A polymer, a composition containing the same and use in anti-dispersion

Abstract

The present application relates to a kind of polymer, the composition containing it and in for the application in anti dispersion.Monomer unit is acrylamide compound unit, cationic organic compound unit and carboxylic acid unit, and polyvinyl alcohol is also contained in the composition.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil well cement, in particular to an anti-dispersant for oil well cement. BACKGROUND

[0002] In recent years, most of the domestic onshore oilfields have entered the late stage of high water cut development, and most of the newly developed reservoirs also use early water injection development to maintain formation productivity. For old oilfields developed by water injection, in order to improve development effect and ultimate recovery, it is necessary to drill more wells for adjustment, so that the number of adjustment wells drilled is increasing, and due to long-term water injection development, the formation pressure becomes very complex, and the water content in the formation increases, so that cement often needs to be used in water environment during oil well operation, but there are also serious problems such as difficulty in forming due to water erosion and inability to use.

[0003] Because the use environment of oil well cement is more harsh than ordinary concrete, it often faces more complex underground environments such as high temperature and high pressure, and underwater pouring is also prone to cement particle dispersion due to water erosion, which makes the cement slurry system unable to be used underwater. In addition, the cement has higher requirements for filtration, rheological property, thickening time and compressive strength. Therefore, in view of the high temperature and high pressure use environment of oil well cement, especially the underwater dispersion problem and the requirement for the thickening performance of the cement slurry, it is urgent to develop an anti-dispersant for oil well cement suitable for well cementing operation, so that it can ensure that the components are aggregated together when directly contacted with water and washed by water during underwater pouring, and will not be separated and dispersed, thereby ensuring the construction quality of the cement slurry underwater. SUMMARY

[0004] One of the present application provides a polymer, the polymer unit is acrylamide compound unit, cationic organic compound unit and carboxylic acid unit.

[0005] In one embodiment, the acrylamide compound is acrylamide and / or N,N-dimethyl acrylamide.

[0006] In one embodiment, the cationic organic compound is dimethyl diallyl ammonium chloride and / or dimethyl octadecyl allyl ammonium chloride.

[0007] In one embodiment, the carboxylic acid is at least one of maleic anhydride, acrylic acid and itaconic acid.

[0008] In one embodiment, the mass ratio of the acrylamide compound unit, the cationic organic compound unit and the carboxylic acid unit is (80-100):(80-120):(3-5).

[0009] In one embodiment, the mass ratio of the acrylamide compound unit, the cationic organic compound unit, and the carboxylic acid unit is (60-80):(72-80):3.

[0010] The second aspect of the present application provides a composition comprising polyvinyl alcohol and a polymer as described in any one of the first aspect of the present application.

[0011] In one embodiment, the mass ratio of the polyvinyl alcohol and the polymer is (8-12):(8.15-11.25).

[0012] The third aspect of the present application provides a method of preparing the composition as described in the second aspect of the present application, comprising the steps of:

[0013] 1-1) adding an acrylamide compound, a cationic organic compound, and polyvinyl alcohol to water to obtain a first solution;

[0014] 1-2) adding a carboxylic acid to water to obtain a second solution;

[0015] 1-3) adding an initiator to water to obtain an initiator solution;

[0016] 1-4) simultaneously adding the second solution and the initiator solution to the first solution, and adjusting the pH after the reaction to obtain the composition;

[0017] or

[0018] 2-1) adding an acrylamide compound and a cationic organic compound to water to obtain a first solution;

[0019] 2-2) adding a carboxylic acid and polyvinyl alcohol to water to obtain a second solution;

[0020] 2-3) adding an initiator to water to obtain an initiator solution;

[0021] 2-4) simultaneously adding the second solution and the initiator solution to the first solution, and adjusting the pH after the reaction to obtain the composition;

[0022] or

[0023] 3-1) adding an acrylamide compound and a cationic organic compound to water to obtain a first solution;

[0024] 3-2) adding a carboxylic acid to water to obtain a second solution;

[0025] 3-3) adding an initiator to water to obtain an initiator solution;

[0026] 3-4) adding a second solution and the initiator solution into the first solution simultaneously, adding polyvinyl alcohol after the reaction, adjusting the pH value to obtain the composition.

[0027] In step 1-1) or 2-2), polyvinyl alcohol is added, so that polyvinyl alcohol has sufficient time to dissolve, thereby shortening the time of the entire preparation process.

[0028] In one specific embodiment, the temperature of the reaction is 65 to 75℃, and the time of the reaction is 1.5 to 2.5 hours.

[0029] In one specific embodiment, the adjusted pH value is 6 to 7.

[0030] In one specific embodiment, the initiator is at least one of ammonium persulfate, potassium persulfate and azobisdimethylaminoformamide hydrochloride.

[0031] In one specific embodiment, the ratio of the mass of the initiator to the total mass of the acrylamide compound, the cationic organic compound and the carboxylic acid is (0.15-0.25) to (9.8-11.25).

[0032] The fourth aspect of the present application provides the use of the composition prepared according to the second aspect of the present application or the method according to the third aspect of the present application as an anti-dispersion agent.

[0033] The beneficial effects of the present application are:

[0034] (1) The polymer of the present application can be used as an anti-dispersion agent for oil well cement, and has good adaptability to oil well cement. The cement slurry has a certain flocculation, and can not be separated and dispersed under the action of water washing, has a remarkable water washing resistance, and is suitable for use as a cement anti-dispersion agent.

[0035] (2) The combination of polyvinyl alcohol and the polymer of the present application can produce a synergistic effect, thereby producing better flocculation.

[0036] (3) The present application uses water as a solvent, has a simple preparation process, low cost and easy industrialization. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The infrared spectrum of the anti-dispersion agent prepared for Example 1.

[0038] Figure 2 The thermogravimetric curve of the anti-dispersion agent prepared for Example 1.

[0039] Figure 3 The initial consistency test diagram of the cement slurry containing the anti-dispersion agent prepared for Example 1. DETAILED DESCRIPTION

[0040] The above content of the present application is further explained in detail in the form of preferred embodiments, but it does not constitute a limitation to the present application.

[0041] Unless otherwise specified, the reagents in the embodiments of the present application can be purchased through commercial channels.

[0042] Example 1

[0043] A preparation method of an anti-dispersant for oil well cement, comprising the following steps:

[0044] (1) 4g of acrylamide and 4g of dimethyl diallyl ammonium chloride are weighed and added into 55g of distilled water, and stirred to obtain a mixed solution;

[0045] (2) 0.15g of acrylic acid is weighed and added into 5g of distilled water, and stirred to obtain A liquid;

[0046] (3) 0.15g of ammonium persulfate is weighed and dissolved in 5g of distilled water, and stirred to obtain B liquid;

[0047] (4) A liquid and B liquid are simultaneously added dropwise into the mixed solution obtained in step (1), after the addition is completed, the solution is incubated at 70°C and stirred for 1.5 hours, and the pH is adjusted to 6, to obtain an anti-dispersant for oil well cement with an effective ingredient mass of 8.15g.

[0048] Example 2

[0049] A preparation method of an anti-dispersant for oil well cement, comprising the following steps:

[0050] (1) 5g of acrylamide and 6g of dimethyl diallyl ammonium chloride are weighed and added into 65g of distilled water, and stirred to obtain a mixed solution;

[0051] (2) 0.25g of acrylic acid is weighed and added into 15g of distilled water, and stirred to obtain A liquid;

[0052] (3) 0.25g of ammonium persulfate is weighed and dissolved in 15g of distilled water, and stirred to obtain B liquid;

[0053] (4) A liquid and B liquid are simultaneously added dropwise into the mixed solution obtained in step (1), after the addition is completed, the solution is incubated at 70°C and stirred for 2.5 hours, and the pH is adjusted to 7, to obtain an anti-dispersant for oil well cement with an effective ingredient mass of 11.25g.

[0054] Example 3

[0055] A preparation method of an anti-dispersant for oil well cement, comprising the following steps:

[0056] (1) Take 4.6 g of acrylamide and 5 g of dimethyl diallyl ammonium chloride into 60 g of distilled water, and stir to obtain a mixed solution;

[0057] (2) Take 0.2 g of acrylic acid, add 10 g of distilled water, and stir to obtain A liquid;

[0058] (3) Take 0.2 g of ammonium persulfate, dissolve in 10 g of distilled water, and stir to obtain B liquid;

[0059] (4) Add A liquid and B liquid into the mixed solution obtained in step (1) at the same time, and after the addition is completed, keep the temperature at 70°C and stir for 2 hours, and adjust the pH to 7 to obtain an anti-dispersant for oil well cement with an effective ingredient mass of 9.8 g.

[0060] Example 4

[0061] A method for preparing an anti-dispersant for oil well cement comprises the following steps:

[0062] (1) Take 10 g of polyvinyl alcohol (PVA), 4.6 g of acrylamide, and 5 g of dimethyl diallyl ammonium chloride into 60 g of distilled water, and stir to obtain a mixed solution;

[0063] (2) Take 0.2 g of acrylic acid, add 10 g of distilled water, and stir to obtain A liquid;

[0064] (3) Take 0.2 g of ammonium persulfate, dissolve in 10 g of distilled water, and stir to obtain B liquid;

[0065] (4) Add A liquid and B liquid into the mixed solution obtained in step (1) at the same time, and after the addition is completed, keep the temperature at 70°C and stir for 2 hours, and adjust the pH to 7 to obtain an anti-dispersant for oil well cement with an effective ingredient mass of 21.8 g.

[0066] Example 5

[0067] A method for preparing an anti-dispersant for oil well cement comprises the following steps:

[0068] (1) Take 8 g of polyvinyl alcohol, 4 g of N,N-dimethyl acrylamide, and 4 g of dimethyl octadecyl allyl ammonium chloride into 55 g of distilled water, and stir to obtain a mixed solution;

[0069] (2) Take 0.15 g of maleic anhydride, add 5 g of distilled water, and stir to obtain A liquid;

[0070] (3) Take 0.15 g of potassium persulfate, dissolve in 5 g of distilled water, and stir to obtain B liquid;

[0071] (4) to the mixture obtained in step (1), A liquid and B liquid are added simultaneously, after the addition, the mixture is kept at 65°C and stirred for 1.5 hours, the pH is adjusted to 6, to obtain the anti-dispersant for oil well cement with the effective ingredient mass of 16.15g.

[0072] Example 6

[0073] A preparation method of an anti-dispersant for oil well cement, comprising the following steps:

[0074] (1) 12g of polyvinyl alcohol, 5g of acrylamide and 6g of dimethyl diallyl ammonium chloride are weighed and added into 65g of distilled water, and stirred to obtain a mixture;

[0075] (2) 0.25g of itaconic acid is weighed and added into 15g of distilled water, and stirred to obtain A liquid;

[0076] (3) 0.25g of azobisdimethylaminoformamide hydrochloride is weighed and dissolved in 15g of distilled water, and stirred to obtain B liquid;

[0077] (4) A liquid and B liquid are added simultaneously into the mixture obtained in step (1), after the addition, the mixture is kept at 75°C and stirred for 2.5 hours, the pH is adjusted to 7, to obtain the anti-dispersant for oil well cement with the effective ingredient mass of 23.25g.

[0078] Example 7

[0079] A preparation method of an anti-dispersant for oil well cement, comprising the following steps:

[0080] (1) 4.6g of acrylamide and 5g of dimethyl diallyl ammonium chloride are weighed and added into 60g of distilled water, and stirred to obtain a mixture;

[0081] (2) 0.2g of itaconic acid is weighed and added into 10g of distilled water, and stirred to obtain A liquid;

[0082] (3) 0.2g of azobisdimethylaminoformamide hydrochloride is weighed and dissolved in 10g of distilled water, and stirred to obtain B liquid;

[0083] (4) A liquid and B liquid are added simultaneously into the mixture obtained in step (1), after the addition, the mixture is kept at 70°C and stirred for 2.5 hours, 12g of polyvinyl alcohol is weighed and added into the system, and stirred to obtain the anti-dispersant for oil well cement with the effective ingredient mass of 21.8g.

[0084] Comparative Example 1

[0085] A preparation method of an anti-dispersant for oil well cement, comprising the following steps:

[0086] (1) 19.8 g of polyvinyl alcohol was weighed into 80 g of distilled water, and the mixture was kept at 70°C and stirred for 2 hours to obtain 19.8 g of an anti-dispersant for oil well cement with an effective ingredient mass.

[0087] Performance analysis

[0088] 1. Infrared spectrum analysis of the anti-dispersant

[0089] The anti-dispersants prepared in Examples 1 to 7 were ground respectively, and then mixed with dried potassium bromide in a mass ratio of 1:50, ground and tabletted. The chemical structure of the anti-dispersant was tested by infrared spectrum using a Bio-Rad FTS 3000 Fourier infrared spectrometer (FTIR) with a scanning wave number range of 400-4000 cm -1 . Among them, Figure 1 is the infrared spectrum of the anti-dispersant prepared in Example 4.

[0090] From Figure 1 it can be seen that 1660 cm -1 is the C=O stretching vibration peak of the amide group in acrylamide (AM), 1260 cm -1 and 956 cm -1 are the characteristic absorption peaks of -C-N and -N+R3 on dimethyl diallyl ammonium chloride (DMDAAC), respectively; 1734 cm -1 and 1450 cm -1 are the symmetric and antisymmetric stretching vibration peaks of -COOH on acrylic acid (AA), respectively, indicating that all monomers participate in the polymerization reaction; the absorption peak at 3292.30 cm -1 is attributed to the OH stretching vibration mode of polyvinyl alcohol (PVA) molecules, the absorption peak at 2930 cm -1 is attributed to the CH2 stretching vibration mode of polyvinyl alcohol molecules, and the absorption peak at 1100 cm -1 is attributed to the C-O stretching vibration mode of polyvinyl alcohol molecules, so PVA exists in the anti-dispersant. In summary, the anti-dispersant prepared in Example 4 contains polymers formed by AM, DMDMMC and AA monomers and PVA.

[0091] The infrared spectrum results of the anti-dispersants prepared in Examples 1 to 3 and 5 to 7 are similar to those of the anti-dispersant prepared in Example 4, respectively containing polymers formed by the respective reaction monomers, or in the case of adding PVA, also containing PVA.

[0092] 2. Thermal gravimetric analysis of the anti-dispersant

[0093] The anti-dispersants prepared in Examples 1 to 7 were subjected to thermal gravimetric analysis after drying. The test conditions were as follows: temperature range 35 to 800℃, temperature increase rate 10℃ / min, nitrogen as protective gas, and the results are shown in Table 1 and Figure 2 . Among them, Figure 2 is the thermal gravimetric curve of the anti-dispersant prepared in Example 4.

[0094] Table 1

[0095] Example Loss on ignition temperature °C Example 1 190 Example 2 195 Example 3 190 Example 4 200 Example 5 190 Example 6 195 Example 7 185

[0096] As can be seen from Table 1, the anti-dispersants of Examples 1 to 7 all started to lose weight at 185℃ or above, and had comparable temperature resistance. In summary, the temperature resistance of the anti-dispersants of all examples was good.

[0097] As can be seen from Figure 2 , at 35 to 200℃, the weight loss of the anti-dispersant prepared in Example 4 was only about 4%, which was mainly due to the volatilization of combined water in the anti-dispersant; at 200 to 460℃, the weight loss of the anti-dispersant was about 83%, which was mainly caused by the rupture of the main chain and part of the side chain of the anti-dispersant molecular chain; at 460 to 800℃, the final residual weight was about 9%, which was mainly due to the carbonization of the anti-dispersant. Therefore, the anti-dispersant prepared in Example 4 started to decompose at 200℃, and therefore had good temperature resistance.

[0098] 3. Performance analysis of cement slurry

[0099] The cement slurry was prepared according to GB / T 19139-2012 “Oil Well Cement Test Method”.

[0100] Cement paste: 500g of Jiahua G-grade oil well cement and 220g of tap water were weighed, the switch of the constant speed stirrer was turned on, the oil well cement was added into the water within 15s at a low speed of 4000r / min, and the mixture was kept at a high speed of 12000r / min for 35s to obtain a uniformly mixed cement slurry. Among them, when preparing the cement slurry, the water-cement ratio (w / c) of water and cement was 0.44:1.

[0101] Cement slurry containing anti-dispersant: 500g of Jiahua G-grade oil well cement, anti-dispersants prepared in Examples 1 to 7 and Comparative Example 1 with an effective ingredient addition amount of 0.5wt% of cement, and 220g of tap water were weighed, the switch of the constant speed stirrer was turned on, the oil well cement was added into the water containing the anti-dispersant within 15s at a low speed of 4000r / min, and the mixture was kept at a high speed of 12000r / min for 35s to obtain a uniformly mixed cement slurry. Among them, when preparing the cement slurry, the water-cement ratio (w / c) of water and cement was 0.44:1.

[0102] 3.1 Initial consistency analysis

[0103] The initial consistency of cement neat paste and cement paste containing anti-dispersant was tested using a TG-8040DA type double-cylinder high temperature and high pressure consistency instrument. The specific test method is as follows: pour the prepared cement paste into the consistency instrument slurry cup, assemble the slurry cup and place it in the high temperature and high pressure consistency instrument kettle body, turn on the motor to rotate the slurry cup, tighten the high pressure kettle body top cover, insert the temperature sensor, fill the high pressure kettle body with hydrocarbon oil, and set the required program for the experiment, wherein the temperature is set to 60°C and the pressure is set to 33Mpa. The initial consistency results are shown in Table 2. Figure 3 The initial consistency test chart of cement paste containing the anti-dispersant prepared in Example 4. In engineering applications, the initial consistency is the maximum value of the consistency of the cement paste within 15-30 minutes after the start of the consistency experiment.

[0104] Table 2

[0105] Example Initial consistency / Bc Example 1 28.4 Example 2 29.6 Example 3 29.4 Example 4 29.2 Example 5 29.3 Example 6 29.5 Example 7 29.8 Comparative Example 1 30.1

[0106] From Figure 3 It can be seen that the initial consistency of the cement paste containing Example 4 is less than 30Bc after 60°C curing, indicating that the cement paste with anti-dispersant will not be severely thickened.

[0107] According to the results in Table 2, the initial consistency analysis results of Examples 1 to 3 and 5 to 7 are comparable to Example 4.

[0108] 3.2 Anti-dispersion performance analysis

[0109] Cement loss determination: The cement neat paste or cement paste containing anti-dispersant was stirred and cured at 60°C in a normal pressure consistency instrument for 20min to obtain the cured cement paste. Pour the cured cement paste into a 1000mL beaker containing 800mL tap water, and require the slurry to be slowly and freely poured into the container from the water surface within 2min, and stand for 5min. Then take 500ml of supernatant, stir evenly and measure its density, the results are shown in Table 2. Multiply the obtained density by 500ml, subtract the weight of water itself 500g, and the weight of the solid particles dispersed in the 500mL water on the upper layer of the beaker due to the scouring action of water when 500g of cement paste is poured into the container, i.e. the cement loss, is obtained, the results are shown in Table 2.

[0110] pH value determination: The cement neat paste or cement paste containing anti-dispersant was stirred and cured at 60°C in a normal pressure consistency instrument for 20min. Take a 1000mL beaker, pour the cured cement paste into a 1000mL beaker containing 800mL tap water, and require the slurry to be slowly and freely poured into the container from the water surface within 2min, and stand for 5min. Use a pipette to suck 10mL of solution from the supernatant in the beaker within 30s as the experimental sample, and use precise pH test paper to determine its pH value, the results are shown in Table 2.

[0111] Table 2

[0112] Supernatant density / (g / cm 3 )]]> Cement loss (g / L) pH Cement paste 1.003 3.0 13 Example 1 1.002 2.0 11 Example 2 1.002 2.0 11 Example 3 1.002 2.0 11 Example 4 1.001 1.0 10 Example 5 1.001 1.0 10 Example 6 1.001 1.0 10 Example 7 1.001 1.0 11 Comparative Example 1 1.002 2.0 12

[0113] From the results of cement loss and pH value in Table 1, it can be seen that the cement loss and pH value and supernatant density of cement paste added with cement paste of Examples 1 to 7 are all reduced compared with cement paste; for example, the cement loss of cement paste added with cement of Example 4 is reduced from 3.0 g to 1.0 g, and the pH value is reduced from 13 to 10. Compared with Examples 1 to 3 and Comparative Example 1, the cement loss of cement paste of Examples 4 to 7 is further reduced, and the pH value is also further reduced compared with Comparative Example 1. The above data results show that the polymer of the present application and polyvinyl alcohol have a synergistic effect.

[0114] In summary, the anti-dispersion agent of the present application has excellent anti-dispersion performance.

Claims

1. A composition comprising polyvinyl alcohol and a polymer; units of the polymer are acrylamide compound units, cationic organic compound units, and carboxylic acid units; wherein a mass ratio of the acrylamide compound units, the cationic organic compound units, and the carboxylic acid units is (60-69) : (72-75) : 3; a mass ratio of the polyvinyl alcohol to the polymer is (8-12) : (8.15-11.25); the acrylamide compound is acrylamide and / or N, N-dimethyl acrylamide; the cationic organic compound is dimethyldiallylammonium chloride and / or dimethyloctadecylammonium allyl chloride; the carboxylic acid is at least one of maleic anhydride, acrylic acid, and itaconic acid. 2.A method for preparing the composition of claim 1, comprising the following steps: 1-1) adding an acrylamide compound, a cationic organic compound, and polyvinyl alcohol into water to obtain a first solution; 1-2) adding a carboxylic acid into water to obtain a second solution; 1-3) adding an initiator into water to obtain an initiator solution; 1-4) adding the second solution and the initiator solution into the first solution simultaneously, and adjusting the pH value after reaction to obtain the composition; or 2-1) adding an acrylamide compound and a cationic organic compound into water to obtain a first solution; 2-2) adding a carboxylic acid and polyvinyl alcohol into water to obtain a second solution; 2-3) adding an initiator into water to obtain an initiator solution; 2-4) adding the second solution and the initiator solution into the first solution simultaneously, and adjusting the pH value after reaction to obtain the composition; or 3-1) adding an acrylamide compound and a cationic organic compound into water to obtain a first solution; 3-2) adding a carboxylic acid into water to obtain a second solution; 3-3) adding an initiator into water to obtain an initiator solution; 3-4) adding the second solution and the initiator solution into the first solution simultaneously, and adding polyvinyl alcohol after reaction, and adjusting the pH value to obtain the composition.

3. The method of claim 2, wherein, a temperature of the reaction is 65 to 75 °C, a time of the reaction is 1.5 to 2.5 hours;and / or an adjusted pH value is 6 to 7;and / or the initiator is at least one of ammonium persulfate, potassium persulfate, and azobisdimethylvaleronitrile hydrochloride;and / or a proportion of a mass of the initiator to a total mass of the acrylamide compound, the cationic organic compound, and the carboxylic acid is (0.15-0.25) to (9.8-11.25). 4.Use of the composition of claim 1 or the composition prepared by the method of claim 2 or 3 as an anti-dispersant.

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