. Based on the total weight of the composition, the content of the AM / AMPS binary copolymer in the composition is 0.4wt%-1.0wt%, the content of the metal ion crosslinking agent is 0.01wt%-0.02wt%, the content of the non-metal ion organic crosslinking agent is 0.4wt%-1.0wt%, and the content of the accelerator is 0.2wt%-0.6wt%. In the AM / AMPS binary copolymer, the content of AMPS as a structural unit is 5-10 mol%. The non-metallic ionic organic crosslinking agent is a phenolic prepolymer crosslinking agent.
2. The composition for a composite dual-network polymer gel plug according to claim 1, wherein The phenolic molar ratio of the phenolic prepolymer crosslinking agent is 1:2-3.
3. The composition for a composite dual-network polymer gel plug according to claim 2, wherein The degree of polymerization of the phenolic prepolymer crosslinking agent is 2-8, and the solid content is 30-35 wt%.
4. The composition for a composite dual-network polymer gel plugging agent according to any one of claims 1-3, characterized in that, The relative molecular mass of the AM / AMPS binary copolymer is between 6 million and 8 million.
5. The composition for a composite dual-network polymer gel plugging agent according to any one of claims 1-3, characterized in that, The composition also includes water as an adjuvant, the water having a mineralization of 80,000 mg / L-120,000 mg / L, and the water containing Ca... 2+ and Mg 2+ The sum of their concentrations is 5000mg / L-10000mg / L.
6. The composition for a composite dual-network polymer gel plug according to claim 5, wherein The water content is the balance based on the total weight of the composition.
7. The composition for a composite dual-network polymer gel plugging agent according to any one of claims 1-3, characterized in that, The metal ion crosslinking agent is selected from at least one of aluminum citrate crosslinking agent, chromium acetate crosslinking agent, and organozirconium crosslinking agent.
8. The composition for a composite dual-network polymer gel plug according to claim 7, wherein The metal ion crosslinking agent is a chromium acetate crosslinking agent.
9. The composition for a composite dual-network polymer gel plugging agent according to any one of claims 1-3, characterized in that, The accelerator is ammonium chloride.
10. A method of preparing a composite dual network polymer gel plug comprising, The method is carried out using the composite dual-network polymer gel plugging agent composition according to any one of claims 1-9, comprising: mixing and contacting the main agent and the components of the auxiliary agent in the composite dual-network polymer gel plugging agent composition in the presence of water.
11. The method of claim 10, wherein, The method further includes: before the mixing contact, first mixing the main agent with a portion of water to obtain a main agent stock solution I with a concentration of 0.5-1.5 wt%; second mixing the main agent stock solution I with another portion of water to obtain a main agent stock solution II with a concentration of 0.4-1.0 wt%; and then mixing the main agent stock solution II with the remaining components in the composite dual-network polymer gel plugging agent composition.
12. The method of claim 11, wherein, The first mixing is carried out under stirring condition I, wherein the stirring speed of stirring condition I is 300-400 rpm; Preferably, the first mixing time is 3-4 hours.
13. The method of claim 11, wherein, The second mixing is carried out under stirring condition II, wherein the stirring speed of stirring condition II is 200-400 rpm; Preferably, the second mixing time is 5-60 minutes.
14. A composite dual-network polymer gel plugging agent prepared by the method according to any one of claims 10-13.
15. The application of the composite dual-network polymer gel plugging agent according to claim 14 in deep profile modification and plugging of low-temperature, high-salinity oil reservoirs.
16. Use according to claim 15, characterized in that, The temperature of the low-temperature, high-salinity oil reservoir is 30℃-50℃; And / or, the formation water salinity of the said low-temperature, high-salinity reservoir is 80,000 mg / L-120,000 mg / L, and the formation water Ca... 2+ and Mg 2+ The sum of their concentrations is 5000mg / L-10000mg / L.