A thermal gradient self-adaptive hybrid modified retarder and a preparation method thereof

Abstract

The application discloses a preparation method of a thermal gradient self-adaptive hybrid modified retarder, and the method comprises the following steps: dissolving a metal chelating agent monomer and a hydroxide into water and stirring to obtain a first solution; adding an organic small molecule into the first solution to react and obtain a second solution; adding a reaction agent dropwise into the second solution to react and obtain a third solution; and filtering the third solution to obtain the retarder. The thickening time of the cement slurry added with the retarder can meet the construction requirements of high temperature and high pressure, and the cement slurry still has good early strength and other characteristics under the condition of lower temperature, so that the purpose of temperature self-adaptation is achieved, and the construction safety and quality of the ultra-deep well cementing are ensured.

Description

Technical Field

[0001] This invention relates to the field of cementing technology for ultra-deep wells with large temperature differences, and particularly to a thermal gradient adaptive hybrid modified retarder and its preparation method. Background Technology

[0002] Currently, oil and gas well development is increasingly moving towards deeper depths and greater temperature differences, which brings numerous difficulties and challenges to cementing engineering. During cementing operations, different admixtures need to be added to the cement slurry system to improve its fluidity, suspension stability, and thickening time. The main role of retarders in cement slurry is to extend the cement hydration induction period, reduce the hydration reaction rate, thereby regulating the thickening time of the cement slurry. Simultaneously, this maintains a certain level of fluidity, meeting the pumpability requirements downhole and ensuring the cement slurry is pumped to the target well section requiring cementing.

[0003] Conventionally used oil well cement retarders mainly include lignin sulfonates, hydroxycarboxylic acids and their salts, sugar compounds, and inorganic compounds. Although widely used, they still face challenges when cementing ultra-deep wells with large temperature differences, such as dosage sensitivity, excessive retardation, poor high-temperature retardation, and slow strength development of the top cement stone in the large temperature difference environment of long cementing sections.

[0004] The thermal gradient adaptive cement slurry system is a method that can effectively solve problems such as ultra-deep wells, long cementing sections, and large temperature differences in cementing. It utilizes temperature-sensitive retarder to achieve different retarding effects at different temperatures, effectively ensuring the sealing quality of the cement sheath in cementing. For example, Cheng Xiaowei's team synthesized a novel chelate-type retarder using a chelation-esterification method. This retarder effectively meets the requirements of high-temperature retarding and normal strength development at low temperatures in long cementing sections. However, it is extremely sensitive to dosage; even a 1% dosage may result in insufficient early strength. Zuo Tianpeng et al. synthesized borate-intercalated hydrotalcite using an ion exchange method. Its composite intercalation structure enables controlled release of the retarder at different temperatures, thus improving the non-linear relationship between retarder dosage and thickening time, and addressing the resulting over-retardation. However, because its intercalation release varies with temperature, the amount released also changes, leading to problems in oil and gas wells with large temperature gradients. Feng Dejie's team successfully synthesized a cement retarder suitable for wells with large temperature differences using a polymer synthesis method. While this retarder can achieve high-temperature retarding and low-temperature early strength development, its compatibility with existing admixture systems remains unknown. The retarders prepared using the above-mentioned retarder design and synthesis methods suffer from problems such as dosage sensitivity, temperature sensitivity, and unclear admixture compatibility. Therefore, this patent proposes a thermal gradient adaptive hybrid modified retarder and its preparation method, which can effectively play the role of a thermal gradient adaptive retarder, and the dosage is controllable and does not react with other admixtures. Summary of the Invention

[0005] The purpose of this invention is to provide a thermal gradient adaptive hybrid modified retarder and its preparation method, which can achieve the requirements of thermal gradient adaptation, extended thickening time at high temperatures, and high early strength at medium and low temperatures.

[0006] To achieve the above objectives, the present invention provides a method for preparing a thermal gradient adaptive hybrid modified retarder, the method comprising:

[0007] The metal chelating agent monomer and hydroxide were dissolved in water and stirred to obtain the first solution;

[0008] Organic small molecules are added to the first solution to react and obtain the second solution;

[0009] A reactant is added dropwise to the second solution to carry out the reaction and obtain a third solution;

[0010] The third solution is filtered to obtain the retarder.

[0011] Optionally, the metal chelating agent includes at least one of the following: ethylenediaminetetraacetic acid (EDTA) or triethanolamine (TEA).

[0012] Optionally, the hydroxide includes at least one of the following: sodium hydroxide and calcium hydroxide.

[0013] Optionally, the content of the metal chelating agent monomer in the first solution is 20% to 40%.

[0014] Optionally, the stirring is magnetic stirring at 1200 r / min.

[0015] Optionally, the organic small molecule is added to the first solution to react and obtain a second solution, including: adding the organic small molecule to the first solution, heating to 40-80℃ under magnetic stirring at 1200 r / min and reacting for 10-14 h to obtain the second solution.

[0016] Optionally, the organic small molecule includes at least one of the following: citric acid, glucose, and potassium gluconate.

[0017] Optionally, a reactant is added dropwise to the second solution to obtain a third solution, comprising: adding a reactant dropwise to the second solution, maintaining the temperature at 40-80°C under magnetic stirring at 2000 r / min, and reacting for 12 h to obtain the third solution.

[0018] Optionally, the reactant includes at least one of the following: ethylene glycol, acetone, and ethanol.

[0019] Optionally, the third solution is filtered to obtain the retarder, comprising:

[0020] The third solution was vacuum filtered using filter paper to obtain the filtration product.

[0021] The filtered product was placed in water and allowed to stand at room temperature for 48 hours to settle, thus obtaining a precipitate.

[0022] The precipitate was dried for 48 hours using a freeze dryer at a cold trap temperature of -60°C and a vacuum of 10Pa to obtain the dried product.

[0023] The dried material was pulverized using an agate mortar to obtain the retarder with a particle size of 100–200 μm.

[0024] The present invention also provides a thermal gradient adaptive hybrid modified retarder obtained by a preparation method.

[0025] The present invention also provides an application of the aforementioned thermal gradient adaptive hybrid modified retarder in cementing of ultra-deep wells.

[0026] The technical effects and advantages of this invention are as follows:

[0027] 1. The cement slurry system of the large temperature difference thermal gradient adaptive hybrid modified retarder for ultra-deep well cementing of the present invention exhibits good low-temperature early strength. The added metal chelating agent monomer can effectively delay the high-temperature solidification of the cement slurry.

[0028] 2. This retarder combines metal chelating agent monomers with small organic molecules, which can effectively avoid the retarding failure caused by the extreme sensitivity of hydroxycarboxylic acid and its salt retarder to dosage, and the extremely rapid hydrolysis of sugar retarder, which is extremely sensitive to even small concentration changes.

[0029] 3. Metal chelating agent monomers can effectively inhibit the formation and growth of Ca(OH)2 crystals in the early stage of cement hydration, and to a certain extent promote the initial hydration of C3S.

[0030] 4. The present invention provides a novel thermal gradient adaptive retarder applicable to cementing of ultra-deep wells with large temperature differences, and the preparation method is simple and low in cost.

[0031] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0032] Figure 1 This is a flowchart of the preparation method for thermal gradient adaptive hybrid modified retarder;

[0033] Figure 2The image shows the infrared analysis results of thermal gradient adaptive retarder No. 1 in Example 1.

[0034] Figure 3 The image shows the infrared analysis results of thermal gradient adaptive retarder No. 1 in Example 2.

[0035] Figure 4 The image shows the infrared analysis results of thermal gradient adaptive retarder No. 1 in Example 3;

[0036] Figure 5 The infrared analysis results of thermal gradient adaptive retarder No. 1 in Example 4 are shown in the figure.

[0037] Figure 6 The image shows the infrared analysis results of thermal gradient adaptive retarder No. 1 in Example 5.

[0038] Figure 7 This is a diagram showing the compressive strength effect of cement slurry under low-temperature curing in Example 1;

[0039] Figure 8 This is a diagram showing the compressive strength effect of cement slurry under low-temperature curing in Example 2;

[0040] Figure 9 This is a diagram showing the compressive strength effect of cement slurry under low-temperature curing in Example 3;

[0041] Figure 10 This is a diagram showing the compressive strength effect of cement slurry under low-temperature curing in Example 4;

[0042] Figure 11 This is a diagram showing the compressive strength effect of cement slurry under low-temperature curing in Example 5;

[0043] Figure 12 This is a diagram showing the high-temperature thickening effect of cement slurry in Example 1;

[0044] Figure 13 This is a diagram showing the high-temperature thickening effect of cement slurry in Example 2;

[0045] Figure 14 This is a diagram showing the high-temperature thickening effect of cement slurry in Example 3;

[0046] Figure 15 This is a diagram illustrating the high-temperature thickening effect of cement slurry in Example 4;

[0047] Figure 16 This is a diagram showing the high-temperature thickening effect of cement slurry in Example 5. Detailed Implementation

[0048] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Furthermore, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0049] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0050] To address the shortcomings of existing technologies, this invention discloses a method for preparing a thermal gradient adaptive hybrid modified retarder, which is described below in conjunction with... Figure 1 The method will be explained in detail.

[0051] A method for preparing a thermal gradient adaptive hybrid modified retarder, the method comprising:

[0052] 1. Dissolve the metal chelating agent monomer and hydroxide in water and stir to obtain the first solution.

[0053] Specifically, the metal chelating agent monomer and hydroxide are dissolved in deionized water and magnetically stirred at 1200 r / min to mix them evenly, while controlling the content of the metal chelating agent monomer in the system to be 20% to 40%.

[0054] The metal chelating agent includes at least one of the following: ethylenediaminetetraacetic acid (EDTA) and triethanolamine (TEA).

[0055] The hydroxide includes at least one of the following: sodium hydroxide and calcium hydroxide.

[0056] 2. Add the small organic molecules to the first solution to react and obtain the second solution.

[0057] Specifically, the organic small molecules are added to the solution described in step 1 above, and the mixture is stirred magnetically at a constant speed to ensure homogeneity. The temperature is then raised to 40–80°C, and the reaction is carried out for 10–14 hours.

[0058] The organic small molecules include at least one of the following: citric acid and glucose.

[0059] 3. Add the reactant dropwise to the second solution to carry out the reaction and obtain the third solution.

[0060] Specifically, the reactant is slowly added dropwise to the solution described in step 2 above, the rotation speed is increased to 2000 r / min, and magnetic stirring is used to induce the reaction. The temperature is maintained at 40-80℃, and the reaction continues for 12 hours.

[0061] The reactants include at least one of the following: ethylene glycol, acetone, and ethanol.

[0062] 4. Filter the third solution to obtain the retarder.

[0063] Specifically, the product from step 3 is vacuum filtered for 30 minutes using 15-20 μm filter paper to remove unreacted monomers. Then, it is placed in deionized water and allowed to settle at room temperature for 48 hours. After removing the supernatant, the product is dried using a freeze dryer at a cold trap temperature of -60℃ and a vacuum degree of 10 Pa for 48 hours. Finally, it is pulverized using an agate mortar to a particle size of 100-200 μm to obtain the thermal gradient adaptive hybrid modified retarder.

[0064] This invention also provides a thermal gradient adaptive hybrid modified retarder obtained based on the above method. The retarder is synthesized from the following raw materials: a metal chelating agent monomer, a small organic molecule, a hydroxide, a reactant, and deionized water, with the total mass fraction of each raw material component being 100%.

[0065] The present invention also provides an application of the thermal gradient adaptive hybrid modified retarder in cementing of ultra-deep wells.

[0066] To better understand this solution, the following embodiments are also provided.

[0067] Example 1

[0068] A cement slurry system containing 1 part of thermal gradient adaptive retarder No. 1 was prepared. This experiment was named No. 1. 100 parts of oil well cement, 1 part of dispersant, 5.5 parts of fluid loss reducer, and 44 parts of water were used. Thermal gradient adaptive retarder No. 1 was synthesized from 8 parts of ethylenediaminetetraacetic acid, 4 parts of sodium hydroxide, 14 parts of citric acid, 1 part of ethylene glycol, and 100 parts of deionized water.

[0069] Example 2

[0070] A cement slurry system containing 1 part of thermal gradient adaptive retarder No. 2 was prepared. This experiment was named No. 2. The mixture consisted of 100 parts of oil well cement, 1 part of dispersant, 5.5 parts of fluid loss reducer, and 44 parts of water. Thermal gradient adaptive retarder No. 2 was synthesized from 8 parts of ethylenediaminetetraacetic acid, 4 parts of sodium hydroxide, 12 parts of potassium gluconate, 1 part of ethylene glycol, and 100 parts of deionized water.

[0071] Example 3

[0072] A cement slurry system containing 1 part of thermal gradient adaptive retarder No. 3 was prepared. This experiment was named No. 3. The system consisted of 100 parts of oil well cement, 1 part of dispersant, 5.5 parts of fluid loss reducer, and 44 parts of water. Thermal gradient adaptive retarder No. 3 was synthesized from 12 parts of triethanolamine, 4 parts of sodium hydroxide, 14 parts of citric acid, 1 part of ethylene glycol, and 100 parts of deionized water.

[0073] Example 4

[0074] A cement slurry system containing 1 part of thermal gradient adaptive retarder No. 3 was prepared. This experiment was named No. 4. 100 parts of oil well cement, 1 part of dispersant, 5.5 parts of fluid loss reducer, and 44 parts of water were used. Thermal gradient adaptive retarder No. 4 was synthesized from 9 parts of triethanolamine, 4 parts of sodium hydroxide, 14 parts of potassium gluconate, 1 part of ethylene glycol, and 100 parts of deionized water.

[0075] Example 5

[0076] A cement slurry system containing 1 part of thermal gradient adaptive retarder No. 4 was prepared. This experiment was named No. 5. The system consisted of 100 parts of oil well cement, 1 part of dispersant, 5.5 parts of fluid loss reducer, and 44 parts of water. Thermal gradient adaptive retarder No. 5 was synthesized from 8 parts of ethylenediaminetetraacetic acid, 8 parts of triethanolamine, 4 parts of calcium hydroxide, 16 parts of citric acid, 2 parts of ethylene glycol, and 100 parts of deionized water.

[0077] The thermal gradient adaptive retarder and cement slurry system described in the above embodiments were tested, and the results are as follows:

[0078] Take thermal gradient adaptive retarders 1, 2, 3, 4, and 5 from Examples 1-5, place them in an infrared spectrometer, detect the functional groups in the chelates, and then compare them with the infrared spectra of standard ethylenediaminetetraacetic acid and triethanolamine. The experimental results are as follows: Figures 2-6 As shown in the figure. The results indicate that the synthesis reaction was complete.

[0079] Cement slurries numbered 1, 2, 3, 4, and 5 prepared in Examples 1-5 were mixed evenly and placed in a compression mold for curing at 60°C for 1 day, 2 days, 3 days, and 7 days. The experimental results are as follows: Figures 7-11As shown in the figure. Experimental results show that the cement grout containing the thermal gradient adaptive retarder, when cured at 60℃, has a 7-day strength greater than 20MPa, which can meet the strength requirements of cement stone for wellbore sealing.

[0080] Cement slurries No. 1, 2, 3, 4, and 5 prepared in Examples 1-5 were placed in a high-temperature and high-pressure thickening apparatus for thickening experiments at 205°C, 90 MPa, and a heating time of 110 min. The experimental results are as follows. Figures 12-16 As shown in the figure. Experimental results indicate that cement slurry containing a thermal gradient adaptive retarder is stable at high temperatures and exhibits good retarding properties.

[0081] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a thermal gradient self-adapting hybrid-modified retarder, characterized in that, The method comprises: dissolving and stirring a metal chelator monomer and a hydroxide in water to obtain a first solution; adding an organic small molecule to the first solution to obtain a second solution; adding a reaction agent dropwise to the second solution to obtain a third solution; filtering the third solution to obtain the retarder; the metal chelator monomer comprises at least one of ethylenediaminetetraacetic acid and triethanolamine; the organic small molecule comprises at least one of citric acid, glucose and potassium gluconate; the reaction agent is ethylene glycol.

2. The method of claim 1, wherein, the hydroxide comprises at least one of sodium hydroxide and calcium hydroxide.

3. The method of claim 1, wherein, the content of the metal chelator monomer in the first solution is 20-40%.

4. The method of claim 1, wherein, the stirring is magnetic stirring at 1200 r / min.

5. The method of claim 1, wherein, adding an organic small molecule to the first solution to obtain a second solution comprises: adding the organic small molecule to the first solution, heating to 40-80 DEG C under magnetic stirring at 1200 r / min and reacting for 10-14 h to obtain the second solution.

6. The method of claim 1, wherein, adding a reaction agent dropwise to the second solution to obtain a third solution comprises: adding the reaction agent dropwise to the second solution, keeping the temperature at 40-80 DEG C under magnetic stirring at 2000 r / min and reacting for 12 h to obtain the third solution.

7. The method of claim 1, wherein, filtering the third solution to obtain the retarder comprises: vacuum filtering the third solution using filter paper to obtain a vacuum filtration product; placing the vacuum filtration product in water, standing and settling at room temperature for 48 h to obtain a precipitate; drying the precipitate using a freeze dryer at a cold trap temperature of -60 DEG C and a vacuum degree of 10 Pa for 48 h to obtain a dried product; crushing the dried product using a maraglock mortar to obtain the retarder with a particle size of 100-200 μm.

8. A thermal gradient adaptive hybrid-modified retarder, characterized by: obtained by the preparation method of any one of claims 1-7.

9. The set retarding agent of claim 8, wherein application of the thermal gradient adaptive hybrid modified retarder in well cementation in ultra-deep wells.

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