Oil well cement retarder and preparation method thereof

Abstract

The invention relates to the technical field of oil well cement retarders, in particular to an oil well cement retarder and a preparation method thereof.According to the oil well cement retarder, through mutual cooperation of retarders with different effects, the fluidity of cement paste can be effectively adjusted, early-stage coagulation can be prevented, smooth flowing of the cement paste in the pumping process is ensured, the pumping pressure can be reduced, and the pumping efficiency is improved. The construction efficiency is improved, the fault time and the downtime in the construction process are shortened, more operation time can be provided for constructors by delaying the setting time of the cement paste, it is ensured that the cement paste can fully fill and solidify the gap between the oil well casing and the stratum, the sealing performance and stability of an oil well are improved, and the construction cost is reduced. The service life of the oil well is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of oil well cement retarders, and in particular to an oil well cement retarder and a preparation method thereof. Background Art

[0002] In the process of oil extraction, oil well cement is a key material to ensure the stability and safety of the wellbore. Oil well cement is mixed with water to form cement slurry, which is then pumped downhole to fill and seal the annular space between the casing and the formation. However, under certain specific conditions, such as high temperature, high pressure or high salinity environment, the setting time of the cement slurry may be affected, resulting in construction difficulties or poor sealing effect. In order to solve these problems, retarders are usually added to oil well cement.

[0003] Traditional oil well cement retarders mostly use a single chemical component, such as lignin sulfonate, phosphate, etc., but the performance of these retarders in complex well conditions is often unsatisfactory, especially in high temperature environments, traditional retarders may quickly fail, causing cement slurry to coagulate prematurely, affecting construction quality and wellbore stability. In recent years, with the continuous advancement of oil extraction technology and increasingly stringent environmental protection requirements, higher requirements have been placed on the performance of oil well cement retarders. Ideal oil well cement retarders should have the following characteristics: First, they can maintain a stable retarding effect in complex environments such as high temperature, high pressure, and high salinity; second, they have good dispersibility and fluidity, which can ensure the smooth pumping and uniform distribution of cement slurry; third, they are environmentally friendly and non-toxic, and will not pollute the formation and the environment; fourth, the preparation process is simple and easy to industrialize.

[0004] However, most of the oil well cement retarders on the market currently cannot meet these requirements. Although some retarders have a certain retarding effect, they are easy to fail in high temperature environments; although other retarders can withstand high temperatures, their dispersibility and fluidity are poor, affecting construction efficiency; and although some retarders are environmentally friendly and non-toxic, their preparation process is complicated and the cost is high. Therefore, it is necessary to develop a new oil well cement retarder to solve the above problems. Summary of the invention

[0005] Technical issues solved

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides an oil well cement retarder and a preparation method thereof, which can effectively solve the problems of poor high temperature resistance and environmental protection of the oil well cement retarder in the prior art.

[0007] Technical Solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] An oil well cement retarder, the oil well cement retarder is composed of the following components: a zwitterionic retarder, a high temperature resistant retarder, an organic phosphonate retarder, an oxidatively modified calcium lignin sulfonate and an auxiliary component;

[0010] The zwitterionic retarder is prepared by polymerization reaction of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, dimethyldiallylammonium chloride and maleic anhydride as monomers;

[0011] The high temperature resistant retarder is prepared by reacting itaconic acid, acrylic acid and 2-acrylamide-2-methylpropane sulfonic acid as monomers and silicon carbide micropowder as an inorganic material adding component;

[0012] The organic phosphonate retarder is prepared by using diethylenetriamine as a monomer through a Mannich reaction;

[0013] The oxidatively modified calcium lignin sulfonate is obtained by oxidatively modifying calcium lignin sulfonate.

[0014] Furthermore, the preparation steps of the zwitterionic retarder are:

[0015] Step A, weigh 15g acrylamide, 18g 2-acrylamide-2-methylpropanesulfonic acid and 15g dimethyldiallylammonium chloride into a flask, add 40g deionized water under stirring, and then add sodium hydroxide solution dropwise to adjust the pH value to 7, and the result is recorded as the component to be reacted;

[0016] Step B, placing the components to be reacted in a water bath at 80°C, adding 2g of ammonium persulfate solution and 16g of maleic anhydride, and controlling the adding time to be 30min. After the adding, the mixture is stirred for 3h. After cooling to room temperature, the obtained mixture is a zwitterionic retarder.

[0017] Furthermore, the stirring speed of the stirring condition in step A is 200 r / min, the mass fraction of the sodium hydroxide solution in step A is 40%, the mass fraction of the ammonium persulfate solution in step B is 10%, and the specific operation of heat preservation and stirring in step B is stirring at a stirring speed of 300 r / min at a water bath temperature of 85°C.

[0018] Furthermore, the preparation steps of the high temperature resistant retarder are:

[0019] Step 1, weigh 2g of itaconic acid and 30g of deionized water into a flask, heat to 50°C in a water bath and stir to dissolve, then add 1g of acrylic acid, 14g of 2-acrylamide-2-methylpropanesulfonic acid and 20g of deionized water, and the result is recorded as a mixed component;

[0020] Step 2: After adjusting the pH value of the mixed components to 4, add 1g of silicon carbide powder and 0.5g of silane coupling agent KH-570, stir and react at a water bath temperature of 52°C for 30min, then raise the temperature to 65°C and add 5g of ammonium persulfate solution, and react at a constant temperature for 8h to obtain a high temperature resistant retarder.

[0021] Furthermore, the specific operation of stirring and dissolving in step 1 is stirring at a stirring speed of 500 r / min for 20 minutes, a sodium hydroxide solution with a mass fraction of 20% is used to adjust the pH value in step 2, the stirring speed of the stirring reaction in step 2 is 300 r / min, and the mass fraction of the ammonium persulfate solution in step 2 is 10%.

[0022] Furthermore, the preparation method of the organic phosphonate retarder is:

[0023] Add 45g of deionized water, 102g of phosphorous acid and 25g of concentrated sulfuric acid into a flask, stir at a stirring speed of 500r / min for 20min, then add 26g of diethylenetriamine dropwise, heat the oil bath to 105°C after the addition, and add 122g of formaldehyde dropwise at a rate of 1 drop / s. After keeping the temperature for 5h, adjust the pH value to 5 with a 30% by mass sodium hydroxide solution to obtain an organic phosphonate retarder.

[0024] Furthermore, the preparation steps of the oxidatively modified calcium lignin sulfonate are:

[0025] Step i, weigh 10g of calcium lignin sulfonate and 20g of deionized water into a flask, stir to dissolve, and then adjust the pH value to 5 with a 10% mass fraction of p-toluenesulfonic acid solution, and the result is recorded as a pretreatment component;

[0026] Step ii, heating the pretreatment component to 85° C. in an oil bath under stirring conditions, adding 1 g of hydrogen peroxide solution and keeping the mixture warm for 5 hours, then cooling to room temperature, then adding 25-30 g of anhydrous ethanol for precipitation, drying the filtered precipitate, and grinding it through a 200-mesh sieve to obtain oxidatively modified calcium lignin sulfonate.

[0027] Furthermore, the specific operation of stirring and dissolving in step i is stirring at a stirring speed of 500 r / min for 10 minutes, the stirring speed of the stirring condition in step ii is 200 r / min, and the specific operation of drying in step ii is placing in a drying oven at 45°C and drying to constant weight.

[0028] Furthermore, the auxiliary agent component is iron chromium lignin sulfonate.

[0029] A method for preparing an oil well cement retarder, the preparation method comprising:

[0030] 2-3 parts by weight of oxidatively modified calcium lignin sulfonate and 1-2 parts by weight of iron-chromium lignin sulfonate are weighed and poured into a ball mill for ball milling for 10 minutes, 10-12 parts by weight of deionized water are added and the ball milling is continued for 10 minutes, the obtained mixture is poured into 25-30 parts by weight of amphoteric ionic retarder, 18-20 parts by weight of high temperature resistant retarder and 15-16 parts by weight of organic phosphonate retarder are added at a stirring speed of 200 r / min, and stirring is continued for 10 minutes to obtain an oil well cement retarder.

[0031] Beneficial Effects

[0032] The present invention provides an oil well cement retarder and a preparation method thereof. Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The zwitterionic retarder in the present invention is a key component of the oil well cement retarder, which is prepared by polymerization reaction of acrylamide, 2-acrylamide-2-methylpropane sulfonic acid, dimethyldiallylammonium chloride and maleic anhydride, and can improve the dispersibility and stability of the retarder. It can not only maintain stable performance under different pH environments, but also effectively adjust the fluidity of cement slurry to prevent early coagulation; secondly, the high temperature resistant retarder in the present invention uses itaconic acid, acrylic acid and 2-acrylamide-2-methylpropane sulfonic acid as monomers, combined with silicon carbide powder as an inorganic material additive component, so that the prepared retarder can maintain a stable retarding effect under high temperature environment. The addition of silicon carbide powder can not only improve the heat resistance of the retarder, but also enhance its compatibility with cement slurry, so that the coagulation time of cement slurry can be effectively delayed under high temperature well conditions, ensuring the smooth pumping and solidification of cement slurry.

[0034] 2. The organic phosphonate retarder in the present invention is environmentally friendly, non-toxic and biodegradable. It can not only effectively adjust the pH value of cement slurry, but also provide a lasting retarding effect. The raw materials used in the preparation process, such as diethylenetriamine, phosphorous acid and formaldehyde, can be recycled or safely treated, which is in line with the development trend of green chemistry. Secondly, after the calcium lignin sulfonate in the present invention is oxidatively modified, its retarding performance and dispersing performance can be significantly improved. During the oxidative modification process, by adjusting the pH value, reaction temperature and stirring speed and other conditions, the structure of calcium lignin sulfonate can be optimized, so that it can better interact with the ions in the cement slurry, thereby enhancing the retarding effect. At the same time, the modified calcium lignin sulfonate also has a certain water-reducing effect, which helps to improve the fluidity of the cement slurry.

[0035] 3. The iron-chrome lignin sulfonate in the present invention, as an auxiliary component, can produce a synergistic effect with the retarder component to further improve the retarding effect and the stability of the cement slurry. Moreover, the iron-chrome lignin sulfonate has excellent dispersibility and salt resistance, and can maintain a stable retarding effect in a high-salinity environment to meet the needs under complex well conditions. The present invention can effectively adjust the fluidity of the cement slurry and prevent early coagulation by cooperating with retarders with different functions, thereby ensuring the smooth flow of the cement slurry during the pumping process, helping to reduce the pumping pressure, improve the construction efficiency, and reduce failures and downtime during the construction process. Moreover, by delaying the coagulation time of the cement slurry, it can provide more operating time for the construction personnel, ensuring that the cement slurry can fully fill and solidify the gap between the oil well casing and the formation, which helps to improve the sealing and stability of the oil well and extend the service life of the oil well. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are 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.

[0037] The present invention will be further described below in conjunction with the embodiments.

[0038] The sources of some components in the embodiments and comparative examples are as follows:

[0039] Acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, dimethyldiallylammonium chloride, ammonium persulfate, itaconic acid, acrylic acid, maleic anhydride, analytical grade, purchased from Chengdu Kelong Chemical Reagent Factory;

[0040] Silicon carbide powder, 800 mesh, Xubao Abrasive Materials Co., Ltd.;

[0041] Silane coupling agent KH-570, industrial grade, Hangzhou Jessica Chemical Co., Ltd.;

[0042] Phosphorous acid, concentrated sulfuric acid, diethylenetriamine, formaldehyde, industrial grade, Sinopharm Chemical Reagent Co., Ltd.;

[0043] Calcium lignin sulfonate, industrial grade, Jilin Yanbian Chenming Paper Co., Ltd.;

[0044] p-Toluenesulfonic acid, hydrogen peroxide, industrial grade, Chengdu Kelong Chemical Reagent Factory;

[0045] Ferrochrome lignin sulfonate, industrial grade, Henan Yuanchun Chemical Co., Ltd.;

[0046] Example 1

[0047] An oil well cement retarder of the present embodiment, the oil well cement retarder is composed of the following components: a zwitterionic retarder, a high temperature resistant retarder, an organic phosphonate retarder, an oxidatively modified calcium lignin sulfonate and an auxiliary component;

[0048] The zwitterionic retarder is prepared by polymerization reaction of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, dimethyldiallylammonium chloride and maleic anhydride as monomers, and the preparation steps are as follows:

[0049] Step A, weighing 15g acrylamide, 18g 2-acrylamide-2-methylpropanesulfonic acid and 15g dimethyldiallylammonium chloride into a flask, adding 40g deionized water under stirring at a speed of 200r / min, and then dropping a 40% sodium hydroxide solution to adjust the pH value to 7, and the resultant is recorded as the component to be reacted;

[0050] Step B, placing the components to be reacted at a water bath temperature of 80°C, adding 2g of 10% ammonium persulfate solution and 16g of maleic anhydride, and controlling the dropping time to be 30min. After the dropping is completed, stirring at a water bath temperature of 85°C at a stirring speed of 300r / min for 3h, and cooling to room temperature to obtain a zwitterionic retarder.

[0051] The high temperature resistant retarder is prepared by using itaconic acid, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid as monomers and silicon carbide micropowder as inorganic material adding components after reaction. The preparation steps are as follows:

[0052] Step 1, weigh 2 g of itaconic acid and 30 g of deionized water into a flask, heat to 50° C. in a water bath and stir at 500 r / min for 20 min, then add 1 g of acrylic acid, 14 g of 2-acrylamide-2-methylpropanesulfonic acid and 20 g of deionized water, and the result is recorded as a mixed component;

[0053] Step 2: Use 20% by mass sodium hydroxide solution to adjust the pH value of the mixed components to 4, then add 1g of silicon carbide powder and 0.5g of silane coupling agent KH-570, stir and react at a water bath temperature of 52°C at a stirring speed of 300r / min for 30min, then raise the temperature to 65°C and add 5g of 10% by mass ammonium persulfate solution, and react at a constant temperature for 8h to obtain a high temperature resistant retarder.

[0054] The organic phosphonate retarder is prepared by using diethylenetriamine as a monomer through the Mannich reaction, and the preparation method thereof is as follows:

[0055] Add 45g of deionized water, 102g of phosphorous acid and 25g of concentrated sulfuric acid into a flask, stir at a stirring speed of 500r / min for 20min, then add 26g of diethylenetriamine dropwise, heat the oil bath to 105°C after the addition, and add 122g of formaldehyde dropwise at a rate of 1 drop / s. After keeping the temperature for 5h, adjust the pH value to 5 with a 30% by mass sodium hydroxide solution to obtain an organic phosphonate retarder.

[0056] Oxidatively modified calcium lignin sulfonate is obtained by oxidatively modifying calcium lignin sulfonate, and the preparation steps are as follows:

[0057] Step i, weighing 10 g of calcium lignin sulfonate and 20 g of deionized water into a flask, stirring at a stirring speed of 500 r / min for 10 min, and then adjusting the pH value to 5 with a 10% mass fraction of p-toluenesulfonic acid solution, and the resultant is recorded as a pretreatment component;

[0058] Step ii, heating the pretreatment component to 85°C in an oil bath at a stirring speed of 200 r / min, adding 1 g of hydrogen peroxide solution to keep the reaction for 5 hours and then cooling to room temperature, then adding 25 g of anhydrous ethanol for precipitation, and drying the filtered precipitate in a drying oven at 45°C to constant weight, and grinding it through a 200-mesh sieve to obtain oxidatively modified calcium lignin sulfonate.

[0059] The auxiliary component is iron chromium lignin sulfonate.

[0060] A method for preparing an oil well cement retarder, the preparation method comprising:

[0061] Weigh 2 parts by weight of oxidatively modified calcium lignin sulfonate and 1 part by weight of iron-chromium lignin sulfonate, pour them into a ball mill and mill for 10 minutes, add 10 parts by weight of deionized water and continue milling for 10 minutes, pour the resulting mixture into 25 parts by weight of amphoteric ionic retarder, add 18 parts by weight of high temperature resistant retarder and 15 parts by weight of organic phosphonate retarder at a stirring speed of 200 r / min, continue stirring for 10 minutes to obtain an oil well cement retarder.

[0062] Example 2

[0063] An oil well cement retarder of the present embodiment, the oil well cement retarder is composed of the following components: a zwitterionic retarder, a high temperature resistant retarder, an organic phosphonate retarder, an oxidatively modified calcium lignin sulfonate and an auxiliary component;

[0064] The zwitterionic retarder is prepared by polymerization reaction of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, dimethyldiallylammonium chloride and maleic anhydride as monomers, and the preparation steps are as follows:

[0065] Step A, weighing 15g acrylamide, 18g 2-acrylamide-2-methylpropanesulfonic acid and 15g dimethyldiallylammonium chloride into a flask, adding 40g deionized water under stirring at a speed of 200r / min, and then dropping a 40% sodium hydroxide solution to adjust the pH value to 7, and the resultant is recorded as the component to be reacted;

[0066] Step B, placing the components to be reacted at a water bath temperature of 80°C, adding 2g of 10% ammonium persulfate solution and 16g of maleic anhydride, and controlling the dropping time to be 30min. After the dropping is completed, stirring at a water bath temperature of 85°C at a stirring speed of 300r / min for 3h, and cooling to room temperature to obtain a zwitterionic retarder.

[0067] The high temperature resistant retarder is prepared by using itaconic acid, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid as monomers and silicon carbide micropowder as inorganic material adding components after reaction. The preparation steps are as follows:

[0068] Step 1, weigh 2 g of itaconic acid and 30 g of deionized water into a flask, heat to 50° C. in a water bath and stir at 500 r / min for 20 min, then add 1 g of acrylic acid, 14 g of 2-acrylamide-2-methylpropanesulfonic acid and 20 g of deionized water, and the result is recorded as a mixed component;

[0069] Step 2: Use 20% by mass sodium hydroxide solution to adjust the pH value of the mixed components to 4, then add 1g of silicon carbide powder and 0.5g of silane coupling agent KH-570, stir and react at a water bath temperature of 52°C at a stirring speed of 300r / min for 30min, then raise the temperature to 65°C and add 5g of 10% by mass ammonium persulfate solution, and react at a constant temperature for 8h to obtain a high temperature resistant retarder.

[0070] The organic phosphonate retarder is prepared by using diethylenetriamine as a monomer through the Mannich reaction, and the preparation method thereof is as follows:

[0071] Add 45g of deionized water, 102g of phosphorous acid and 25g of concentrated sulfuric acid into a flask, stir at a stirring speed of 500r / min for 20min, then add 26g of diethylenetriamine dropwise, heat the oil bath to 105°C after the addition, and add 122g of formaldehyde dropwise at a rate of 1 drop / s. After keeping the temperature for 5h, adjust the pH value to 5 with a 30% by mass sodium hydroxide solution to obtain an organic phosphonate retarder.

[0072] Oxidatively modified calcium lignin sulfonate is obtained by oxidatively modifying calcium lignin sulfonate, and the preparation steps are as follows:

[0073] Step i, weighing 10 g of calcium lignin sulfonate and 20 g of deionized water into a flask, stirring at a stirring speed of 500 r / min for 10 min, and then adjusting the pH value to 5 with a 10% mass fraction of p-toluenesulfonic acid solution, and the resultant is recorded as a pretreatment component;

[0074] Step ii, heating the pretreatment component to 85°C in an oil bath at a stirring speed of 200 r / min, adding 1 g of hydrogen peroxide solution and keeping the reaction for 5 hours, then cooling to room temperature, then adding 30 g of anhydrous ethanol for precipitation, and drying the filtered precipitate in a drying oven at 45°C to constant weight, and grinding through a 200 mesh sieve to obtain oxidatively modified calcium lignin sulfonate.

[0075] The auxiliary component is iron chromium lignin sulfonate.

[0076] A method for preparing an oil well cement retarder, the preparation method comprising:

[0077] Weigh 3 parts by weight of oxidatively modified calcium lignin sulfonate and 2 parts by weight of iron-chromium lignin sulfonate, pour them into a ball mill and mill for 10 minutes, add 12 parts by weight of deionized water and continue milling for 10 minutes, pour the resulting mixture into 30 parts by weight of amphoteric ionic retarder, add 20 parts by weight of high temperature resistant retarder and 16 parts by weight of organic phosphonate retarder at a stirring speed of 200 r / min, continue stirring for 10 minutes to obtain an oil well cement retarder.

[0078] Example 3

[0079] An oil well cement retarder of the present embodiment, the oil well cement retarder is composed of the following components: a zwitterionic retarder, a high temperature resistant retarder, an organic phosphonate retarder, an oxidatively modified calcium lignin sulfonate and an auxiliary component;

[0080] The zwitterionic retarder is prepared by polymerization reaction of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, dimethyldiallylammonium chloride and maleic anhydride as monomers, and the preparation steps are as follows:

[0081] Step A, weighing 15g acrylamide, 18g 2-acrylamide-2-methylpropanesulfonic acid and 15g dimethyldiallylammonium chloride into a flask, adding 40g deionized water under stirring at a speed of 200r / min, and then dropping a 40% sodium hydroxide solution to adjust the pH value to 7, and the resultant is recorded as the component to be reacted;

[0082] Step B, placing the components to be reacted at a water bath temperature of 80°C, adding 2g of 10% ammonium persulfate solution and 16g of maleic anhydride, and controlling the dropping time to be 30min. After the dropping is completed, stirring at a water bath temperature of 85°C at a stirring speed of 300r / min for 3h, and cooling to room temperature to obtain a zwitterionic retarder.

[0083] The high temperature resistant retarder is prepared by using itaconic acid, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid as monomers and silicon carbide micropowder as inorganic material adding components after reaction. The preparation steps are as follows:

[0084] Step 1, weigh 2 g of itaconic acid and 30 g of deionized water into a flask, heat to 50° C. in a water bath and stir at 500 r / min for 20 min, then add 1 g of acrylic acid, 14 g of 2-acrylamide-2-methylpropanesulfonic acid and 20 g of deionized water, and the result is recorded as a mixed component;

[0085] Step 2: Use 20% by mass sodium hydroxide solution to adjust the pH value of the mixed components to 4, then add 1g of silicon carbide powder and 0.5g of silane coupling agent KH-570, stir and react at a water bath temperature of 52°C at a stirring speed of 300r / min for 30min, then raise the temperature to 65°C and add 5g of 10% by mass ammonium persulfate solution, and react at a constant temperature for 8h to obtain a high temperature resistant retarder.

[0086] The organic phosphonate retarder is prepared by using diethylenetriamine as a monomer through the Mannich reaction, and the preparation method thereof is as follows:

[0087] Add 45g of deionized water, 102g of phosphorous acid and 25g of concentrated sulfuric acid into a flask, stir at a stirring speed of 500r / min for 20min, then add 26g of diethylenetriamine dropwise, heat the oil bath to 105°C after the addition, and add 122g of formaldehyde dropwise at a rate of 1 drop / s. After keeping the temperature for 5h, adjust the pH value to 5 with a 30% by mass sodium hydroxide solution to obtain an organic phosphonate retarder.

[0088] Oxidatively modified calcium lignin sulfonate is obtained by oxidatively modifying calcium lignin sulfonate, and the preparation steps are as follows:

[0089] Step i, weighing 10 g of calcium lignin sulfonate and 20 g of deionized water into a flask, stirring at a stirring speed of 500 r / min for 10 min, and then adjusting the pH value to 5 with a 10% mass fraction of p-toluenesulfonic acid solution, and the resultant is recorded as a pretreatment component;

[0090] Step ii, the pretreatment component is heated to 85°C in an oil bath at a stirring speed of 200 r / min, 1 g of hydrogen peroxide solution is added and kept warm for 5 hours, then cooled to room temperature, and then 27 g of anhydrous ethanol is added for precipitation, and the filtered precipitate is placed in a drying oven at 45°C and dried to constant weight, and the obtained oxidatively modified calcium lignin sulfonate is obtained after grinding through a 200 mesh sieve.

[0091] The auxiliary component is iron chromium lignin sulfonate.

[0092] A method for preparing an oil well cement retarder, the preparation method comprising:

[0093] Weigh 2 parts by weight of oxidatively modified calcium lignin sulfonate and 2 parts by weight of iron-chromium lignin sulfonate, pour them into a ball mill and mill for 10 minutes, add 11 parts by weight of deionized water and continue milling for 10 minutes, pour the resulting mixture into 28 parts by weight of amphoteric ionic retarder, add 19 parts by weight of high temperature resistant retarder and 16 parts by weight of organic phosphonate retarder at a stirring speed of 200 r / min, continue stirring for 10 minutes to obtain an oil well cement retarder.

[0094] Comparative Example 1

[0095] The oil well cement retarder and preparation method thereof provided in this comparative example are substantially the same as those in Example 1, with the main difference being that in this comparative example, the zwitterionic retarder and high temperature resistant retarder in Example 1 are replaced with the organic phosphonate retarder in Example 1.

[0096] Comparative Example 2

[0097] The oil well cement retarder and preparation method thereof provided in this comparative example are substantially the same as those in Example 1, with the main difference being that in this comparative example, the zwitterionic retarder and the organic phosphonate retarder in Example 1 are replaced with the high temperature resistant retarder in Example 1.

[0098] Comparative Example 3

[0099] The oil well cement retarder and preparation method thereof provided in this comparative example are substantially the same as those in Example 1, with the main difference being that in this comparative example, the organic phosphonate retarder and the high temperature resistant retarder in Example 1 are replaced by the zwitterionic retarder in Example 1.

[0100] Performance Testing

[0101] The oil well cement retarders prepared in Examples 1-3 and Comparative Examples 1-3 are marked as Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3, respectively, and then the performance of Examples 1-3 and Comparative Examples 1-3 is tested, the cement slurry system includes: oil well cement of model Jiahua G grade + 35% of silica powder + 4% of fluid loss additive of model SCF200L + 0.2% of dispersant of model DZS + 5% of the oil well cement retarders prepared in Examples 1-3 and Comparative Examples 1-3, and then the thickening time and compressive strength of the cement slurry under different conditions are tested, and the obtained data are recorded in the following table;

[0102]

[0103] It can be seen from the data in the above table that the oil well cement retarders in Examples 1-3 have longer thickening time under different high temperature and pressure conditions. Compared with Comparative Examples 1-3, the oil well cement retarders in the present invention can improve the fluidity of cement, indicating that the compounding of the three retarders of zwitterionic retarder, high temperature resistant retarder and organic phosphonate retarder can achieve better retarding effect than a single type of retarder.

[0104] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0105] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An oil well cement retarder, characterized in that: The oil well cement retarder is composed of the following components: a zwitterionic retarder, a high temperature resistant retarder, an organic phosphonate retarder, an oxidatively modified calcium lignin sulfonate and an auxiliary component; The zwitterionic retarder is prepared by polymerization reaction of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, dimethyldiallylammonium chloride and maleic anhydride as monomers; The high temperature resistant retarder is prepared by reacting itaconic acid, acrylic acid and 2-acrylamide-2-methylpropane sulfonic acid as monomers and silicon carbide micropowder as an inorganic material adding component; The organic phosphonate retarder is prepared by using diethylenetriamine as a monomer through a Mannich reaction; The oxidatively modified calcium lignin sulfonate is obtained by oxidatively modifying calcium lignin sulfonate.

2. The oil well cement retarder according to claim 1, characterized in that: The preparation steps of the zwitterionic retarder are: Step A, weigh 15g acrylamide, 18g 2-acrylamide-2-methylpropanesulfonic acid and 15g dimethyldiallylammonium chloride into a flask, add 40g deionized water under stirring, and then add sodium hydroxide solution dropwise to adjust the pH value to 7, and the result is recorded as the component to be reacted; Step B, placing the components to be reacted in a water bath at 80°C, adding 2g of ammonium persulfate solution and 16g of maleic anhydride, and controlling the adding time to be 30min. After the adding, the mixture is stirred for 3h. After cooling to room temperature, the obtained mixture is a zwitterionic retarder.

3. An oil well cement retarder according to claim 2, characterized in that: The stirring speed of the stirring condition in step A is 200 r / min, the mass fraction of the sodium hydroxide solution in step A is 40%, the mass fraction of the ammonium persulfate solution in step B is 10%, and the specific operation of heat preservation and stirring in step B is stirring at a stirring speed of 300 r / min at a water bath temperature of 85°C.

4. The oil well cement retarder according to claim 1, characterized in that: The preparation steps of the high temperature resistant retarder are as follows: Step 1, weigh 2g of itaconic acid and 30g of deionized water into a flask, heat to 50°C in a water bath and stir to dissolve, then add 1g of acrylic acid, 14g of 2-acrylamide-2-methylpropanesulfonic acid and 20g of deionized water, and the result is recorded as a mixed component; Step 2: After adjusting the pH value of the mixed components to 4, add 1g of silicon carbide powder and 0.5g of silane coupling agent KH-570, stir and react at a water bath temperature of 52°C for 30min, then raise the temperature to 65°C and add 5g of ammonium persulfate solution, and react at a constant temperature for 8h to obtain a high temperature resistant retarder.

5. The oil well cement retarder according to claim 4, characterized in that: The specific operation of stirring and dissolving in step 1 is stirring at a stirring speed of 500 r / min for 20 minutes, and in step 2, a sodium hydroxide solution with a mass fraction of 20% is used to adjust the pH value, the stirring speed of the stirring reaction in step 2 is 300 r / min, and the mass fraction of the ammonium persulfate solution in step 2 is 10%.

6. The oil well cement retarder according to claim 1, characterized in that: The preparation method of the organic phosphonate retarder is: Add 45g of deionized water, 102g of phosphorous acid and 25g of concentrated sulfuric acid into a flask, stir at a stirring speed of 500r / min for 20min, then add 26g of diethylenetriamine dropwise, heat the oil bath to 105°C after the addition, and add 122g of formaldehyde dropwise at a rate of 1 drop / s. After keeping the temperature for 5h, adjust the pH value to 5 with a 30% by mass sodium hydroxide solution to obtain an organic phosphonate retarder.

7. The oil well cement retarder according to claim 1, characterized in that: The preparation steps of the oxidatively modified calcium lignin sulfonate are: Step i, weigh 10g of calcium lignin sulfonate and 20g of deionized water into a flask, stir to dissolve, and then adjust the pH value to 5 with a 10% mass fraction of p-toluenesulfonic acid solution, and the result is recorded as a pretreatment component; Step ii, heating the pretreatment component to 85° C. in an oil bath under stirring conditions, adding 1 g of hydrogen peroxide solution and keeping the mixture warm for 5 hours, then cooling to room temperature, then adding 25-30 g of anhydrous ethanol for precipitation, drying the filtered precipitate, and grinding it through a 200-mesh sieve to obtain oxidatively modified calcium lignin sulfonate.

8. The oil well cement retarder according to claim 7, characterized in that: The specific operation of stirring and dissolving in step i is stirring at a stirring speed of 500 r / min for 10 minutes, the stirring speed of the stirring condition in step ii is 200 r / min, and the specific operation of drying in step ii is placing in a drying oven at 45°C and drying to constant weight.

9. The oil well cement retarder according to claim 1, characterized in that: The auxiliary component is iron chromium lignin sulfonate.

10. The method for preparing an oil well cement retarder according to any one of claims 1 to 9, characterized in that: The preparation method is: 2-3 parts by weight of oxidatively modified calcium lignin sulfonate and 1-2 parts by weight of iron-chromium lignin sulfonate are weighed and poured into a ball mill for ball milling for 10 minutes, 10-12 parts by weight of deionized water are added and the ball milling is continued for 10 minutes, the obtained mixture is poured into 25-30 parts by weight of amphoteric ionic retarder, 18-20 parts by weight of high temperature resistant retarder and 15-16 parts by weight of organic phosphonate retarder are added at a stirring speed of 200 r / min, and stirring is continued for 10 minutes to obtain an oil well cement retarder.

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