Ultrahigh-temperature retarder for well cementation cement and preparation method thereof

Abstract

The invention relates to the technical field of oilfield chemistry, and provides an ultrahigh-temperature retarder for well cementation cement and a preparation method of the ultrahigh-temperature retarder. Comprising the following raw materials in parts by weight: 80 to 90 parts of 2-acrylamido-2-methylpropanesulfonic acid, 30 to 40 parts of 4-vinylphenylboronic acid, 20 to 30 parts of a fluorine-containing acrylic acid compound, 0.5 to 0.8 part of an initiator, 140 to 150 parts of water and 130 to 140 parts of a sodium hydroxide aqueous solution. According to the technical scheme, the problem of poor high temperature resistance of the retarder for well cementation cement in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield chemistry. Specifically, it relates to an ultra-high temperature retarder for well cementing and a preparation method thereof. Background Art

[0002] In the well cementing operations for the extraction of energy such as oil and natural gas, the retarder for well cementing is a crucial admixture. Its main function is to delay the setting time of the cement slurry, ensuring that in the downhole environment of high temperature and high pressure, the cement slurry has sufficient time for construction operations such as pumping and cement injection, thus guaranteeing the well cementing quality.

[0003] However, as the well depth increases, the formation temperature will rise due to heat transfer within the earth. When some retarders exceed a certain temperature (such as above 150°C), the retardation effect will decline sharply, and the cement slurry will set in a short time, resulting in the inability to smoothly complete the well cementing construction. Some retarders will also decompose and deteriorate at high temperatures, not only losing the retardation effect but also possibly having a negative impact on other properties of the cement slurry, such as fluidity and strength development. Therefore, it is necessary to develop a retarder for well cementing with high temperature resistance. Summary of the Invention

[0004] The present invention provides an ultra-high temperature retarder for well cementing and a preparation method thereof, which solves the problem of poor high temperature resistance of the retarder for well cementing in the related art.

[0005] The technical solution of the present invention is as follows: The present invention provides an ultra-high temperature retarder for well cementing, which comprises the following raw materials in parts by weight: 80 - 90 parts of 2-acrylamido-2-methylpropanesulfonic acid, 30 - 40 parts of 4-vinylbenzeneboronic acid, 20 - 30 parts of fluorinated benzoic acid compound, 0.5 - 0.8 parts of initiator, 140 - 150 parts of water, and 130 - 140 parts of sodium hydroxide aqueous solution.

[0006] As a further technical solution, the fluorinated benzoic acid compound includes one or more of 2,3,4-trifluorobenzoic acid, 3,4-difluorobenzoic acid, and p-fluoropentaenoic acid.

[0007] As a further technical solution, the initiator includes one or more of sodium persulfate, potassium persulfate, and 2,2'-azobis(2-methylpropionamidine) dihydrochloride.

[0008] As a further technical solution, the initiator is preferably 2,2'-azobis(2-methylpropionamidine) dihydrochloride.

[0009] In the present invention, 2,2'-azobis(2-methylpropionamidine) dihydrochloride is an azo initiator, and its decomposition rate is relatively mild and controllable. It can continuously and stably generate free radicals within a certain temperature range to initiate the polymerization of monomers.

[0010] As a further technical solution, the mass concentration of the sodium hydroxide aqueous solution is 30%.

[0011] In the present invention, the mass concentration of the sodium hydroxide aqueous solution is 30%. During the polymerization reaction for preparing the retarder, an appropriate pH value is one of the key factors to ensure the smooth progress of the reaction. The 30% mass concentration of the sodium hydroxide aqueous solution can effectively adjust the pH value of the reaction system to an appropriate range. This concentration can not only provide sufficient hydroxide ions to make the reaction system reach an alkaline environment and meet the requirements of the polymerization reaction of certain monomers for alkaline conditions, but also prevent the occurrence of side reactions due to excessive alkalinity, ensuring that each monomer can polymerize according to the expected reaction path, thereby generating a retarder with a stable structure and excellent performance.

[0012] As a further technical solution, the raw materials further include 5 - 10 parts of cis - 9 - styrylanthracene.

[0013] In the present invention, cis - 9 - styrylanthracene has a large conjugated system. The anthracene ring and the styryl group are connected by a conjugation effect to form a highly conjugated planar structure. The planar rigid structure is not easily twisted and bent, which enhances the rigidity of the polymer chain, thereby ensuring that the retarder still maintains its structural integrity and functional stability at high temperatures, and further improving the strength of the well - cementing slurry.

[0014] The present invention also provides a preparation method of an ultra - high - temperature retarder for well - cementing slurry, comprising the following steps: S1. Weigh 2 - acrylamido - 2 - methylpropanesulfonic acid, 4 - vinylbenzeneboronic acid, a fluorinated styrenic acid compound and water. After mixing, add the sodium hydroxide aqueous solution to obtain a mixed solution; S2. Add an initiator to the mixed solution. After the reaction, the ultra - high - temperature retarder for well - cementing slurry is obtained.

[0015] As a further technical solution, the temperature of the mixing in S1 is 15 - 30°C.

[0016] As a further technical solution, the initiator in S2 is an initiator aqueous solution, and the content of the initiator in the initiator aqueous solution is 20 wt%.

[0017] As a further technical solution, before adding the initiator in S2, a de - oxygenation treatment is also included. The way of the de - oxygenation treatment is to introduce nitrogen, and the time for introducing nitrogen is 1 - 1.5 h.

[0018] As a further technical solution, the temperature of the reaction in S2 is 60 - 70°C, and the time of the reaction is 6 - 8 h.

[0019] The working principle and beneficial effects of the present invention are as follows: In the present invention, 2-acrylamido-2-methylpropanesulfonic acid, as one of the main components, can effectively adsorb on the surface of cement particles by virtue of its unique molecular structure, delaying the hydration reaction process of cement and providing basic retardation guarantee for cement slurry in high-temperature environments. The addition of 4-vinylbenzeneboronic acid, on the one hand, the benzene ring structure enhances the intermolecular interaction through π-π stacking, improving the structural stability of the retarder at high temperatures. On the other hand, the borate group can react with calcium ions in the cement hydration products to form stable complexes, further regulating the setting time of cement and enabling precise control of the retardation effect even under ultra-high temperature conditions. The fluorine group in the fluorinated styrene acid compound not only significantly improves the chemical stability of the retarder, reducing its degradation rate at high temperatures, but also improves the dispersibility of the retarder in the cement slurry, making the retarder more evenly distributed in the system, thereby enhancing the consistency of the overall retardation effect. At the same time, the conjugated system in the styrene acid structure synergistically acts with the conjugated structures of other components, further strengthening the thermal stability of the molecule and improving the high-temperature resistance of the retarder. Detailed implementation manners

[0020] The following will describe clearly and completely the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0021] Example 1 A preparation method of an ultra-high temperature retarder for well cementing includes the following steps: S1. Weigh 80 parts of 2-acrylamido-2-methylpropanesulfonic acid, 30 parts of 4-vinylbenzeneboronic acid, 20 parts of a fluorinated styrene acid compound, and 140 parts of water. After mixing at 15°C, add 130 parts of an aqueous sodium hydroxide solution to obtain a mixed solution, where the fluorinated styrene acid compound is p-fluorophenylpentenoic acid; S2. Dissolve 0.5 part of azodiisobutyramidine hydrochloride in 2.5 parts of water to obtain an initiator solution. After introducing nitrogen for 1 h, add the initiator solution to the mixed solution and react at 60°C for 8 h to obtain the ultra-high temperature retarder for well cementing.

[0022] Example 2 A preparation method of an ultra-high temperature retarder for well cementing includes the following steps: S1. Weigh 85 parts of 2-acrylamido-2-methylpropanesulfonic acid, 35 parts of 4-vinylbenzeneboronic acid, 25 parts of a fluorinated styrene acid compound, and 145 parts of water. After mixing at 20°C, add 135 parts of an aqueous sodium hydroxide solution to obtain a mixed solution, where the fluorinated styrene acid compound is p-fluorophenylpentenoic acid; S2. Dissolve 0.6 part of 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 3 parts of water to obtain an initiator solution. After purging with nitrogen for 1.2 h, add the initiator solution to the mixture. React at 65 °C for 7 h to obtain the ultra-high temperature retarder for well cementing.

[0023] Example 3 A preparation method of an ultra-high temperature retarder for well cementing, comprising the following steps: S1. Weigh 90 parts of 2-acrylamido-2-methylpropanesulfonic acid, 40 parts of 4-vinylbenzeneboronic acid, 30 parts of fluorinated styrenic acid compound, and 150 parts of water. After mixing at 30 °C, add 140 parts of sodium hydroxide aqueous solution to obtain a mixture, wherein the fluorinated styrenic acid compound is p-fluoropentenoic acid; S2. Dissolve 0.8 part of 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 4 parts of water to obtain an initiator solution. After purging with nitrogen for 1.5 h, add the initiator solution to the mixture. React at 70 °C for 6 h to obtain the ultra-high temperature retarder for well cementing.

[0024] Example 4 Compared with Example 1, the difference in Example 4 is that the fluorinated styrenic acid compound is 3,4-difluorostyrenic acid.

[0025] Example 5 Compared with Example 1, the difference in Example 5 is that the fluorinated styrenic acid compound is 2,3,4-trifluorocinnamic acid.

[0026] Example 6 A preparation method of an ultra-high temperature retarder for well cementing, comprising the following steps: S1. Weigh 80 parts of 2-acrylamido-2-methylpropanesulfonic acid, 30 parts of 4-vinylbenzeneboronic acid, 20 parts of fluorinated styrenic acid compound, 140 parts of water, and 5 parts of cis-9-styrylanthracene. After mixing at 15 °C, add 130 parts of sodium hydroxide aqueous solution to obtain a mixture, wherein the fluorinated styrenic acid compound is 3,4-difluorostyrenic acid; S2. Dissolve 0.5 part of 2,2'-azobis(2-methylpropionamidine) dihydrochloride in 2.5 parts of water to obtain an initiator solution. After purging with nitrogen for 1 h, add the initiator solution to the mixture. React at 60 °C for 8 h to obtain the ultra-high temperature retarder for well cementing.

[0027] Example 7 Compared with Example 6, the difference in Example 7 is that the addition amount of cis-9-styrylanthracene is 10 parts.

[0028] Example 8 Compared with Example 6, the difference in Example 8 is that cis-9-styrylanthracene is replaced with an equal amount of acrylamide.

[0029] Comparative Example 1 Compared with Example 1, the difference in Comparative Example 1 is that p-fluorophenylpentenoic acid is replaced with an equal amount of N-vinylpyrrolidone.

[0030] Experimental Example 1 For the ultra-high temperature retarders for well cementing prepared in Examples 1 to 5 and Comparative Example 1, according to the test method specified in SY / T 5504.1-2013 "Evaluation Method for Oil Well Cement Additives - Part 1: Retarder", the thickening time of the samples was tested. The reference formula of the cement slurry was: 600 g of Jiahua Grade G oil well cement (high sulfur-resistant type) + 240 g of quartz sand (200 mesh) + 12 g of retarder + 348 g of water. The test temperature was 220 °C and the pressure was 140 MPa.

[0031] The test results are shown in Table 1: Table 1 Performance test results of ultra-high temperature retarders for well cementing prepared in Examples 1 to 5 and Comparative Example 1

[0032] Compared with Comparative Example 1, the thickening time of Example 1 is higher than that of Comparative Example 1, indicating that when a fluorobenzoic acid compound is added, the high temperature resistance of the retarder can be improved.

[0033] Experimental Example 2 For the ultra-high temperature retarders for well cementing prepared in Example 4 and Examples 6 to 8, according to the test method specified in SY / T 5504.1-2013 "Evaluation Method for Oil Well Cement Additives - Part 1: Retarder", a compressive strength test was carried out on the samples. The reference formula of the cement slurry was: 600 g of Jiahua Grade G oil well cement (high sulfur-resistant type) + 240 g of quartz sand (200 mesh) + 12 g of retarder + 348 g of water. The test temperature was 150 °C and the curing time was 24 h.

[0034] The test results are shown in Table 2: Table 2 Performance test results of ultra-high temperature retarders for well cementing prepared in Example 4 and Examples 6 to 8

[0035] Compared with Examples 4 and 8, the compressive strength of Examples 6 and 7 is higher than that of Examples 4 and 8, indicating that when cis-9-styryl anthracene is added, the compressive strength of the well cement slurry can be improved.

[0036] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ultra-high temperature retarder for cementing, characterized in that: The invention comprises the following raw materials in parts by weight: 80-90 parts of 2-acrylamide-2-methylpropanesulfonic acid, 30-40 parts of 4-vinylbenzeneboric acid, 20-30 parts of fluorine-containing benzoic acid compound, 0.5-0.8 parts of initiator, 140-150 parts of water and 130-140 parts of sodium hydroxide aqueous solution.

2. The ultra-high temperature retarder for cementing according to claim 1, characterized in that: The fluorine-containing benzoic acid compound includes one or more of 2,3,4-trifluorobenzoic acid, 3,4-difluorophenylacetic acid, and p-fluorophenylvaleric acid.

3. The ultra-high temperature retarder for cementing according to claim 1, characterized in that: The initiator includes one or more of sodium persulfate, potassium persulfate, and azobisisobutylimidazoline hydrochloride.

4. The ultra-high temperature retarder for cementing according to claim 1, characterized in that: The mass concentration of the sodium hydroxide aqueous solution is 30%.

5. The ultra-high temperature retarder for cementing according to claim 1, characterized in that: The raw materials also include 5 to 10 parts of cis-9-phenylvinyl anthracene.

6. The method for preparing an ultra-high temperature retarder for cementing cement according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, weighing 2-acrylamide-2-methylpropanesulfonic acid, 4-vinylbenzeneboronic acid, a fluorine-containing benzoic acid compound and water, mixing, and adding a sodium hydroxide aqueous solution to obtain a mixed solution; S2. Adding an initiator into the mixed solution, after reaction, an ultra-high temperature retarder for cementing cement is obtained.

7. The method for preparing an ultra-high temperature retarder for cementing cement according to claim 6, characterized in that: The mixing temperature in S1 is 15-30°C.

8. The method for preparing an ultra-high temperature retarder for cementing according to claim 6, characterized in that: The initiator in S2 is an initiator aqueous solution, and the content of the initiator in the initiator aqueous solution is 20 wt %.

9. The method for preparing an ultra-high temperature retarder for cementing cement according to claim 6, characterized in that: The step S2 also includes deoxygenation treatment before the initiator is added, wherein the deoxygenation treatment is carried out by introducing nitrogen gas, and the time for introducing nitrogen gas is 1 to 1.5 hours.

10. The method for preparing an ultra-high temperature retarder for cementing according to claim 6, characterized in that: The reaction temperature in S2 is 60-70° C., and the reaction time is 6-8 h.

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