Inorganic gel coalescence inhibitor, method for its preparation and use

Abstract

The application provides an inorganic gel coagulation inhibitor and a preparation method and application thereof, and the preparation raw material of the inorganic gel coagulation inhibitor comprises acrylamide, temperature-resistant and salt-resistant monomers, cationic monomers and initiators in specific proportions. The acrylamide, temperature-resistant and salt-resistant monomers and cationic monomers are selected and matched, so that the obtained inorganic gel coagulation inhibitor has high steric hindrance effect and cationic group shielding effect, can inhibit the rapid coagulation of silicate and metal cations to form a precipitate, can effectively delay the gelation time of the inorganic gel, and is further applied to water control in the profile control and flooding of high water content oilfields, is helpful to realize the expansion of the swept volume of injected water, improves the water flooding sweep effect, and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of oilfield development technology, specifically relating to an inorganic gel polymerization inhibitor, its preparation method, and its application. Background Technology

[0002] As oilfield development continues, the later stages of water-injected development of old oilfields often result in single-layer surges of injected water due to long-term water injection, leading to severe interlayer conflicts and interference. Deep fluid flow diversion and regulation technology is an important means to solve the problem of inefficient and ineffective water injection circulation in water-driven oilfields and improve the recovery rate of water-driven development.

[0003] Commonly used inorganic gel regulation systems include silicate systems such as water glass and sodium silicate. CN112625666A discloses an oilfield oily sludge regulating agent and its preparation method. The operation steps are as follows: the oily sludge sample is thoroughly dried to obtain dried sludge; then the dried sludge is pulverized and sieved to obtain dried sludge powder; water and dried sludge powder are mixed, a rheology modifier is added while stirring, and then stirring is continued; then a curing time control agent and a gel strength regulator are added in sequence and stirred; finally, dried sludge powder is added and stirring is continued to obtain a suspension; the obtained suspension is placed in a sealed bag and placed in a constant temperature water bath at 50°C for 3 to 25 days to obtain the oilfield oily sludge regulating agent.

[0004] However, due to the interaction between silicate ions and divalent metal ions (Ca... 2+ Mg 2+ When they meet, they quickly form a precipitate, especially under high temperature conditions. The rate of gelation cannot be controlled, which can easily cause blockage in the near-wellbore area, making subsequent plugging agent injection very difficult. At the same time, the two-liquid method is generally used for injection during field construction. The silicate slug and the calcium chloride slug are separated by a water slug, which is injected alternately and repeatedly, causing inconvenience to field construction. In addition, the water slug cannot completely isolate the silicate and calcium chloride effectively, causing gelation in the near-wellbore area, which seriously affects the efficiency of oilfield development.

[0005] Therefore, in order to solve the above-mentioned technical problems, it is urgent to develop an inorganic gel polymerization inhibitor that can effectively inhibit the polymerization and precipitation of silicate and divalent metal ions. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an inorganic gel polymerization inhibitor, its preparation method, and its application. The inorganic gel polymerization inhibitor has cation shielding and steric hindrance effects, which can inhibit the rapid polymerization of silicate ions and divalent metal ions to form precipitates, and can also delay the gelation time of inorganic gels. Furthermore, it has a significant thickening effect, thereby enabling the injection of water to expand the swept volume and effectively improve the water-driven sweep effect.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an inorganic gel polymerization inhibitor, wherein the raw materials for preparing the inorganic gel polymerization inhibitor comprise the following components in parts by weight:

[0009]

[0010] The acrylamide may be in the form of 15.5 parts by weight, 16 parts by weight, 16.5 parts by weight, 17 parts by weight, 17.5 parts by weight, 18 parts by weight, 18.5 parts by weight, 19 parts by weight, or 19.5 parts by weight.

[0011] The temperature- and salt-resistant monomer can be 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, or 8.5 parts by weight, etc.

[0012] The cationic monomer can be 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, or 7.5 parts by weight, etc.

[0013] The initiator can be 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, or 0.45 parts by weight, etc.

[0014] The inorganic gel polymerization inhibitor provided by this invention comprises specific proportions of acrylamide, temperature-resistant and salt-resistant monomer, cationic monomer, and initiator. By selecting and combining the above-mentioned acrylamide, temperature-resistant and salt-resistant monomer, and cationic monomer, the resulting inorganic gel polymerization inhibitor has a high steric hindrance effect and cationic group shielding effect. It can inhibit the rapid polymerization of silicate and metal cations to form precipitates and delay the gelation time of inorganic gel. Therefore, it can be applied to water control in high water-cut oilfields, which helps to expand the swept volume of injected water and improve the water drive sweep effect.

[0015] Preferably, the temperature- and salt-resistant monomer comprises any one or a combination of at least two of N-vinylpyrrolidone, 2-vinylmorpholine, or sodium vinyl sulfonate, and more preferably 2-vinylmorpholine and sodium vinyl sulfonate.

[0016] Preferably, the cationic monomer comprises any one or a combination of at least two of dimethyl diallyl ammonium chloride, methacryloyloxyethyltrimethyl ammonium chloride, acryloyloxyethyltrimethyl ammonium chloride, or allyltrimethyl ammonium chloride, and more preferably allyltrimethyl ammonium chloride.

[0017] Preferably, the initiator comprises any one or a combination of at least two of ammonium persulfate, sodium persulfate, sodium metabisulfite, sodium sulfite, tetramethylethylenediamine, or triethylamine, and more preferably tetramethylethylenediamine, ammonium persulfate, and sodium bisulfite.

[0018] Preferably, the raw materials for preparing the inorganic gel polymerization inhibitor also include water.

[0019] Preferably, the water content in the raw materials for preparing the inorganic gel polymerization inhibitor is 62.5 to 77.8 parts by weight, for example, 64 parts by weight, 66 parts by weight, 68 parts by weight, 70 parts by weight, 72 parts by weight, 74 parts by weight, or 76 parts by weight.

[0020] In a second aspect, the present invention provides a method for preparing an inorganic gel polymerization inhibitor as described in the first aspect, the method comprising: mixing acrylamide, a heat-resistant and salt-resistant monomer and a cationic monomer in water, adding an initiator to carry out a polymerization reaction, and obtaining the inorganic gel polymerization inhibitor.

[0021] Preferably, the polymerization reaction temperature is 12 to 16°C, such as 12.5°C, 13°C, 13.5°C, 14°C, 14.5°C, 15°C, or 15.5°C.

[0022] Preferably, the polymerization reaction takes 4 to 6 hours, for example, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5 hours, 5.2 hours, 5.4 hours, 5.6 hours, or 5.8 hours.

[0023] Preferably, the polymerization reaction further includes granulation, drying, and sieving steps after completion.

[0024] Thirdly, the present invention provides an application of the inorganic gel polymerization inhibitor as described in the first aspect in the oilfield development process.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The raw materials for preparing the inorganic gel polymerization inhibitor provided by the present invention include a specific number of acrylamide, temperature-resistant and salt-resistant monomer, cationic monomer and initiator. By selecting the above acrylamide, temperature-resistant and salt-resistant monomer and cationic monomer to match, the resulting inorganic gel polymerization inhibitor has a high steric hindrance effect and cationic group shielding effect, which can inhibit the rapid polymerization of silicate and divalent metal ions to form precipitation, and can also delay the gelation time of inorganic gel. In addition, it can be applied to the water control of high water-cut oilfields, which helps to expand the sweep volume of injected water and improve the water drive sweep effect.

[0027] (2) The preparation process of the inorganic gel polymerization inhibitor provided by the present invention is simple. It can be achieved by directly reacting acrylamide, heat-resistant and salt-resistant monomer, cationic monomer and initiator. It is suitable for mass production and use.

[0028] (3) Specifically, the inorganic gel polymerization inhibitor provided by this invention is effective in high-mineralized saline (10 × 10⁻⁶) water. 4 mg / L simulated saline, Ca 2+ In a concentration of 4000 mg / L, the apparent viscosity of an inorganic gel polymerization inhibitor with a mass percentage of 0.4% reached over 89.4 mPa·s, which is twice that of conventional HPAM polymers, demonstrating a significant thickening effect. Furthermore, the inorganic gel particles formed after adding the inorganic gel polymerization inhibitor with a mass percentage of 0.4% provided by this invention have a particle size of 75–85 nm, which is only about 1 / 3 of the particle size of HPAM polymers. The particle size of the polymerization particles is significantly reduced, indicating a promising application prospect. Detailed Implementation

[0029] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0030] Example 1

[0031] An inorganic gel polymerization inhibitor is prepared by means of the following steps: 77.8 parts by weight of deionized water, 15 parts by weight of acrylamide, 2 parts by weight of sodium vinyl sulfonate, 1 part by weight of 2-vinylmorpholine, and 4 parts by weight of allyltrimethylammonium chloride are added sequentially to a stoppered wide-mouth bottle; nitrogen gas is introduced for 20 min, and the polymerization temperature is controlled at 12°C; then 0.1 parts by weight of tetramethylethylenediamine, 0.075 parts by weight of ammonium persulfate, and 0.025 parts by weight of sodium bisulfite are added; nitrogen gas is introduced for another 10 min; the polymerization reaction is carried out for 5 h; the resulting polymer colloid is granulated, dried at 60°C for 8 h, and passed through a 50-mesh standard sieve to obtain the inorganic gel polymerization inhibitor.

[0032] Example 2

[0033] An inorganic gel polymerization inhibitor is prepared by means of the following steps: 71.7 parts by weight of deionized water, 18 parts by weight of acrylamide, 3 parts by weight of sodium vinyl sulfonate, 2 parts by weight of 2-vinylmorpholine, and 5 parts by weight of allyltrimethylammonium chloride are added sequentially to a stoppered wide-mouth bottle; nitrogen gas is introduced for 20 min, and the polymerization temperature is controlled at 12°C; then 0.14 parts by weight of tetramethylethylenediamine, 0.12 parts by weight of ammonium persulfate, and 0.04 parts by weight of sodium bisulfite are added; nitrogen gas is introduced for another 10 min; the polymerization reaction is carried out for 5 h; the resulting polymer colloid is granulated, dried at 60°C for 8 h, and passed through a 50-mesh standard sieve to obtain the inorganic gel polymerization inhibitor.

[0034] Example 3

[0035] An inorganic gel polymerization inhibitor is prepared by means of the following steps: 66.6 parts by weight of deionized water, 20 parts by weight of acrylamide, 4 parts by weight of sodium vinyl sulfonate, 3 parts by weight of 2-vinylmorpholine, and 6 parts by weight of allyltrimethylammonium chloride are added sequentially to a stoppered wide-mouth bottle. Nitrogen gas is introduced for 20 minutes, and the polymerization temperature is controlled at 12°C. Then, 0.2 parts by weight of tetramethylethylenediamine, 0.15 parts by weight of ammonium persulfate, and 0.05 parts by weight of sodium bisulfite are added. Nitrogen gas is introduced for another 10 minutes, and the polymerization reaction is carried out for 5 hours. The resulting polymer colloid is granulated, dried at 60°C for 8 hours, and passed through a 50-mesh standard sieve to obtain the inorganic gel polymerization inhibitor.

[0036] Example 4

[0037] An inorganic gel polymerization inhibitor is prepared by means of the following steps: 62.5 parts by weight of deionized water, 20 parts by weight of acrylamide, 5 parts by weight of sodium vinyl sulfonate, 4 parts by weight of 2-vinylmorpholine, and 8 parts by weight of allyltrimethylammonium chloride are added sequentially to a stoppered wide-mouth bottle. Nitrogen gas is introduced for 20 minutes, and the polymerization temperature is controlled at 12°C. Then, 0.26 parts by weight of tetramethylethylenediamine, 0.18 parts by weight of ammonium persulfate, and 0.06 parts by weight of sodium bisulfite are added. Nitrogen gas is introduced for another 10 minutes, and the polymerization reaction is carried out for 5 hours. The resulting polymer colloid is granulated, dried at 60°C for 8 hours, and passed through a 50-mesh standard sieve to obtain the inorganic gel polymerization inhibitor.

[0038] Comparative Example 1

[0039] An inorganic gel polymerization inhibitor, which differs from Example 1 only in that allyltrimethylammonium chloride is not added, while the other substances, amounts and preparation methods are the same as in Example 1.

[0040] Comparative Example 2

[0041] An inorganic gel polymerization inhibitor, which differs from Example 2 only in that allyltrimethylammonium chloride is not added, while the other substances, amounts and preparation methods are the same as in Example 2.

[0042] Comparative Example 3

[0043] An inorganic gel polymerization inhibitor, which differs from Example 3 only in that allyltrimethylammonium chloride is not added, while the other substances, amounts and preparation methods are the same as in Example 3.

[0044] Comparative Example 4

[0045] An inorganic gel polymerization inhibitor, which differs from Example 4 only in that allyltrimethylammonium chloride is not added, while the other substances, amounts and preparation methods are the same as in Example 4.

[0046] Comparative Example 5

[0047] An inorganic gel polymerization inhibitor, which differs from Example 1 only in that 2-vinylmorpholine and sodium vinylsulfonate are not added, while the other substances, amounts and preparation methods are the same as in Example 1.

[0048] Comparative Example 6

[0049] A conventional polymer inhibitor, specifically HPAM.

[0050] Performance testing:

[0051] (1) Thickening properties:

[0052] Add 99.5 parts by weight (10 × 10) to a 250 mL beaker. 4 mg / L, Ca 2+ =4000mg / L) of simulated saline solution, turn on the electric stirrer, and slowly add different weight parts of the inhibitors provided in the examples and comparative examples (so that the mass percentage of the inhibitors is 0.2%, 0.3% and 0.4% respectively) to the beaker, stir continuously for 60 minutes until completely dissolved, and test the apparent viscosity.

[0053] The inhibitors provided in Examples 1-4 and Comparative Examples 1-6 were tested according to the above test methods, and the test results are shown in Table 1:

[0054] Table 1

[0055]

[0056]

[0057] As can be seen from the data in Table 1, the apparent viscosity increases accordingly with the increase of the concentration of the inorganic gel polymerization inhibitor. At the same concentration, the inorganic gel polymerization inhibitor provided in Example 3 has the best thickening effect, while the conventional HPAM polymer inhibitor provided in Comparative Example 6 has the worst thickening effect.

[0058] (2) Delaying aggregation effect:

[0059] Using 10×10 4 mg / L simulated saline (Ca 2+Inhibitor solutions with a mass percentage of 0.2%, 0.3%, and 0.4% (4000 mg / L) were prepared. An electric stirrer was used to continuously stir the solution at 400 rpm for 60 minutes. A 20% sodium silicate solution was prepared using deionized water. The inhibitor solution and sodium silicate solution were mixed at a weight ratio of 97.5:2.5 and 95:5 (the mass percentage of sodium silicate in the mixture was 0.5% and 1%, respectively), and stirred until homogeneous. The mixture was then placed in a drying oven at 80℃ for 8 hours. The particle size of the polymerized particles was measured using a laser particle size analyzer to evaluate the polymer's effect on delaying the aggregation of inorganic gel particles.

[0060] The inhibitors provided in Examples 1-4 and Comparative Examples 1-6 were tested according to the above test methods, and the test results are shown in Table 2:

[0061] Table 2

[0062]

[0063]

[0064] According to the data in Table 2, as the concentration of the inhibitor increases, the particle size of the inorganic gel particles gradually decreases, and at the same concentration, the inorganic gel polymerization inhibitor provided in Example 3 has the best inhibitory effect on polymerization.

[0065] Comparing the data from Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, and Example 4 and Comparative Example 4, it can be seen that the polymer particles formed by combining 0.4% inhibitor with 0.5% sodium silicate solution in Examples 1-4 have a particle size of only 75-85 nm, while the polymer particles formed by combining 0.4% inhibitor with 0.5% sodium silicate solution in Comparative Examples 1-4 have a particle size as high as 170-185 nm, showing a significant increase in particle size. This is because, under the same conditions, the inhibitor provided in Comparative Examples 1-4 lacks the shielding effect of cationic groups due to the absence of allyltrimethylammonium chloride in the raw materials, resulting in a reduced effect in delaying particle aggregation and a significant increase in the particle size of the formed inorganic gel particles.

[0066] Further comparison of the data from Example 1 and Comparative Example 5 also shows that the inhibitor provided by Comparative Example 5 has poor salt resistance because the raw materials for its preparation do not contain 2-vinylmorpholine and sodium vinyl sulfonate, resulting in a larger particle size of the inorganic gel particles formed.

[0067] Finally, comparing the data of Example 1 and Comparative Example 6, it can be seen that the HPAM polymer provided by Comparative Example 6 has a poor effect on delaying particle agglomeration. The particle size of the polymer particles formed by 0.4% HPAM polymer with 0.5% sodium silicate solution is as high as 265nm.

[0068] The applicant declares that this invention illustrates an inorganic gel polymerization inhibitor, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above process steps, meaning that this invention does not necessarily rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. The application of an inorganic gel polymerization inhibitor in oilfield development, characterized in that, The raw materials for preparing the inorganic gel polymerization inhibitor include the following components in parts by weight: Acrylamide 15-20 parts by weight; 3-9 parts by weight of heat-resistant and salt-resistant monomer; 4-8 parts by weight of cationic monomer; Initiator 0.2~0.5 parts by weight; The temperature- and salt-resistant monomers include any one or a combination of at least two of N-vinylpyrrolidone, 2-vinylmorpholine, or sodium vinyl sulfonate.

2. The application of the inorganic gel polymerization inhibitor according to claim 1 in the oilfield development process, characterized in that, The temperature- and salt-resistant monomers are 2-vinylmorpholine and sodium vinyl sulfonate.

3. The application of the inorganic gel polymerization inhibitor according to claim 1 in the oilfield development process, characterized in that, The cationic monomer includes any one or a combination of at least two of dimethyl diallyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, or allyl trimethyl ammonium chloride.

4. The application of the inorganic gel polymerization inhibitor according to claim 3 in the oilfield development process, characterized in that, The cationic monomer is allyltrimethylammonium chloride.

5. The application of the inorganic gel polymerization inhibitor according to claim 1 in the oilfield development process, characterized in that, The initiator includes any one or a combination of at least two of the following: ammonium persulfate, sodium persulfate, sodium metabisulfite, sodium sulfite, tetramethylethylenediamine, or triethylamine.

6. The application of the inorganic gel polymerization inhibitor according to claim 5 in the oilfield development process, characterized in that, The initiator is tetramethylethylenediamine, ammonium persulfate, and sodium bisulfite.

7. The application of the inorganic gel polymerization inhibitor according to claim 1 in the oilfield development process, characterized in that, The raw materials for preparing the inorganic gel polymerization inhibitor also include water.

8. The application of the inorganic gel polymerization inhibitor according to claim 7 in the oilfield development process, characterized in that, The water content in the raw materials for preparing the inorganic gel polymerization inhibitor is 62.5~77.8 parts by weight.

9. The application of the inorganic gel polymerization inhibitor according to any one of claims 1 to 8 in the oilfield development process, characterized in that, The method for preparing the inorganic gel polymerization inhibitor includes: mixing acrylamide, a temperature- and salt-resistant monomer, and a cationic monomer in water, adding an initiator to carry out a polymerization reaction, and obtaining the inorganic gel polymerization inhibitor.

10. The application of the inorganic gel polymerization inhibitor according to claim 9 in the oilfield development process, characterized in that, The polymerization reaction is carried out at a temperature of 12~16℃.

11. The application of the inorganic gel polymerization inhibitor according to claim 9 in the oilfield development process, characterized in that, The polymerization reaction takes 4 to 6 hours.

12. The application of the inorganic gel polymerization inhibitor according to claim 9 in the oilfield development process, characterized in that, The polymerization reaction also includes granulation, drying and sieving steps after completion.

Images