Retarder suitable for large temperature difference and high temperature resistance and preparation method thereof

Abstract

The invention discloses a retarder suitable for large temperature difference and high temperature resistance and a preparation method thereof, and relates to the field of petroleum drilling, the retarder comprises the following components: a polymeric monomer, deionized water and an initiator; wherein the polymeric monomer is prepared from the following components in parts by weight: 8 to 15 parts of fumaric acid, 30 to 50 parts of 2-acrylamide-2-methylpropanesulfonic acid and 5 to 9 parts of acrylic acid; the weight of the deionized water is 3-6 times of the total weight of the polymerization monomers; according to the retarder suitable for large temperature difference and high temperature resistance and the preparation method thereof, the high-temperature-resistant and high-adsorbability cationic monomer is introduced, so that the strong polarity characteristic of an ultrahigh-temperature retarder is improved, and the problem that under high temperature and high pressure, subcritical water with special properties is not beneficial to effective exertion of the efficiency of a water-soluble additive is effectively solved; the charge density of adsorption groups is improved, a more compact impermeable membrane and a hydration layer are formed on the surfaces of cement hydration particles through adsorption, and the adsorption stability of retarder molecules at high temperature is improved.

Description

Technical Field

[0001] The invention relates to oil drilling technology, and in particular to a high temperature resistant retarder suitable for large temperature difference and a preparation method thereof. Background Art

[0002] Retarder is an oil well cement admixture used to adjust the thickening time of cement slurry. The main problems with retarders at present are: the narrow operating temperature range, the maximum operating temperature of 190°C, which cannot meet the cementing needs of ultra-deep wells; compatibility issues, some retarders are not well adapted to fluid loss additives, oil well cement, etc., causing abnormal cement slurry performance and affecting on-site promotion. There are many types of oil well cement retarders, mainly including lignin sulfonates, cellulose, sugar polymers, inorganic salts, polymers, etc. Retarders such as lignin sulfonates, cellulose, and sugar polymers have unstable product performance due to the dispersion of material sources and the heterogeneity of composition and structure. The molecular structure of traditional retarders is mostly dominated by anionic functional groups, which have strong hydrophilicity. They prolong the high-temperature thickening time by adsorption on the surface of cement particles. Under high temperature and high pressure environment, water is in a subcritical state. Compared with liquid water at normal pressure, as the temperature rises, the surface tension of subcritical water gradually decreases, the dielectric constant gradually decreases, and the hydrogen bonding effect and hydrogen bonding density gradually decrease. This change in physical and chemical properties is not conducive to the effective performance of strong polar admixtures. Therefore, under ultra-high temperature and high pressure conditions, traditional retarders have serious desorption and hydrolysis phenomena, resulting in reduced retarding effect, a sharp increase in retarder dosage, and even inability to effectively extend the thickening time of cement slurry.

[0003] CN105061661B discloses a medium-high temperature retarder for oil well cement, which includes 10-25wt% of 2-acrylamido-2-methylpropanesulfonic acid, 20%-35% of acrylic acid, 10%-35% of itaconic acid, 5%-10% of N,N-dimethylacrylamide and 15%-35% of acrylamide. The retarder is insensitive to dosage and has a good linear relationship between dosage and thickening time, which can meet the technical requirements of cementing construction, but the temperature resistance of the retarder and the strength of cement stone are still not high enough. Summary of the invention

[0004] The purpose of the present invention is to provide a high-temperature resistant retarder suitable for large temperature differences and a preparation method thereof, so as to solve the technical problems in the prior art that traditional retarders have serious desorption and hydrolysis phenomena under ultra-high temperature and high pressure conditions, resulting in reduced retarding effect, a sharp increase in the amount of retarder added, and even the inability to effectively extend the thickening time of cement slurry.

[0005] In order to achieve the above object, the present invention provides the following technical solution: a retarder suitable for large temperature difference and high temperature resistance, comprising the following components: a polymerizable monomer, deionized water and an initiator;

[0006] The polymerizable monomers include, by weight: 8 to 15 parts of fumaric acid, 30 to 50 parts of 2-acrylamide-2-methylpropanesulfonic acid, and 5 to 9 parts of acrylic acid;

[0007] The deionized water is 3 to 6 times of the total weight of the polymerization monomers, the initiator is 0.6% to 1.5% of the total weight of the polymerization monomers, and the initiator is ammonium persulfate or sodium persulfate.

[0008] A retarder suitable for large temperature difference and high temperature resistance, comprising a polymerization monomer, deionized water, and an initiator;

[0009] The polymerizable monomers include, by weight: 10 to 12 parts by weight of fumaric acid, 38 to 42 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, and 6 to 8 parts by weight of acrylic acid;

[0010] The deionized water is 4 to 5 times of the total weight of the polymerization monomers, the initiator is 0.8% to 1.2% of the total weight of the polymerization monomers, and the initiator is ammonium persulfate or sodium persulfate.

[0011] A method for preparing a retarder suitable for large temperature difference and high temperature resistance, which is used to prepare the retarder suitable for large temperature difference and high temperature resistance as described above, comprises the following steps:

[0012] S1. Prepare the raw materials of each component according to the above ratio;

[0013] S2. Dissolve the three monomers of fumaric acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid in deionized water in sequence under a nitrogen environment, and stir until fully dissolved;

[0014] S3, controlling the reaction temperature to 70°C, adding deionized water to control the total monomer concentration, and obtaining a mixed solution;

[0015] S4. Adjust the pH of the mixed solution, slowly add the initiator solution, and react at a constant temperature for 6 hours to obtain a viscous liquid, which is a retarder suitable for large temperature difference and high temperature resistance.

[0016] Furthermore, in step S4, the pH value of the mixed solution is adjusted to 4-7 by sodium hydroxide.

[0017] Furthermore, in step S4, the pH value of the mixed solution is adjusted to 5-6 by sodium hydroxide.

[0018] Furthermore, in step S3, the total monomer concentration is controlled to be between 20% and 30%.

[0019] Furthermore, in step S3, the total monomer concentration is controlled at 25%.

[0020] Furthermore, the mass fraction of the initiator solution added dropwise in step S4 is 1.0%.

[0021] Furthermore, the mass fraction of the initiator solution added dropwise in step S4 is 1.2%.

[0022] Compared with the prior art, the present invention provides a high temperature resistant retarder suitable for large temperature difference and a preparation method thereof. By introducing a high temperature resistant and strongly adsorbable cationic monomer, the strong polarity characteristics of the ultra-high temperature retarder are improved, and the problem that the special properties of subcritical water are not conducive to the effective performance of water-soluble admixtures under high temperature and high pressure is effectively overcome. By introducing a polycarboxyl monomer, the charge density of the adsorption group is increased, and a denser impermeable membrane and hydration layer are formed on the surface of cement hydration particles, the adsorption stability of the retarder molecules at high temperature is improved, and the thickening time of ultra-high temperature cement slurry is effectively prolonged. By introducing a high temperature resistant rigid monomer with a special configuration, the ultra-high temperature zwitterionic retarder molecules are not easy to agglomerate at high temperature, which is beneficial to improving the high temperature structural stability of the retarder molecules.

[0023] The retarder of the present invention exhibits good temperature sensitivity under high temperature and high pressure environment. When the temperature changes, the thickening time change rate of the cement slurry is small, which is conducive to maintaining the stability of the cement slurry performance.

[0024] The preparation method of the high temperature resistant retarder applicable to large temperature difference of the present invention has simple steps, is green, safe and environmentally friendly, has readily available raw materials and low production cost, and can realize industrial production and large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0026] Figure 1 A thickening curve diagram of a setting retarder at 115°C provided by an embodiment of the present invention when the setting retarder is added at 2%;

[0027] Figure 2 This is a thickening curve diagram of an embodiment of the present invention at 115°C when the retarder dosage is 1.8%. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] See also Figure 1 to Figure 2 , a retarder suitable for large temperature difference and high temperature resistance, comprising the following components: polymerization monomer, deionized water and initiator;

[0030] The polymerizable monomers include, by weight: 8 to 15 parts of fumaric acid, 30 to 50 parts of 2-acrylamide-2-methylpropanesulfonic acid, and 5 to 9 parts of acrylic acid;

[0031] The deionized water is 3 to 6 times of the total weight of the polymerization monomers, the initiator is 0.6% to 1.5% of the total weight of the polymerization monomers, and the initiator is ammonium persulfate or sodium persulfate.

[0032] As a preferred embodiment, the polymerizable monomers include 10 to 12 parts by weight of fumaric acid, 38 to 42 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, and 6 to 8 parts by weight of acrylic acid;

[0033] The deionized water is 4 to 5 times the total weight of the polymerization monomers, and the initiator is 0.8% to 1.2% of the total weight of the polymerization monomers.

[0034] A method for preparing a retarder suitable for large temperature difference and high temperature resistance is also provided, which is used to prepare the retarder suitable for large temperature difference and high temperature resistance as mentioned above, comprising the following steps:

[0035] S1. Prepare the raw materials of each component according to the above ratio;

[0036] S2. Dissolve the three monomers of fumaric acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid in deionized water in sequence under a nitrogen environment, and stir until fully dissolved;

[0037] S3, controlling the reaction temperature to 70°C, adding deionized water to control the total monomer concentration, the total monomer concentration is 20%-30%, preferably the total monomer concentration is controlled at 25%, to obtain a mixed solution;

[0038] S4. Adjust the pH value of the mixed solution to 4-6, preferably to 5-6, by using sodium hydroxide, slowly dropwise add the initiator solution, preferably an initiator solution with a mass fraction of 1 or 1.2%, and react at a constant temperature for 6 hours to obtain a viscous liquid, which is a retarder suitable for large temperature difference and high temperature resistance.

[0039] The high temperature resistant retarder suitable for large temperature difference prepared by the above-mentioned proportion and method has a high temperature resistant and strongly adsorbable cationic monomer introduced into its structure, which improves the strong polarity characteristics of the ultra-high temperature retarder and effectively overcomes the problem that the special properties of subcritical water under high temperature and high pressure are not conducive to the effective performance of water-soluble admixtures; a multi-carboxyl monomer is introduced into its structure to increase the charge density of the adsorption group, which is adsorbed on the surface of cement hydration particles to form a denser impermeable membrane and hydration layer, thereby improving the adsorption stability of the retarder molecules at high temperature and effectively prolonging the thickening time of ultra-high temperature cement slurry; a high temperature resistant and rigid monomer with a special configuration is introduced into its structure, and the ultra-high temperature zwitterionic retarder molecules are not easy to agglomerate at high temperature, which is beneficial to improving the high temperature structural stability of the retarder molecules.

[0040] The retarder suitable for large temperature difference and high temperature resistance belongs to the AMPS multipolymer retarder, which has the characteristics of wide temperature range, easy adjustment of thickening time, strong cement adaptability, etc. The maximum applicable temperature is 90℃-200℃; the prepared cement slurry will not be over-diluted; it can meet the requirements of deep well and ultra-deep well cementing, and the retarder has stable performance. The recommended dosage in cementing cement slurry is 1.0-4.0%, and the thickening time has a good linear relationship with temperature and dosage.

[0041] The preparation method of the retarder suitable for large temperature difference and high temperature resistance in the present application has simple steps, is green, safe and environmentally friendly, has readily available raw materials and low production cost, and can realize industrial production and large-scale promotion and application.

[0042] Embodiment 1:

[0043] Weigh 12 parts of fumaric acid, 40 parts of 2-acrylamide-2-methylpropanesulfonic acid, and 7.4 parts of acrylic acid by weight; dissolve all the three monomers in 270 parts of deionized water in a nitrogen environment, stir to fully dissolve, control the reaction temperature at 70°C, add deionized water, control the total monomer concentration at 25%, adjust the pH of the mixed solution to 6, slowly dropwise add a 1.0% initiator solution, and react at a constant temperature for 6 hours to obtain a viscous liquid that is a high-temperature resistant retarder suitable for large temperature differences.

[0044] Embodiment 2:

[0045] Weigh 10 parts of fumaric acid, 39 parts of 2-acrylamide-2-methylpropanesulfonic acid, and 8 parts of acrylic acid by weight; dissolve the other three monomers in 280 parts by weight of deionized water in a nitrogen environment, stir until fully dissolved, control the reaction temperature at 70°C, add deionized water, control the total monomer concentration at 25%, adjust the pH of the mixed solution to 6, slowly dropwise add a 1.2% mass fraction initiator solution, and react at a constant temperature for 6 hours to obtain a viscous liquid that is a high temperature resistant retarder suitable for large temperature difference.

[0046] Comparative Example 1:

[0047] This comparative example is to illustrate a retarder prepared outside the scope specified in the present invention, and to compare it with Examples 1-2. A high-temperature retarder that is currently widely used in the field is used, and the high-temperature retarder is an AMPS polymer retarder.

[0048] Comparative Example 2:

[0049] Weigh 8 parts of fumaric acid, 45 parts of 2-acrylamide-2-methylpropanesulfonic acid, and 15 parts of acrylic acid by weight; dissolve the other three monomers in 270 parts by weight of deionized water in a nitrogen environment, stir until fully dissolved, control the reaction temperature at 70°C, add deionized water, control the total monomer concentration at 25%, adjust the pH of the mixed solution to 6, slowly dropwise add an initiator solution with a mass fraction of 1.2%, and react at a constant temperature for 6 hours to obtain a viscous liquid, which is an ultra-high temperature zwitterionic retarder.

[0050] In order to verify the performance of the high-temperature retarder prepared by the present invention, the following cement slurry formula, cement slurry preparation and performance test are carried out according to GB / T19139-2012 "Test Methods for Oil Well Cement", and comprehensive performance tests are carried out with reference to SY / T6544-2017 "Performance Requirements for Oil Well Cement Slurry", SY / T6466-2000 "Evaluation Method for High Temperature Resistance of Oil Well Cement Stone", and SY / T5504.1-2013 "Evaluation Method for Oil Well Cement Admixtures Part 1: Retarders";

[0051] 1. Comparative test of thickening time under different experimental conditions:

[0052] Formula G grade cement (100 parts), silica fume (35 parts), low viscosity fluid loss reducer (1 part), defoamer (0.1 parts), water (55 parts) and new large temperature difference retarder. The addition amount of the new large temperature difference retarder is shown in Table 1:

[0053]

[0054] Table 1

[0055] It can be seen from the test results in Table 1 that the ultra-high temperature retarder prepared in Examples 1-2 of the present invention has good retarding performance for oil well cement under the condition of 110-200°C, and has good temperature resistance, which can effectively prolong the thickening time of cement slurry and meet the requirements of cementing for cement slurry at different temperatures; at the same time, after adding the retarder prepared in the example, the right-angle thickening phenomenon is obvious, and once the cement slurry is poured into place between the casings, it can quickly lose fluidity and form early strength, reducing the possibility of accidents. However, the ultra-high temperature retarder prepared in Comparative Examples 1-2 has poor retarding effect under the condition of 110-200°C, and even the retarding performance decreases rapidly at 160°C and above, and loses its effect.

[0056] 2. Test the compressive strength of cement paste to verify the effect of the retarder on improving the early strength of the top cement paste under different temperature conditions:

[0057] Taking Examples 1-2 and Comparative Examples 1-2 as test objects, different mass fractions of retarder (retarder prepared in Example 1) were added to the formulated cement slurry, and the top cementing environment was simulated under different temperature conditions. The compressive strength of the cement stone after curing for different times was tested to verify the improvement effect of the ultra-high temperature retarder on the early strength of the top cement stone under the conditions. The results are shown in Table 2:

[0058]

[0059] Table 2

[0060] For the retarder, it is required that it should not have a significant adverse effect on the strength of the cement paste. From the results in Table 2, it can be seen that, referring to Examples 1-2 and Comparative Examples 1-2, it is found that the ultra-high temperature retarder is cured for different times under different temperature conditions, and each cement paste shows a high strength and can meet the requirements of cementing operations. However, the retarder of Comparative Examples 1-2 has a greater impact on the strength, and there are potential safety hazards in cementing quality in actual on-site operations.

[0061] 3. Dosage sensitivity test:

[0062] According to the standard SY / T5504.1-2013 "Evaluation Methods for Oil Well Cement Admixtures Part 1: Retarder", the dosage sensitivity test is carried out. In the benchmark formula at a representative temperature point, the retarder dosage is increased by 10% to carry out the thickening test and the thickening time is read. The retarder dosage sensitivity is calculated according to the formula. The standard indicator is dosage sensitivity ≤ 25%.

[0063] Calculate the thickening time increase rate using the formula: R D =(t D -t p ) / t p *100%, where: R D is the sensitivity of retarder dosage, expressed as a percentage; t D To increase the thickening time of cement slurry under the condition of 10% addition, min; t P is the thickening time of the base formula, min.

[0064] The ultra-high temperature retarder prepared in Example 1 was added in a mass fraction of 1.0-3.3% to the prepared cement slurry, and the experiment was carried out in the temperature range of 110-200° C. The experimental results are shown in Table 3 below:

[0065] Table 3 Dosage sensitivity test:

[0066]

[0067] Table 3

[0068] According to the data in Table 3, when the amount of retarder increases, the change rate of thickening time is less than 10%. It can be seen that the ultra-high temperature retarder in the present invention has a small amount sensitivity coefficient, which can effectively meet the performance requirements of cementing engineering and ensure the safety of cementing construction.

[0069] 4. Temperature sensitivity test:

[0070] RT=(t T -t p ) / t p *100%, where RT is the temperature sensitivity of the retarder, expressed as a percentage; t P is the thickening time of the base formula, min; t T is the thickening time of cement slurry under test temperature T, min.

[0071] Table 4 Temperature sensitivity test:

[0072]

[0073] Table 4

[0074] According to the data in Table 4, when the temperature increases by 5°C, the temperature sensitivity is less than 20%. It can be seen that the ultra-high temperature retarder has low temperature sensitivity and can effectively meet the performance requirements of cementing engineering and ensure the safety of cementing construction.

[0075] In summary, the ultra-high temperature retarder of the present invention can effectively prolong the thickening time of cement slurry at high temperature, ensure the early strength of cement stone at low temperature, thereby improving the comprehensive performance of the cement slurry system, reducing the damage to the cement ring and casing, preventing the occurrence of accidents such as water channeling and gas channeling, improving the safety of oil well production, meeting the time requirements of cementing projects, and ensuring the quality of cementing.

[0076] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A retarder suitable for large temperature difference and high temperature resistance, characterized in that: The method comprises the following components: polymerization monomer, deionized water and initiator; The polymerizable monomers include, by weight: 8 to 15 parts of fumaric acid, 30 to 50 parts of 2-acrylamide-2-methylpropanesulfonic acid, and 5 to 9 parts of acrylic acid; The deionized water is 3 to 6 times of the total weight of the polymerization monomers, the initiator is 0.6% to 1.5% of the total weight of the polymerization monomers, and the initiator is ammonium persulfate or sodium persulfate.

2. A retarder suitable for large temperature difference and high temperature resistance, characterized in that: Including polymerization monomer, deionized water, initiator; The polymerizable monomers include, by weight: 10 to 12 parts by weight of fumaric acid, 38 to 42 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid, and 6 to 8 parts by weight of acrylic acid; The deionized water is 4 to 5 times of the total weight of the polymerization monomers, the initiator is 0.8% to 1.2% of the total weight of the polymerization monomers, and the initiator is ammonium persulfate or sodium persulfate.

3. A method for preparing a retarder suitable for large temperature difference and high temperature resistance, characterized in that: The method for preparing the retarder applicable to large temperature difference and high temperature resistance as claimed in claim 1 or 2 comprises the following steps: S1. Prepare the raw materials of each component according to the ratio in claim 1 or 2; S2. Dissolve the three monomers of fumaric acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylic acid in deionized water in sequence under a nitrogen environment, and stir until fully dissolved; S3, controlling the reaction temperature to 70°C, adding deionized water to control the total monomer concentration, and obtaining a mixed solution; S4. Adjust the pH of the mixed solution, slowly add the initiator solution, and react at a constant temperature for 6 hours to obtain a viscous liquid, which is a retarder suitable for large temperature difference and high temperature resistance.

4. The method for preparing a high temperature resistant retarder suitable for large temperature difference according to claim 3, characterized in that: In step S4, the pH value of the mixed solution is adjusted to 4-7 by sodium hydroxide.

5. The method for preparing a high temperature resistant retarder suitable for large temperature difference according to claim 3, characterized in that: In step S4, the pH value of the mixed solution is adjusted to 5-6 by sodium hydroxide.

6. The method for preparing a high temperature resistant retarder suitable for large temperature difference according to claim 3, characterized in that: In step S3, the total monomer concentration is controlled at 20%-30%.

7. The method for preparing a high temperature resistant retarder suitable for large temperature difference according to claim 3, characterized in that: In step S3, the total monomer concentration is controlled at 25%.

8. The method for preparing a high temperature resistant retarder suitable for large temperature difference according to claim 3, characterized in that: The mass fraction of the initiator solution added dropwise in step S4 is 1.0%.

9. The method for preparing a high temperature resistant retarder suitable for large temperature difference according to claim 3, characterized in that: The mass fraction of the initiator solution added dropwise in step S4 is 1.2%.

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