Metal ion crosslinking stabilizing and retarding agent as well as preparation method and application thereof

Abstract

The invention relates to a metal ion crosslinking stabilizing and retarding agent. The problems that an existing gel profile control agent is short in gelling time, middle and low permeability layers are prone to being damaged in the injection process, and deep plugging of oil reservoirs cannot be achieved are mainly solved. The water purifying agent comprises the following components in percentage by mass: 1%-2% of a retardant, 3%-5% of a reinforcing agent, 1%-3% of a conditioning agent, 4%-5% of an ion stabilizer, 1%-2% of a water purifying agent and the balance of water. The preparation method comprises the following steps: 1) adding the ion stabilizer and the enhancer into water in proportion, and uniformly mixing in a water bath at 45 DEG C; (2) adding a regulator into the mixed solution, and uniformly mixing; the metal ion crosslinking stabilizing and retarding agent can be used as an auxiliary additive component for preparation of a polyacrylamide ion crosslinking profile control agent system, and can prolong the gelling time of the profile control agent, ensure the gelling viscosity of the profile control agent, improve the stability of the profile control agent and realize effective plugging of the system.

Description

Technical field:

[0001] The invention relates to the field of oilfield chemistry, and in particular to a metal ion cross-linking stabilizer, a preparation method and application thereof. Background technology:

[0002] Commonly used crosslinking agent systems mostly use metal complex crosslinking, and the gel viscosity is related to the metal ion complexing ability. Since there is a contradictory relationship between the gel viscosity and the gel time in this system: on the one hand, extending the gel time and delaying the release rate of the effective components of the crosslinker is conducive to the injection of the profile control agent to reach deeper formations and achieve the purpose of deep profile control; but at the same time, due to the long gel time, the effective components of the crosslinker are exposed to high temperature and oxygen environment for a long time, completely or partially losing crosslinking (inactivation), which greatly affects the subsequent gel viscosity of the profile control agent and ultimately affects the profile control construction effect. Summary of the invention:

[0003] The purpose of the present invention is to overcome the problems in the background technology that the common cross-linking agents in existing oil fields have a short gelling time, are easy to damage the medium and low permeability layers during the injection process, and cannot achieve deep plugging of the oil reservoir, and to provide a metal ion cross-linking stabilizer. The metal ion cross-linking stabilizer can be used in the preparation of a polyacrylamide ion cross-linking profile control agent system as an auxiliary additive component to extend the gelling time of the profile control agent, ensure the gelling viscosity of the profile control agent, improve the stability of the profile control agent, and achieve effective plugging of the system. The present invention also provides a preparation method and application of a metal ion cross-linking stabilizer.

[0004] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a metal ion cross-linking stabilizer, whose components and proportions are as follows in mass percentage: retarder 1%-2%, enhancer 3%-5%, regulator 1%-3%, ion stabilizer 4%-5%, water purifier 1%-2%, and the balance is water.

[0005] Preferably, the retarder is citric acid, which has a larger coordination constant, stronger chelation coordination, and stronger chelation ability, and plays a role in complexing and cross-linking ions and delaying the gelation time of the system;

[0006] Preferably, the enhancer is at least one of nonionic surfactants such as polyoxyethylene octylphenol ether-10 (OP-10), fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene (10) ester, fatty amine polyoxyethylene ether (leveling agent AN), alkyl alcohol amide polyoxyethylene ether, block polyoxyethylene-polyoxypropylene ether, and alkyl alcohol amide;

[0007] Preferably, the regulator is triethanolamine, or a weakly alkaline substance such as disodium hydrogen phosphate.

[0008] Preferably, the ionic stabilizer is potassium sorbate, and may also be preservatives such as benzoic acid, sorbic acid, dehydroacetic acid, paraben, sodium diacetate, calcium propionate, sodium lactate, etc.

[0009] Preferably, the water purifier is polyaluminium chloride, or may be an iron-free water purifier such as basic aluminium chloride or aluminium sulfate.

[0010] The retarder is citric acid, which plays the role of complexing cross-linking ions and delaying the gelation time of the system;

[0011] The reinforcing agent plays a role in enhancing the viscosity of the system after the system has gelled;

[0012] The regulator makes the system environment neutral to weakly alkaline, ensuring the gelling effect of the system;

[0013] The ionic stabilizer plays a role in stabilizing the viscosity of the system;

[0014] The water purifier, as a sewage purifier, plays a role in purifying sewage and ensuring the gelling performance of the system.

[0015] Another aspect of the present invention provides a method for preparing a metal ion cross-linking stabilizer, comprising the following steps:

[0016] (1) Add the ionic stabilizer and the enhancer to water in proportion and mix them evenly in a water bath at 45°C-60°C;

[0017] (2) adding a regulator to the mixed solution container while stirring and mixing thoroughly;

[0018] (3) Add a retarder and maintain the water bath for 2-3 hours;

[0019] (4) Finally, a water purifier is added to obtain the target product, a metal ion cross-linking stabilizer.

[0020] The third aspect of the present invention provides the use of a metal ion cross-linking stabilizer in deep oilfield plugging control. Specifically, the following steps are included:

[0021] 1) The metal ion cross-linking stabilizer prepared by the present invention is compounded with the cross-linking agent in the profile control agent for use;

[0022] 2) The usage of the metal ion cross-linking stabilizer is determined according to the site requirements and the metal ion content in the cross-linking agent;

[0023] The specific determination method is:

[0024] The higher the metal ion content in the cross-linking agent, the higher the concentration of the metal ion cross-linking stabilizer used;

[0025] When the gelation time required on site is longer, the concentration of metal ion cross-linking stabilizer should be higher;

[0026] 3) The profile control agent used on site is prepared according to 0.1%-0.4% polyacrylamide,

[0027] The preparation of 0.25%-1% Cr3+ crosslinking agent and 1-2% metal ion crosslinking stabilizer can achieve a gelation time of 30 days.

[0028] Compared with the above background technology, the present invention has the following beneficial effects:

[0029] The metal ion cross-linking stabilizer of the present invention has a good shielding effect on the carboxylic acid (root) group in the system, and finally achieves a better delayed cross-linking effect on the metal ion cross-linking system. The metal ion cross-linking stabilizer can be used as an auxiliary agent of the cross-linking agent in the deep profile control agent in the deep plugging control process of the oil field, which further delays the gelation time of the system, enhances the performance of the deep profile control agent, and expands the application range of the deep profile control agent.

[0030] The metal ion cross-linking stabilizer described in the present invention utilizes the chelating coordination effect of the retarder therein to form a relatively stable structure with the metal ions, releases the metal ions at a slow rate, and can delay the gelation rate of the system, thereby achieving the purpose of delaying cross-linking; an enhancer and a regulator are added to the system, and the enhancer, with the assistance of the regulator, forms spherical micelles in the water and links with the -COOH group through hydrogen bonds, thereby significantly improving the final gelation viscosity of the profile control system; at the same time, a stabilizer and a water purifier are added to avoid or slow down the degradation of the system under complex geological and various component conditions, and keep the system from breaking and maintaining a high viscosity for a long time; therefore, the metal ion cross-linking stabilizer described in the present invention can, on the one hand, prolong the gelation time of the profile control agent system, move the system to the deep part of the formation, and achieve the purpose of deep profile control; on the other hand, it can ensure the gelation viscosity and stability of the profile control system, and achieve effective plugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] Figure 1 This is a schematic diagram of the mechanism by which the stabilizer of the present invention "binds" the -COOH group carried by the hydrolyzed polyacrylamide through hydrogen bonding;

[0033] Figure 2 It is a comparison chart of the gelling performance of the profile control agent system without adding the stabilizer and after adding the stabilizer;

[0034] Figure 3This is a comparison chart of the gelling properties of the profile control agent system prepared after the retarders in the stabilizer of the present invention are citric acid and salicylic acid respectively;

[0035] Figure 4 This is a comparison chart of the gelling properties of the profile adjusting agent at different dosages of the stabilizer and retarder of the present invention. Specific implementation method:

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0037] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0038] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0039] A metal ion cross-linking stabilizer, the components and proportions of which are as follows by mass percentage: 1%-2% of a retarder, 3%-5% of a reinforcing agent, 1%-3% of a regulating agent, 4%-5% of an ion stabilizer, 1%-2% of a water purifier, and the balance is water.

[0040] The retarder is citric acid.

[0041] The enhancer is OP-10, and can also be non-ionic surfactants such as fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene (10) ester, fatty amine polyoxyethylene ether (leveling agent AN), alkyl alcohol amide polyoxyethylene ether, block polyoxyethylene-polyoxypropylene ether, alkyl alcohol amide, etc.

[0042] The regulator is triethanolamine, or it can be a weak alkaline substance such as disodium hydrogen phosphate.

[0043] The ionic stabilizer is potassium sorbate, and may also be preservatives such as benzoic acid, sorbic acid, dehydroacetic acid, paraben, sodium diacetate, calcium propionate, sodium lactate, etc.

[0044] The water purifier is polyaluminium chloride, and may also be iron-free water purifiers such as basic aluminium chloride and aluminium sulfate.

[0045] A method for preparing a metal ion cross-linking stabilizer comprises the following steps:

[0046] Another aspect of the present invention provides a method for preparing a metal ion cross-linking stabilizer, comprising the following steps:

[0047] (1) Add the ionic stabilizer and the enhancer to water in proportion and mix them evenly in a water bath at 45°C-60°C;

[0048] (2) adding a regulator to the mixed solution container while stirring and mixing thoroughly;

[0049] (3) Add a retarder and maintain the water bath for 2-3 hours;

[0050] (4) Finally, a water purifier is added to obtain the target product, a metal ion cross-linking stabilizer.

[0051] The present invention also provides the use of metal ion cross-linking stabilizer in deep oil field plugging control. Specifically, the method comprises the following steps:

[0052] 1) The metal ion cross-linking stabilizer prepared by the present invention is compounded with the cross-linking agent in the profile control agent for use;

[0053] 2) The amount of the metal ion cross-linking stabilizer used is determined according to the site needs and the metal ion content in the cross-linking agent; the specific determination method is:

[0054] The higher the metal ion content in the cross-linking agent, the higher the concentration of the metal ion cross-linking stabilizer used;

[0055] When the gelation time required on site is longer, the concentration of metal ion cross-linking stabilizer should be higher;

[0056] 3) The profile control agent used on site is prepared according to 0.1%-0.4% polyacrylamide, 0.25%-1% Cr3+ crosslinking agent, and 1-2% metal ion crosslinking stabilizer, which can achieve a gelation time of 30 days.

[0057] like Figure 1 As shown, the working principle of the metal ion cross-linking stabilizer of the present invention is:

[0058] By comparing the delaying effects of different organic acids and regulators on the HPAM / Cr(C3H5O3)3 gel profile control system, it can be seen that since the "shielding" of metal ions is achieved through chelation, when the organic acid has a weak coordination effect on metal ions, it is difficult to "bind" the metal ions, causing them to undergo a cross-linking reaction quickly, and the delaying cross-linking effect is not good; and when the organic acid has a strong coordination effect on metal ions, more metal ions will be completely "bound" by it and cannot be released, so the degree of cross-linking is not enough, resulting in a very weak gel viscosity of the system. However, when the regulator "shields" the -COO- group through the hydrogen bond between the -COOH group, due to the moderate interaction between the two, and the equilibrium shift caused by the mutual transformation of the -COO- group and the -COOH, the regulator shows a better delaying cross-linking effect than the organic acid, and has almost no effect on the final viscosity of the system. The metal ion cross-linking stabilizer of the present invention has a good shielding effect on the carboxylic acid (root) group in the system, and finally achieves a better delaying cross-linking effect on the system.

[0059] Embodiment 1:

[0060] In this embodiment, the prepared stabilizer K-001 is composed of the following components by weight: 4% potassium sorbate, 3% OP-10, 1% triethanolamine, 1% citric acid, 1% polyaluminium chloride, and the balance is water. The specific preparation process is as follows:

[0061] (1) Place a three-necked flask in a constant temperature water bath, add a corresponding amount of clean water (90 g weighed using an electronic balance) into the three-necked flask, heat the constant temperature water bath to 45° C., place a thermometer and an electric stirrer into the three-necked flask, and after the temperature reaches a constant temperature of 45° C., add 4 g of potassium sorbate and 3 g of OP-10, and stir and mix them evenly using an electric stirrer;

[0062] (2) Add 1 g of triethanolamine into the three-necked flask while stirring, and stir with an electric stirrer to mix evenly;

[0063] (3) Add 1 g of citric acid to the three-necked flask while stirring, and stir with an electric stirrer for 2-3 h;

[0064] (4) Finally, add 1 g of polyaluminium chloride into the three-necked flask and stir with an electric stirrer to obtain the target product K-001;

[0065] Application Example 1

[0066] After preparing the stabilizer K-001, the profile control agent system T-001 and T-002 are compounded with a crosslinker and polyacrylamide. The profile control agent system T-001 contains the stabilizer K-001, while T-002 does not contain the stabilizer K-001. The specific steps are:

[0067] (1) Prepare 0.1% polyacrylamide in beaker 1;

[0068] (2) Add 0.25% Cr into beaker 1 3+ The cross-linking agent and 1% of the stabilizer K-001 are fully stirred to finally obtain the profile control agent system T-001.

[0069] (3) Prepare 0.1% polyacrylamide in beaker 2;

[0070] (4) Add 0.25% Cr into beaker 2 3+ The cross-linking agent is stirred sufficiently to finally obtain the profile control agent system T-002.

[0071] The comparison of the gelling properties of the profile control agent system without the stabilizer of the present invention and with the stabilizer of the present invention is shown in Figure 2 .

[0072] like Figure 2As shown, it can be seen from the experimental results that the introduction of the stabilizer K-001 of the present invention into the profile control agent system effectively prolongs the gelation time of the profile control agent. At the same time, since the stabilizer K-001 of the present invention contains an enhancer, when the system is gelled, it plays a role in enhancing the viscosity of the system in the later stage. Therefore, the final gelation strength of the gel system with the stabilizer K-001 added is greater than that of the gel system without the stabilizer K-001 added.

[0073] Comparative Example 1

[0074] In this embodiment, the prepared stabilizer K-002 is composed of the following ingredients by weight: 4% potassium sorbate, 3% OP-10, 1% triethanolamine, 1% salicylic acid, 1% polyaluminium chloride, and the balance is water.

[0075] The specific preparation process is as follows:

[0076] (1) Place a three-necked flask in a constant temperature water bath, add a corresponding amount of clean water (90 g weighed using an electronic balance) into the three-necked flask, heat the constant temperature water bath to 45° C., place a thermometer and an electric stirrer into the three-necked flask, and after the temperature reaches a constant temperature of 45° C., add 4 g of potassium sorbate and 3 g of OP-10, and stir and mix them evenly using an electric stirrer;

[0077] (2) Add 1 g of triethanolamine into the three-necked flask while stirring, and stir with an electric stirrer to mix evenly;

[0078] (3) Add 1 g of salicylic acid to the three-necked flask while stirring, and stir with an electric stirrer for 2-3 h;

[0079] (4) Finally, add 1 g of polyaluminium chloride into the three-necked flask and stir with an electric stirrer to obtain the target product.

[0080] Application Example 2

[0081] After the stabilizer K-002 was prepared, it was compared with the stabilizer K-001 in Example 1, and the profile control agent systems T-003 and T-004 were compounded using a crosslinking agent and polyacrylamide. The retarder in the stabilizer in the profile control agent system T-003 was citric acid, while the retarder in the stabilizer in T-004 was salicylic acid.

[0082] (1) Prepare 0.1% polyacrylamide in beaker 3;

[0083] (2) Add 0.25% Cr into beaker 3 3+ The cross-linking agent and 1% of the stabilizer K-001 are fully stirred to finally obtain the profile control agent system T-003.

[0084] (3) Prepare 0.1% polyacrylamide in beaker 4;

[0085] (4) Add 0.25% Cr into beaker 4 3+ The cross-linking agent and 1% of the stabilizer K-002 are fully stirred to finally obtain the profile control agent system T-004.

[0086] The comparison of the gelling properties of the profile control agent system prepared with citric acid and salicylic acid as the retarder in the stabilizer is shown in Figure 3 .

[0087] like Figure 3 As shown, it can be seen from the experimental results that when the retarder in the stabilizer is salicylic acid, due to its small coordination constant and weak chelating ability, the gelling time of the profile control agent system is short. When the retarder is citric acid, the chelating ability is strong, which leads to a long gelling time of the profile control agent system.

[0088] Application Example 3

[0089] In this embodiment, the stabilizer K-001 is used in different dosage ratios and compounded with a cross-linking agent and polyacrylamide to obtain profile control agent systems T-005, T-006 and T-007.

[0090] The preparation process is as follows:

[0091] (1) Prepare 0.1% polyacrylamide in beaker 5;

[0092] (2) Add 0.25% Cr into beaker 5 3+ The cross-linking agent and 0.5% of the stabilizer K-001 are fully stirred to finally obtain the profile control agent system T-005.

[0093] (3) Prepare 0.1% polyacrylamide in beaker 6;

[0094] (4) Add 0.25% Cr into beaker 6 3+ The cross-linking agent and 0.8% of the stabilizer K-001 are fully stirred to finally obtain the profile control agent system T-006.

[0095] (5) Prepare 0.1% polyacrylamide in beaker 7;

[0096] (6) Add 0.25% Cr into beaker 7 3+ The cross-linking agent and 1.0% of the stabilizer K-001 are fully stirred to finally obtain the profile control agent system T-007.

[0097] Comparison of the gelling properties of the profile control agent at different dosages of stabilizer and retarder is shown in Figure 4 .

[0098] like Figure 4As shown, it can be seen from the experimental results that with the increase in the amount of stabilizer and retarder, the gelation time of the profile control agent is gradually prolonged, and the final gelation viscosity remains basically unchanged. Therefore, by introducing the stabilizer and retarder K-001 of the present invention, a series of profile control agent systems with different gelation times can be formed to meet the plugging needs of different oil reservoirs.

[0099] Field application examples

[0100] After preparing the stabilizer K-001, the cross-linking agent and polyacrylamide are used to compound the profile control agent system. The mobile liquid preparation device is used for on-site construction. When preparing the profile control agent on site, the three chemical agents are added to the profile control agent preparation tank in the order of polymer, cross-linking agent, and stabilizer with an ejector. Stir while adding. After adding, add preparation water to 15m 3 , stir for 30 minutes, then put it into the maturation tank for 2 hours, and stir for another 10 minutes before injection. The specific construction steps are as follows:

[0101] (1) Prepare 0.1% polyacrylamide, usually 15m 3 First, add half of the water into the pool, then add 15kg of polyacrylamide, stirring while adding;

[0102] (2) Add 0.25% Cr 3+ Cross-linking agent (37.5 kg) was added while stirring;

[0103] (3) Add 1% stabilizer K-001 (150 kg) while stirring;

[0104] (4) Add prepared water to 15m 3 , stir for 30 minutes. Then put it into the maturation tank for 2 hours, and stir for another 10 minutes before injection.

[0105] (5) Finally, inject into the formation.

[0106] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to perform equivalent replacements on parts thereof. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention. Although the above describes the specific implementation methods of the present invention, it is not intended to limit the protection scope of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative labor are still within the protection scope of the present invention.

Claims

1. A metal ion cross-linking stabilizer, characterized in that: The components and proportions thereof are as follows by mass percentage: retardant 1%-2%, enhancer 3%-5%, regulator 1%-3%, ion stabilizer 4%-5%, water purifier 1%-2%, and the balance is water.

2. The metal ion cross-linking stabilizer according to claim 1, characterized in that: The retarder is citric acid.

3. The metal ion cross-linking stabilizer according to claim 1, characterized in that: The enhancer is at least one of polyoxyethylene octylphenol ether-10, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene (10) ester, fatty amine polyoxyethylene ether, alkyl alcohol amide polyoxyethylene ether, block polyoxyethylene-polyoxypropylene ether or alkyl alcohol amide.

4. The metal ion cross-linking stabilizer according to claim 1, characterized in that: The regulator is a weakly alkaline substance; The weakly alkaline substance is triethanolamine or disodium hydrogen phosphate.

5. The metal ion cross-linking stabilizer according to claim 1, characterized in that: The ionic stabilizer is at least one of potassium sorbate, benzoic acid, sorbic acid, dehydroacetic acid, paraben, sodium diacetate, calcium propionate or sodium lactate.

6. The metal ion cross-linking stabilizer according to claim 1, characterized in that: The water purifier is an iron-free water purifier.

7. A metal ion cross-linking stabilizer according to claim 6, characterized in that: The iron-free water purifier is at least one of polyaluminium chloride, basic aluminium chloride or aluminium sulfate.

8. A method for preparing a metal ion cross-linking stabilizer according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Add the ionic stabilizer and the enhancer to water in proportion and mix them evenly in a water bath at 45°C-60°C; (2) adding a regulator to the mixed solution container while stirring and mixing thoroughly; (3) Add a retarder and maintain the water bath for 2-3 hours; (4) Finally, a water purifier is added to obtain the target product, a metal ion cross-linking stabilizer.

9. Use of the metal ion cross-linking stabilizer according to any one of claims 1 to 7 in deep plugging control in oil fields.

10. The use according to claim 9, characterized in that: The specific steps include: 1) The metal ion cross-linking stabilizer prepared by the present invention is compounded with the cross-linking agent in the profile control agent for use; 2) The amount of the metal ion cross-linking stabilizer used is determined according to the site needs and the metal ion content in the cross-linking agent; the specific determination method is: The higher the metal ion content in the cross-linking agent, the higher the concentration of the metal ion cross-linking stabilizer used; When the gelation time required on site is longer, the concentration of metal ion cross-linking stabilizer should be higher; 3) The profile control agent used on site is prepared according to 0.1%-0.4% polyacrylamide, 0.25%-1% Cr3+ crosslinking agent, and 1-2% metal ion crosslinking stabilizer, which can achieve a gelation time of 30 days.

Images