Polymers and methods for making the same, set retarders, and oil well cement slurries

Abstract

The application relates to the field of petroleum drilling aids, in particular to a polymer and a preparation method thereof, a retarder and an oil well cement slurry. The polymer comprises a hydrophilic main chain and end-capping structures at both ends of the hydrophilic main chain; the hydrophilic main chain contains structural unit A, structural unit B and structural unit C; the molar ratio of the structural unit A, the structural unit B and the structural unit C is 10:(0.5-8):(0.1-4); the polymer chain segment in the end-capping structure contains structural unit D and structural unit E, and the molar ratio of the structural unit D and the structural unit E is 1:(0.5-5). The polymer is applied to long cementing section cementing as a retarder component, can accelerate the strength development of the top cement slurry under the premise of guaranteeing the retarding effect of the oil well cement slurry, has little influence on the water loss of the oil well cement slurry, is beneficial to cement slurry formula design, construction safety and cost saving of well construction.

Description

Technical Field

[0001] This invention relates to the field of oil drilling additives, specifically to a polymer and its preparation method, a retarder, and an oil well cement slurry. Background Technology

[0002] Cementing is the process of pumping cement slurry into the annulus between the casing and the formation according to design requirements. After solidification, it isolates, supports, and protects the casing from inter-layer fluids. Cementing quality directly affects reservoir oil and gas production and the lifespan of oil and gas wells. With the depletion of shallow oil and gas resources, exploration targets have shifted to deeper and ultra-deep formations. Because deep and ultra-deep wells face more complex geological structures, more casing layers, and higher well construction costs, a common approach to more efficient and cost-effectively develop deep oil and gas resources is to reduce the number of casing layers. However, this inevitably leads to an increase in the length of cement slurry deposited at one time. To achieve the required pumping time in the cementing design, a certain amount of oil well cement retarder needs to be added to ensure good fluidity of the cement before it is fully displaced. Generally, within the applicable temperature range of retarder, if the same thickening time is achieved, the amount of retarder added increases with increasing temperature. However, due to the influence of the downhole geothermal gradient, the bottom hole temperature increases with increasing well depth. The test temperature (i.e., circulation temperature) for testing thickening time is generally taken as 0.75-0.9 times the bottom hole static temperature. As a result, after the cement slurry is pumped into place, the static temperature of the top cement slurry (30-90℃) is much lower than the circulation temperature during the thickening time test. This leads to the top cement slurry exhibiting over-retarded setting or prolonged non-solidification, severely affecting cementing quality and well construction cycle. If a gas layer exists in the top layer being sealed, it may lead to sealing failure, and in severe cases, a blowout. Below 110℃, existing retarder generally meets the construction requirements, but above 110℃, the prepared cement slurry is prone to over-retarded setting.

[0003] Therefore, there is an urgent need to develop a cement retarder suitable for cementing long sealing sections at temperatures above 110℃, to shorten the setting time of cement slurry at the top of long sealing sections, and to solve the problem of excessively slow setting or long-term non-setting of cement slurry at the top of long sealing sections, so as to meet the cementing construction needs of deep and ultra-deep wells with long sealing sections. Summary of the Invention

[0004] This invention addresses the problems of excessively slow setting and slow strength development of top well cement slurry in long cementing sections using existing retarders, as well as the problem that existing retarders easily damage the water loss performance of oil well cement slurry. It provides a polymer and its preparation method, a retarder, and an oil well cement slurry.

[0005] To achieve the above objectives, a first aspect of the present invention provides a polymer comprising a hydrophilic backbone and end-capping structures at both ends of the hydrophilic backbone; wherein,

[0006] The hydrophilic backbone contains structural unit A, structural unit B and structural unit C;

[0007] Structural unit A has the structure shown in equation (1); structural unit B has the structure shown in equation (2); structural unit C has the structure shown in equation (3);

[0008]

[0009] Among them, R1, R2, R3, R4, and R5 are each independently selected from -H or C. 1- C2 alkyl group; R6 is selected from C1-C3 alkylene group; Z is selected from H + K + Na + or NH4 + R7, R8, R9, R 10 Each is independently selected from -H, -CH3, and -COOM. 1 or -CH2COOM 2 And R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; where M 1 M 2 Each independently selected from H + K + Na + or NH4 + ;R 11 R 12 R 13 R 14 R 15 Each is independently selected from -H or C. 1- C2 alkyl group;

[0010] The molar ratio of structural unit A: structural unit B: structural unit C is 10:(0.5-8):(0.1-4);

[0011] The end cap structure has the structure shown in formula (4);

[0012]

[0013] Wherein, Q1, Q2 and Q3 are polymer chain segments, and each of Q1, Q2 and Q3 independently contains structural unit D and structural unit E; wherein, the structural unit D has the structure shown in formula (5); the structural unit E has the structure shown in formula (6);

[0014]

[0015] Among them, R 16 R17 R 18 R 19 R 20 R 21 R 22 R 23 Each can be independently selected from -H or -CH3;

[0016] The molar ratio of structural unit D to structural unit E is 1:(0.5-5).

[0017] A second aspect of the present invention provides a method for preparing a polymer, comprising: performing a polymerization reaction on monomers A', B', C' and initiator G in the presence of a first solvent to obtain a polymer;

[0018] Wherein, monomer A' has the structure shown in formula (7); monomer B' has the structure shown in formula (8); and monomer C' has the structure shown in formula (9).

[0019]

[0020] Among them, R1, R2, R3, R4, and R5 are each independently selected from -H or C. 1- C2 alkyl group; R6 is selected from C1-C3 alkylene group; Z is selected from H + K + Na + or NH4 + R7, R8, R9, R 10 Each is independently selected from -H, -CH3, and -COOM. 1 or -CH2COOM 2 And R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; where M 1 M 2 Each independently selected from H + K + Na + or NH4 + ;R 11 R 12 R 13 R 14 R 15 Each is independently selected from -H or C. 1- C2 alkyl group;

[0021] The initiator G has the structure shown in formula (10);

[0022]

[0023] Wherein, Q1, Q2, Q3, Q4, Q5, and Q6 are polymer chain segments, and each of Q1, Q2, Q3, Q4, Q5, and Q6 independently contains structural unit D and structural unit E; wherein, the structural unit D has the structure shown in formula (11); and the structural unit E has the structure shown in formula (12);

[0024]

[0025] Among them, R 16 R 17 R 18 R 19 R 20 R 21 R 22 R 23 Each can be independently selected from -H or -CH3;

[0026] The molar ratio of structural unit D to structural unit E is 1:(0.5-5);

[0027] The molar ratio of monomer A': monomer B': monomer C': initiator G is 10:(0.5-8):(0.1-4):(0.5-2).

[0028] The third aspect of the present invention provides a polymer prepared by the preparation method described in the second aspect above.

[0029] A fourth aspect of the present invention provides a retarder, comprising: a main polymer and a cosolvent;

[0030] The weight ratio of the main polymer to the cosolvent is 10:(0.4-2);

[0031] The main polymer is the polymer described in the first or third aspect.

[0032] The fifth aspect of the present invention provides an oil well cement slurry containing the retarder described in the fourth aspect above.

[0033] Through the above technical solution, the present invention has the following beneficial effects:

[0034] (1) The polymer provided by the present invention adopts a main chain containing sulfonic acid group, amide group and carboxyl group. These hydrophilic groups provide the polymer with excellent water solubility and ion complexing ability. The end cap structure at both ends of the main chain has multiple branches, thereby forming a polymer structure with temperature-sensitive water solubility. This polymer has excellent ability to promote the setting of cement slurry at high temperature. As the temperature decreases, the setting ability weakens. Using this polymer as the main component of the retarder can accelerate the strength development of the oil well cement slurry at the top of the long cementing section, and achieve a compressive strength of more than 7MPa for the top cement slurry at 80℃ for 48 hours.

[0035] (2) The polymer provided by the present invention has good compatibility through the design of main chain and end cap structure. It will not compete with polymer-based water loss reducing agents in oil well cement slurry for adsorption. It has little impact on the water loss of oil well cement slurry, which is conducive to cement slurry formulation design and field application. Attached Figure Description

[0036] Figure 1 The infrared spectrum of polymer P1 prepared in Example 1 of the present invention.

[0037] Figure 2 The thickening curve of experimental oil well cement slurry using the retarder S1 (containing the polymer prepared in Example 1) provided by the present invention is shown at 125°C.

[0038] Figure 3 The compressive strength development curve of experimental oil well cement slurry using the retarder S1 (containing the polymer prepared in Example 1) provided by the present invention is shown at 80°C.

[0039] Figure 4 The compressive strength development curve of experimental oil well cement slurry using the retarder S1 (containing the polymer prepared in Example 1) provided by the present invention is shown at 30°C.

[0040] Figure 5 The thickening curve of the experimental oil well cement slurry using retarder DS1 (containing the polymer prepared in Comparative Example 1) at 125°C is shown.

[0041] Figure 6 The compressive strength development curve of experimental oil well cement slurry using retarder DS1 (containing the polymer prepared in Comparative Example 1) at 80°C is shown. Detailed Implementation

[0042] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0043] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0044] A first aspect of the present invention provides a polymer comprising a hydrophilic backbone and end-capping structures at both ends of the hydrophilic backbone; wherein,

[0045] The hydrophilic backbone contains structural unit A, structural unit B and structural unit C;

[0046] Structural unit A has the structure shown in equation (1); structural unit B has the structure shown in equation (2); structural unit C has the structure shown in equation (3);

[0047]

[0048] Among them, R1, R2, R3, R4, and R5 are each independently selected from -H or C. 1- C2 alkyl group; R6 is selected from C1-C3 alkylene group; Z is selected from H + K + Na + or NH4 + R7, R8, R9, R 10 Each is independently selected from -H, -CH3, and -COOM. 1 or -CH2COOM 2 And R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; where M 1 M 2 Each independently selected from H + K + Na + or NH4 + ;R 11 R 12 R 13 R 14 R 15 Each is independently selected from -H or C. 1- C2 alkyl group;

[0049] The molar ratio of structural unit A: structural unit B: structural unit C is 10:(0.5-8):(0.1-4);

[0050] The end cap structure has the structure shown in formula (4);

[0051]

[0052] Wherein, Q1, Q2 and Q3 are polymer chain segments, and each of Q1, Q2 and Q3 independently contains structural unit D and structural unit E; wherein, the structural unit D has the structure shown in formula (5); the structural unit E has the structure shown in formula (6);

[0053]

[0054] Among them, R 16 R 17 R18 R 19 R 20 R 21 R 22 R 23 Each can be independently selected from -H or -CH3;

[0055] The molar ratio of structural unit D to structural unit E is 1:(0.5-5).

[0056] According to the present invention, the hydrophilic backbone of the polymer contains specific structural units A, B, and C, wherein structural unit A contains sulfonic acid groups, structural unit B contains carboxyl groups, and structural unit C contains amide groups. Under the combined action of the hydrophilic sulfonic acid groups, carboxyl groups, and amide groups, the backbone exhibits excellent water solubility and ion complexing ability, which is beneficial to improving the polymer's retarding ability in oil well cement slurry and reducing damage to the water loss performance of oil well cement slurry.

[0057] According to the present invention, in the structural unit A of the hydrophilic backbone, preferably, R1, R2, R3, R4, and R5 are each independently selected from -H or -CH3; R6 is -CH2-, which is more conducive to improving the stability of the polymer molecular structure and improving the chemical stability of the polymer under the high temperature and high alkalinity conditions of oil well cement slurry.

[0058] According to the present invention, in the structural unit B of the hydrophilic main chain, R7, R8, R9, and R 10 Meeting the above-mentioned limits is beneficial to improving the polymer's adsorption and complexation capacity for calcium ions, cement particles and hydration products in oil well cement slurry.

[0059] According to the present invention, in the structural unit C of the hydrophilic backbone, preferably, R 11 R 12 R 13 R 14 R 15 Each component is independently selected from -H or -CH3, which is more conducive to increasing the liquid phase viscosity of the polymer in the oil well cement slurry and assisting in reducing water loss performance. It also reduces the competitive adsorption between the polymer and the water loss reducing agent in the oil well cement slurry, thereby reducing the damage to the water loss performance of the oil well cement slurry.

[0060] According to the present invention, in addition to satisfying the above-mentioned proportions, the structural unit A, structural unit B and structural unit C in the hydrophilic main chain preferably have a molar ratio of 10:(1-6):(1-3) for structural unit A:structural unit B:structural unit C, which can further balance the effects of the polymer on the retarding performance of oil well cement slurry and on the water loss performance of oil well cement slurry.

[0061] According to the present invention, the main chain of the polymer has specific end-capping structures at both ends, as shown in formula (4). In the end-capping structure, a benzene ring is located at one end adjacent to the main chain, and the carbon atoms at positions 3, 4 and 5 of the benzene ring are connected to the side chains by ether bonds (see the structural units shown in formula (5) and (6) for the position of the ether bonds). The side chains contain polymer chain segments Q1, Q2 or Q3 respectively, and hydroxyl groups are connected to the carbon atoms at the ends of the side chains. With such a structural design, the end-capping structure can have temperature-sensitive characteristics, so that the polymer can exhibit different conformations in water with temperature changes, and thus exhibit different degrees of retarding performance. Specifically, it can have excellent retarding performance under high temperature conditions (e.g., the bottom of a long cementing section well), delaying the thickening of the well cement slurry at the bottom, and can have relatively reduced retarding performance under relatively low temperature conditions (e.g., the top of a long cementing section well), promoting the development of the strength of the top cement slurry.

[0062] According to the present invention, in the end-capping structure of the polymer, polymer segments Q1, Q2 and Q3 are independent of each other, and may be the same or different, but preferably the same.

[0063] According to the present invention, in the polymer segments Q1, Q2, and Q3, structural units D and E together form an amphiphilic thermosensitive polyether segment, thereby giving the polymer thermosensitive properties. Preferably, the molar ratio of structural unit D to structural unit E is 1:(1-3).

[0064] According to the present invention, in the structural unit D, preferably, R 16 R 17 R 18 and R 19 The -H designation enhances the hydrophilicity of the structural unit D, providing a hydrophilic segment within the amphiphilic thermosensitive polyether segment.

[0065] According to the present invention, in the structural unit E, preferably, R 20 R 21 and R 22 -H, R 23 The -CH3 group imparts a certain degree of hydrophobicity to the structural unit E, providing a hydrophobic segment in the amphiphilic thermosensitive polyether chain.

[0066] According to the present invention, the end-capping structures at both ends of the polymer main chain are independent of each other and can be the same or different, as long as they satisfy the structure shown in formula (4). Preferably, the end-capping structures at both ends of the polymer main chain are the same.

[0067] According to the present invention, in formula (4), This indicates the connection position between the end cap structure and the hydrophilic backbone.

[0068] According to the present invention, the weight-average molecular weight of the polymer is (10-80)×10 4 g / mol, preferably (30-60)×10 4 g / mol.

[0069] The polymer provided by this invention has a specific hydrophilic backbone and multi-branched end-capped structure. The hydrophilic backbone contains sulfonic acid groups, amide groups, and carboxyl groups in its structural units, endowing the backbone with excellent water solubility and superior ion-complexing ability. The end-capped structure has multiple branches, and the hydrophilic backbone and end-capped structure together form a thermosensitive, water-soluble amphiphilic polymer structure, resulting in different molecular conformations of the polymer at different temperatures. As the ambient temperature increases, the solubility of the multi-branched chains at both ends of the polymer decreases, exposing the middle linear segments. Under these conditions, the polymer exhibits excellent retarding ability for oil well cement slurry. Conversely, as the ambient temperature decreases, the solubility of the multi-branched chains at both ends of the polymer increases, encapsulating the middle linear segments. This reduces the polymer's complexing ability and weakens its retarding ability, which is beneficial for the strength development of the oil well cement slurry. Using the polymer provided by this invention as the main component of the retarder, in long cementing sections, it can accelerate the strength development of the top cement slurry while ensuring the retarding effect of the oil well cement slurry under the circulating temperature conditions. Specifically, it enables the top cement slurry to solidify rapidly at temperatures below the circulating temperature, achieving a compressive strength of over 7 MPa after 48 hours at 80°C. Furthermore, conventional polymer-based retarders and polymer-based fluid loss reducers compete for adsorption in cement slurry, often resulting in excessive fluid loss and jeopardizing construction safety. The polymer provided by this invention, through its main chain functional groups and end-cap structure design, does not compete for adsorption with polymer-based fluid loss reducers in the oil well cement slurry, thus having minimal impact on the fluid loss of the oil well cement slurry and benefiting cement slurry formulation design and construction safety.

[0070] According to a preferred embodiment of the present invention, in the polymer, the hydrophilic backbone contains structural unit A. Structural Unit B and structural unit C Wherein, the molar ratio of structural unit A: structural unit B: structural unit C is 10:(3-4):(2-3); in the end cap structure, Q1, Q2 and Q3 each independently contain structural unit D. and structural unit E Wherein, the molar ratio of structural unit D to structural unit E is 1:(2-2.5); the weight-average molecular weight of the polymer is (40-55)×10⁻⁶. 4g / mol. The polymer of the above-mentioned preferred embodiment has the effect of further shortening the setting time of the cement slurry at the top of the long cementing section, which can better solve the problem of ultra-slow setting of the top cement slurry, and has better compatibility.

[0071] A second aspect of the present invention provides a method for preparing a polymer, comprising:

[0072] In the presence of a first solvent, monomers A', B', C' and initiator G are subjected to a polymerization reaction to obtain a polymer;

[0073] Wherein, monomer A' has the structure shown in formula (7); monomer B' has the structure shown in formula (8); and monomer C' has the structure shown in formula (9).

[0074]

[0075] Among them, R1, R2, R3, R4, and R5 are each independently selected from -H or C. 1- C2 alkyl group; R6 is selected from C1-C3 alkylene group; Z is selected from H + K + Na + or NH4 + R7, R8, R9, R 10 Each is independently selected from -H, -CH3, and -COOM. 1 or -CH2COOM 2 And R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; where M 1 M 2 Each independently selected from H + K + Na + or NH4 + ;R 11 R 12 R 13 R 14 R 15 Each is independently selected from -H or C. 1- C2 alkyl group;

[0076] The initiator G has the structure shown in formula (10);

[0077]

[0078] Wherein, Q1, Q2, Q3, Q4, Q5, and Q6 are polymer chain segments, and each of Q1, Q2, Q3, Q4, Q5, and Q6 independently contains structural unit D and structural unit E; wherein, the structural unit D has the structure shown in formula (11); and the structural unit E has the structure shown in formula (12);

[0079]

[0080] Among them, R 16 R 17 R 18 R 19 R 20 R 21 R 22 R 23 Each can be independently selected from -H or -CH3;

[0081] The molar ratio of structural unit D to structural unit E is 1:(0.5-5);

[0082] The molar ratio of monomer A': monomer B': monomer C': initiator G is 10:(0.5-8):(0.1-4):(0.5-2).

[0083] According to the present invention, in the preparation method of the polymer, monomers A', B' and C' are polymerized to form a main chain structure, wherein monomer A' can provide sulfonic acid groups, monomer B' can provide carboxyl groups, and monomer C' can provide amide groups. The hydrophilic groups contained in the above-mentioned raw material monomers enable the polymerized main chain structure to have excellent water solubility and ion complexing ability.

[0084] According to the present invention, for the monomer A', preferably, R1, R2, R3, R4, and R5 are each independently selected from -H or -CH3; R6 is -CH2-.

[0085] According to the present invention, for the monomer C', preferably, R 11 R 12 R 13 R 14 R 15 Each can be independently selected from -H or -CH3.

[0086] According to the present invention, in the method for preparing the polymer, the initiator G is capable of forming end-capping structures connected to both ends of the main chain structure.

[0087] According to the present invention, in the initiator G, polymer segments Q1, Q2, Q3, Q4, Q5, and Q6 are independent of each other and may be the same or different, but are preferably the same.

[0088] According to the present invention, in the structural unit D contained in the initiator G, preferably, R 16 R 17 R 18 and R 19 It is -H.

[0089] According to the present invention, in the structural unit E contained in the initiator G, preferably, R 20 R 21 and R 22 -H, R 23 It is -CH3.

[0090] According to the present invention, in the initiator G, the structural unit D and the structural unit E, based on the above-mentioned proportional relationship, preferably have a molar ratio of structural unit D: structural unit E of 1:(1-3), which enables the polymer chain segments Q1, Q2, Q3, Q4, Q5, and Q6 to have better amphiphilic thermosensitive properties.

[0091] According to the present invention, preferably, the initiator G has a weight-average molecular weight of (0.5-3)×10⁻⁶. 4 g / mol.

[0092] According to the present invention, in the preparation method of the polymer, the monomers A', B', C', and initiator G, while satisfying the above-mentioned feeding ratio, preferably have a molar ratio of monomer A':monomer B':monomer C':initiator G of 10:(1-6):(1-3):(1-1.5). Using the above-mentioned preferred feeding ratio, the effects of the polymer on the retarding properties and the water loss properties of the oil well cement slurry can be further balanced.

[0093] According to the present invention, in the method for preparing the polymer, the first solvent is selected from alcohol solvents and / or ketone solvents. Preferably, the first solvent may be selected from at least one of methyl isobutyl ketone, ethanol, propanol, butanol and acetone, and more preferably methyl isobutyl ketone.

[0094] According to the present invention, in the method for preparing the polymer, the conditions for the polymerization reaction include: a temperature of 60-90°C and a time of 2-4 hours.

[0095] According to a preferred embodiment of the present invention, the process for preparing the polymer includes:

[0096] (I) The first solvent is divided into two parts, first solvent-i and first solvent-ii, and the monomer A', monomer B', monomer C', initiator G and first solvent-i are mixed to obtain a mixture;

[0097] (II) The first solvent-ii is heated to the temperature required for the polymerization reaction, and then the mixture is added to carry out the polymerization reaction to obtain the reaction product system;

[0098] (III) The reaction product system is separated to obtain the polymer.

[0099] According to the present invention, in step (I), preferably, the molar ratio of the first solvent-i to the first solvent-ii is 1:(0.5-5).

[0100] According to the present invention, in step (II), preferably, the mixture is added dropwise to the first solvent-ii, which is heated to the temperature required for the polymerization reaction, in a uniform manner. The dropwise addition process lasts for 3-8 hours, and then the polymerization reaction is carried out by keeping the temperature at 2-4 hours.

[0101] According to the present invention, in step (III), preferably, the separation process is carried out by vacuum distillation to separate and remove the first solvent in the reaction product system to obtain the target polymer.

[0102] In this invention, the preparation method of the initiator G includes:

[0103] (1) In the presence of a first catalyst, 5-bromo-1,2,3-phenylpyrogallol is reacted with monomers D' and E' to obtain the first product;

[0104] Wherein, the monomer D' has the structure shown in formula (13); the monomer E' has the structure shown in formula (14);

[0105]

[0106] Among them, R 16 R 17 R 18 R 19 R 20 R 21 R 22 R 23 Each can be independently selected from -H or -CH3;

[0107] (2) In the presence of a second solvent, the first product is reacted with metal powder L to obtain a second product; the second product is reacted with carbon dioxide to obtain a third product; then the third product is reacted with acid to obtain a fourth product, and the resulting product system is separated to obtain a fourth product.

[0108] (3) In the presence of a third solvent, the fourth product is reacted with thionyl chloride in a fifth reaction to obtain a fifth product;

[0109] (4) The fifth product is reacted with hydrogen peroxide to obtain the initiator G.

[0110] According to the present invention, in step (1), the main process of the first reaction is as follows:

[0111]

[0112] Among them, Q1, Q2 and Q3 each independently contain structural units. and structural units Among them, R 16 R 17 R 18 R 19 R 20 R 21 R 22 R 23 Each can be independently selected from -H or -CH3.

[0113] According to the present invention, in step (1), preferably, the first catalyst is mixed with 5-bromo-1,2,3-phenylpyrogallol, and then the monomer D' and monomer E are added to carry out the first reaction to obtain a viscous first product.

[0114] According to the present invention, in step (1), the first catalyst may be selected from at least one of boron trifluoride-diethyl ether complex, sodium hydroxide and potassium hydroxide.

[0115] According to the present invention, in step (1), the molar ratio of 5-bromo-1,2,3-phenylpyrogallol: first catalyst: monomer D': monomer E' is 1:(0.01-0.05):(1-3):(3-9).

[0116] According to the present invention, in step (1), the conditions for the first reaction include: a temperature of 100-150°C, a pressure of 2.5-3 MPa, and a time of 2-5 h.

[0117] According to the present invention, in step (2), the main process of the second reaction is as follows:

[0118]

[0119] According to the present invention, in step (2), preferably, the second solvent is mixed with metal powder L, and then the first product is added to carry out the second reaction.

[0120] According to the present invention, the main process of the third reaction in step (2) is as follows:

[0121]

[0122] According to the present invention, in step (2), preferably, carbon dioxide is introduced into the product system obtained from the second reaction, so that the second product undergoes a third reaction with carbon dioxide.

[0123] According to the present invention, the main process of the fourth reaction in step (2) is as follows:

[0124]

[0125] According to the present invention, in step (2), preferably, after the third reaction is completed, an acid solution (e.g., hydrochloric acid aqueous solution) is added to adjust the pH value of the reaction product system to 2-4, and a fourth reaction (hydrolysis reaction) is carried out. After standing and separating the layers, the precipitate phase is obtained, and the fourth product is obtained.

[0126] According to the present invention, in step (2), the second solvent may be an ether solvent. Preferably, the second solvent may be selected from at least one of tetrahydrofuran, diethyl ether, butyl ether, and pentyl ether.

[0127] According to the present invention, in step (2), the metal powder L can be selected from magnesium powder or zinc powder.

[0128] According to the present invention, in step (2), when all the second product obtained from the second reaction participates in the third reaction, preferably, the molar ratio of the first product: metal powder L: carbon dioxide is 1:(1-2):(2-4).

[0129] According to the present invention, in step (2), the conditions for the second reaction include: a temperature of -5 to 0°C and a time of 3 to 5 hours.

[0130] According to the present invention, in step (2), the conditions for the third reaction include: a temperature of -5 to 0°C and a time of 2 to 8 hours.

[0131] According to the present invention, in step (2), the conditions for the fourth reaction include: a temperature of 0-10°C, a pH of 2-4, and a time of 4-5 h.

[0132] According to the present invention, the main process of the fifth reaction in step (3) is as follows:

[0133]

[0134] According to the present invention, in step (3), preferably, the fourth product, thionyl chloride and the third solvent are mixed and heated under reflux to obtain the fifth product.

[0135] According to the present invention, in step (3), the third solvent may be a benzene-based solvent. Preferably, the third solvent may be selected from at least one of benzene, toluene, ethylbenzene, and xylene.

[0136] According to the present invention, in step (3), the molar ratio of the fourth product to thionyl chloride is 1:(5-7).

[0137] According to the present invention, in step (3), the conditions for the fifth reaction include: a temperature of 80-150°C and a time of 5-8 hours.

[0138] According to the present invention, the main process of the sixth reaction in step (4) is as follows:

[0139]

[0140] According to the present invention, in step (4), preferably, the fifth product is mixed with an aqueous solution of hydrogen peroxide, the resulting mixture is added to an aqueous solution of a co-solvent, the temperature is raised to the required temperature for the reaction to carry out the sixth reaction, and the product is filtered to obtain the initiator G.

[0141] According to the present invention, in step (4), the molar ratio of the fifth product to hydrogen peroxide is 1:(1.5-2).

[0142] According to the present invention, in step (4), the co-solvent can be a compound reagent of surfactant and soluble carbonate; wherein, the surfactant is preferably at least one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate and sodium dodecyl diphenyl ether disulfonate; and the soluble carbonate is preferably sodium carbonate and / or potassium carbonate.

[0143] According to the present invention, preferably, in the aqueous solution of the cosolvent, the weight ratio of the surfactant: soluble carbonate: water is (0.5-5): (15-20): 100.

[0144] According to the present invention, in step (4), the conditions for the sixth reaction include: a temperature of 30-40°C and a time of 2-4 hours.

[0145] This invention involves polymerizing specific monomers A' (providing sulfonic acid groups), B' (providing carboxyl groups), and C' (providing amide groups) with an initiator G having a specific multi-branched structure. The resulting polymer has a hydrophilic backbone with multi-branched end-cap structures at both ends. The hydrophilic backbone and the multi-branched end-cap structures work together to volatilize, giving the polymer excellent retarding ability for oil well cement slurry at high temperatures. This retarding ability weakens as the temperature decreases. As a retarder component, this polymer can accelerate the strength development of the top cement slurry while ensuring the retarding effect of the oil well cement slurry under circulating temperature conditions. It can achieve a compressive strength of over 7 MPa in the top cement slurry after 48 hours at 80°C. Furthermore, this polymer has good compatibility and minimal impact on the water loss of the oil well cement slurry.

[0146] The third aspect of the present invention provides a polymer prepared by the preparation method described in the second aspect above.

[0147] According to the present invention, the polymer obtained by the method described in the second aspect above has the same structure, parameters and properties as the polymer described in the first aspect above, and will not be repeated here.

[0148] A fourth aspect of the present invention provides a retarder, comprising: a main polymer and a cosolvent;

[0149] The weight ratio of the main polymer to the cosolvent is 10:(0.4-2);

[0150] The main polymer is the polymer described in the first or third aspect.

[0151] According to the present invention, in the retarder, the co-solvent may be selected from alcohols and / or ketones, preferably at least one of ethanol, isopropanol, butanol and methyl isobutyl ketone.

[0152] According to the present invention, the retarder can be prepared by mixing the main polymer and the additives in the above proportions.

[0153] The retarder provided by this invention uses a specific polymer provided by this invention as the main functional component. It is a novel retarder that can rapidly solidify cement slurry under conditions below the circulating temperature. When applied to cementing in long cementing sections, this retarder can accelerate the strength development of top cement slurry while ensuring the retarding effect of bottom oil well cement slurry. It can enable the top cement slurry to reach a compressive strength of over 7 MPa after 48 hours at 80°C. Moreover, this retarder has good compatibility and has little impact on the water loss of oil well cement slurry.

[0154] According to the present invention, preferably, the retarder is prepared into a solution with water before use, and is used in the form of an aqueous solution and added to the oil well cement slurry. Preferably, in the aqueous solution of the retarder, the weight ratio of the main polymer:cosolvent:water is 10:(0.4-2):(20-30).

[0155] The fifth aspect of the present invention provides an oil well cement slurry containing the retarder described in the fourth aspect above.

[0156] According to the present invention, the components of the oil well cement slurry, in addition to oil well cement and the retarder, may also include various conventional oil well cement slurry admixtures in the art, including but not limited to weighting agents, weight-reducing agents, fluid loss reducing agents, drag reducing agents, defoamers, etc.

[0157] According to the present invention, the content of the retarder in the oil well cement slurry is not particularly limited. In some embodiments of the present invention, preferably, the weight ratio of the retarder to the oil well cement in the oil well cement slurry is (1-8):100.

[0158] The present invention will be described in detail below through examples. Unless otherwise specified, the preparation examples, embodiments and comparative examples described below are all conventional methods; unless otherwise specified, the reagents and materials are all commercially available.

[0159] In the following preparation examples and embodiments, the molar ratio of the initiator G and the structural units contained in the polymer was calculated by the amount of raw materials fed.

[0160] Preparation Example 1

[0161] This preparation example illustrates the preparation of initiator G.

[0162] (1) 5-bromo-1,2,3-benzenepyrogallol and potassium hydroxide were added to a high-pressure reactor and mixed. Nitrogen gas was introduced to maintain a pressure of 3 MPa. Monomer D' (ethylene oxide) was introduced and reacted for 3 h (reaction temperature 110 °C). Then monomer E' (propylene oxide) was introduced and reacted for 3 h (reaction temperature 110 °C) to obtain a viscous first product.

[0163] The molar ratio of 5-bromo-1,2,3-phenylpyrogallol: potassium hydroxide: monomer D': monomer E' is 1:0.03:2:5.

[0164] (2) Add magnesium powder to anhydrous tetrahydrofuran, cool to 0°C in an ice-water bath and react for 4 hours. Then keep the temperature at 0°C and introduce carbon dioxide gas into the reaction system for 6 hours. After the reaction is completed, slowly add 10wt% hydrochloric acid aqueous solution to the reaction product system while keeping the temperature of the reaction system in the range of 0-10°C, the pH value of the reaction system is 3, and the reaction time is 4 hours. Then let it stand to separate into layers, collect the precipitate phase, and obtain the second product.

[0165] The molar ratio of the first product, magnesium powder, to carbon dioxide is 1:1.5:3.

[0166] (3) The second product was added to toluene, and then thionyl chloride was added. The mixture was heated to reflux at 110°C for 6 hours. After the reaction was completed, the toluene was removed by vacuum distillation to obtain the third product.

[0167] The molar ratio of the second product to thionyl chloride is 1:6.

[0168] (4) Mix the above third product with an aqueous solution of hydrogen peroxide evenly, and slowly add it dropwise to an aqueous solution of a co-solvent (sodium dodecylbenzenesulfonate: sodium carbonate: water in a weight ratio of 1:18:100). The dropwise addition is completed within 30 minutes. After the dropwise addition is completed, the temperature is raised to 40°C and the reaction is carried out for 4 hours. The reaction product is filtered to obtain a solid. The solid is washed with deionized water and dried to obtain initiator G-1.

[0169] The molar ratio of the third product, hydrogen peroxide, to sodium carbonate is 1:1.7:2.

[0170] G-1 has the structure shown in equation (10). The structural units Q1, Q2, Q3, Q4, Q5, and Q6 of the polymer chain in G-1 are calculated based on the amount of raw materials fed. Structural unit The molar ratio is 1:2.5.

[0171] The weight-average molecular weight of G-1 is 1.2 × 10⁻⁶. 4 g / mol.

[0172] Preparation Example 2

[0173] This preparation example illustrates the preparation of initiator G.

[0174] Following the method of Preparation Example 1, except that monomer D' is (1,2-dimethylethylene oxide) and monomer E' is (methylpropylene oxide), while other conditions and steps are the same as in Preparation Example 1, initiator G-2 is obtained.

[0175] G-2 has the structure shown in equation (10). The structural units Q1, Q2, Q3, Q4, Q5, and Q6 of the polymer chain in G-2 are calculated based on the amount of raw materials fed. Structural unit The molar ratio is 1:2.5.

[0176] The weight-average molecular weight of G-2 is 2.2 × 10⁻⁶. 4 g / mol.

[0177] Preparation Example 3

[0178] This preparation example illustrates the preparation of initiator G.

[0179] The method of Preparation Example 1 was followed, except that the molar ratio of 5-bromo-1,2,3-phenylpyrogallol: potassium hydroxide: monomer D' (ethylene oxide): monomer E' (propylene oxide) was 1:0.03:3:3, and the other conditions and steps were the same as in Preparation Example 1, to obtain initiator G-3.

[0180] G-3 has the structure shown in equation (10). The structural units Q1, Q2, Q3, Q4, Q5, and Q6 of the polymer chain in G-3 are calculated based on the amount of raw materials fed. Structural unit The molar ratio is 1:1.

[0181] The weight-average molecular weight of G-3 is 0.8 × 10⁻⁶. 4 g / mol.

[0182] Preparation Example 4

[0183] This preparation example illustrates the preparation of initiator G.

[0184] The method of Preparation Example 1 was followed, except that the molar ratio of 5-bromo-1,2,3-phenylpyrogallol: potassium hydroxide: monomer D' (ethylene oxide): monomer E' (propylene oxide) was 1:0.03:6:3, and the other conditions and steps were the same as in Preparation Example 1, to obtain initiator G-4.

[0185] G-4 has the structure shown in equation (10). The structural units Q1, Q2, Q3, Q4, Q5, and Q6 of the polymer chain in G-4 are calculated based on the amount of raw materials fed. Structural unit The molar ratio is 1:0.5.

[0186] The weight-average molecular weight of G-4 is 1.5 × 10⁻⁶. 4 g / mol.

[0187] Preparation Example 5

[0188] This preparation example illustrates the preparation of initiator G.

[0189] The method of Preparation Example 1 was followed, except that the order of introducing monomers D' (ethylene oxide) and E' (propylene oxide) in step (1) was changed. That is, monomer E' was introduced first and reacted for 3 hours, followed by monomer D' and reacted for 3 hours. All other conditions and steps were the same as in Preparation Example 1, and initiator G-5 was obtained.

[0190] G-5 has the structure shown in equation (10). The structural units Q1, Q2, Q3, Q4, Q5, and Q6 of the polymer chain in G-4 are calculated based on the amount of raw materials fed. Structural unit The molar ratio is 1:0.5.

[0191] The weight-average molecular weight of G-5 is 1.8 × 10⁻⁶. 4 g / mol.

[0192] Example 1

[0193] This example illustrates the preparation of polymers.

[0194] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:1.5), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (itaconic acid, i.e. ), monomer C'(N,N-dimethylacrylamide, i.e. Initiator G-1 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0195] The molar ratio of monomer A': monomer B': monomer C': initiator G-1: first solvent-i is 10:3:2:1.2:35.

[0196] (II) The first solvent-ii was added to the reactor and heated to 80°C. Then the mixture was added dropwise to the first solvent-ii at 80°C. The dropwise addition process lasted for 4 hours. After that, the temperature was kept for 4 hours to carry out the polymerization reaction and obtain the reaction product system.

[0197] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and a polymer (denoted as P1) was obtained.

[0198] Infrared spectroscopy was performed on P1, and the results are as follows: Figure 1 As shown, the stretching vibration absorption peak of the amide group is at 3464.1 cm⁻¹. -1 At this point, the absorption peak of the carbonyl -C=O stretching vibration in the carboxyl group of the amide group and itaconic acid is at 1641.4 cm⁻¹. -1 At the location, sulfonic acid group -SO3 - The stretching vibration absorption peak is at 1224.7 cm⁻¹. -1 The absorption peaks for the -CO- stretching vibration and bending vibration of the polyether segment are at 1039.6 cm⁻¹. -1 881cm -1 At this point, all functional groups in the raw material monomers appear in the polymer infrared spectrum, indicating that the polymerization was successfully initiated and the polymer of the present invention was obtained.

[0199] In P1, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:3:2; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of P1 is 53 × 10⁻⁶. 4 g / mol.

[0200] Example 2

[0201] This example illustrates the preparation of polymers.

[0202] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:1.5), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (maleic acid, i.e. ), monomer C'(N,N-dimethylacrylamide, i.e. Initiator G-1 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0203] The molar ratio of monomer A': monomer B': monomer C': initiator G-1: first solvent-i is 10:4:3:1.2:35.

[0204] (II) The first solvent-ii was added to the reactor and heated to 80°C. Then the mixture was added dropwise to the first solvent-ii at 80°C. The dropwise addition process lasted for 4 hours. After that, the temperature was kept for 4 hours to carry out the polymerization reaction and obtain the reaction product system.

[0205] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as P2) was obtained.

[0206] In P2, structural unit A in the hydrophilic main chain ( Structural Unit B ( Structural unit C The molar ratio is 10:4:3; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of P2 is 41 × 10⁻⁶. 4 g / mol.

[0207] Example 3

[0208] This example illustrates the preparation of polymers.

[0209] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:2), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (sodium methacrylate, i.e. ), monomer C' acrylamide (acrylamide, i.e. Initiator G-1 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0210] The molar ratio of monomer A': monomer B': monomer C': initiator G-1: first solvent-i is 10:0.6:4:1.5:30.

[0211] (II) The first solvent-ii was added to the reactor and heated to 80°C. Then the mixture was added dropwise to the first solvent-ii at 80°C. The dropwise addition process lasted for 4 hours. After that, the temperature was kept for 4 hours to carry out the polymerization reaction and obtain the reaction product system.

[0212] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as P3) was obtained.

[0213] In P3, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:0.6:4; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of P3 is 15 × 10⁻⁶. 4 g / mol.

[0214] Example 4

[0215] This example illustrates the preparation of polymers.

[0216] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:3), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (acrylic acid, i.e. ), monomer C' (methacrylamide, i.e. Initiator G-1 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0217] The molar ratio of monomer A': monomer B': monomer C': initiator G-1: first solvent-i is 10:7:0.5:1:35.

[0218] (II) The first solvent-ii was added to the reactor and heated to 90°C. Then the mixture was added dropwise to the first solvent-ii at 90°C. The dropwise addition process lasted for 3 hours. After that, the temperature was kept for 3 hours to carry out the polymerization reaction and obtain the reaction product system.

[0219] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as P4) was obtained.

[0220] In P4, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:7:0.5; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of P4 is 24 × 10⁻⁶. 4 g / mol.

[0221] Example 5

[0222] This example illustrates the preparation of polymers.

[0223] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:3), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (acrylic acid, i.e. ), monomer C' (methacrylamide, i.e. Initiator G-1 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0224] The molar ratio of monomer A': monomer B': monomer C': initiator G-1: first solvent-i is 10:8:4:1:35.

[0225] (II) The first solvent-ii was added to the reactor and heated to 90°C. Then the mixture was added dropwise to the first solvent-ii at 90°C. The dropwise addition process lasted for 3 hours. After that, the temperature was kept for 3 hours to carry out the polymerization reaction and obtain the reaction product system.

[0226] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as P5) was obtained.

[0227] In P5, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:8:4; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of P5 is 30 × 10⁻⁶. 4 g / mol.

[0228] Example 6

[0229] This example illustrates the preparation of polymers.

[0230] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:3), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (acrylic acid, i.e. ), monomer C' (methacrylamide, i.e. Initiator G-2 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0231] The molar ratio of monomer A': monomer B': monomer C': initiator G-2: first solvent-i is 10:7:0.5:1:35.

[0232] (II) The first solvent-ii was added to the reactor and heated to 90°C. Then the mixture was added dropwise to the first solvent-ii at 90°C. The dropwise addition process lasted for 3 hours. After that, the temperature was kept for 3 hours to carry out the polymerization reaction and obtain the reaction product system.

[0233] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as P6) was obtained.

[0234] In P6, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:7:0.5; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of P6 is 30 × 10⁻⁶. 4 g / mol.

[0235] Example 7

[0236] This example illustrates the preparation of polymers.

[0237] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:3), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (acrylic acid, i.e. ), monomer C' (methacrylamide, i.e. Initiator G-3 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0238] The molar ratio of monomer A': monomer B': monomer C': initiator G-3: first solvent-i is 10:7:0.5:1:35.

[0239] (II) The first solvent-ii was added to the reactor and heated to 90°C. Then the mixture was added dropwise to the first solvent-ii at 90°C. The dropwise addition process lasted for 3 hours. After that, the temperature was kept for 3 hours to carry out the polymerization reaction and obtain the reaction product system.

[0240] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as P7) was obtained.

[0241] In P7, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:7:0.5; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:1; the weight-average molecular weight of P7 is 42 × 10⁻⁶. 4 g / mol.

[0242] Example 8

[0243] This example illustrates the preparation of polymers.

[0244] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:3), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (acrylic acid, i.e. ), monomer C' (methacrylamide, i.e. Initiator G-4 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0245] The molar ratio of monomer A': monomer B': monomer C': initiator G-4: first solvent-i is 10:7:0.5:1:35.

[0246] (II) The first solvent-ii was added to the reactor and heated to 90°C. Then the mixture was added dropwise to the first solvent-ii at 90°C. The dropwise addition process lasted for 3 hours. After that, the temperature was kept for 3 hours to carry out the polymerization reaction and obtain the reaction product system.

[0247] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as P8) was obtained.

[0248] In P8, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:7:0.5; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:0.5; the weight-average molecular weight of P8 is 35 × 10⁻⁶. 4 g / mol.

[0249] Example 9

[0250] This example illustrates the preparation of polymers.

[0251] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:3), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid, i.e. ), monomer B' (acrylic acid, i.e. ), monomer C' (methacrylamide, i.e. Initiator G-5 is added to the first solvent-i and mixed evenly to obtain a mixture;

[0252] The molar ratio of monomer A': monomer B': monomer C': initiator G-5: first solvent-i is 10:7:0.5:1:35.

[0253] (II) The first solvent-ii was added to the reactor and heated to 90°C. Then the mixture was added dropwise to the first solvent-ii at 90°C. The dropwise addition process lasted for 3 hours. After that, the temperature was kept for 3 hours to carry out the polymerization reaction and obtain the reaction product system.

[0254] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as P9) was obtained.

[0255] In P9, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:7:0.5; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:0.5; the weight-average molecular weight of P9 is 48 × 10⁻⁶. 4 g / mol.

[0256] Comparative Example 1

[0257] Dissolve monomers A' (2-acrylamide-2-methylpropanesulfonic acid), B' (itaconic acid), and C' (N,N-dimethylacrylamide) in deionized water to obtain a mixture.

[0258] The above mixture was heated to 80°C, ammonium persulfate was added, and the polymerization reaction was carried out at 80°C for 4 hours to obtain the polymer (denoted as D1).

[0259] The molar ratio of monomer A': monomer B': monomer C': ammonium persulfate: deionized water is 10:3:2:1.2:60.

[0260] In D1, structural unit A Structural Unit B Structural unit C The molar ratio is 10:3:2; the weight-average molecular weight of D1 is 43 × 10⁻⁶. 4 g / mol.

[0261] Comparative Example 2

[0262] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:1.5). Monomer B' (itaconic acid), monomer C' (N,N-dimethylacrylamide), and initiator G-1 are added to first solvent-i and mixed evenly to obtain a mixture.

[0263] The molar ratio of monomer B': monomer C': initiator G-1: first solvent-i is 3:2:1.2:35.

[0264] (II) The first solvent-ii was added to the reactor and heated to 80°C. Then the mixture was added dropwise to the first solvent-ii at 80°C. The dropwise addition process lasted for 4 hours. After that, the temperature was kept for 4 hours to carry out the polymerization reaction and obtain the reaction product system.

[0265] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as D2) was obtained.

[0266] In D2, structural unit B in the hydrophilic main chain Structural unit C The molar ratio is 3:2; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of D2 is 48 × 10⁻⁶. 4 g / mol.

[0267] Comparative Example 3

[0268] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:1.5). Monomer A' (2-acrylamido-2-methylpropanesulfonic acid), monomer C' (N,N-dimethylacrylamide), and initiator G-1 are added to first solvent-i and mixed evenly to obtain a mixture.

[0269] The molar ratio of monomer A': monomer C': initiator G-1: first solvent-i is 10:2:1.2:35.

[0270] (II) The first solvent-ii was added to the reactor and heated to 80°C. Then the mixture was added dropwise to the first solvent-ii at 80°C. The dropwise addition process lasted for 4 hours. After that, the temperature was kept for 4 hours to carry out the polymerization reaction and obtain the reaction product system.

[0271] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as D3) was obtained.

[0272] In D3, structural unit A in the hydrophilic main chain Structural unit C The molar ratio is 10:2; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of D3 is 38 × 10⁻⁶. 4 g / mol.

[0273] Comparative Example 4

[0274] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:1.5). Monomer A' (2-acrylamido-2-methylpropanesulfonic acid), monomer B' (itaconic acid), and initiator G-1 are added to first solvent-i and mixed evenly to obtain a mixture.

[0275] The molar ratio of monomer A': monomer B': initiator G-1: first solvent-i is 10:3:1.2:35.

[0276] (II) The first solvent-ii was added to the reactor and heated to 80°C. Then the mixture was added dropwise to the first solvent-ii at 80°C. The dropwise addition process lasted for 4 hours. After that, the temperature was kept for 4 hours to carry out the polymerization reaction and obtain the reaction product system.

[0277] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as D4) was obtained.

[0278] In D4, structural unit A in the hydrophilic main chain Structural Unit B The molar ratio is 10:3; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of P1 is 26 × 10⁻⁶. 4 g / mol.

[0279] Comparative Example 5

[0280] (I) Methyl isobutyl ketone is divided into two parts: first solvent-i and first solvent-ii (the molar ratio of first solvent-i to first solvent-ii is 1:1.5). Monomer A' (2-acrylamido-2-methylpropanesulfonic acid), monomer B' (itaconic acid), monomer C' (N,N-dimethylacrylamide), and initiator G-1 are added to first solvent-i and mixed evenly to obtain a mixture.

[0281] The molar ratio of monomer A': monomer B': monomer C': initiator G-1: first solvent-i is 10:10:7:3:40.

[0282] (II) The first solvent-ii was added to the reactor and heated to 80°C. Then the mixture was added dropwise to the first solvent-ii at 80°C. The dropwise addition process lasted for 4 hours. After that, the temperature was kept for 4 hours to carry out the polymerization reaction and obtain the reaction product system.

[0283] (III) The above reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone, and the polymer (denoted as D5) was obtained.

[0284] In D5, structural unit A in the hydrophilic main chain Structural Unit B Structural unit C The molar ratio is 10:10:7; structural unit D in the end cap structure Structural Unit E The molar ratio is 1:2.5; the weight-average molecular weight of D5 is 47 × 10⁻⁶. 4 g / mol.

[0285] Test case

[0286] The polymers P1-P9 and D1-D5 obtained in Examples 1-9 and Comparative Examples 1-5 were mixed with anhydrous ethanol and deionized water at a weight ratio of 10:1:30 to prepare oil well cement retarder (referred to as S1-S9 and DS1-DS5 respectively).

[0287] Experimental oil well cement slurry was prepared using the above-mentioned retarders S1-S9 and DS1-DS5. The cement slurry was prepared and tested according to GB / T19139-2012 "Test Methods for Cement in Oil Wells", and the cement slurry thickening time, water loss, free liquid and compressive strength were measured.

[0288] Experimental oil well cement slurry formula: 100g Jiahua G-grade oil well cement + 25g microsilica + 35g glass microspheres + 4g suspending agent BCJ-300S + 95g deionized water + 7.5g fluid loss reducing agent BXF-200L + 2.8g retarder + 2.5g drag reducing agent CF40L + 0.1g defoamer G603;

[0289] Among them, microsilicon: silicon content ≥95%, specific surface area 15-25m² 2 / g;

[0290] Hollow glass microspheres: density 0.6 g / cm³ 3 The diameter is 5-30μm;

[0291] Suspension agent BCJ-300S: purchased from Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.;

[0292] BXF-200L fluid loss reducer: purchased from Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0293] Drag reducer CF40L: purchased from Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0294] Defoamer G603: Purchased from Tianjin Zhongyou Boxing Engineering Technology Co., Ltd.

[0295] The results are shown in Table 1.

[0296] Table 1

[0297]

[0298] Note: In Table 1, the thickening temperature is 125℃, the test pressure is 90MPa, and the top temperature is 80℃.

[0299] As shown in Table 1, the oil well cement retarder S1-S9 prepared using polymers P1-P9 provided by this invention has excellent retarding effect on the experimental oil well cement slurry. The thickening time of the oil well cement slurry can reach more than 350 min, and the top compressive strength after 48 h is greater than 7 MPa. Figure 2 The above-mentioned thickening curve of the experimental cement slurry using retarder S1 at 125℃ is shown, with a thickening time of 432 min. Figure 3 The above-mentioned experimental cement slurry using retarder S1 exhibits a compressive strength development curve at 80℃. It begins to harden and gain strength after 13.5 hours, and reaches a compressive strength of 17.2 MPa after 48 hours. The top strength development is rapid, and no over-retardation phenomenon is observed. Moreover, the water loss is not higher than 45 mL, which meets the requirements for deep well cementing construction. Among them, retarder S1 and S2 show particularly excellent overall performance, with the oil well cement slurry thickening time reaching more than 430 minutes, the top compressive strength reaching more than 12 MPa after 48 hours, and the water loss not exceeding 40 mL.

[0300] In addition, the strength development of the cement grout was tested under the condition that the ultra-long sealing section was returned to the ground in one go, with the top temperature at 30°C. Figure 4 The above-mentioned experimental cement slurry using retarder S1 shows the compressive strength development curve at 30℃. The cement slurry begins to harden after 36 hours and reaches a compressive strength of 3.2 MPa after 48 hours. No over-retardation phenomenon was observed, which can meet the cementing construction requirements of long sealing sections.

[0301] The above results show that the polymer and oil well cement retarder provided by the present invention can solve the problem of excessively slow setting of cement slurry at the top of long sealing sections in deep wells. The top strength develops rapidly, has no effect on the water loss of cement slurry, and has no free liquid, thus showing good prospects for engineering applications.

[0302] In particular, the retarder D1-D5 do not contain the polymer of this invention, and therefore cannot solve the problem of excessively slowed setting of cement slurry at the top of long sealing sections. Figure 5 The above-mentioned thickening curve of the experimental cement slurry using retarder DS1 at 125℃, with a thickening time of 406 min; Figure 6 The above-mentioned experimental cement slurry using retarder DS1 shows the compressive strength development curve at 80℃. It has no strength after 48 hours, begins to harden after 130 hours, and maintains a low compressive strength throughout, exhibiting an over-retarded setting phenomenon, which cannot meet the cementing requirements of long sealing sections.

[0303] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polymer, characterized in that, It includes a hydrophilic backbone and end-capping structures at both ends of the hydrophilic backbone; wherein, The hydrophilic backbone contains structural unit A, structural unit B and structural unit C; Structural unit A has the structure shown in equation (1); structural unit B has the structure shown in equation (2); structural unit C has the structure shown in equation (3); Equation (1); Equation (2); Equation (3); Among them, R1, R2, R3, R4, and R5 are each independently selected from -H or C. 1- C2 alkyl group; R6 is selected from C1-C3 alkylene group; Z is selected from H + K + Na + or NH4 + R7, R8, R9, R 10 Each is independently selected from -H, -CH3, and -COOM. 1 or -CH2COOM 2 And R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; where M 1 M 2 Each independently selected from H + K + Na + or NH4 + ;R 11 R 12 R 13 R 14 R 15 Each is independently selected from -H or C. 1- C2 alkyl group; The molar ratio of structural unit A: structural unit B: structural unit C is 10:(0.5-8):(0.1-4). The end cap structure has the structure shown in formula (4); Equation (4); Wherein, Q1, Q2 and Q3 are polymer chain segments, and each of Q1, Q2 and Q3 independently contains structural unit D and structural unit E; wherein, the structural unit D has the structure shown in formula (5); The structural unit E has the structure shown in equation (6); Equation (5); Equation (6); Among them, R 16 R 17 R 18 and R 19 -H;R 20 R 21 and R 22 -H, R 23 -CH3; The molar ratio of structural unit D to structural unit E is 1:(0.5-5).

2. The polymer according to claim 1, wherein, R1, R2, R3, R4, and R5 are each independently selected from -H or -CH3; R6 is -CH2-; R 11 R 12 R 13 R 14 R 15 Each can be independently selected from -H or -CH3; And / or, the molar ratio of structural unit A: structural unit B: structural unit C is 10:(1-6):(1-3); And / or, the molar ratio of structural unit D to structural unit E is 1:(1-3).

3. The polymer according to claim 1 or 2, wherein, The weight-average molecular weight of the polymer is (10-80)×10 4 g / mol.

4. A method for preparing a polymer, comprising: In the presence of a first solvent, monomers A', B', C' and initiator G are subjected to a polymerization reaction to obtain a polymer; Wherein, monomer A' has the structure shown in formula (7); monomer B' has the structure shown in formula (8); and monomer C' has the structure shown in formula (9). Equation (7); Equation (8); Equation (9); Among them, R1, R2, R3, R4, and R5 are each independently selected from -H or C. 1- C2 alkyl group; R6 is selected from C1-C3 alkylene group; Z is selected from H + K + Na + or NH4 + R7, R8, R9, R 10 Each is independently selected from -H, -CH3, and -COOM. 1 or -CH2COOM 2 And R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; where M 1 M 2 Each independently selected from H + K + Na + or NH4 + ;R 11 R 12 R 13 R 14 R 15 Each is independently selected from -H or C. 1- C2 alkyl group; The initiator G has the structure shown in formula (10). Equation (10); Wherein, Q1, Q2, Q3, Q4, Q5, and Q6 are polymer chain segments, and each of Q1, Q2, Q3, Q4, Q5, and Q6 independently contains structural unit D and structural unit E; wherein, the structural unit D has the structure shown in formula (11); and the structural unit E has the structure shown in formula (12); Equation (11); Equation (12); Among them, R 16 R 17 R 18 and R 19 -H;R 20 R 21 and R 22 -H, R 23 -CH3; The molar ratio of structural unit D to structural unit E is 1:(0.5-5). The molar ratio of monomer A': monomer B': monomer C': initiator G is 10:(0.5-8):(0.1-4):(0.5-2).

5. The method according to claim 4, wherein, R1, R2, R3, R4, and R5 are each independently selected from -H or -CH3; R6 is -CH2-; R 11 R 12 R 13 R 14 R 15 Each can be independently selected from -H or -CH3; And / or, the molar ratio of structural unit D to structural unit E is 1:(1-3); And / or, the molar ratio of monomer A': monomer B': monomer C': initiator G is 10:(1-6):(1-3):(1-1.5).

6. The method according to claim 4 or 5, wherein, The first solvent is selected from alcohol solvents and / or ketone solvents; And / or, the conditions for the polymerization reaction include: a temperature of 60-90°C and a time of 2-4 hours.

7. The method according to claim 4 or 5, wherein, The preparation method of the initiator G includes: (1) In the presence of a first catalyst, 5-bromo-1,2,3-phenylpyrogallol is reacted with monomers D' and E' to obtain the first product; Wherein, the monomer D' has the structure shown in formula (13); the monomer E' has the structure shown in formula (14); Equation (13); Equation (14); Among them, R 16 R 17 R 18 and R 19 -H;R 20 R 21 and R 22 -H, R 23 -CH3; (2) In the presence of a second solvent, the first product is reacted with metal powder L to obtain a second product; the second product is reacted with carbon dioxide to obtain a third product; then the third product is reacted with acid to obtain a fourth product, and the resulting product system is separated to obtain a fourth product. (3) In the presence of a third solvent, the fourth product is reacted with thionyl chloride in a fifth reaction to obtain a fifth product; (4) The fifth product is reacted with hydrogen peroxide to obtain the initiator G.

8. The method according to claim 7, wherein, In step (1), the first catalyst is selected from at least one of boron trifluoride-diethyl ether complex, sodium hydroxide, and potassium hydroxide; And / or, the molar ratio of 5-bromo-1,2,3-phenylpyrogallol: first catalyst: monomer D': monomer E' is 1:(0.01-0.05):(1-3):(3-9); And / or, the conditions for the first reaction include: a temperature of 100-150°C, a pressure of 2.5-3 MPa, and a time of 2-6 h.

9. The method according to claim 7, wherein, In step (2), the second solvent is an ether solvent; And / or, the metal powder L is selected from magnesium powder or zinc powder; And / or, the molar ratio of the first product: metal powder L: carbon dioxide is 1:(1-2):(2-4); And / or, the conditions for the second reaction include: a temperature of -5 to 0°C and a time of 3 to 5 hours; And / or, the conditions for the third reaction include: a temperature of -5 to 0°C and a time of 2 to 8 hours; And / or, the conditions for the fourth reaction include: a temperature of 0-10°C, a pH of 2-4, and a time of 4-5 h.

10. The method according to claim 7, wherein, In step (3), the third solvent is a benzene-based solvent; And / or, the molar ratio of the fourth product to thionyl chloride is 1:(5-7); And / or, the conditions for the fifth reaction include: a temperature of 80-150°C and a time of 5-8 hours.

11. The method according to claim 7, wherein, In step (4), the molar ratio of the fifth product to hydrogen peroxide is 1:(1.5-2). And / or, the conditions for the sixth reaction include: a temperature of 30-40°C and a time of 2-4 hours.

12. The polymer prepared by the method according to any one of claims 4-11.

13. A retarder, comprising: Main polymer and cosolvent; The weight ratio of the main polymer to the cosolvent is 10:(0.4-2). The main polymer is the polymer described in any one of claims 1-3 and 12.

14. The retarder according to claim 13, wherein, The co-solvent is an alcohol and / or a ketone.

15. An oil well cement slurry containing the retarder as described in claim 13 or 14.

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