A polymer, an ultra-high temperature oil well cement retarder, its preparation method and application, and cement slurry

Abstract

This invention provides a polymer, an ultra-high temperature oil well cement retarder, its preparation method and application, and a cement slurry. The molecular structure of the polymer is shown in formula (1): In formula (1), a, b, and c are all molar numbers, and the ratio of the three is 40-85:10-40:5-20; R1 is one of -H, -CH3, and -CH2COOH; R2 is selected from one of the following compounds: The ultra-high temperature oil well cement retarder provided by this invention can withstand temperatures up to 240℃. In the temperature range of 110-240℃, the cement slurry thickening time is linearly adjustable within 200-500 min and has a good linear relationship with temperature and dosage. It has good compatibility with other admixtures, has little impact on the mechanical properties of cement stone, and can ensure the safety of ultra-high temperature cementing operations and meet the cementing technical requirements of complex and difficult wells.

Description

Technical Field

[0001] This invention relates to a polymer, an ultra-high temperature oil well cement retarder, its preparation method and application, and cement slurry, belonging to the technical field of oil and gas well cementing admixtures. Background Technology

[0002] China's remaining onshore oil resources (39%) and natural gas resources (57%) are located in deep formations. Deep and ultra-deep formations have become crucial areas for increasing oil and gas reserves and production, significantly contributing to China's energy security and alleviating its dependence on foreign energy. The safe and efficient exploration and development of ultra-deep oil and gas resources faces a series of major engineering and technical challenges, including deeper wells (above 8000m), higher temperatures (above 240℃), and more complex well conditions. Cementing is a key engineering technology for ensuring safe and efficient exploration and development, directly impacting oil and gas recovery rates, well life, and long-term safe production. Therefore, complex operating conditions such as ultra-high temperatures place extremely high demands on cementing slurry systems and key materials. Under ultra-high temperatures, effectively controlling the thickening time of the cementing slurry system is crucial for ensuring the safety of cementing operations. Retarders are one of the main agents for extending the thickening time of the cement slurry, improving the system's rheological properties, and ensuring its overall performance. They are key materials for ensuring the safety of cementing operations in deep and ultra-deep wells, directly determining the success or failure of the cementing operation.

[0003] There are many types of retarder for oil well cement. Among them, 2-acrylamide-2-methylpropanesulfonic acid (AMPS) polymers have become a research and application hotspot due to their strong temperature and salt resistance, diverse molecular structure design, and controllable production. For example, Chinese patent CN 102040987A discloses a retarder for oil well cement with a temperature resistance of 230℃, which is prepared by free radical aqueous solution polymerization of AMPS and acrylic acid. The thickening time of cement slurry with a 3% admixture is 330 minutes. However, the evaluation of the cement slurry system by this technology is relatively simple, and there are no ultrafine materials or stabilizers to ensure the stability of the system. The poor stability of the cement slurry system may have a significant impact on the thickening time. Chinese patent CN 104403056B discloses an ultra-high temperature retarder copolymerized from four monomers: AMPS, DMDAAC (diallyl dimethyl ammonium chloride), MAH (maleic anhydride), IA (itaconic acid), FA (fumaric acid), AA (acrylic acid), or methacrylic acid. A dosage of 6.0% can thicken cement slurry at 230°C for 289 minutes. However, this product requires a large dosage and does not address setting regulation performance above 230°C. Therefore, it cannot meet the requirements of ultra-deep well ultra-high temperature cementing technology with bottom hole temperatures above 230°C. US5536311 developed a variety of multi-component copolymer high-temperature retarders by using one of AMPS, sodium methyl allyl sulfonate, SSS (sodium styrene sulfonate), VS (vinyl sulfonic acid), NNDMA (N,N-dimethylacrylamide), AM (acrylamide), NVP (N-vinylpyrrolidone), acrylonitrile, etc. as the first monomer, one of IA, MA (maleic acid), MAH, FA, citric acid, TA, etc. as the second monomer, and one of AA, MA as the third monomer. Among them, the AMPS / IA / MAH ternary copolymer retarder has a temperature resistance of up to 260℃. However, the cement slurry evaluation formula in this patent is too simple (the formula contains H-grade cement, 35% silica fume, 4% retarder and 38% water), and the system's settling stability cannot be guaranteed. In addition, the retarder has strong high-temperature dispersibility, which may lead to a long thickening time of cement slurry at 260℃ due to poor system stability.

[0004] It is evident that, although the domestic oil well cement retarders represented by the aforementioned patents have improved in terms of temperature and salt resistance, they have still failed to break through the technical bottleneck of ultra-high temperature of 232℃. Currently, ultra-high temperature cementing retarder products mainly rely on imports. In the complex international environment, the existing domestic retarders can no longer fully meet the requirements of ultra-high temperature cementing operations under the new situation of exploration and development.

[0005] Therefore, providing a novel ultra-high temperature oil well cement retarder, its preparation method and application, and cement slurry has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] In order to overcome the above-mentioned disadvantages and deficiencies, one object of the present invention is to provide a polymer.

[0007] Another objective of this invention is to provide an ultra-high temperature oil well cement retarder.

[0008] Another object of the present invention is to provide a method for preparing the above-described ultra-high temperature oil well cement retarder.

[0009] Another object of the present invention is to provide the application of the polymer described above or the ultra-high temperature oil well cement retarder in cementing operations under complex working conditions.

[0010] A final objective of this invention is to provide a cement slurry comprising the polymer described above or the ultra-high temperature oil well cement retarder described above. The ultra-high temperature oil well cement retarder provided by this invention has a temperature resistance of up to 240℃. Within a temperature range of 110-240℃, the cement slurry thickening time is linearly adjustable within 200-500 minutes and exhibits a good linear relationship with temperature and dosage. It has good compatibility with other admixtures, minimal impact on the mechanical properties of the cement stone, and can ensure the safety of ultra-high temperature cementing operations and meet the cementing technical requirements of complex and difficult wells such as deep wells, ultra-deep wells, 10,000-meter exploration wells, high-temperature and high-pressure gas wells, unconventional oil and gas wells, and gas storage wells.

[0011] To achieve the above objectives, on the one hand, the present invention provides a polymer, wherein the molecular structure of the polymer is shown in formula (1):

[0012] ;

[0013] Equation (1);

[0014] In equation (1), a, b, and c are all moles, and the ratio of the three is 40-85:10-40:5-20.

[0015] R1 is one of -H, -CH3, and -CH2COOH;

[0016] R2 is selected from one of the following compounds:

[0017] , ,

[0018] , and .

[0019] On the other hand, the present invention also provides an ultra-high temperature oil well cement retarder, wherein the ultra-high temperature oil well cement retarder comprises the polymer described above and water, and the polymer content is 20-40% and the water content is 60-80% based on the total weight of the ultra-high temperature oil well cement retarder as 100%.

[0020] In another aspect, the present invention also provides a method for preparing the above-mentioned ultra-high temperature oil well cement retarder, wherein the preparation method includes:

[0021] (1) Dissolve 2-acrylamido-2-methylpropanesulfonic acid monomer, unsaturated carboxylic acid monomer and rigid unsaturated monomer in deionized water, and add alkaline substances to the resulting solution to adjust the pH value of the solution to 3-5; wherein the weight ratio of 2-acrylamido-2-methylpropanesulfonic acid monomer, unsaturated carboxylic acid monomer and rigid unsaturated monomer is 45-92: 4-32: 4-30;

[0022] (2) After adding a chain transfer agent to the system obtained in step (1), the temperature is increased, then an initiator is added, and the temperature is increased again to carry out the polymerization reaction;

[0023] (3) Add reducing inorganic salts to the solution obtained after the reaction in step (2) for post-treatment. After the post-treatment is completed, a viscous liquid polymer solution is obtained, which is the ultra-high temperature oil well cement retarder.

[0024] As a specific embodiment of the preparation method described above in this invention, in step (1), the weight ratio of 2-acrylamido-2-methylpropanesulfonic acid monomer, unsaturated carboxylic acid monomer, rigid unsaturated monomer and deionized water ranges from 45-92: 4-32: 4-30: 150-300.

[0025] As a specific embodiment of the preparation method described above in this invention, in step (1), the unsaturated carboxylic acid monomer includes one or a combination of itaconic acid, methacrylic acid, acrylic acid and butenoic acid.

[0026] As a specific embodiment of the preparation method described above in this invention, in step (1), the rigid unsaturated monomer includes diethyl 4-vinylbenzylphosphonate, 2,2 ' One or a combination of several of the following: -(4-vinylbenzylaminoidene)diacetic acid, vinylbenzyltrimethylammonium chloride (N-trimethyl-(4-vinylbenzyl)ammonium chloride), and N-(4-vinylbenzyl)-N,N-dimethylamine.

[0027] As a specific embodiment of the preparation method described above in this invention, in step (1), the alkaline substance includes sodium hydroxide, and the amount used is 10-20 parts by weight.

[0028] As a specific embodiment of the preparation method described above in this invention, in step (2), the amount of chain transfer agent used is 0.05-1.0% of the total mass of the monomer.

[0029] As a specific embodiment of the preparation method described above in this invention, in step (2), the chain transfer agent includes one or more of 3-mercaptopropionic acid, 3-mercaptoacetic acid, mercaptoethanol, n-butanethiol, n-dodecyl mercaptoethanol and isopropanol.

[0030] As a specific embodiment of the preparation method described above in this invention, in step (2), the amount of the initiator is 0.5-2.5% of the total mass of the monomer.

[0031] As a specific embodiment of the preparation method described above in this invention, in step (2), the initiator includes one or more of ammonium persulfate, potassium persulfate and azobisisobutyrazoline hydrochloride.

[0032] As a specific embodiment of the preparation method described above in this invention, in step (2), after adding the chain transfer agent to the system obtained in step (1), the temperature is raised to 50-65°C and kept at that temperature for 10-30 minutes.

[0033] As a specific embodiment of the preparation method described above in this invention, in step (2), the step of continuing to heat up to carry out the polymerization reaction includes: heating to 70-90℃ and reacting at a constant temperature for 2-5 hours.

[0034] As a specific embodiment of the preparation method described above in this invention, in step (2), the heating rate is 0.5-2℃ / min.

[0035] As a specific embodiment of the preparation method described above in this invention, in step (3), the amount of the reducing inorganic salt is 0.2-1.0% of the total mass of the solution obtained after the reaction in step (2).

[0036] As a specific embodiment of the preparation method described above in this invention, in step (3), the reducing inorganic salt includes one or more of sodium sulfite, sodium bisulfite, ammonium sulfite, potassium sulfite and potassium bisulfite.

[0037] As a specific embodiment of the preparation method described above in this invention, in step (3), the post-processing time is 30-60 min.

[0038] As a specific embodiment of the preparation method described above in this invention, step (3) further includes: after the post-treatment is completed, the system is naturally cooled to room temperature to obtain a viscous liquid polymer solution, which is the ultra-high temperature oil well cement retarder.

[0039] In this invention, after obtaining the ultra-high temperature oil well cement retarder, it can first be washed with acetone, and then subjected to vacuum freeze-drying to obtain the purified product, namely the polymer. The number of acetone washes and the temperature and time of the vacuum freeze-drying can be reasonably adjusted according to actual operational needs, as long as the objective of this invention is achieved.

[0040] Furthermore, the present invention also provides the application of the polymer described above or the ultra-high temperature oil well cement retarder described above in cementing operations in complex well conditions.

[0041] As a specific embodiment of the application described above in this invention, the complex working condition well includes deep wells, ultra-deep wells, scientific drilling wells at depths of 10,000 meters, high-temperature and high-pressure gas wells, unconventional oil and gas wells, or gas storage wells.

[0042] Finally, the present invention also provides a cement slurry, wherein the cement slurry comprises the polymer described above or the ultra-high temperature oil well cement retarder described above.

[0043] In one specific embodiment of the cement slurry described above in this invention, the amount of ultra-high temperature oil well cement retarder added is 1.5-6.5%, based on the total weight of cement contained in the cement slurry being 100%.

[0044] This invention improves the ultra-high temperature resistance and setting performance of polymer retarder through optimized molecular structure design, effective intervention of temperature-resistant and salt-resistant rigid groups, synergistic effect of multiple adsorption groups, and efficient treatment of reducing inorganic salts. Specifically, firstly, the introduction of high-temperature resistant and salt-resistant rigid groups such as vinyl benzyl groups increases the rigidity of the polymer molecular chain and its ultra-high temperature structural stability, endowing the polymer retarder with ultra-high temperature resistance. Secondly, the introduction of multiple adsorption groups such as carboxylic acids, dicarboxylic acids, and phosphonic acids into the polymer molecular structure for synergistic enhancement greatly improves its adsorption and chelation capacity on the surface of cement particles under ultra-high temperature conditions, synergistically improving the ultra-high temperature setting performance and environmental adaptability of the polymer retarder product. Thirdly, reasonable control of the polymer molecular weight can reduce the linear length of the polymer molecular chain, thereby avoiding the conformational transformation of the polymer under high temperature and strong adsorption, which leads to abnormal gelation of the cement paste system. Finally, the post-treatment of the product obtained after the polymerization reaction with reducing inorganic salts can reorganize the molecular conformation, annihilate the oxidative initiator in the system, and ensure the quality stability of the polymer product, thereby further improving and alleviating the abnormal high-temperature gelation phenomenon of cement paste caused by polycarboxylic acid retarders. In summary, reasonable molecular structure, functional groups and other technical means endow ultra-high temperature oil well cement retarder with good ultra-high temperature setting regulation performance, so that it can meet the cementing operation requirements of complex working conditions such as high temperature and high pressure gas wells, unconventional oil and gas wells, gas storage wells, deep wells, ultra-deep wells and scientific drilling wells at depths of 10,000 meters.

[0045] Compared with the prior art, the beneficial effects achieved by the present invention include:

[0046] (1) This invention improves the ultra-high temperature resistance and stable setting performance of polymer retarder through measures such as optimized molecular structure design, effective intervention of temperature-resistant and salt-resistant rigid groups, synergistic effect of multiple adsorption groups, and efficient treatment of reducing inorganic salts. In addition, the introduction of functional groups such as phosphonic acid groups, amine groups, quaternary ammonium salts, and imidazole groups can further improve the charge density of polymer corrosion inhibitors and enhance their ultra-high temperature adsorption stability, thereby effectively controlling the thickening time of ultra-high temperature cement slurry system.

[0047] (2) The ultra-high temperature oil well cement retarder provided by the present invention has a wide applicable temperature range (70-240℃). Within the temperature range of 110-240℃, the cement slurry thickening time is linearly adjustable within 200-500 min and has a good linear relationship with temperature and dosage. It has good compatibility with other admixtures and has little impact on the mechanical properties of cement stone (the development of mechanical strength of cement stone).

[0048] (3) The ultra-high temperature oil well cement retarder provided by the present invention has strong adaptability and is suitable for various cement slurry systems such as conventional density, low density, high density, high strength and toughness, and latex. It can effectively ensure the safety of cementing construction, reduce the risk of cementing operation, and meet the cementing technical requirements of complex and difficult wells such as deep wells, ultra-deep wells, 10,000-meter exploration wells, high temperature and high pressure gas wells, unconventional oil and gas wells, and gas storage wells.

[0049] (4) The preparation method of the ultra-high temperature oil well cement retarder provided by the present invention is simple, green, safe and environmentally friendly, the raw materials are readily available and the production cost is low, and it can realize industrial production and large-scale application. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 The infrared spectrum is shown for the purified product of ultra-high temperature oil well cement retarder S1 provided in Example 1 of this invention.

[0052] Figure 2 The thickening curve of cement slurry with an ultra-high temperature oil well cement retarder dosage of 1.5% provided in Example 1 of the present invention at 110℃×70MPa.

[0053] Figure 3 The thickening curve of cement slurry with an ultra-high temperature oil well cement retarder dosage of 5% provided in Example 1 of the present invention at 240℃×120MPa.

[0054] Figure 4 The thickening curve of cement slurry with 5% oil well cement retarder provided in Comparative Example 1 at 240℃×120MPa.

[0055] Figure 5 The thickening curve of the cement slurry with 2% oil well cement retarder provided in Comparative Example 2 at 130℃×70 MPa. Detailed Implementation

[0056] To provide a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail with reference to the following specific embodiments, but this should not be construed as limiting the scope of implementation of the present invention.

[0057] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0058] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0059] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0060] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0061] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0062] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to tables, drawings, and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0063] Example 1

[0064] This embodiment provides an ultra-high temperature oil well cement retarder, which is prepared by a method including the following specific steps:

[0065] (1) Weigh 72.4 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 17 parts by weight of itaconic acid and 10.6 parts by weight of diethyl 4-vinylbenzylphosphonate, and dissolve them completely in 140 parts by weight of deionized water. Slowly add 12.6 parts by weight of sodium hydroxide to the resulting solution to adjust the pH of the solution to 4-5.

[0066] (2) Then, add 0.4 parts by weight of 3-mercaptopropionic acid to the solution obtained in step (1), and slowly heat it to 60°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 1.5 parts by weight of potassium persulfate in 10 parts by weight of deionized water, and slowly add it dropwise to the above solution system over a period of about 30 min, and then slowly heat it to 80°C at a heating rate of 0.6°C / min and continue the reaction for 4 h.

[0067] (3) Add 1.13 parts by weight of sodium sulfite to the 264.5 parts by weight of the solution obtained in step (2) and continue to treat for 30 minutes. Then, allow it to cool naturally to room temperature to obtain a viscous liquid polymer solution, which is the ultra-high temperature oil well cement retarder, labeled as S1. The ultra-high temperature oil well cement retarder S1 contains a polymer retarder, the molecular structure of which is shown in formula (1.1):

[0068] ;

[0069] Equation (1.1);

[0070] In equation (1.1), the ratio of a:b:c is 67:25:8.

[0071] Example 2

[0072] This embodiment provides an ultra-high temperature oil well cement retarder, which is prepared by a method including the following specific steps:

[0073] (1) Weigh 67.7 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 13.1 parts by weight of itaconic acid and 19.2 parts by weight of diethyl 4-vinylbenzylphosphonate and dissolve them completely in 175 parts by weight of deionized water. Slowly add 11.3 parts by weight of sodium hydroxide to the resulting solution to adjust the pH of the solution to 4-5.

[0074] (2) Then, add 0.5 parts by weight of mercaptoethanol to the solution obtained in step (1), and slowly heat to 55°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 2 parts by weight of ammonium persulfate in 10 parts by weight of deionized water, and slowly add it dropwise to the above solution system over a period of about 30 min, and then slowly heat to 80°C at a heating rate of 1°C / min and continue to react for 4 h.

[0075] (3) Add 1.28 parts by weight of sodium sulfite to the 298.8 parts by weight of the solution obtained in step (2) and continue to treat for 30 minutes. Then, allow it to cool naturally to room temperature to obtain a viscous liquid polymer solution, which is the ultra-high temperature oil well cement retarder, labeled as S2. The ultra-high temperature oil well cement retarder S2 contains a polymer retarder, the molecular structure of which is shown in formula (1.2):

[0076] ;

[0077] In equation (1.2), the ratio of a:b:c is 65:20:15.

[0078] Example 3

[0079] This embodiment provides an ultra-high temperature oil well cement retarder, which is prepared by a method including the following specific steps:

[0080] (1) Weigh out 71.7 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 17.8 parts by weight of itaconic acid, and 10.5 parts by weight of 2,2-propanesulfonic acid. ' -((4-vinylbenzyl)aminoxylidene)diacetic acid and completely dissolved it in 140 parts by weight of deionized water, and slowly added 14 parts by weight of sodium hydroxide to the resulting solution to adjust the pH of the solution to 4-5.

[0081] (2) Then, add 0.3 parts by weight of 3-mercaptoacetic acid to the solution obtained in step (1), and slowly heat to 60°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 1 part by weight of ammonium persulfate in 10 parts by weight of deionized water, and slowly add it dropwise to the above solution system over a period of about 30 min, and then slowly heat to 80°C at a heating rate of 0.6°C / min and continue to react for 4 h.

[0082] (3) Add 2 parts by weight of sodium bisulfite to the 265.3 parts by weight of the solution obtained in step (2) and continue to treat for 50 minutes. Then, allow it to cool naturally to room temperature to obtain a viscous liquid polymer solution, which is the ultra-high temperature oil well cement retarder, labeled as S3. The ultra-high temperature oil well cement retarder S3 contains a polymer retarder, the molecular structure of which is shown in formula (1.3):

[0083] ;

[0084] Equation (1.3);

[0085] In equation (1.3), the ratio of a:b:c is 66:26:8.

[0086] Example 4

[0087] This embodiment provides an ultra-high temperature oil well cement retarder, which is prepared by a method including the following specific steps:

[0088] (1) Weigh out 69.5 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 11.7 parts by weight of itaconic acid, and 18.8 parts by weight of 2,2-propanesulfonic acid. ' -((4-vinylbenzyl)aminoxylidene)diacetic acid and completely dissolved it in 223 parts by weight of deionized water. Slowly add 14.2 parts by weight of sodium hydroxide to the resulting solution and adjust the pH of the solution to 4-5.

[0089] (2) Then, add 0.9 parts by weight of n-dodecyl mercaptan to the solution obtained in step (1) and slowly heat it to 65°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 0.8 parts by weight of azobisisobutyrazoline hydrochloride in 10 parts by weight of deionized water and slowly add it dropwise to the above solution system over a period of about 30 min; then slowly heat it to 80°C at a heating rate of 0.5°C / min and continue the reaction for 5 h.

[0090] (3) Add 1.6 parts by weight of potassium bisulfite to the 348.9 parts by weight of the solution obtained in step (2) and continue to treat for 30 minutes. Then, allow it to cool naturally to room temperature to obtain a viscous liquid polymer solution, which is the ultra-high temperature oil well cement retarder, labeled as S4. The ultra-high temperature oil well cement retarder S4 contains a polymer retarder, the molecular structure of which is shown in formula (1.4):

[0091] ;

[0092] Equation (1.4);

[0093] In equation (1.4), the ratio of a:b:c is 67:18:15.

[0094] Example 5

[0095] This embodiment provides an ultra-high temperature oil well cement retarder, which is prepared by a method including the following specific steps:

[0096] (1) Weigh 62.4 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 18.6 parts by weight of itaconic acid and 19 parts by weight of N-trimethyl-(4-vinylbenzyl)ammonium chloride and dissolve them completely in 140 parts by weight of deionized water. Slowly add 11.4 parts by weight of sodium hydroxide to the resulting solution and adjust the pH of the solution to 4-5.

[0097] (2) Then, add 0.5 parts by weight of 3-mercaptopropionic acid to the solution obtained in step (1), and slowly heat it to 60°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 1 part by weight of potassium persulfate in 10 parts by weight of deionized water, and slowly add it dropwise to the above solution system over a period of about 30 min, and then slowly heat it to 85°C at a heating rate of 0.8°C / min and continue the reaction for 2 h.

[0098] (3) Add 1.6 parts by weight of potassium bisulfite to the 262.9 parts by weight of the solution obtained in step (2) and continue to treat for 30 minutes. Then, allow it to cool naturally to room temperature to obtain a viscous liquid polymer solution, which is the ultra-high temperature oil well cement retarder, labeled as S5. The ultra-high temperature oil well cement retarder S5 contains a polymer retarder, the molecular structure of which is shown in formula (1.5):

[0099] ;

[0100] Equation (1.5);

[0101] In equation (1.5), the ratio of a:b:c is 57:27:17.

[0102] Example 6

[0103] This embodiment provides an ultra-high temperature oil well cement retarder, which is prepared by a method including the following specific steps:

[0104] (1) Weigh 67.8 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 16.5 parts by weight of acrylic acid and 15.7 parts by weight of diethyl 4-vinylbenzylphosphonate and dissolve them completely in 300 parts by weight of deionized water. Slowly add 10.2 parts by weight of sodium hydroxide to the resulting solution to adjust the pH of the solution to 4-5.

[0105] (2) Then, add 0.8 parts by weight of n-butanethiol to the solution obtained in step (1), and slowly heat it to 55°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 2 parts by weight of ammonium persulfate in 10 parts by weight of deionized water, and slowly add it dropwise to the above solution system over a period of about 30 min, and then slowly heat it to 80°C at a heating rate of 0.5°C / min and continue the reaction for 3 h.

[0106] (3) Add 1.8 parts by weight of potassium sulfite to the 423 parts by weight of the solution obtained in step (2) and continue to treat for 60 minutes. Then, allow it to cool naturally to room temperature to obtain a viscous liquid polymer solution, which is the ultra-high temperature oil well cement retarder, labeled as S6. The ultra-high temperature oil well cement retarder S6 contains a polymer retarder, the molecular structure of which is shown in formula (1.6):

[0107] ;

[0108] Equation (1.6);

[0109] In equation (1.6), the ratio of a:b:c is 53:37:10.

[0110] Comparative Example 1

[0111] This comparative example provides an oil well cement retarder, which is prepared by a method including the following specific steps:

[0112] (1) Weigh 77 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid and 23 parts by weight of itaconic acid and dissolve them completely in 140 parts by weight of deionized water. Slowly add 14.2 parts by weight of sodium hydroxide to the resulting solution to adjust the pH value of the solution to 4-5.

[0113] (2) Then, add 0.4 parts by weight of 3-mercaptopropionic acid to the solution obtained in step (1), and slowly heat it to 60°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 1.5 parts by weight of potassium persulfate in 10 parts by weight of deionized water, and slowly add it dropwise to the above solution system over a period of about 30 min, and then slowly heat it to 80°C at a heating rate of 0.6°C / min and continue the reaction for 4 h.

[0114] (3) Add 1.13 parts by weight of sodium sulfite to the 266.1 parts by weight of solution obtained in step (2) and continue to treat for 30 minutes. Then, cool naturally to room temperature to obtain a viscous liquid polymer solution, which is the oil well cement retarder.

[0115] Comparative Example 2

[0116] This comparative example provides an oil well cement retarder, which is prepared by a method including the following specific steps:

[0117] (1) Weigh 72.4 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 17 parts by weight of itaconic acid and 10.6 parts by weight of diethyl 4-vinylbenzylphosphonate, and dissolve them completely in 140 parts by weight of deionized water. Slowly add 12.6 parts by weight of sodium hydroxide to the resulting solution to adjust the pH of the solution to 4-5.

[0118] (2) Then, add 0.4 parts by weight of 3-mercaptopropionic acid to the solution obtained in step (1), and slowly heat it to 60°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 1.5 parts by weight of potassium persulfate in 10 parts by weight of deionized water, and slowly add it dropwise to the above solution system over a period of about 30 min, and then slowly heat it to 80°C at a heating rate of 0.6°C / min and continue the reaction for 4 h. After naturally cooling to room temperature, a viscous liquid polymer solution is obtained, which is the oil well cement retarder.

[0119] Comparative Example 3

[0120] This comparative example provides an oil well cement retarder, which is prepared by a method including the following specific steps:

[0121] (1) Weigh 33.7 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid, 31.8 parts by weight of itaconic acid and 34.5 parts by weight of diethyl 4-vinylbenzylphosphonate, and dissolve them completely in 140 parts by weight of deionized water. Slowly add 12.6 parts by weight of sodium hydroxide to the resulting solution to adjust the pH of the solution to 4-5.

[0122] (2) Then, add 0.4 parts by weight of 3-mercaptopropionic acid to the solution obtained in step (1), and slowly heat it to 60°C at a stirring rate of 200 r / min ± 20 r / min; then dissolve 1.5 parts by weight of potassium persulfate in 10 parts by weight of deionized water, and slowly add it dropwise to the above solution system over a period of about 30 min, and then slowly heat it to 80°C at a heating rate of 0.6°C / min and continue the reaction for 4 h.

[0123] (3) Add 1.13 parts by weight of sodium sulfite to the 264.5 parts by weight solution obtained in step (2) and continue to treat for 30 minutes. Then, allow it to cool naturally to room temperature to obtain a viscous liquid polymer solution, which is the oil well cement retarder. The oil well cement retarder contains a polymer retarder, the molecular structure of which is shown in formula (1.7):

[0124]

[0125] Equation (1.7);

[0126] In equation (1.7), the ratio of a:b:c is 30:45:25.

[0127] Test Example 1

[0128] In this test example, the ultra-high temperature oil well cement retarder S1 provided in Example 1 of this invention was first washed with acetone, then vacuum freeze-dried to obtain a purified product. The purified product was then subjected to infrared spectroscopy analysis, and the results are as follows: Figure 1 As shown, from Figure 1 As can be seen from this, 3448cm -1 The peak at 2940 cm⁻¹ is the absorption peak of the stretching vibration of NH in AMPS; -1 2984 cm -1 The peaks at 1723 cm⁻¹ are absorption peaks of the stretching vibrations of -CH₃ and -CH₂-, respectively; -1 The peak at 1659 cm⁻¹ represents the stretching vibration peak of the -COOH group in IA. -1 The peak at 1256 cm⁻¹ represents the stretching vibration peak of the -C=O group in the amide group of AMPS; -1 The peak at 1012 cm⁻¹ is the characteristic absorption peak of P=O. -1 The peak at 962 cm⁻¹ is the characteristic absorption peak of POC. -1 The peak at 1485 cm⁻¹ is the characteristic absorption peak of PO. -1 1467 cm -1 and 1410 cm -1 The peak is a characteristic absorption peak of the benzene ring, at 726 cm⁻¹. -1 The peak at 1620-1650 cm⁻¹ is the out-of-plane bending vibration peak of the benzene ring; -1 No C=C characteristic absorption peak was found, indicating that all comonomers participated in copolymerization. In Example 1, a polymer with the molecular structure shown in formula (1.1) was prepared.

[0129] Test Example 2

[0130] This test example evaluates the comprehensive performance of the retarders prepared in Examples 1-6 and Comparative Examples 1-3 according to the relevant provisions of the petroleum and natural gas industry standards SY / T5504.1-2013 "Evaluation Methods for Oil Well Cement Admixtures Part 1: Retarder" and GB / T 19139-2012 "Test Methods for Oil Well Cement". The evaluation results are shown in Table 1 and... Figures 2-5 As shown.

[0131] Table 1

[0132]

[0133] Note: The cement used in this invention is Jiahua G-grade oil well cement (high sulfur resistance, HSR). # represents the percentage by mass of the cement. The representative curing temperature for cement stone strength is (experimental temperature + 20℃).

[0134] The cement slurry formula for 110-180℃ in Table 1 is: Jiahua G-grade oil well cement (HSR) + 35% silica fume (BWOC, the same below) + 3% microsilica + x% retarder + 4% water loss reducer + 1.2% dispersant + 2% high temperature stabilizer + water;

[0135] The cement slurry formula in Table 1 for 200-240℃ is: Jiahua G-grade oil well cement (HSR) + 50% silica fume + 3% microsilica + 10% anti-fading material + x% retarder + 5% water loss reducer + 1.5% dispersant + 4% high-temperature stabilizer + water, with a cement slurry density of 1.88 g / cm³. 3 .

[0136] Among them, the silica powder is 200-mesh quartz sand with a microsilica particle size of 0.1-0.3μm, the water loss reducing agent is an AMPS-type multi-component copolymer product, the dispersant is a deeply sulfonated aldehyde-ketone condensate, the high temperature stabilizer is a compound product of AMPS-type multi-component copolymer and ultrafine mineral materials, and the anti-fading material is a high aluminate inorganic mineral material. All additive products are from China Petroleum Engineering Technology Research Institute Co., Ltd.

[0137] From such Figure 2 The thickening curve of the cement slurry with an ultra-high temperature oil well cement retarder dosage of 1.5% provided in Example 1 of the present invention at 110℃×70MPa shows that the cement slurry thickening curve is normal, the initial consistency is low and the consistency curve is stable, the thickening time of the system is 503min, the thickening transition time is short (5min), and the thickening is basically right angled. This indicates that the ultra-high temperature oil well cement retarder prepared in Example 1 can effectively prolong the thickening time of the medium and high temperature cement slurry system and has little impact on the development of the mechanical strength of the cement slurry.

[0138] From such Figure 3 As shown in the thickening curve of the cement slurry with an ultra-high temperature oil well cement retarder dosage of 5% provided in Example 1 of the present invention at 240℃×120MPa, the ultra-high temperature cement slurry thickening curve is normal, without abnormal gelation phenomena such as bulging or "core encapsulation". The initial consistency is about 20Bc. Although the slurry consistency decreases with the increase of temperature, it eventually maintains at about 10Bc. The thickening time of the system is 330min, and the thickening curve is basically "right angle".

[0139] from Figure 4The thickening curve of the cement slurry with 5% oil well cement retarder provided in Comparative Example 1 at 240℃×120MPa shows that the initial consistency of the cement slurry is relatively high, and the consistency gradually decreases with the increase of temperature. When the temperature rises to the experimental temperature, the consistency of the system rises rapidly, and the thickening time is 108 min. Moreover, the thickening time cannot be effectively extended with the increase of retarder dosage, indicating that the retarder prepared in Comparative Example 1 has lost its retarding performance at 240℃.

[0140] from Figure 5 The thickening curve of the cement slurry with an oil well cement retarder dosage of 2% shown in Comparative Example 2 at 130℃×70 MPa shows that abnormal gelation phenomena such as bulging and core formation occur near 120℃, and the temperature fluctuates greatly. This indicates that the oil well cement retarder prepared without inorganic salt treatment in Comparative Example 2 is prone to abnormal thickening performance of the cement slurry system, which directly affects the safety of cementing operations in deep wells and ultra-deep wells.

[0141] Referring to Table 1, within the temperature range of 110-240℃, the ultra-high temperature oil well cement retarder S1 prepared in Example 1 of this invention can effectively prolong the thickening time of cement slurry. By changing the dosage of the ultra-high temperature oil well cement retarder, the thickening time of cement slurry can be linearly adjusted within 200-500 min, and shows a good linear relationship with temperature and dosage. Simultaneously, at 130℃ and 240℃, the dosage sensitivity of the ultra-high temperature oil well cement retarder is 11.7% and 13.6%, respectively, both meeting the requirement of "dosage sensitivity ≤ 20%" in SY / T5504.1-2013. Furthermore, the API water loss of the cement slurry system containing the ultra-high temperature oil well cement retarder prepared in Example 1 of this invention is < 60 mL, and the settling stability is ≤ 0.04 g / cm³. 3 The compressive strength of the cement stone is higher than 30.6 MPa. These results indicate that the ultra-high temperature oil well cement retarder prepared in Example 1 of this invention has good compatibility with other admixtures such as fluid loss reducers, and has little impact on the system's settling stability and the mechanical strength of the cement stone.

[0142] The experimental data in Table 1 also show that the ultra-high temperature oil well cement retarder S2-S6 prepared in Examples 2-6 of this invention also have good ultra-high temperature setting performance and adaptability. However, although the oil well cement retarder prepared in Comparative Example 1 showed good setting performance at 130℃, its retarding performance failed at 240℃, resulting in the inability to extend the thickening time of the cement slurry. Although the oil well cement retarder prepared in Comparative Example 2 had good retarding performance at both 130℃ and 240℃, its retarding performance was worse than that of the ultra-high temperature oil well cement retarder provided in the examples, and at low dosages, the high temperature (greater than 120℃) thickening curve was prone to abnormal gelation phenomena such as core encapsulation and bulging (see...). Figure 5 As shown in the figure, this leads to certain construction risks in the cement slurry system. This indicates that post-treatment of the product obtained after polymerization with reducing inorganic salts can reorganize the molecular conformation, annihilate the oxidized initiator in the system, and ensure the quality stability of the polymer product. This can further improve and alleviate the abnormal high-temperature gelation phenomenon of cement slurry caused by polycarboxylic acid retarders. In addition, the retarding effect of the oil well cement retarder prepared in Comparative Example 3 is basically the same as that of the oil well cement retarder provided in Comparative Example 1. Its ultra-high temperature retarding effect is weak and has a certain adverse effect on the water loss reduction performance of the cement slurry system. This is mainly due to the unreasonable distribution ratio of each monomer component in the polymer retarder molecular structure (i.e., the molar ratio of a, b, and c in the polymer retarder is not within the numerical range claimed in this application). Specifically, the excessive amount of strong adsorption groups makes the retarder have a stronger competitive adsorption capacity than the high-temperature water loss reduction agent, so the water loss reduction performance of the system deteriorates. Therefore, the comprehensive performance of the ultra-high temperature oil well cement retarder provided in the embodiments of the present invention is better than that of the oil well cement retarder prepared in the comparative example.

[0143] In summary, (1) the embodiments of the present invention improve the ultra-high temperature resistance and stable setting performance of polymer retarder through measures such as optimized molecular structure design, effective intervention of temperature-resistant and salt-resistant rigid groups, synergistic effect of multiple adsorption groups, and efficient treatment of reducing inorganic salts. In addition, the introduction of functional groups such as phosphonic acid groups, amine groups, quaternary ammonium salts, and imidazole groups can further improve the charge density of polymer corrosion inhibitors and enhance their ultra-high temperature adsorption stability, thereby effectively controlling the thickening time of ultra-high temperature cement slurry system.

[0144] (2) The ultra-high temperature oil well cement retarder provided in the embodiments of the present invention has a wide applicable temperature range (70-240℃). Within the temperature range of 110-240℃, the cement slurry thickening time is linearly adjustable within 200-500 min and has a good linear relationship with temperature and dosage. It has good compatibility with other admixtures and has little impact on the mechanical properties of cement stone.

[0145] (3) The ultra-high temperature oil well cement retarder provided in the embodiments of the present invention has strong adaptability and is suitable for various cement slurry systems such as conventional density, low density, high density, high strength and toughness, and latex. It can effectively ensure the safety of cementing construction, reduce the risk of cementing operation, and meet the cementing technical requirements of complex and difficult wells such as deep wells, ultra-deep wells, 10,000-meter scientific exploration wells, high temperature and high pressure gas wells, unconventional oil and gas wells, and gas storage wells.

[0146] (4) The preparation method of the ultra-high temperature oil well cement retarder provided in the embodiments of the present invention is simple, green, safe and environmentally friendly, the raw materials are readily available and the production cost is low, and it can realize industrial production and large-scale application.

[0147] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. A polymer, characterized in that, The molecular structure of the polymer is shown in formula (1): ； Equation (1); In equation (1), a, b, and c are all moles, and the ratio of the three is 40-85:10-40:5-20. R1 is one of -H, -CH3, and -CH2COOH; R2 is selected from one of the following compounds: 、 、 and .

2. A high-temperature oil well cement retarder, characterized in that, The ultra-high temperature oil well cement retarder comprises the polymer described in claim 1 and water, wherein the polymer content is 20-40% and the water content is 60-80% based on the total weight of the ultra-high temperature oil well cement retarder as 100%.

3. The preparation method of the ultra-high temperature oil well cement retarder according to claim 2, characterized in that, The preparation method includes: (1) Dissolve 2-acrylamido-2-methylpropanesulfonic acid monomer, unsaturated carboxylic acid monomer and rigid unsaturated monomer in deionized water, and add alkaline substances to the resulting solution to adjust the pH value of the solution to 3-5; wherein the weight ratio of 2-acrylamido-2-methylpropanesulfonic acid monomer, unsaturated carboxylic acid monomer and rigid unsaturated monomer is 45-92: 4-32: 4-30; (2) After adding a chain transfer agent to the system obtained in step (1), the temperature is increased, then an initiator is added, and the temperature is increased again to carry out the polymerization reaction; (3) Add reducing inorganic salts to the solution obtained after the reaction in step (2) for post-treatment. After the post-treatment is completed, a viscous liquid polymer solution is obtained, which is the ultra-high temperature oil well cement retarder.

4. The preparation method according to claim 3, characterized in that, In step (1), the unsaturated carboxylic acid monomer includes one or a combination of itaconic acid, methacrylic acid, acrylic acid and butenoic acid.

5. The preparation method according to claim 3 or 4, characterized in that, In step (1), the rigid unsaturated monomer includes diethyl 4-vinylbenzylphosphonate, 2,2-diethyl phosphonate, and 2,2-diethyl phosphonate. ' One or a combination of several of the following: -(4-vinylbenzylaminoidene)diacetic acid, vinylbenzyltrimethylammonium chloride, and N-(4-vinylbenzyl)-N,N-dimethylamine.

6. The preparation method according to claim 3 or 4, characterized in that, In step (1), the alkaline substance includes sodium hydroxide, and the amount used is 10-20 parts by weight.

7. The preparation method according to claim 3, characterized in that, In step (2), the amount of chain transfer agent used is 0.05-1.0% of the total mass of the monomer.

8. The preparation method according to claim 3 or 7, characterized in that, In step (2), the chain transfer agent includes one or more of 3-mercaptopropionic acid, 3-mercaptoacetic acid, mercaptoethanol, n-butanethiol, n-dodecyl mercaptoethanol and isopropanol.

9. The preparation method according to claim 3, characterized in that, In step (2), the amount of the initiator is 0.5-2.5% of the total mass of the monomer.

10. The preparation method according to claim 3 or 9, characterized in that, In step (2), the initiator includes one or more of ammonium persulfate, potassium persulfate, and azobisisobutyrazoline hydrochloride.

11. The preparation method according to claim 3, characterized in that, In step (2), after adding the chain transfer agent to the system obtained in step (1), the temperature is raised to 50-65℃ and kept at that temperature for 10-30 minutes.

12. The preparation method according to claim 3, characterized in that, In step (2), the continued heating to carry out the polymerization reaction includes heating to 70-90℃ and reacting at a constant temperature for 2-5 hours.

13. The preparation method according to claim 12, characterized in that, The heating rate is 0.5-2℃ / min.

14. The preparation method according to claim 3, characterized in that, In step (3), the amount of the reducing inorganic salt is 0.2-1.0% of the total mass of the solution obtained after the reaction in step (2).

15. The preparation method according to claim 3 or 14, characterized in that, In step (3), the reducing inorganic salt includes one or more of sodium sulfite, sodium bisulfite, ammonium sulfite, potassium sulfite, and potassium bisulfite.

16. The preparation method according to claim 3 or 14, characterized in that, In step (3), the post-processing time is 30-60 minutes.

17. The preparation method according to claim 3 or 14, characterized in that, Step (3) also includes: after the post-treatment is completed, the system is naturally cooled to room temperature to obtain a viscous liquid polymer solution, which is the ultra-high temperature oil well cement retarder.

18. The application of the polymer of claim 1 or the ultra-high temperature oil well cement retarder of claim 2 in cementing operations under complex working conditions.

19. The application according to claim 18, characterized in that, The complex working condition wells include deep wells, high-temperature and high-pressure gas wells, unconventional oil and gas wells, or gas storage wells.

20. The application according to claim 18, characterized in that, The complex working condition wells include ultra-deep wells.

21. The application according to claim 18, characterized in that, The complex working condition wells include scientific drilling wells with a depth of 10,000 meters.

22. A cement grout, characterized in that, The cement slurry comprises the polymer of claim 1 or the ultra-high temperature oil well cement retarder of claim 2.

23. The cement grout according to claim 22, characterized in that, Based on the total weight of cement in the cement slurry being 100%, the amount of ultra-high temperature oil well cement retarder added is 1.5-6.5%.

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