Retarder for large temperature difference oil well cement and preparation method thereof

Abstract

The invention discloses a retarder for large temperature difference oil well cement and a preparation method thereof, and belongs to the technical field of retarder preparation. The retarder for large temperature difference oil well cement is composed of the following components in parts by weight: 20-34 parts of effective component A, 22-32 parts of effective component B, and 44-58 parts of distilled water, wherein the effective component A is prepared from tetraethylenepentamine, n-hexyl methacrylate and hydroxyethylidene diphosphonic acid, and the effective component B is prepared from 1-methylimidazole, chlorobutane, chitosan, sorbitol and polyethyleneimine. The coagulant prepared by the method can effectively improve the retarding effect of cement, thereby improving the durability of cement and extending the service life of cement.

Description

Technical Field

[0001] The invention belongs to the technical field of retarder preparation, and in particular relates to a retarder for large temperature difference oil well cement and a preparation method thereof. Background Art

[0002] With the continuous deepening of oil and gas resource exploration and development, especially the advancement to deep formations and extreme environmental conditions, oil well cementing technology faces unprecedented challenges. Under these complex geological conditions, high temperature, high pressure and huge formation temperature gradient have become key factors restricting the safety and quality of cementing operations.

[0003] In cementing operations in deep and ultra-deep wells, cement slurry needs to undergo significant temperature changes from low temperature at the wellhead to high temperature at the bottom of the well. This large temperature difference environment places stringent requirements on the rheological properties, setting time, and strength development of cement slurry. Although traditional retarders can delay the setting time of cement slurry to a certain extent, their use temperature range is limited and they are often difficult to adapt to cementing needs under large temperature difference conditions. In the high temperature section, the retarding effect may be insufficient, resulting in premature setting of the cement slurry; in the low temperature section, super-retarded setting or non-setting may occur, seriously affecting the cementing quality and subsequent construction progress. Therefore, the development of a retarder suitable for large temperature difference oil well cement has become an important topic in the field of cementing technology.

[0004] Patent CN 106632842 B discloses a preparation method and application method of an oil well cement retarder. The preparation method is to dissolve an olefin monomer with anionic sulfonic acid group, an olefin monomer with ammonium cation and an unsaturated monomer containing a carboxylic acid group in deionized water and adjust the pH value of the system, add an initiator under nitrogen flow, and continuously react in a constant temperature water bath to obtain an oil well cement retarder. The obtained retarder has good stability, degradation resistance, and high temperature resistance in a high temperature environment, and can achieve an ideal retarding effect in the cement system. However, the retarding effect of the retarder prepared by this method still has room for improvement. Summary of the invention

[0005] The object of the present invention is to provide a retarder for large temperature difference oil well cement and a preparation method thereof, so as to solve the technical problem that the retarder has poor retarding effect in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention provides a retarder for large temperature difference oil well cement, which is composed of the following components in parts by weight: 20-34 parts of an effective component A, 22-32 parts of an effective component B, and 44-58 parts of distilled water, wherein the effective component A is prepared from tetraethylenepentamine, n-hexyl methacrylate and hydroxyethylidene diphosphonic acid, and the effective component B is prepared from 1-methylimidazole, chlorobutane, chitosan, sorbitol and polyethyleneimine.

[0008] Preferably, the preparation method of the effective component A comprises the following steps:

[0009] Q1: Tetraethylenepentamine and methanol are added to a container containing a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, n-hexyl methacrylate is added to the constant pressure dropping funnel, stirred under nitrogen and low temperature environment, and then n-hexyl methacrylate is added dropwise. After the addition is completed, the temperature is raised to continue the reaction. After the reaction is completed, distillation is performed under reduced pressure to obtain intermediate product 1;

[0010] Q2: Add the intermediate product 1 and methanol into a container, slowly drop tetraethylenepentamine under nitrogen and low temperature environment, after the dropwise addition is completed, heat up and continue the reaction, after the reaction is completed, perform reduced pressure distillation to obtain the intermediate product 2;

[0011] Q3: Add hydroxyethylidene diphosphonic acid and deionized water into a three-necked flask equipped with a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, then add 4-dimethylaminopyridine, stir evenly, slowly dropwise add the intermediate 2, heat to react, obtain a yellow liquid, dialyze it, and dry it to obtain effective component A.

[0012] In the above process, tetraethylenepentamine is used as the reaction core, methanol is used as the solvent, and n-hexyl methacrylate is used as the monomer. Through addition and amidation reactions, an intermediate product 2 having an amino terminal group is obtained. Hydroxyethylidene diphosphonic acid is used as a capping agent for the intermediate product 2, and the hydroxyl group contained therein reacts with the amino group to prepare an effective component A.

[0013] Preferably, in Q1, the molar ratio of tetraethylenepentamine to n-hexyl methacrylate is (1-1.5): (7-10.5), the low temperature environment temperature is 0-2°C, the stirring time is 20-30min, the dropping time is 2-3h, the heating continuous reaction temperature is 30-45°C, the reaction time is 20-24h, the reduced pressure distillation temperature is 50-65°C, and the pressure is 130-150Pa.

[0014] Preferably, in Q2, the molar ratio of the intermediate product 1 and tetraethylenepentamine is (1-1.3): (7-9.1), the low temperature environment temperature is 0-2°C, the continuous heating reaction temperature is 20-30°C, the reaction time is 20-24h, the reduced pressure distillation temperature is 60-65°C, and the pressure is 220-230Pa.

[0015] Preferably, in Q3, the molar ratio of hydroxyethylidene diphosphonic acid and intermediate 2 is (7-8.4): (1-1.2), the mass fraction of 4-dimethylaminopyridine is 1wt%, the heating reaction temperature is 70-80°C, the reaction time is 10-12h, the dialysis time is 6-8h, the drying temperature is 70-80°C, and the time is 20-24h.

[0016] Preferably, the method for preparing the active ingredient B comprises the following steps:

[0017] S1: adding 1-methylimidazole and chlorobutane into a container, introducing argon gas, stirring magnetically and heating for reaction, cooling and freezing after the reaction is completed, removing the upper liquid and washing with toluene, and then vacuum drying to obtain a reaction medium;

[0018] S2: adding the reaction medium to a container, heating and introducing argon, adding chitosan under magnetic stirring, stirring and dissolving, adding sorbitol to react, dialyzing and freeze-drying after the reaction, to obtain solid 1;

[0019] S3: Add the reaction medium into a container, heat it, introduce argon, add solid 1 under magnetic stirring, stir and dissolve it, add carbonyldiimidazole to react, then add polyethyleneimine and continue the reaction. After the reaction is completed, dialyze and freeze-dry to obtain active ingredient B.

[0020] In the above process, 1-methylimidazole and chlorobutane are reacted to prepare a reaction medium, and then carbonyldiimidazole is used as a coupling agent, chitosan is used as the main chain, and sorbitol and polyethyleneimine are grafted to prepare the effective ingredient B.

[0021] Preferably, in S1, the dosage ratio of 1-methylimidazole and chlorobutane is (50-75) g: (90-135) mL, the time of passing argon is 0.5-1.5 h, the heating reaction temperature is 80-85°C, the reaction time is 20-24 h, the freezing time is 2-4 h, the washing times are 3-5 times, the vacuum drying temperature is 80-90°C, and the time is 8-10 h.

[0022] Preferably, in S2, the dosage ratio of the reaction medium, chitosan and sorbitol is (35-40) mL: (3-3.4) g: (2-2.3) g, the heating temperature is 70-75°C, the argon gas introduction time is 0.5-1 h, the reaction time is 6-8 h, the molecular weight cutoff of the dialysis bag during the dialysis process is 2000, distilled water is used for dialysis for 3-4 days, and the freeze-drying time is 20-24 h.

[0023] Preferably, in S3, the amount ratio of the reaction medium, solid 1, carbonyldiimidazole and polyethyleneimine is (35-40) mL: (1-1.3) g: (0.81-0.92) g: (1-3) g, the heating temperature is 70-75°C, the time for passing argon is 0.5-1 h, the reaction time is 4-6 h, the continued reaction time is 4-5 h, the dialysis bag used in the dialysis process has a molecular weight cutoff of 2000, distilled water is used for dialysis for 2-3 days, and the freeze-drying time is 20-24 h.

[0024] Preferably, the method for preparing the retarder for large temperature difference oil well cement comprises the following steps:

[0025] Step (1): adding active ingredient A to distilled water and stirring with ultrasonic to obtain an active ingredient A solution;

[0026] Step (2): Slowly add the active ingredient B into the active ingredient A solution, mix and stir, and obtain a retarder for large temperature difference oil well cement.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] 1. The present invention first uses tetraethylenepentamine, n-hexyl methacrylate and hydroxyethylenediphosphonic acid as raw materials to prepare effective component A, then uses 1-methylimidazole, chlorobutane, chitosan, sorbitol and polyethyleneimine as raw materials to prepare effective component B, and the effective component A and the effective component B are compounded to prepare a retarder. The retarder is applied to large temperature difference oil well cement, which can effectively control the setting time of cement, and the prepared retarder has excellent high temperature resistance, is not easy to decompose or destroy, and is helpful to maintain the physical and chemical properties of cement.

[0029] 2. The present invention uses tetraethylenepentamine, n-hexyl methacrylate and hydroxyethylidene diphosphonic acid as raw materials to prepare effective component A. The molecular structure of effective component A is complex and contains amino and phosphoric acid groups. The presence of these functional groups can be adsorbed on the surface of cement particles to form a dense protective film, which slows down the contact between cement particles and water molecules, reduces the rate of cement hydration reaction, and prolongs the initial and final setting times of cement. The long-chain structure contained in the effective component A forms a steric hindrance between cement particles, hinders the mutual approach and combination of cement particles, and prolongs the coagulation time of cement. The presence of effective component A can make the cement hydration reaction more uniform, reduce the internal stress generated by the concentrated release of hydration heat, thereby reducing the formation of microcracks and improving the durability of cement. At the same time, the functional groups and long-chain structures in the effective component A are firmly connected by chemical bonds to form a stable molecular structure. Under high temperature environment, the stable molecular structure can maintain its integrity and is not easy to decompose or destroy, thereby helping to maintain the physical and chemical properties of cement.

[0030] 3. The present invention uses 1-methylimidazole, chlorobutane, chitosan, sorbitol and polyethyleneimine as raw materials to prepare effective component B. The effective component B has chitosan as the main chain. Chitosan itself has certain adsorption and film-forming properties. Through the coupling effect of carbonyldiimidazole, sorbitol and polyethyleneimine are successfully grafted onto chitosan to form molecules with complex functional groups and long-chain structures. These functional groups can react with calcium ions on the surface of cement to form a dense protective film, thereby slowing down the hydration reaction rate of cement. The polar groups contained in the effective component B can form hydrogen bonds with water molecules, which helps to form a lubricating film in the cement, making the cement smoother during stirring and pouring, reducing internal friction resistance, and improving the working performance of the cement; and the protective film formed by the effective component B slows down the hydration reaction rate of cement, improves the impermeability of cement, and prolongs the service life of cement. DETAILED DESCRIPTION

[0031] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Embodiment 1: This embodiment discloses a method for preparing effective component A, comprising the following steps:

[0033] Q1: 4.5 mL of tetraethylenepentamine and 5.43 g of methanol were added to a container containing a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, 33 mL of n-hexyl methacrylate was added to the constant pressure dropping funnel, and stirred for 30 min under nitrogen and 0°C, and then n-hexyl methacrylate was added dropwise for 2 h. After the addition was completed, the temperature was raised to 45°C and the reaction was continued for 24 h. After the reaction was completed, it was distilled under reduced pressure at 65°C and 133 Pa to obtain intermediate 1;

[0034] Q2: 2.9g of intermediate product 1 and 5.05g of methanol were added to a container, and 2.67g of tetraethylenepentamine was slowly added dropwise under nitrogen and 0°C. After the addition was completed, the temperature was raised to 30°C and the reaction was continued for 24h. After the reaction was completed, the reaction was carried out under reduced pressure distillation at 65°C and 225Pa to obtain intermediate product 2;

[0035] Q3: Add 1.1 g of hydroxyethylidene diphosphonic acid and 10 mL of deionized water into a three-necked flask equipped with a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, then add 0.01 g of 1 wt% 4-dimethylaminopyridine, stir evenly, slowly add 1.21 g of intermediate 2, react at 80°C for 12 h to obtain a yellow liquid, dialyze it for 8 h, and dry it at 80°C for 24 h to obtain effective component A.

[0036] This embodiment discloses a method for preparing an active ingredient B, comprising the following steps:

[0037] S1: 57.5 g of 1-methylimidazole and 112.5 mL of chlorobutane were added to a container, argon was introduced for 1.5 hours, magnetic stirring was performed, and the reaction was performed at 85° C. for 24 hours. After the reaction was completed, the reaction was cooled and refrigerated for 4 hours. The upper liquid was removed and washed with toluene 5 times, and then vacuum dried at 90° C. for 10 hours to obtain a reaction medium;

[0038] S2: 37.5 mL of the reaction medium was added to the container, heated to 75°C and then argon was introduced for 0.5 h. Under magnetic stirring, 3.2 g of chitosan was added, stirred and dissolved, and then 2.15 g of sorbitol was added to react for 8 h. After the reaction was completed, it was dialyzed with distilled water for 3 days. The molecular weight cutoff of the dialysis bag during the dialysis process was 2000. It was freeze-dried for 24 h to obtain solid 1;

[0039] S3: Add 37.5 mL of reaction medium into the container, heat to 75°C and introduce argon for 1 hour. Under magnetic stirring, add 1.15 g of solid 1, stir to dissolve, add 0.86 g of carbonyldiimidazole and react for 6 hours, then add 2 g of polyethyleneimine and continue to react for 5 hours. After the reaction is completed, dialyze with distilled water for 3 days. The molecular weight cutoff of the dialysis bag used in the dialysis process is 2000. Freeze-dry for 24 hours to obtain the active ingredient B.

[0040] The present embodiment discloses a retarder for large temperature difference oil well cement, which is composed of the following components in parts by weight: 27 parts of effective component A, 27 parts of effective component B, and 51 parts of distilled water.

[0041] This embodiment discloses a method for preparing a retarder for large temperature difference oil well cement, comprising the following steps:

[0042] Step (1): adding active ingredient A to distilled water and stirring with ultrasonic to obtain an active ingredient A solution;

[0043] Step (2): Slowly add the active ingredient B into the active ingredient A solution, mix and stir, and obtain a retarder for large temperature difference oil well cement.

[0044] Embodiment 2: This embodiment discloses a method for preparing effective component A, comprising the following steps:

[0045] Q1: 3.6 mL of tetraethylenepentamine and 5.43 g of methanol were added to a container containing a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, 26.4 mL of n-hexyl methacrylate was added to the constant pressure dropping funnel, and stirred for 30 min under nitrogen and 0°C, and then n-hexyl methacrylate was added dropwise for 2 h. After the addition was completed, the temperature was raised to 45°C and the reaction was continued for 24 h. After the reaction was completed, it was distilled under reduced pressure at 65°C and 133 Pa to obtain intermediate 1;

[0046] Q2: 2.52g of intermediate product 1 and 5.05g of methanol were added to a container, and 2.31g of tetraethylenepentamine was slowly added dropwise under nitrogen and 0°C. After the addition was completed, the temperature was raised to 30°C and the reaction was continued for 24h. After the reaction was completed, the reaction was carried out under reduced pressure distillation at 65°C and 225Pa to obtain intermediate product 2;

[0047] Q3: Add 1 g of hydroxyethylidene diphosphonic acid and 10 mL of deionized water into a three-necked flask equipped with a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, then add 0.01 g of 1 wt% 4-dimethylaminopyridine, stir evenly, slowly add 1.1 g of intermediate 2, react at 80°C for 12 h to obtain a yellow liquid, dialyze it for 8 h, and dry it at 80°C for 24 h to obtain effective component A.

[0048] This embodiment discloses a method for preparing an active ingredient B, comprising the following steps:

[0049] S1: 50 g of 1-methylimidazole and 90 mL of chlorobutane were added to a container, argon was introduced for 1.5 hours, magnetic stirring was performed, and the reaction was performed at 85° C. for 24 hours. After the reaction was completed, the reaction was cooled and frozen for 4 hours. The upper liquid was removed and washed with toluene for 5 times, and then vacuum dried at 90° C. for 10 hours to obtain a reaction medium;

[0050] S2: 35 mL of the reaction medium was added to the container, heated to 75°C, and argon was introduced for 0.5 h. Under magnetic stirring, 3 g of chitosan was added, stirred and dissolved, and 2 g of sorbitol was added to react for 8 h. After the reaction, distilled water was used for dialysis for 3 days. The molecular weight cutoff of the dialysis bag during the dialysis process was 2000. The solid 1 was freeze-dried for 24 h to obtain solid 1;

[0051] S3: Add 35 mL of reaction medium into the container, heat to 75°C and introduce argon for 1 hour. Under magnetic stirring, add 1 g of solid 1, stir and dissolve, add 0.81 g of carbonyldiimidazole and react for 6 hours, then add 1 g of polyethyleneimine and continue to react for 5 hours. After the reaction is completed, dialyze with distilled water for 3 days. The molecular weight cutoff of the dialysis bag used in the dialysis process is 2000. Freeze-dry for 24 hours to obtain the active ingredient B.

[0052] This embodiment discloses a retarder for large temperature difference oil well cement, which is composed of the following components in parts by weight: 20 parts of effective component A, 22 parts of effective component B, and 44 parts of distilled water.

[0053] This embodiment discloses a method for preparing a retarder for large temperature difference oil well cement, comprising the following steps:

[0054] Step (1): adding active ingredient A to distilled water and stirring with ultrasonic to obtain an active ingredient A solution;

[0055] Step (2): Slowly add the active ingredient B into the active ingredient A solution, mix and stir, and obtain a retarder for large temperature difference oil well cement.

[0056] Embodiment 3: This embodiment discloses a method for preparing effective component A, comprising the following steps:

[0057] Q1: 5.4 mL of tetraethylenepentamine and 5.43 g of methanol were added to a container containing a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, 39.6 mL of n-hexyl methacrylate was added to the constant pressure dropping funnel, stirred for 30 min under nitrogen and 0°C, and then n-hexyl methacrylate was added dropwise for 2 h. After the addition was completed, the temperature was raised to 45°C and the reaction was continued for 24 h. After the reaction was completed, it was distilled under reduced pressure at 65°C and 133 Pa to obtain intermediate 1;

[0058] Q2: 3.27g of intermediate product 1 and 5.05g of methanol were added to a container, and 3g of tetraethylenepentamine was slowly added dropwise under nitrogen and 0°C. After the addition was completed, the temperature was raised to 30°C and the reaction was continued for 24h. After the reaction was completed, the reaction was carried out under reduced pressure distillation at 65°C and 225Pa to obtain intermediate product 2;

[0059] Q3: Add 1.2 g of hydroxyethylidene diphosphonic acid and 10 mL of deionized water into a three-necked flask equipped with a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, then add 0.01 g of 1 wt% 4-dimethylaminopyridine, stir evenly, slowly add 1.32 g of intermediate 2, react at 80°C for 12 h to obtain a yellow liquid, dialyze it for 8 h, and dry it at 80°C for 24 h to obtain effective component A.

[0060] This embodiment discloses a method for preparing an active ingredient B, comprising the following steps:

[0061] S1: 75 g of 1-methylimidazole and 135 mL of chlorobutane were added to a container, argon was introduced for 1.5 hours, magnetic stirring was performed, and the reaction was performed at 85° C. for 24 hours. After the reaction was completed, the reaction was cooled and refrigerated for 4 hours. The upper liquid was removed and washed with toluene for 5 times, and then vacuum dried at 90° C. for 10 hours to obtain a reaction medium;

[0062] S2: 40 mL of the reaction medium was added to the container, heated to 75°C, and argon was introduced for 0.5 h. Under magnetic stirring, 3.4 g of chitosan was added, stirred and dissolved, and 2.3 g of sorbitol was added to react for 8 h. After the reaction, distilled water was used for dialysis for 3 days. The molecular weight cutoff of the dialysis bag during the dialysis process was 2000. The solid 1 was freeze-dried for 24 h to obtain solid 1;

[0063] S3: Add 40 mL of reaction medium into the container, heat to 75°C and introduce argon for 1 hour. Under magnetic stirring, add 1.3 g of solid 1, stir and dissolve, add 0.92 g of carbonyldiimidazole and react for 6 hours, then add 3 g of polyethyleneimine and continue to react for 5 hours. After the reaction is completed, dialyze with distilled water for 3 days. The molecular weight cutoff of the dialysis bag used in the dialysis process is 2000. Freeze-dry for 24 hours to obtain the active ingredient B.

[0064] This embodiment discloses a retarder for large temperature difference oil well cement, which is composed of the following components in parts by weight: 34 parts of effective component A, 32 parts of effective component B, and 58 parts of distilled water.

[0065] This embodiment discloses a method for preparing a retarder for large temperature difference oil well cement, comprising the following steps:

[0066] Step (1): adding active ingredient A to distilled water and stirring with ultrasonic to obtain an active ingredient A solution;

[0067] Step (2): Slowly add the active ingredient B into the active ingredient A solution, mix and stir, and obtain a retarder for large temperature difference oil well cement.

[0068] Embodiment 4: This embodiment discloses a method for preparing effective component A, comprising the following steps:

[0069] Q1: 4 mL of tetraethylenepentamine and 5.43 g of methanol were added to a container containing a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, 36.3 mL of n-hexyl methacrylate was added to the constant pressure dropping funnel, and stirred for 30 min under nitrogen and 0°C, and then n-hexyl methacrylate was added dropwise for 2 h. After the addition was completed, the temperature was raised to 45°C and the reaction was continued for 24 h. After the reaction was completed, it was distilled under reduced pressure at 65°C and 133 Pa to obtain intermediate 1;

[0070] Q2: 2.71g of intermediate product 1 and 5.05g of methanol were added to a container, and 2.85g of tetraethylenepentamine was slowly added dropwise under nitrogen and 0°C. After the addition was completed, the temperature was raised to 30°C and the reaction was continued for 24h. After the reaction was completed, the reaction was carried out under reduced pressure distillation at 65°C and 225Pa to obtain intermediate product 2;

[0071] Q3: Add 1.05 g of hydroxyethylidene diphosphonic acid and 10 mL of deionized water into a three-necked flask equipped with a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, then add 0.01 g of 1 wt% 4-dimethylaminopyridine, stir evenly, slowly add 1.15 g of intermediate 2, react at 80 ° C for 12 h to obtain a yellow liquid, dialyze it for 8 h, and dry it at 80 ° C for 24 h to obtain effective component A.

[0072] This embodiment discloses a method for preparing an active ingredient B, comprising the following steps:

[0073] S1: 65 g of 1-methylimidazole and 123.8 mL of chlorobutane were added to a container, argon was introduced for 1.5 hours, magnetic stirring was performed, and the reaction was performed at 85° C. for 24 hours. After the reaction was completed, the reaction was cooled and frozen for 4 hours. The upper liquid was removed and washed with toluene for 5 times, and then vacuum dried at 90° C. for 10 hours to obtain a reaction medium;

[0074] S2: 38 mL of the reaction medium was added to the container, heated to 75°C, and argon was introduced for 0.5 h. Under magnetic stirring, 3.1 g of chitosan was added, stirred and dissolved, and 2.1 g of sorbitol was added to react for 8 h. After the reaction, distilled water was used for dialysis for 3 days. The molecular weight cutoff of the dialysis bag during the dialysis process was 2000. The solid 1 was freeze-dried for 24 h to obtain solid 1;

[0075] S3: Add 36 mL of reaction medium into the container, heat to 75°C and introduce argon for 1 hour. Under magnetic stirring, add 1.2 g of solid 1, stir and dissolve, add 0.83 g of carbonyldiimidazole and react for 6 hours, then add 1.5 g of polyethyleneimine and continue to react for 5 hours. After the reaction is completed, dialyze with distilled water for 3 days. The molecular weight cutoff of the dialysis bag used in the dialysis process is 2000. Freeze-dry for 24 hours to obtain the active ingredient B.

[0076] This embodiment discloses a retarder for large temperature difference oil well cement, which is composed of the following components in parts by weight: 25 parts of effective component A, 24 parts of effective component B, and 48 parts of distilled water.

[0077] This embodiment discloses a method for preparing a retarder for large temperature difference oil well cement, comprising the following steps:

[0078] Step (1): adding active ingredient A to distilled water and stirring with ultrasonic to obtain an active ingredient A solution;

[0079] Step (2): Slowly add the active ingredient B into the active ingredient A solution, mix and stir, and obtain a retarder for large temperature difference oil well cement.

[0080] Embodiment 5: This embodiment discloses a method for preparing effective component A, comprising the following steps:

[0081] Q1: 5 mL of tetraethylenepentamine and 5.43 g of methanol were added to a container containing a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, 29.7 mL of n-hexyl methacrylate was added to the constant pressure dropping funnel, and stirred for 30 min under nitrogen and 0°C, and then n-hexyl methacrylate was added dropwise for 2 h. After the addition was completed, the temperature was raised to 45°C and the reaction was continued for 24 h. After the reaction was completed, it was distilled under reduced pressure at 65°C and 133 Pa to obtain intermediate 1;

[0082] Q2: 3.09g of intermediate product 1 and 5.05g of methanol were added to a container, and 2.49g of tetraethylenepentamine was slowly added dropwise under nitrogen and 0°C. After the addition was completed, the temperature was raised to 30°C and the reaction was continued for 24h. After the reaction was completed, the reaction was carried out under reduced pressure distillation at 65°C and 225Pa to obtain intermediate product 2;

[0083] Q3: Add 1.15 g of hydroxyethylidene diphosphonic acid and 10 mL of deionized water into a three-necked flask equipped with a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, then add 0.01 g of 1 wt% 4-dimethylaminopyridine, stir evenly, slowly add 1.27 g of intermediate 2, react at 80 ° C for 12 h to obtain a yellow liquid, dialyze it for 8 h, and dry it at 80 ° C for 24 h to obtain effective component A.

[0084] This embodiment discloses a method for preparing an active ingredient B, comprising the following steps:

[0085] S1: 70 g of 1-methylimidazole and 101.3 mL of chlorobutane were added to a container, argon was introduced for 1.5 hours, magnetic stirring was performed, and the reaction was performed at 85° C. for 24 hours. After the reaction was completed, the reaction was cooled and frozen for 4 hours. The upper liquid was removed and washed with toluene for 5 times, and then vacuum dried at 90° C. for 10 hours to obtain a reaction medium;

[0086] S2: 36 mL of the reaction medium was added to the container, heated to 75°C, and argon was introduced for 0.5 h. Under magnetic stirring, 3.3 g of chitosan was added, stirred and dissolved, and 2.2 g of sorbitol was added to react for 8 h. After the reaction, distilled water was used for dialysis for 3 days. The molecular weight cutoff of the dialysis bag during the dialysis process was 2000. The solid 1 was freeze-dried for 24 h to obtain solid 1;

[0087] S3: Add 38 mL of reaction medium into the container, heat to 75°C and introduce argon for 1 hour. Under magnetic stirring, add 1.1 g of solid 1, stir and dissolve, add 0.89 g of carbonyldiimidazole and react for 6 hours, then add 2.5 g of polyethyleneimine and continue to react for 5 hours. After the reaction is completed, dialyze with distilled water for 3 days. The molecular weight cutoff of the dialysis bag used in the dialysis process is 2000. Freeze-dry for 24 hours to obtain the active ingredient B.

[0088] This embodiment discloses a retarder for large temperature difference oil well cement, which is composed of the following components in parts by weight: 32 parts of effective component A, 29 parts of effective component B, and 56 parts of distilled water.

[0089] This embodiment discloses a method for preparing a retarder for large temperature difference oil well cement, comprising the following steps:

[0090] Step (1): adding active ingredient A to distilled water and stirring with ultrasonic to obtain an active ingredient A solution;

[0091] Step (2): Slowly add the active ingredient B into the active ingredient A solution, mix and stir, and obtain a retarder for large temperature difference oil well cement.

[0092] Comparative Example 1: Compared with Example 1, in the process of preparing active ingredient A in Comparative Example 1, n-hexyl methacrylate is not added, and other conditions remain unchanged.

[0093] Comparative Example 2: Compared with Example 1, in Comparative Example 2, during the preparation of active ingredient B, sorbitol was not added, and other conditions remained unchanged.

[0094] Comparative Example 3: Compared with Example 1, in the process of preparing the retarder for large temperature difference oil well cement in Comparative Example 3, no effective ingredient A is added, and other conditions remain unchanged.

[0095] Comparative Example 4: Compared with Example 1, in the process of preparing the retarder for large temperature difference oil well cement in Comparative Example 4, no effective ingredient B is added, and other conditions remain unchanged.

[0096] Experimental Example: The prepared sample, oil well cement, silica fume, fluid loss agent and water were mixed in a dosage ratio of 18g:600g:210g:30g:320g to obtain oil well cement. The thickening time and compressive strength of the obtained cement slurry were tested according to GB / T 19139-2012. The test results are shown in Table 1:

[0097] Table 1

[0098]

[0099] It can be seen from the test results in Table 1 that the retarder for large temperature difference oil well cement prepared in Examples 1-5 of the present invention has a good retarding effect and can also improve the compressive strength of cement. By comparing Comparative Example 1 with Examples 1-5, it can be seen that the addition of n-hexyl methacrylate can effectively improve the retarding performance of the retarder and the compressive strength of cement; by comparing Comparative Example 2 with Examples 1-5, it can be seen that the addition of sorbitol can effectively improve the retarding performance of the retarder and the compressive strength of cement; by comparing Comparative Example 3 with Examples 1-5, it can be seen that the addition of active ingredient A can effectively improve the retarding performance of the retarder and the compressive strength of cement; by comparing Comparative Example 4 with Examples 1-5, it can be seen that the addition of active ingredient B can effectively improve the retarding performance of the retarder and the compressive strength of cement.

[0100] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0101] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A retarder for large temperature difference oil well cement, characterized in that: The invention is composed of the following components in parts by weight: 20-34 parts of effective component A, 22-32 parts of effective component B, and 44-58 parts of distilled water, wherein the effective component A is prepared from tetraethylenepentamine, n-hexyl methacrylate and hydroxyethylidene diphosphonic acid, and the effective component B is prepared from 1-methylimidazole, chlorobutane, chitosan, sorbitol and polyethyleneimine; The preparation method of the effective component A comprises the following steps: Q1: Tetraethylenepentamine and methanol are added to a container containing a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, n-hexyl methacrylate is added to the constant pressure dropping funnel, stirred under nitrogen and low temperature environment, and then n-hexyl methacrylate is added dropwise. After the addition is completed, the temperature is raised to continue the reaction. After the reaction is completed, distillation is performed under reduced pressure to obtain intermediate product 1; Q2: Add the intermediate product 1 and methanol into a container, slowly drop tetraethylenepentamine under nitrogen and low temperature environment, after the dropwise addition is completed, heat up and continue the reaction, after the reaction is completed, perform reduced pressure distillation to obtain the intermediate product 2; Q3: Add hydroxyethylidene diphosphonic acid and deionized water into a three-necked flask equipped with a reflux condenser, a magnetic stirrer and a constant pressure dropping funnel, then add 4-dimethylaminopyridine, stir evenly, slowly dropwise add intermediate 2, heat to react, obtain a yellow liquid, dialyze it, and dry it to obtain effective component A; The preparation method of the active ingredient B comprises the following steps: S1: adding 1-methylimidazole and chlorobutane into a container, introducing argon gas, stirring magnetically and heating for reaction, cooling and freezing after the reaction is completed, removing the upper liquid and washing with toluene, and then vacuum drying to obtain a reaction medium; S2: adding the reaction medium to a container, heating and introducing argon, adding chitosan under magnetic stirring, stirring and dissolving, adding sorbitol to react, dialyzing and freeze-drying after the reaction, to obtain solid 1; S3: Add the reaction medium into a container, heat it, introduce argon, add solid 1 under magnetic stirring, stir and dissolve it, add carbonyldiimidazole to react, then add polyethyleneimine and continue the reaction. After the reaction is completed, dialyze and freeze-dry to obtain active ingredient B.

2. The retarder for large temperature difference oil well cement according to claim 1, characterized in that: In the Q1, the molar ratio of tetraethylenepentamine to n-hexyl methacrylate is (1-1.5): (7-10.5), the low temperature environment temperature is 0-2°C, the stirring time is 20-30min, the dropping time is 2-3h, the heating continuous reaction temperature is 30-45°C, the reaction time is 20-24h, the reduced pressure distillation temperature is 50-65°C, and the pressure is 130-150Pa.

3. The retarder for large temperature difference oil well cement according to claim 1, characterized in that: In Q2, the molar ratio of the intermediate product 1 and tetraethylenepentamine is (1-1.3): (7-9.1), the low temperature environment temperature is 0-2°C, the continuous heating reaction temperature is 20-30°C, the reaction time is 20-24h, the reduced pressure distillation temperature is 60-65°C, and the pressure is 220-230Pa.

4. The retarder for large temperature difference oil well cement according to claim 1, characterized in that: In Q3, the molar ratio of hydroxyethylidene diphosphonic acid to intermediate 2 is (7-8.4): (1-1.2), the heating reaction temperature is 70-80°C, the reaction time is 10-12h, the dialysis time is 6-8h, the drying temperature is 70-80°C, and the time is 20-24h.

5. The retarder for large temperature difference oil well cement according to claim 1, characterized in that: In the S1, the dosage ratio of 1-methylimidazole and chlorobutane is (50-75) g: (90-135) mL, the time of passing argon is 0.5-1.5 h, the heating reaction temperature is 80-85° C., the reaction time is 20-24 h, the freezing time is 2-4 h, the washing times are 3-5 times, and the vacuum drying temperature is 80-90° C. for 8-10 h.

6. The retarder for large temperature difference oil well cement according to claim 1, characterized in that: In S2, the dosage ratio of the reaction medium, chitosan and sorbitol is (35-40) mL: (3-3.4) g: (2-2.3) g, the heating temperature is 70-75° C., the argon gas introduction time is 0.5-1 h, the reaction time is 6-8 h, the molecular weight cutoff of the dialysis bag during the dialysis process is 2000, distilled water is used for dialysis for 3-4 days, and the freeze-drying time is 20-24 h.

7. The retarder for large temperature difference oil well cement according to claim 1, characterized in that: In the S3, the amount ratio of the reaction medium, solid 1, carbonyldiimidazole and polyethyleneimine is (35-40) mL: (1-1.3) g: (0.81-0.92) g: (1-3) g, the heating temperature is 70-75°C, the time for passing argon is 0.5-1 h, the reaction time is 4-6 h, the continued reaction time is 4-5 h, the molecular weight cutoff of the dialysis bag used in the dialysis process is 2000, distilled water is used for dialysis for 2-3 days, and the freeze-drying time is 20-24 h.

8. The method for preparing a retarder for large temperature difference oil well cement according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step (1): adding active ingredient A to distilled water and stirring with ultrasonic to obtain an active ingredient A solution; Step (2): Slowly add the active ingredient B into the active ingredient A solution, mix and stir, and obtain a retarder for large temperature difference oil well cement.

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