Fluid loss agent and preparation method thereof

Abstract

The invention provides a fluid loss agent and a preparation method thereof. The preparation method comprises the following steps: mixing 20 to 25 parts by mass of 2-acrylamide-2-methylpropanesulfonic acid, 5 to 14 parts by mass of acrylamide, 10 to 20 parts by mass of p-vinylbenzoic acid, 16 to 24 parts by mass of acryloyloxyethyl dimethyl ammonium chloride and 70 to 85 parts by mass of water to obtain a mixed solution; the pH value of the mixed solution is 7.0-10.0; mixing the mixed solution with an initiator, and carrying out polymerization reaction to obtain an intermediate product; mixing the intermediate product with polyethylene glycol to obtain a mixed colloid; the molecular weight of the polyethylene glycol is 8000 to 12000 g / mol; and drying the mixed colloid to obtain the fluid loss agent. The fluid loss agent disclosed by the invention has good temperature resistance and salt resistance.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum engineering, and in particular to a fluid loss reducer and a preparation method thereof. Background Art

[0002] Deep and ultra-deep oil and gas have become an important alternative energy source, and there are more and more ultra-deep wells. The quality of the wellbore is directly related to the drilling project and the life of the oil and gas well. Cementing is the key technology to ensure the quality of the well project. Cement slurry is the core technology of cementing and an important means to ensure the sustainable and high-quality development of oil and gas field exploration and development. Although there are more and more types of high-temperature resistant cement admixtures, most of them are in liquid form. For the oil industry, the drilling areas are all in open areas in the wild. There is no liquid mixing equipment. Drilling and cementing operations are highly mobile. A set of liquid mixing equipment is very expensive, and the resettlement plot requires a certain degree of flatness. Safety management personnel must be equipped. There is a lot of cost consumption in the liquid transportation process, so there is a serious lack of powder materials.

[0003] CN109503782A provides an inorganic-organic polymer oil well cement fluid loss reducer, its preparation method and application. The method introduces nano-micron inorganic non-metallic particles into the existing organic polymer fluid loss reducer system to improve the high temperature resistance. However, the method has a complex process and high cost, which is not conducive to actual industrial application. Summary of the invention

[0004] In order to solve the above problems in the prior art, the purpose of the present invention is to provide a fluid loss agent and a preparation method thereof. The fluid loss agent of the present invention has good temperature resistance and salt resistance.

[0005] In order to achieve the above object, according to a first aspect of the present invention, a method for preparing a fluid loss additive is provided, comprising: mixing, by mass, 20 to 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 5 to 14 parts of acrylamide, 10 to 20 parts of p-vinylbenzoic acid, 16 to 24 parts of acryloyloxyethyl dimethylammonium chloride, and 70 to 85 parts of water to obtain a mixed solution; the pH value of the mixed solution is 7.0-10.0;

[0006] The mixed solution is mixed with an initiator to carry out a polymerization reaction to obtain an intermediate product;

[0007] The intermediate product is mixed with polyethylene glycol to obtain a mixed colloid; the molecular weight of the polyethylene glycol is 8000-12000 g / mol, and the amount added is 60-85 wt% of the intermediate product; preferably, the molecular weight of the polyethylene glycol is 10000 g / mol; preferably, the amount added is 75 wt% of the intermediate product;

[0008] The mixed colloid is dried to obtain the fluid loss agent.

[0009] The present invention particularly selects four suitable monomers, and under the ratio specified in the present invention, the polymer formed by polymerizing these monomers as a fluid loss reducer material has good temperature resistance and salt resistance. In addition, in the preparation method of the present invention, polyethylene glycol (PEG) molecules are introduced, and the movement of particles in the reaction system can be restricted by its volume steric effect, so that the Brownian motion displacement becomes smaller and the sedimentation speed is slowed down, which can make the fluid loss reducer of the present invention have a certain suspension stability.

[0010] The present invention particularly selects the molecular weight of the polyethylene glycol to be 8000-12000 g / mol, more preferably 10000 g / mol, as the polyethylene glycol with this molecular weight is beneficial to improving the uniformity and dispersibility of the colloid.

[0011] In some preferred embodiments of the present invention, the 2-acrylamide-2-methylpropanesulfonic acid is 23 to 25 parts by mass, the acrylamide is 8 to 14 parts by mass, and the vinylbenzoic acid is 14 to 20 parts by mass. Within the above preferred range, the fluid loss reducer of the present invention not only has good temperature resistance and salt resistance, but also has little effect on the cement thickening time.

[0012] In some preferred embodiments of the present invention, the initiator is a peroxide solution, wherein the mass concentration of the peroxide is 1-3%.

[0013] In some preferred embodiments of the present invention, the peroxide includes one or a combination of two or more of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0014] In some preferred embodiments of the present invention, the polymerization reaction is carried out at a temperature of 50 to 60° C. and for a time of 2 to 5 hours.

[0015] In some preferred embodiments of the present invention, the pH value of the mixed solution is 7-8.

[0016] In some preferred embodiments of the present invention, the method for drying the mixed colloid comprises: drying at 300-350° C. for 20-30 min.

[0017] In some preferred embodiments of the present invention, after the mixed colloid is dried, it is ground to a powder particle size of 300-350 meshes to obtain the fluid loss additive.

[0018] In some preferred embodiments of the present invention, the pH of the mixed solution is adjusted using a sodium hydroxide solution. For example, the concentration of the sodium hydroxide solution may be 0.05 mol / L, 0.1 mol / L, or 0.2 mol / L.

[0019] According to another aspect of the present invention, a fluid loss additive prepared according to the above preparation method is provided.

[0020] The application scope of the fluid loss reducer of the present invention includes application in oil wells.

[0021] Compared with the prior art, the fluid loss agent in the present invention is a solid material, which is convenient for transportation and application, and has good high temperature resistance and salt resistance. In some preferred embodiments, the fluid loss agent of the present invention can withstand high temperatures above 220°C. DETAILED DESCRIPTION

[0022] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0023] In the following embodiments and comparative examples, unless otherwise specified, all parts are parts by mass and all percentages are percentages by mass.

[0024] Example 1

[0025] This embodiment provides a fluid loss additive, and the preparation method thereof comprises:

[0026] 20 parts of 2-acrylamide-2-methylpropanesulfonic acid, 5 parts of acrylamide, 10 parts of p-vinylbenzoic acid, and 15 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added into 70 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution;

[0027] At 50°C and under stirring, 1.5% ammonium persulfate solution was slowly added dropwise to the mixed solution to carry out polymerization reaction for 3 hours to obtain an intermediate product;

[0028] After cooling, 10000 g / mol of PEG accounting for 75% of the mass ratio of the intermediate product was added to obtain a mixed colloid;

[0029] The mixed colloid was dried in a microwave dryer at 300° C. for 0.5 h, and the solid formed by grinding was a 300-mesh powder material.

[0030] To evaluate performance:

[0031] The cement-based slurry used was: 500g of G-grade cement + 300g of quartz sand + 336g of distilled water (BWOC) + 1.6g of GWX-1L (produced by Great Wall Drilling and Cementing Company, an oil well cement defoaming agent) as the blank control group.

[0032] 32 g of the liquid fluid loss additive (i.e., mixed colloid, the same below) prepared in this example was added to the above cement-based slurry to form Experimental Group 1.

[0033] The distilled water in the cement-based slurry was replaced with 18% sodium salt water, and 32 g of the liquid fluid loss additive prepared in this example was added to form Experimental Group 2.

[0034] 4.8 g of the powdered fluid loss additive prepared in this example was added to the above cement-based slurry to form Experimental Group 3.

[0035] The distilled water in the cement-based slurry was replaced with 18% sodium salt water, and 4.8 g of the powdered fluid loss additive prepared in this example was added to form Experimental Group 4.

[0036] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were recorded and entered into Table 1.

[0037] Table 1

[0038] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 100 150 Experimental Group 2 126 146 Experimental Group 3 110 128 Experimental Group 4 107 160

[0039] As can be seen from Table 1, the liquid and powder fluid loss reducers prepared by this method have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0040] Example 2

[0041] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0042] 21 parts of 2-acrylamide-2-methylpropanesulfonic acid, 6 parts of acrylamide, 10 parts of p-vinylbenzoic acid and 12 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 75 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0043] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0044] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were recorded and included in Table 2.

[0045] Table 2

[0046] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 111 102 Experimental Group 2 114 110 Experimental Group 3 110 106 Experimental Group 4 107 110

[0047] It can be seen from Table 2 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0048] Example 3

[0049] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0050] 22 parts of 2-acrylamide-2-methylpropanesulfonic acid, 7 parts of acrylamide, 12 parts of p-vinylbenzoic acid and 14 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0051] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0052] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 3.

[0053] Table 3

[0054]

[0055] It can be seen from Table 3 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0056] Example 4

[0057] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0058] 23 parts of 2-acrylamide-2-methylpropanesulfonic acid, 8 parts of acrylamide, 14 parts of p-vinylbenzoic acid and 16 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water and the pH value was adjusted to 8.0 with NaOH solution to obtain a mixed solution.

[0059] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0060] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were recorded and included in Table 4.

[0061] Table 4

[0062] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 115 90 Experimental Group 2 114 102 Experimental Group 3 109 98 Experimental Group 4 111 108

[0063] It can be seen from Table 4 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0064] Example 5

[0065] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0066] 23.5 parts of 2-acrylamide-2-methylpropanesulfonic acid, 8.5 parts of acrylamide, 14 parts of p-vinylbenzoic acid and 18 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 70 parts of water and the pH value was adjusted to 7.5 with NaOH solution to obtain a mixed solution.

[0067] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0068] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 5.

[0069] Table 5

[0070] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 115 86 Experimental Group 2 114 104 Experimental Group 3 109 104 Experimental Group 4 111 102

[0071] It can be seen from Table 5 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0072] Example 6

[0073] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0074] 24 parts of 2-acrylamide-2-methylpropanesulfonic acid, 9 parts of acrylamide, 14 parts of p-vinylbenzoic acid and 18 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added into 70 parts of water and the pH value was adjusted to 7.5 with NaOH solution to obtain a mixed solution.

[0075] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0076] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 6.

[0077] Table 6

[0078] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 110 86 Experimental Group 2 108 94 Experimental Group 3 112 88 Experimental Group 4 115 92

[0079] It can be seen from Table 6 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0080] Example 7

[0081] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0082] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 10 parts of acrylamide, 16 parts of p-vinylbenzoic acid and 20 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 70 parts of water, and the pH value was adjusted to 7.5 with NaOH solution to obtain a mixed solution.

[0083] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0084] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 7.

[0085] Table 7

[0086] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 110 80 Experimental Group 2 108 90 Experimental Group 3 112 80 Experimental Group 4 115 88

[0087] It can be seen from Table 7 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0088] Example 8

[0089] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0090] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, 18 parts of p-vinylbenzoic acid and 22 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 70 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0091] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0092] The experiment was carried out at 240 degrees Celsius and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 8.

[0093] Table 8

[0094] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 110 72 Experimental Group 2 108 72 Experimental Group 3 112 70 Experimental Group 4 115 68

[0095] It can be seen from Table 8 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0096] Example 9

[0097] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0098] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, 20 parts of p-vinylbenzoic acid and 24 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0099] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0100] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 9.

[0101] Table 9

[0102] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 110 50 Experimental Group 2 108 62 Experimental Group 3 112 62 Experimental Group 4 115 50

[0103] It can be seen from Table 9 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0104] Example 10

[0105] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0106] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, 20 parts of p-vinylbenzoic acid and 24 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 75 parts of water, and the pH value was adjusted to 7.5 with NaOH solution to obtain a mixed solution.

[0107] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0108] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 10.

[0109] Table 10

[0110] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 110 46 Experimental Group 2 108 50 Experimental Group 3 112 50 Experimental Group 4 115 48

[0111] It can be seen from Table 10 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0112] Embodiment 11

[0113] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0114] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, 20 parts of p-vinylbenzoic acid and 24 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 85 parts of water, and the pH value was adjusted to 8.0 with NaOH solution to obtain a mixed solution.

[0115] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0116] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 11.

[0117] Table 11

[0118] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 110 36 Experimental Group 2 108 38 Experimental Group 3 112 40 Experimental Group 4 115 36

[0119] It can be seen from Table 11 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, and have little effect on the thickening time of cement.

[0120] Example 12

[0121] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0122] 30 parts of 2-acrylamide-2-methylpropanesulfonic acid, 10 parts of acrylamide, 4 parts of p-vinylbenzoic acid and 10 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0123] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0124] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 12.

[0125] Table 12

[0126] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 96 140 Experimental Group 2 86 158 Experimental Group 3 72 160 Experimental Group 4 60 158

[0127] It can be seen from Table 12 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, but affect the cement thickening time.

[0128] Embodiment 13

[0129] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0130] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 10 parts of acrylamide, 5 parts of p-vinylbenzoic acid and 15 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0131] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0132] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 13.

[0133] Table 13

[0134] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 92 152 Experimental Group 2 75 142 Experimental Group 3 75 130 Experimental Group 4 75 150

[0135] It can be seen from Table 13 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, but affect the cement thickening time.

[0136] Embodiment 14

[0137] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0138] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 10 parts of acrylamide, 5 parts of p-vinylbenzoic acid and 15 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 70 parts of water, and the pH value was adjusted to 8.0 with NaOH solution to obtain a mixed solution.

[0139] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0140] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 14.

[0141] Table 14

[0142] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 96 152 Experimental Group 2 86 142 Experimental Group 3 72 168 Experimental Group 4 60 180

[0143] It can be seen from Table 14 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, which affect the cement thickening time.

[0144] Embodiment 15

[0145] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0146] 20 parts of 2-acrylamide-2-methylpropanesulfonic acid, 5 parts of acrylamide, 10 parts of p-vinylbenzoic acid and 15 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 70 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0147] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0148] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 15.

[0149] Table 15

[0150] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 110 150 Experimental Group 2 91 146 Experimental Group 3 96 128 Experimental Group 4 42 160

[0151] It can be seen from Table 15 that the liquid and powder fluid loss additives have both temperature resistance and salt resistance, which affect the cement thickening time.

[0152] Comparative Example 1

[0153] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0154] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 8 parts of acrylamide, 4 parts of p-vinylbenzoic acid and 10 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 75 parts of water, and the pH value was adjusted to 8.0 with NaOH solution.

[0155] When the experimental group was prepared according to the performance evaluation method in Example 1, it was found that the slurry prepared in this comparative example could not be poured into the slurry cup of the viscometer, and the evaluation experiment could not be carried out, and the retarder was incompatible with the cement.

[0156] Comparative Example 2

[0157] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0158] 30 parts of 2-acrylamide-2-methylpropanesulfonic acid, 10 parts of acrylamide, 4 parts of p-vinylbenzoic acid and 10 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 75 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0159] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0160] The experiment was carried out at 240 degrees Celsius and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and included in Table 16.

[0161] Table 16

[0162] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 120 146 Experimental Group 2 ---- -------- Experimental Group 3 93 170 Experimental Group 4 ---- --------

[0163] It can be seen from Table 16 that the liquid and powder fluid loss additives have temperature resistance but no salt resistance, which affects the cement thickening time.

[0164] Comparative Example 3

[0165] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0166] 35 parts of 2-acrylamide-2-methylpropanesulfonic acid, 15 parts of acrylamide, 4 parts of p-vinylbenzoic acid and 10 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 75 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0167] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0168] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 17.

[0169] Table 17

[0170] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 100 120 Experimental Group 2 ---- -------- Experimental Group 3 86 150 Experimental Group 4 ---- --------

[0171] It can be seen from Table 17 that the liquid and powder fluid loss additives have temperature resistance but no salt resistance, which affects the cement thickening time.

[0172] Comparative Example 4

[0173] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0174] 40 parts of 2-acrylamide-2-methylpropanesulfonic acid, 20 parts of acrylamide, 5 parts of p-vinylbenzoic acid and 10 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water, and the pH value was adjusted to 7.0 with NaOH solution to obtain a mixed solution.

[0175] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0176] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 18.

[0177] Table 18

[0178] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 86 140 Experimental Group 2 ---- -------- Experimental Group 3 85 160 Experimental Group 4 ---- --------

[0179] It can be seen from Table 18 that the liquid and powder fluid loss additives have temperature resistance but no salt resistance, which affects the cement thickening time.

[0180] Comparative Example 5

[0181] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0182] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, 10 parts of itaconic acid and 24 parts of pyrrolidone were added to 85 parts of water, and the pH value was adjusted to 7.0 with a NaOH solution to obtain a mixed solution.

[0183] When the performance evaluation was conducted, the corresponding test could not be conducted because the product was too dense. It can be seen that the product obtained in this comparative example could not adapt to the construction conditions and the fluid loss reducer in this comparative example had no ability to control water loss.

[0184] Comparative Example 6

[0185] The only difference from Example 1 is the composition of the mixed solution, specifically:

[0186] Take 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, and 10 parts of itaconic acid; adjust the pH value to 8.0 with a NaOH solution to obtain a mixed solution.

[0187] When the performance evaluation was conducted, the corresponding test could not be conducted because the product was too dense. It can be seen that the product obtained in this comparative example could not adapt to the construction conditions and the fluid loss reducer in this comparative example had no ability to control water loss.

[0188] Comparative Example 7

[0189] This comparative example provides a fluid loss additive, and its preparation method comprises:

[0190] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, 20 parts of p-vinylbenzoic acid and 24 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water, and the pH value of the mixed solution was adjusted to 7.0 with a NaOH solution to obtain a mixed solution.

[0191] At 50°C and under stirring, 1.5% ammonium persulfate solution was slowly added dropwise to the mixed solution to carry out polymerization reaction for 3 hours to obtain an intermediate product;

[0192] After cooling, adding 5000 g / mol of PEG, which accounts for 75% of the mass percentage of the intermediate product, to obtain a mixed colloid;

[0193] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0194] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 19.

[0195] Table 19

[0196] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 46 80 Experimental Group 2 58 88 Experimental Group 3 75 120 Experimental Group 4 172 98

[0197] It can be seen from Table 19 that the water loss reducing agent prepared by this method has poor water loss control ability.

[0198] Comparative Example 8

[0199] This comparative example provides a fluid loss additive, and its preparation method comprises:

[0200] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, 20 parts of p-vinylbenzoic acid and 24 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water, and the pH value of the mixed solution was adjusted to 7.0 with a NaOH solution to obtain a mixed solution.

[0201] At 50°C, 1.5% ammonium persulfate solution was slowly added dropwise to the mixed solution under stirring conditions to carry out polymerization reaction for 3 h;

[0202] After cooling, 15000 g / mol of PEG accounting for 75% of the mass ratio of the intermediate product was added to obtain a mixed colloid;

[0203] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0204] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 20.

[0205] Table 20

[0206] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 138 -------- Experimental Group 2 126 -------- Experimental Group 3 118 -------- Experimental Group 4 125 --------

[0207] It can be seen from Table 20 that the fluid loss reducer has no ability to control water loss.

[0208] Comparative Example 9

[0209] This comparative example provides a fluid loss additive, and its preparation method comprises:

[0210] 25 parts of 2-acrylamide-2-methylpropanesulfonic acid, 14 parts of acrylamide, 20 parts of p-vinylbenzoic acid and 24 parts of acryloyloxyethyl dimethylbenzyl ammonium chloride were added to 80 parts of water, and the pH value of the mixed solution was adjusted to 7.0 with a NaOH solution to obtain a mixed solution.

[0211] At 50°C and under stirring, a 1.5% ammonium persulfate solution was slowly added dropwise to the mixed solution to carry out polymerization reaction for 3 hours to obtain a polymer;

[0212] The solid was dried in a microwave dryer at 300°C for 0.5 h and ground into a 300-mesh powder material.

[0213] The method for performing performance evaluation and configuring the blank control group and experimental groups 1 to 4 was the same as in Example 1.

[0214] The experiment was carried out at 240°C and 120 mPa in accordance with Chapter 4 of SY / 5546-92. The thickening time was recorded, and the 48-hour strength test values ​​were also recorded and entered into Table 21.

[0215] Table 21

[0216] Thickening time (minutes) Water loss (mL / 30min) Blank control group 116 -------- Experimental Group 1 180 -------- Experimental Group 2 120 -------- Experimental Group 3 119 -------- Experimental Group 4 141 --------

[0217] It can be seen from Table 21 that the fluid loss reducer has no ability to control water loss.

[0218] In general, it can be seen from Comparative Examples 1-4 that the fluid loss reducers prepared according to the preparation methods therein have neither temperature resistance nor salt resistance, because the polymers prepared therefrom cannot fully bind water molecules. The fluid loss reducers of Comparative Examples 5 to 6 have poor water loss control capabilities. The fluid loss reducers of Comparative Examples 7 to 9 have no water loss control capabilities.

[0219] The fluid loss reducers of Examples 1 to 11 have both temperature resistance and salt resistance, and do not have a significant impact on the thickening time. The fluid loss reducers prepared according to the preparation methods of Examples 12 to 19 have both temperature resistance and salt resistance, but affect the thickening time. This is because the polymers therein lock water in a flocculation or coagulation manner, so they have a greater impact on the thickening time.

Claims

1. A method for preparing a fluid loss additive, characterized in that: include: Mix 20 to 25 parts by mass of 2-acrylamide-2-methylpropanesulfonic acid, 5 to 14 parts of acrylamide, 10 to 20 parts of p-vinylbenzoic acid, 16 to 24 parts of acryloyloxyethyl dimethylammonium chloride, and 70 to 85 parts of water to obtain a mixed solution; the pH value of the mixed solution is 7.0-10.0; The mixed solution is mixed with an initiator to carry out a polymerization reaction to obtain an intermediate product; The intermediate product is mixed with polyethylene glycol to obtain a mixed colloid; the molecular weight of the polyethylene glycol is 8000 to 12000 g / mol, and the amount added is 60 to 85 wt% of the intermediate product; The mixed colloid is dried to obtain the fluid loss agent.

2. The preparation method according to claim 1, characterized in that: The 2-acrylamide-2-methylpropanesulfonic acid is present in an amount of 23 to 25 parts by mass, the acrylamide is present in an amount of 8 to 14 parts by mass, and the vinylbenzoic acid is present in an amount of 14 to 20 parts by mass.

3. The preparation method according to claim 1, characterized in that: The initiator is a peroxide solution, wherein the mass concentration of the peroxide is 1-3%.

4. The preparation method according to claim 3, characterized in that: The peroxide includes one or a combination of two or more of ammonium persulfate, potassium persulfate, and sodium persulfate.

5. The preparation method according to claim 1, characterized in that: The polymerization reaction temperature is 50-60° C. and the reaction time is 2-5 hours.

6. The preparation method according to claim 1, characterized in that: The pH value of the mixed solution is 7-8.

7. The preparation method according to claim 1, characterized in that: The method for drying the mixed colloid comprises: drying at 300-350° C. for 20-30 minutes.

8. The preparation method according to claim 1 or 7, characterized in that: After the mixed colloid is dried, it is ground to a powder particle size of 300-350 meshes to obtain the fluid loss reducer.

9. The preparation method according to claim 1 or 6, characterized in that: The pH of the mixed solution was adjusted using sodium hydroxide solution.

10. A fluid loss agent, characterized in that: The fluid loss additive is prepared according to the preparation method according to any one of claims 1 to 9.

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