Polymer, preparation method therefor, retarder, and oil well cement slurry

Abstract

The present invention relates to the field of petroleum drilling aids, in particular to a polymer, a preparation method therefor, a retarder, and an oil well cement slurry. The polymer comprises a hydrophilic main chain and end-capping structures at the two ends of the hydrophilic main chain, the hydrophilic main chain containing a structural unit A, a structural unit B and a structural unit C, and the molar ratio of the structural unit A, the structural unit B and the structural unit C being 10:(0.5-8):(0.1-4). A polymer chain segment in the end-capping structures comprises a structural unit D and a structural unit E, the molar ratio of the structural unit D to the structural unit E being 1:(0.5-5). The polymer as a retarder component is applied in long-cementing-section cementing, and can accelerate the strength development of the top cement slurry at the top while ensuring a retarding effect of the oil well cement slurry. In addition, the polymer involves a small influence on the water loss of the oil well cement slurry, thereby facilitating formula designing of cement slurry, improving construction safety and saving the shaft building cost.

Description

Polymer and preparation method thereof, retarder and oil well cement slurry

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application No. 202311278907X, filed on September 28, 2023, entitled “Polymer and its preparation method, retarder and oil well cement slurry”, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the field of oil drilling additives, and in particular to a polymer and a preparation method thereof, a retarder and oil well cement slurry. Background Art

[0004] Cementing is the process of pumping oil well cement slurry into the annulus between the casing and the formation according to the design requirements. After solidification, it isolates the interlayer fluid in the well, supports, and protects the casing. The quality of cementing directly affects the oil and gas production capacity of the reservoir and the life of the oil and gas well. With the depletion of shallow oil and gas resources, exploration targets have shifted to deep and ultra-deep layers. Due to the more complex geological structures downhole in deep and ultra-deep wells, the number of casing layers has increased, and the cost of well construction has increased. In order to develop deep oil and gas resources more efficiently and at a lower cost, a design method with fewer casing layers is usually adopted. However, this method will inevitably lead to an increase in the length of the one-time sealing. In order to achieve the construction pumping time required by the cementing design, a certain amount of oil well cement retarder needs to be added to ensure that the oil well cement maintains good fluidity before displacement. Generally speaking, within the applicable temperature range of the retarder, if the same thickening time is achieved, the retarder dosage increases with increasing temperature. However, due to the influence of the downhole geothermal gradient, the bottomhole temperature increases with increasing well depth. The test temperature for testing the thickening time (i.e., the circulating temperature) is generally 0.75-0.9 times the bottomhole static temperature. As a result, after the cement slurry is pumped into place, the static temperature of the top cement slurry (30-90°C) is far lower than the circulating temperature during the thickening time test, resulting in super-retarded setting or long-term non-solidification of the top cement slurry, seriously affecting the cementing quality and well construction cycle. If a gas layer exists in the top seal layer, it may lead to sealing failure and, in severe cases, a blowout accident. Existing retarders basically meet construction requirements when the circulating temperature is below 110°C. However, when the circulating temperature is above 110°C, the prepared cement slurry is prone to super-retarded setting.

[0005] Therefore, it is urgent to develop an oil well cement retarder suitable for long sealing section cementing above 110°C, shorten the waiting time of cement slurry at the top of long sealing section cementing, solve the problem of ultra-slow setting or long-term non-setting of cement slurry at the top of long sealing section cementing, so as to meet the cementing construction needs of long sealing section in deep wells and ultra-deep wells.

[0006] Summary of the Invention

[0007] The present invention aims to solve the problems of excessive retarding of top oil well cement slurry and slow strength development in long sealing section cementing when using existing retarders to prepare oil well cement slurry, and the problem that existing retarders easily destroy the water loss performance of oil well cement slurry. The present invention provides a polymer and a preparation method thereof, a retarder and oil well cement slurry.

[0008] In order to achieve the above object, the present invention provides a polymer in a first aspect, comprising a hydrophilic main chain and end-capping structures at both ends of the hydrophilic main chain; wherein,

[0009] The hydrophilic main chain contains structural unit A, structural unit B and structural unit C;

[0010] The structural unit A has a structure shown in formula (1); the structural unit B has a structure shown in formula (2); the structural unit C has a structure shown in formula (3);

[0011] Wherein, R1, R2, R3, R4, and R5 are each independently selected from -H or C1-C2 alkyl; R6 is selected from C1-C3 alkylene; Z is selected from H + , K + 、Na + or NH4 + ; R7, R8, R9, R 10 Each independently selected from -H, -CH3, -COOM 1 or -CH2COOM 2 , and R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; wherein, M 1 、M 2 Each independently selected from H + , K + 、Na + or NH4 + ; R 11 、R 12 、R 13 、R 14 、R 15 Each independently selected from -H or C1-C2 alkyl;

[0012] The molar ratio of the structural unit A: structural unit B: structural unit C is 10: (0.5-8): (0.1-4);

[0013] The end-capping structure has a structure shown in formula (4);

[0014] Wherein, Q1, Q2 and Q3 are polymer segments, and Q1, Q2 and Q3 each independently contain a structural unit D and a structural unit E; wherein the structural unit D has a structure shown in formula (5);

[0015] The structural unit E has a structure shown in formula (6);

[0016] Among them, R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 Each independently selected from -H or -CH3;

[0017] The molar ratio of the structural unit D:structural unit E is 1:(0.5-5).

[0018] The second aspect of the present invention provides a method for preparing a polymer, comprising: in the presence of a first solvent, polymerizing monomer A', monomer B', monomer C' and initiator G to obtain a polymer;

[0019] Wherein, the monomer A' has a structure shown in formula (7); the monomer B' has a structure shown in formula (8); the monomer C' has a structure shown in formula (9);

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

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

[0022] Wherein, Q1, Q2, Q3, Q4, Q5, and Q6 are polymer segments, and Q1, Q2, Q3, Q4, Q5, and Q6 each independently contain a structural unit D and a structural unit E; wherein the structural unit D has a structure represented by formula (11); and the structural unit E has a structure represented by formula (12);

[0023] Among them, R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 Each independently selected from -H or -CH3;

[0024] The molar ratio of the structural unit D: structural unit E is 1: (0.5-5);

[0025] The molar ratio of the monomer A':monomer B':monomer C':initiator G is 10:(0.5-8):(0.1-4):(0.5-2).

[0026] The third aspect of the present invention provides a polymer obtained by the preparation method described in the second aspect.

[0027] A fourth aspect of the present invention provides a retarder, comprising: a main polymer and a cosolvent;

[0028] Wherein, the weight ratio of the main polymer:cosolvent is 10:(0.4-2);

[0029] The main polymer is the polymer described in the first aspect or the third aspect.

[0030] The fifth aspect of the present invention provides an oil well cement slurry containing the retarder described in the fourth aspect.

[0031] Through the above technical solution, the present invention has the following beneficial effects:

[0032] (1) The polymer provided by the present invention adopts a main chain containing sulfonic acid groups, amide groups and carboxyl groups. These hydrophilic groups provide the polymer with excellent water solubility and ion complexing ability, and the end-capping structure at both ends of the main chain has multiple branches, thereby forming a polymer structure with temperature-sensitive water solubility, so that the polymer has excellent ability to promote the slow setting of cement slurry at high temperature, and the slow setting ability weakens as the temperature decreases. The retarder with this polymer as the main component can accelerate the strength development of the top oil well cement slurry in the long sealing section cementing, and achieve a compressive strength of the top cement slurry of more than 7MPa at 80°C for 48 hours;

[0033] (2) The polymer provided by the present invention has good compatibility through the design of the main chain and end-capping structure, and will not produce competitive adsorption with the polymer-based fluid loss additives in the oil well cement slurry. It has little effect on the water loss of the oil well cement slurry, which is beneficial to the cement slurry formula design and on-site promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is an infrared spectrum of polymer P1 prepared in Example 1 of the present invention.

[0035] FIG2 is a thickening curve of an experimental oil well cement slurry using the retarder S1 provided by the present invention (containing the polymer prepared in Example 1) at 125° C.

[0036] FIG3 is a compressive strength development curve of an experimental oil well cement slurry using the retarder S1 (containing the polymer prepared in Example 1) provided by the present invention at 80° C.

[0037] FIG4 is a compressive strength development curve of an experimental oil well cement slurry using the retarder S1 (containing the polymer prepared in Example 1) provided by the present invention at 30° C.

[0038] FIG5 is a thickening curve of an experimental oil well cement slurry using retarder DS1 (containing the polymer prepared in Comparative Example 1) at 125° C.

[0039] FIG6 is a compressive strength development curve of an experimental oil well cement slurry using retarder DS1 (containing the polymer prepared in Comparative Example 1) at 80° C. DETAILED DESCRIPTION

[0040] The endpoints of the ranges and any values ​​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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0041] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0042] The first aspect of the present invention provides a polymer comprising a hydrophilic main chain and end-capping structures at both ends of the hydrophilic main chain; wherein,

[0043] The hydrophilic main chain contains structural unit A, structural unit B and structural unit C;

[0044] The structural unit A has a structure shown in formula (1); the structural unit B has a structure shown in formula (2); the structural unit C has a structure shown in formula (3);

[0045] Wherein, R1, R2, R3, R4, and R5 are each independently selected from -H or C1-C2 alkyl; R6 is selected from C1-C3 alkylene; Z is selected from H + , K + 、Na + or NH4 + ; R7, R8, R9, R 10 Each independently selected from -H, -CH3, -COOM 1 or -CH2COOM 2 , and R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; wherein, M 1 、M 2 Each independently selected from H + , K + 、Na + or NH4 + ; R 11 、R 12 、R 13 、R 14 、R 15 Each independently selected from -H or C1-C2 alkyl;

[0046] The molar ratio of the structural unit A: structural unit B: structural unit C is 10: (0.5-8): (0.1-4);

[0047] The end-capping structure has a structure shown in formula (4);

[0048] Wherein, Q1, Q2 and Q3 are polymer segments, and Q1, Q2 and Q3 each independently contain a structural unit D and a structural unit E; wherein the structural unit D has a structure shown in formula (5);

[0049] The structural unit E has a structure shown in formula (6);

[0050] Among them, R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 Each independently selected from -H or -CH3;

[0051] The molar ratio of the structural unit D:structural unit E is 1:(0.5-5).

[0052] According to the present invention, the hydrophilic main chain of the polymer contains specific structural units A, B, and C, wherein the structural unit A contains a sulfonic acid group, the structural unit B contains a carboxyl group, and the structural unit C contains an amide group. Under the combined action of the hydrophilic sulfonic acid group, carboxyl group, and amide group, the main chain has excellent water solubility and ion complexing ability, which is beneficial to improving the retarding ability of the polymer in oil well cement slurry and reducing damage to the water loss performance of the oil well cement slurry.

[0053] According to the present invention, in the structural unit A of the hydrophilic main chain, preferably, R1, R2, R3, R4, and R5 are each independently selected from -H or -CH3; and 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 high temperature and high alkalinity conditions of oil well cement slurry.

[0054] According to the present invention, in the structural unit B of the hydrophilic main chain, R7, R8, R9, R 10 Meeting the above-defined range is beneficial to improving the polymer's adsorption and complexing capabilities for calcium ions, cement particles, and hydration products in oil well cement slurry.

[0055] According to the present invention, in the structural unit C of the hydrophilic main chain, preferably, R 11 、R 12 、R 13 、R 14 、R 15 Each independently selected from -H or -CH3 is more conducive to improving the liquid phase viscosity of the polymer in the oil well cement slurry, and assisting in reducing the fluid loss performance, reducing the competitive adsorption between the polymer and the fluid loss reducer in the oil well cement slurry, and thus reducing the damage to the water loss performance of the oil well cement slurry.

[0056] According to the present invention, the structural unit A, structural unit B and structural unit C in the hydrophilic main chain, on the basis of satisfying the above-mentioned proportions, preferably, the molar ratio of the structural unit A:structural unit B:structural unit C is 10:(1-6):(1-3), which can further balance the effects of the polymer on the retarding properties and the water loss properties of the oil well cement slurry.

[0057] According to the present invention, both ends of the main chain of the polymer have specific end-capping structures, as shown in formula (4), in which the end-capping structure is adjacent to the main chain and is a benzene ring, and the carbon atoms at positions 3, 4 and 5 of the benzene ring are connected to the side chain through ether bonds (the positions of the ether bonds are shown in (5) and the structural unit shown in formula (6)), respectively. The side chain contains polymer segments Q1, Q2 or Q3, respectively, and the terminal carbon atom of the side chain is connected to a hydroxyl group. With such a structural design, the end-capping structure can have temperature-sensitive properties, so that the polymer can exhibit different conformations in water with temperature changes, and thus exhibit different degrees of retarding properties. Specifically, it can have excellent retarding properties under high temperature conditions (for example, the bottom of a long sealing section cementing well), delaying the thickening of the oil well cement slurry at the bottom, and can have relatively reduced retarding properties under relatively low temperature conditions (for example, the top oil well cement slurry position of a long sealing section cementing well), promoting the development of the strength of the top cement slurry.

[0058] According to the present invention, in the end-capping structure of the polymer, the polymer segments Q1, Q2 and Q3 are independent of each other and may be the same or different, preferably the same.

[0059] According to the present invention, in the polymer segments Q1, Q2, and Q3, the structural units D and E together form an amphiphilic thermosensitive polyether segment, thereby imparting thermosensitive properties to the polymer. Preferably, the molar ratio of the structural unit D to the structural unit E is 1:(1-3).

[0060] According to the present invention, in the structural unit D, preferably, R 16 、R 17 、R 18 and R 19 The structure unit D is -H, which makes the structure unit D have better hydrophilicity and provides a hydrophilic segment in the amphiphilic thermosensitive polyether segment.

[0061] According to the present invention, in the structural unit E, preferably, R 20 、R 21 and R 22 -H, R 23 It is -CH3, so that the structural unit E has a certain hydrophobicity, providing a hydrophobic segment in the amphiphilic thermosensitive polyether segment.

[0062] According to the present invention, the end-capping structures at both ends of the main chain of the polymer 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 main chain of the polymer are the same.

[0063] According to the present invention, in formula (4), Indicates the connection position between the end-capping structure and the hydrophilic main chain.

[0064] 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.

[0065] The polymer provided by the present invention has a specific hydrophilic main chain and a multi-branched end-capping structure, wherein the structural unit of the hydrophilic main chain contains a sulfonic acid group, an amide group, and a carboxyl group, which gives the main chain excellent water solubility and excellent ion complexing ability. The end-capping structure has multiple branches, and the hydrophilic main chain and the end-capping structure together form an amphiphilic polymer structure with temperature-sensitive water solubility, so that the polymer has different molecular conformations at different temperatures. As the ambient temperature rises, the solubility of the multi-branched chains at both ends of the polymer deteriorates, and the middle linear chain segment is exposed. In this case, the polymer has excellent oil well cement slurry retarding ability. As the ambient temperature decreases, the solubility of the multi-branched chains at both ends of the polymer increases, wrapping the middle linear chain segment. In this case, the complexing ability of the polymer deteriorates and the retarding ability is weakened, which is beneficial to the strength development of the oil well cement slurry. The retarder, comprising the polymer provided herein as its primary component, can accelerate the strength development of the top cement slurry during long cementing sections while maintaining the retarding effect of the oil well cement slurry under circulating temperature conditions. This allows the top cement slurry to solidify rapidly at temperatures below the circulating temperature, achieving a compressive strength of 7 MPa or higher at 80°C within 48 hours. Furthermore, conventional polymer retarders and polymer fluid loss additives compete for adsorption in cement slurries, often resulting in excessive water loss and compromising construction safety. However, the polymer provided herein, through its main chain functional groups and end-capping structure, avoids competitive adsorption with polymer fluid loss additives in oil well cement slurries, minimizing their impact on water loss, thus facilitating cement slurry formulation design and construction safety.

[0066] According to a most preferred embodiment of the present invention, in the polymer, the hydrophilic main chain contains structural unit A Structural unit B and structural unit C The molar ratio of the structural unit A: structural unit B: structural unit C is 10: (3-4): (2-3); in the end-capped structure, Q1, Q2 and Q3 each independently contain structural unit D and structural unit E The molar ratio of the structural unit D: structural unit E is 1: (2-2.5); the weight average molecular weight of the polymer is (40-55) × 10 4 The polymer of the most preferred embodiment has the effect of further shortening the waiting time of the cement slurry at the top of the long sealing section, can better solve the problem of super slow setting of the top cement slurry, and has better compatibility.

[0067] A second aspect of the present invention provides a method for preparing a polymer, comprising:

[0068] In the presence of a first solvent, monomer A', monomer B', monomer C' and initiator G are polymerized to obtain a polymer;

[0069] Wherein, the monomer A' has a structure shown in formula (7); the monomer B' has a structure shown in formula (8); the monomer C' has a structure shown in formula (9);

[0070] Wherein, R1, R2, R3, R4, and R5 are each independently selected from -H or C1-C2 alkyl; R6 is selected from C1-C3 alkylene; Z is selected from H + , K + 、Na + or NH4 + ; R7, R8, R9, R 10 Each independently selected from -H, -CH3, -COOM 1 or -CH2COOM 2 , and R7, R8, R9, R 10 Not simultaneously selected from -H or -CH3; wherein, M 1 、M 2 Each independently selected from H + , K + 、Na + or NH4 + ; R 11 、R 12 、R 13 、R 14 、R 15 Each independently selected from -H or C1-C2 alkyl;

[0071] The initiator G has a structure shown in formula (10);

[0072] Wherein, Q1, Q2, Q3, Q4, Q5, and Q6 are polymer segments, and Q1, Q2, Q3, Q4, Q5, and Q6 each independently contain a structural unit D and a structural unit E; wherein the structural unit D has a structure represented by formula (11); and the structural unit E has a structure represented by formula (12);

[0073] Among them, R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 Each independently selected from -H or -CH3;

[0074] The molar ratio of the structural unit D: structural unit E is 1: (0.5-5);

[0075] The molar ratio of the monomer A':monomer B':monomer C':initiator G is 10:(0.5-8):(0.1-4):(0.5-2).

[0076] According to the present invention, in the preparation method of the polymer, the monomer A', monomer B' and monomer C' are polymerized to form a main chain structure, wherein the monomer A' can provide a sulfonic acid group, the monomer B' can provide a carboxyl group, and the monomer C' can provide an amide group. The hydrophilic groups contained in the above raw material monomers make the main chain structure formed by polymerization have excellent water solubility and ion complexing ability.

[0077] According to the present invention, for the monomer A', preferably, R1, R2, R3, R4, and R5 are each independently selected from -H or -CH3; and R6 is -CH2-.

[0078] According to the present invention, for the monomer C', preferably, R 11 、R 12 、R 13 、R 14 、R 15 Each is independently selected from -H or -CH3.

[0079] According to the present invention, in the method for preparing the polymer, the initiator G can form a capping structure connected to both ends of the main chain structure.

[0080] According to the present invention, in the initiator G, the polymer segments Q1, Q2, Q3, Q4, Q5, and Q6 are independent of each other and may be the same or different, preferably the same.

[0081] According to the present invention, among the structural units D contained in the initiator G, preferably, R16 、R 17 、R 18 and R 19 is -H.

[0082] According to the present invention, among the structural units E contained in the initiator G, preferably, R 20 、R 21 and R 22 -H, R 23 is -CH3.

[0083] According to the present invention, in the initiator G, the structural unit D and the structural unit E, on the basis of satisfying the above-mentioned proportional relationship, preferably, the molar ratio of the structural unit D:structural unit E is 1:(1-3), which can enable the polymer segments Q1, Q2, Q3, Q4, Q5, and Q6 to have better amphiphilic thermosensitive properties.

[0084] According to the present invention, preferably, the weight average molecular weight of the initiator G is (0.5-3)×10 4 g / mol.

[0085] According to the present invention, in the method for preparing the polymer, the monomers A', B', C', and G, while satisfying the aforementioned feed ratio, preferably have a molar ratio of A':B':C':G of 10:(1-6):(1-3):(1-1.5). This preferred feed ratio further balances the effects of the polymer on the retarding properties and water loss properties of the oil well cement slurry.

[0086] According to the present invention, in the method for preparing the polymer, the first solvent is selected from an alcohol solvent and / or a ketone solvent. Preferably, the first solvent can be selected from at least one of methyl isobutyl ketone, ethanol, propanol, butanol and acetone, and more preferably methyl isobutyl ketone.

[0087] According to the present invention, in the method for preparing the polymer, the polymerization reaction conditions include: temperature of 60-90° C. and time of 2-4 hours.

[0088] According to a preferred embodiment of the present invention, the operation process of preparing the polymer includes:

[0089] (I) dividing the first solvent into two parts, a first solvent-i and a first solvent-ii, and mixing the monomer A', the monomer B', the monomer C', the initiator G, and the first solvent-i to obtain a mixed solution;

[0090] (II) heating the first solvent-ii to a temperature required for a polymerization reaction, and then adding the mixed solution to carry out a polymerization reaction to obtain a reaction product system;

[0091] (III) separating and treating the reaction product system to obtain the polymer.

[0092] According to the present invention, in step (I), preferably, the molar ratio of the first solvent-i:first solvent-ii is 1:(0.5-5).

[0093] According to the present invention, in step (II), preferably, the mixed solution is added dropwise at a uniform rate to the first solvent-ii heated to the temperature required for the polymerization reaction, the dropping process lasts for 3-8 hours, and then the polymerization reaction is carried out by keeping the temperature for 2-4 hours.

[0094] According to the present invention, in step (III), preferably, the separation treatment adopts a vacuum distillation method to separate and remove the first solvent in the reaction product system to obtain the target polymer.

[0095] In the present invention, the preparation method of the initiator G comprises:

[0096] (1) in the presence of a first catalyst, reacting 5-bromo-1,2,3-pyrogallol with monomer D' and monomer E' to obtain a first product;

[0097] Wherein, the monomer D' has a structure shown in formula (13); the monomer E' has a structure shown in formula (14);

[0098] Among them, R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 Each independently selected from -H or -CH3;

[0099] (2) in the presence of a second solvent, subjecting the first product to a second reaction with metal powder L to obtain a second product; subjecting the second product to a third reaction with carbon dioxide to obtain a third product; and subjecting the third product to a fourth reaction in the presence of an acid, and separating the resulting product system to obtain a fourth product;

[0100] (3) in the presence of a third solvent, subjecting the fourth product to a fifth reaction with thionyl chloride to obtain a fifth product;

[0101] (4) The fifth product is reacted with hydrogen peroxide to obtain the initiator G.

[0102] According to the present invention, in step (1), the main process of the first reaction is as follows:

[0103] 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 is independently selected from -H or -CH3.

[0104] According to the present invention, in step (1), preferably, the first catalyst and 5-bromo-1,2,3-pyrogallol are mixed, and then the monomer D' and monomer E are added to carry out the first reaction to obtain a viscous first product.

[0105] According to the present invention, in step (1), the first catalyst can be selected from at least one of boron trifluoride-diethyl ether complex, sodium hydroxide and potassium hydroxide.

[0106] According to the present invention, in step (1), the molar ratio of 5-bromo-1,2,3-benzenetriol: first catalyst: monomer D': monomer E' is 1: (0.01-0.05): (1-3): (3-9).

[0107] According to the present invention, in step (1), the conditions of the first reaction include: temperature of 100-150° C., pressure of 2.5-3 MPa, and time of 2-5 h.

[0108] According to the present invention, in step (2), the main process of the second reaction is as follows:

[0109] According to the present invention, in step (2), preferably, the second solvent is mixed with the metal powder L, and then the first product is added to carry out the second reaction.

[0110] According to the present invention, in step (2), the main process of the third reaction is as follows:

[0111] According to the present invention, in step (2), preferably, carbon dioxide is introduced into the product system obtained by the second reaction, so that the second product undergoes a third reaction with carbon dioxide.

[0112] According to the present invention, in step (2), the main process of the fourth reaction is as follows:

[0113] According to the present invention, in step (2), preferably, after the third reaction is completed, an acid solution (such as a 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 that, the mixture is allowed to stand for stratification and the precipitate phase is separated to obtain the fourth product.

[0114] 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, dibutyl ether and dipentyl ether.

[0115] According to the present invention, in step (2), the metal powder L can be selected from magnesium powder or zinc powder.

[0116] According to the present invention, in step (2), when all the second products obtained from the second reaction participate in the third reaction, preferably, the molar ratio of the first product: metal powder L: carbon dioxide is 1:(1-2):(2-4).

[0117] According to the present invention, in step (2), the conditions of the second reaction include: temperature of -5-0°C and time of 3-5h.

[0118] According to the present invention, in step (2), the conditions of the third reaction include: temperature of -5-0°C and time of 2-8h.

[0119] According to the present invention, in step (2), the conditions of the fourth reaction include: temperature of 0-10°C, pH of 2-4, and time of 4-5h.

[0120] According to the present invention, in step (3), the main process of the fifth reaction is as follows:

[0121] 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 react to obtain the fifth product.

[0122] According to the present invention, in step (3), the third solvent may be a benzene solvent. Preferably, the third solvent may be selected from at least one of benzene, toluene, ethylbenzene and xylene.

[0123] According to the present invention, in step (3), the molar ratio of the fourth product to thionyl chloride is 1:(5-7).

[0124] According to the present invention, in step (3), the conditions of the fifth reaction include: temperature of 80-150° C. and time of 5-8 h.

[0125] According to the present invention, in step (4), the main process of the sixth reaction is as follows:

[0126] According to the present invention, in step (4), preferably, the fifth product is mixed with an aqueous hydrogen peroxide solution, the resulting mixture is added to an aqueous solution of a co-solvent, and the temperature is raised to the required reaction temperature to carry out the sixth reaction, and the product is filtered to obtain the initiator G.

[0127] According to the present invention, in step (4), the molar ratio of the fifth product to hydrogen peroxide is 1:(1.5-2).

[0128] According to the present invention, in step (4), the cosolvent can be a composite reagent of a surfactant and a 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.

[0129] According to the present invention, preferably, in the aqueous solution of the co-solvent, the weight ratio of the surfactant: the soluble carbonate: water is (0.5-5): (15-20):100.

[0130] According to the present invention, in step (4), the conditions of the sixth reaction include: temperature of 30-40° C. and time of 2-4 h.

[0131] The present invention carries out a polymerization reaction between a specific monomer A' capable of providing a sulfonic acid group, a monomer B' capable of providing a carboxyl group, and a monomer C' capable of providing an amide group and an initiator G having a specific multi-branched structure, thereby obtaining a polymer having a hydrophilic main chain and multi-branched end-capping structures at both ends of the hydrophilic main chain. The hydrophilic main chain and the multi-branched end-capping structures volatilize together, so that the obtained polymer has excellent retarding ability for oil well cement slurry at high temperature, and the retarding ability weakens as the temperature decreases. The polymer, as a retarder component, can accelerate the strength development of the top cement slurry while ensuring the retarding effect of the oil well cement slurry under cyclic temperature conditions, and can make the compressive strength of the top cement slurry reach above 7MPa at 80°C for 48 hours. The polymer also has good compatibility and little effect on the water loss of the oil well cement slurry.

[0132] The third aspect of the present invention provides a polymer obtained by the preparation method described in the second aspect.

[0133] According to the present invention, the structure, parameters and properties of the polymer prepared by the method described in the second aspect are the same as those of the polymer described in the first aspect of the present invention, and will not be described in detail here.

[0134] A fourth aspect of the present invention provides a retarder, comprising: a main polymer and a cosolvent;

[0135] Wherein, the weight ratio of the main polymer:cosolvent is 10:(0.4-2);

[0136] The main polymer is the polymer described in the first aspect or the third aspect.

[0137] According to the present invention, in the retarder, the cosolvent may be selected from alcohols and / or ketones, preferably at least one of ethanol, isopropanol, butanol and methyl isobutyl ketone.

[0138] According to the present invention, the retarder can be prepared by mixing the main polymer and the auxiliary agent according to the above ratio.

[0139] The retarder provided by the present invention uses the specific polymer provided by the present invention as a main functional component. It is a new type of retarder that can quickly solidify cement slurry under conditions below the circulating temperature. The retarder is used in cementing long sealing sections. Under the premise of ensuring the retarding effect of the bottom oil well cement slurry, it can accelerate the strength development of the top cement slurry, and can make the top cement slurry reach a compressive strength of more than 7MPa at 80°C for 48 hours. The retarder has good compatibility and has little effect on the water loss of the oil well cement slurry.

[0140] According to the present invention, the retarder is preferably 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: the cosolvent: the water is 10: (0.4-2): (20-30).

[0141] The fifth aspect of the present invention provides an oil well cement slurry containing the retarder described in the fourth aspect.

[0142] According to the present invention, the components of the oil well cement slurry, in addition to the 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, lightening agents, fluid loss additives, drag reducers, defoaming agents, etc.

[0143] 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, in the oil well cement slurry, the weight ratio of the retarder to the oil well cement in the oil well cement slurry is (1-8):100.

[0144] The present invention will be described in detail below through examples. In the following preparation examples, examples and comparative examples, unless otherwise specified, all methods are conventional methods; and the reagents and materials described, unless otherwise specified, can be obtained from commercial sources.

[0145] In the following preparation examples and embodiments, the molar ratio of the prepared initiator G and the structural units contained in the polymer is calculated based on the feed amounts of the raw materials.

[0146] Preparation Example 1

[0147] This preparation example illustrates the preparation of initiator G.

[0148] (1) 5-bromo-1,2,3-pyrogallol and potassium hydroxide are added into a high-pressure reactor and mixed.

[0149] Nitrogen was introduced to maintain a pressure of 3 MPa, and monomer D' (ethylene oxide) was introduced to react for 3 h (reaction temperature was 110°C), and then monomer E' (propylene oxide) was introduced to react for 3 h (reaction temperature was 110°C) to obtain a viscous first product;

[0150] The molar ratio of 5-bromo-1,2,3-benzenetriol: potassium hydroxide: monomer D': monomer E' is 1:0.03:2:5;

[0151] (2) adding magnesium powder to anhydrous tetrahydrofuran, cooling the temperature to 0°C in an ice-water bath and reacting for 4 hours, then maintaining 0°C and introducing carbon dioxide gas into the reaction system for 6 hours; after the reaction, slowly adding a 10 wt% hydrochloric acid aqueous solution to the reaction product system while maintaining the temperature of the reaction system within the range of 0-10°C, the pH value of the reaction system is 3, and the reaction time is 4 hours; then standing and separating, collecting the precipitate phase to obtain the second product;

[0152] The molar ratio of the first product: magnesium powder: carbon dioxide is 1:1.5:3;

[0153] (3) adding the second product to toluene, then adding thionyl chloride, heating under reflux at 110° C. for 6 h, and removing the toluene by vacuum distillation after the reaction to obtain the third product;

[0154] Wherein, the molar ratio of the second product to thionyl chloride is 1:6;

[0155] (4) The third product and an aqueous solution of hydrogen peroxide were mixed evenly, and the mixture was slowly added dropwise to an aqueous solution of a cosolvent (the weight ratio of sodium dodecylbenzenesulfonate: sodium carbonate: water was 1:18:100). The addition was completed within 30 minutes. After the addition was completed, the mixture was heated to 40°C and reacted for 4 hours. The reaction product was filtered to obtain a solid, which was rinsed with deionized water and dried to obtain initiator G-1.

[0156] Wherein, the molar ratio of the third product: hydrogen peroxide: sodium carbonate is 1:1.7:2.

[0157] G-1 has the structure shown in formula (10), and the structural units of the polymer segments Q1, Q2, Q3, Q4, Q5, and Q6 in G-1 are calculated by the feed amount of raw materials. Structural unit The molar ratio is 1:2.5.

[0158] The weight average molecular weight of G-1 is 1.2×10 4 g / mol.

[0159] Preparation Example 2

[0160] This preparation example illustrates the preparation of initiator G.

[0161] According to the method of Preparation Example 1, the difference is that monomer D' is (1,2-dimethylethylene oxide) and monomer E' is (methylpropylene oxide). Other conditions and steps are the same as Preparation Example 1 to obtain initiator G-2.

[0162] G-2 has the structure shown in formula (10), and the structural units of the polymer segments Q1, Q2, Q3, Q4, Q5, and Q6 in G-2 are calculated by the feed amount of raw materials. Structural unit The molar ratio is 1:2.5.

[0163] The weight average molecular weight of G-2 is 2.2×10 4 g / mol.

[0164] Preparation Example 3

[0165] This preparation example illustrates the preparation of initiator G.

[0166] The method of Preparation Example 1 was followed, except that the molar ratio of 5-bromo-1,2,3-benzenetriol: potassium hydroxide: monomer D' (ethylene oxide): monomer E' (propylene oxide) was 1:0.03:3:3. Other conditions and steps were the same as those of Preparation Example 1 to obtain initiator G-3.

[0167] G-3 has the structure shown in formula (10), and the structural units of the polymer segments Q1, Q2, Q3, Q4, Q5, and Q6 in G-3 are calculated by the feed amount of raw materials. Structural unit The molar ratio is 1:1.

[0168] The weight average molecular weight of G-3 is 0.8×10 4 g / mol.

[0169] Preparation Example 4

[0170] This preparation example illustrates the preparation of initiator G.

[0171] The method of Preparation Example 1 was followed, except that the molar ratio of 5-bromo-1,2,3-benzenetriol: potassium hydroxide: monomer D' (ethylene oxide): monomer E' (propylene oxide) was 1:0.03:6:3. Other conditions and steps were the same as those of Preparation Example 1 to obtain initiator G-4.

[0172] G-4 has the structure shown in formula (10), and the structural units of the polymer segments Q1, Q2, Q3, Q4, Q5, and Q6 in G-4 are calculated by the feed amount of raw materials. Structural unit The molar ratio is 1:0.5.

[0173] The weight average molecular weight of G-4 is 1.5×10 4 g / mol.

[0174] Preparation Example 5

[0175] This preparation example illustrates the preparation of initiator G.

[0176] 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 reversed, i.e., monomer E' was introduced first and reacted for 3 h, followed by monomer D', which was then reacted for 3 h. Other conditions and steps were the same as those of Preparation Example 1, to obtain initiator G-5.

[0177] G-5 has the structure shown in formula (10), and the structural units of the polymer segments Q1, Q2, Q3, Q4, Q5, and Q6 in G-4 are calculated by the feed amount of raw materials. Structural unit The molar ratio is 1:0.5.

[0178] The weight average molecular weight of G-5 is 1.8×10 4 g / mol.

[0179] Example 1

[0180] This example illustrates the preparation of the polymer

[0181] (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 mixed solution;

[0182] The molar ratio of monomer A':monomer B':monomer C':initiator G-1:first solvent-i is 10:3:2:1.2:35;

[0183] (II) adding the first solvent-ii into a reactor, heating the temperature to 80° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 80° C. for 4 hours, and then maintaining the temperature for 4 hours to carry out a polymerization reaction to obtain a reaction product system;

[0184] (III) The reaction product system is subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P1).

[0185] The infrared spectrum of P1 is tested, and the results are shown in Figure 1. The stretching vibration absorption peak of the amide group is at 3464.1 cm -1 The carbonyl -C=O stretching vibration absorption peaks of amide group and carboxyl group in itaconic acid are at 1641.4 cm -1 At, sulfonic acid -SO3 - The stretching vibration absorption peak is at 1224.7 cm -1 The -CO- stretching vibration and bending vibration absorption peaks of the polyether segment are at 1039.6 cm -1 881cm -1 At this point, all the functional groups in the raw monomers appear in the infrared spectrum of the polymer, indicating that the polymerization is successfully initiated and the polymer of the present invention is prepared.

[0186] In P1, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:3:2; the structural unit D in the end-capping structure Structural unit E The molar ratio of P1 is 1:2.5; the weight average molecular weight of P1 is 53×10 4 g / mol.

[0187] Example 2

[0188] This example illustrates the preparation of the polymer

[0189] (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 mixed solution;

[0190] The molar ratio of monomer A':monomer B':monomer C':initiator G-1:first solvent-i is 10:4:3:1.2:35;

[0191] (II) adding the first solvent-ii into a reactor, heating the temperature to 80° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 80° C. for 4 hours, and then maintaining the temperature for 4 hours to carry out a polymerization reaction to obtain a reaction product system;

[0192] (III) The reaction product system is subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P2).

[0193] In P2, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:4:3; the structural unit D in the end-capping structure Structural unit E The molar ratio of P2 is 1:2.5; the weight average molecular weight of P2 is 41×10 4 g / mol.

[0194] Example 3

[0195] This example illustrates the preparation of the polymer

[0196] (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 mixed solution;

[0197] The molar ratio of monomer A':monomer B':monomer C':initiator G-1:first solvent-i is 10:0.6:4:1.5:30;

[0198] (II) adding the first solvent-ii into a reactor, heating the temperature to 80° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 80° C. for 4 hours, and then maintaining the temperature for 4 hours to carry out a polymerization reaction to obtain a reaction product system;

[0199] (III) The reaction product system is subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P3).

[0200] In P3, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:0.6:4; the structural unit D in the end-capping structure Structural unit E The molar ratio of P3 is 1:2.5; the weight average molecular weight of P3 is 15×10 4 g / mol.

[0201] Example 4

[0202] This example illustrates the preparation of the polymer

[0203] (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 mixed solution;

[0204] The molar ratio of monomer A':monomer B':monomer C':initiator G-1:first solvent-i is 10:7:0.5:1:35;

[0205] (II) adding the first solvent-ii into a reactor, heating the temperature to 90° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 90° C. for 3 hours, and then maintaining the temperature for 3 hours to carry out a polymerization reaction to obtain a reaction product system;

[0206] (III) The reaction product system is subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P4).

[0207] In P4, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:7:0.5; the structural unit D in the end-capping structure Structural unit E The molar ratio of P4 is 1:2.5; the weight average molecular weight of P4 is 24×10 4 g / mol.

[0208] Example 5

[0209] This example illustrates the preparation of the polymer

[0210] (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 mixed solution;

[0211] The molar ratio of monomer A':monomer B':monomer C':initiator G-1:first solvent-i is 10:8:4:1:35;

[0212] (II) adding the first solvent-ii into a reactor, heating the temperature to 90° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 90° C. for 3 hours, and then maintaining the temperature for 3 hours to carry out a polymerization reaction to obtain a reaction product system;

[0213] (III) The reaction product system is subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P5).

[0214] In P5, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:8:4; the structural unit D in the end-capping structure Structural unit E The molar ratio of P5 is 1:2.5; the weight average molecular weight of P5 is 30×10 4 g / mol.

[0215] Example 6

[0216] This example illustrates the preparation of the polymer

[0217] (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 mixed solution;

[0218] The molar ratio of monomer A':monomer B':monomer C':initiator G-2:first solvent-i is 10:7:0.5:1:35;

[0219] (II) adding the first solvent-ii into a reactor, heating the temperature to 90° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 90° C. for 3 hours, and then maintaining the temperature for 3 hours to carry out a polymerization reaction to obtain a reaction product system;

[0220] (III) The reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P6).

[0221] In P6, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:7:0.5; the structural unit D in the end-capping structure Structural unit E The molar ratio of P6 is 1:2.5; the weight average molecular weight of P6 is 30×10 4 g / mol.

[0222] Example 7

[0223] This example illustrates the preparation of the polymer

[0224] (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 mixed solution;

[0225] The molar ratio of monomer A':monomer B':monomer C':initiator G-3:first solvent-i is 10:7:0.5:1:35;

[0226] (II) adding the first solvent-ii into a reactor, heating the temperature to 90° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 90° C. for 3 hours, and then maintaining the temperature for 3 hours to carry out a polymerization reaction to obtain a reaction product system;

[0227] (III) The reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P7).

[0228] In P7, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:7:0.5; the structural unit D in the end-capping structure Structural unit E The molar ratio of P7 is 1:1; the weight average molecular weight of P7 is 42×10 4 g / mol.

[0229] Example 8

[0230] This example illustrates the preparation of the polymer

[0231] (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 mixed solution;

[0232] The molar ratio of monomer A':monomer B':monomer C':initiator G-4:first solvent-i is 10:7:0.5:1:35;

[0233] (II) adding the first solvent-ii into a reactor, heating the temperature to 90° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 90° C. for 3 hours, and then maintaining the temperature for 3 hours to carry out a polymerization reaction to obtain a reaction product system;

[0234] (III) The reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P8).

[0235] In P8, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:7:0.5; the structural unit D in the end-capping structure Structural unit E The molar ratio of P8 is 1:0.5; the weight average molecular weight of P8 is 35×10 4 g / mol.

[0236] Example 9

[0237] This example illustrates the preparation of the polymer

[0238] (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 mixed solution;

[0239] The molar ratio of monomer A':monomer B':monomer C':initiator G-5:first solvent-i is 10:7:0.5:1:35;

[0240] (II) adding the first solvent-ii into a reactor, heating the temperature to 90° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 90° C. for 3 hours, and then maintaining the temperature for 3 hours to carry out a polymerization reaction to obtain a reaction product system;

[0241] (III) The reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as P9).

[0242] In P9, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:7:0.5; the structural unit D in the end-capping structure Structural unit E The molar ratio of P9 is 1:0.5; the weight average molecular weight of P9 is 48×10 4 g / mol.

[0243] Comparative Example 1

[0244] Dissolve monomer A' (2-acrylamide-2-methylpropanesulfonic acid), monomer B' (itaconic acid), and monomer C' (N,N-dimethylacrylamide) in deionized water to obtain a mixed solution;

[0245] The mixed solution was heated to 80°C, ammonium persulfate was added, and the temperature was maintained at 80°C for polymerization for 4 h to obtain a polymer (denoted as D1);

[0246] The molar ratio of monomer A':monomer B':monomer C':ammonium persulfate:deionized water is 10:3:2:1.2:60;

[0247] In D1, structural unit A Structural unit B Structural unit C The molar ratio of D1 is 10:3:2; the weight average molecular weight of D1 is 43×10 4 g / mol.

[0248] Comparative Example 2

[0249] (I) Methyl isobutyl ketone is divided into two parts, namely a first solvent-i and a first solvent-ii (the molar ratio of the first solvent-i to the first solvent-ii is 1:1.5), and monomer B' (itaconic acid), monomer C' (N,N-dimethylacrylamide), and initiator G-1 are added to the first solvent-i and mixed uniformly to obtain a mixed solution;

[0250] The molar ratio of monomer B':monomer C':initiator G-1:first solvent-i is 3:2:1.2:35;

[0251] (II) adding the first solvent-ii into a reactor, heating the temperature to 80° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 80° C. for 4 hours, and then maintaining the temperature for 4 hours to carry out a polymerization reaction to obtain a reaction product system;

[0252] (III) The reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as D2).

[0253] In D2, the structural unit B in the hydrophilic main chain Structural unit C The molar ratio is 3:2; the structural unit D in the end-capping structure Structural unit E The molar ratio of D2 is 1:2.5; the weight average molecular weight of D2 is 48×10 4 g / mol.

[0254] Comparative Example 3

[0255] (I) Methyl isobutyl ketone is divided into two parts, namely a first solvent-i and a first solvent-ii (the molar ratio of the first solvent-i to the first solvent-ii is 1:1.5), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid), monomer C' (N,N-dimethylacrylamide), and initiator G-1 are added to the first solvent-i and mixed uniformly to obtain a mixed solution;

[0256] The molar ratio of monomer A':monomer C':initiator G-1:first solvent-i is 10:2:1.2:35;

[0257] (II) adding the first solvent-ii into a reactor, heating the temperature to 80° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 80° C. for 4 hours, and then maintaining the temperature for 4 hours to carry out a polymerization reaction to obtain a reaction product system;

[0258] (III) The reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as D3).

[0259] In D3, the structural unit A in the hydrophilic main chain Structural unit C The molar ratio is 10:2; the structural unit D in the end-capping structure Structural unit E The molar ratio of D3 is 1:2.5; the weight average molecular weight of D3 is 38×10 4 g / mol.

[0260] Comparative Example 4

[0261] (I) Methyl isobutyl ketone is divided into two parts, namely a first solvent-i and a first solvent-ii (the molar ratio of the first solvent-i to the first solvent-ii is 1:1.5), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid), monomer B' (itaconic acid), and initiator G-1 are added to the first solvent-i and mixed uniformly to obtain a mixed solution;

[0262] The molar ratio of monomer A':monomer B':initiator G-1:first solvent-i is 10:3:1.2:35;

[0263] (II) adding the first solvent-ii into a reactor, heating the temperature to 80° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 80° C. for 4 hours, and then maintaining the temperature for 4 hours to carry out a polymerization reaction to obtain a reaction product system;

[0264] (III) The reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as D4).

[0265] In D4, the structural unit A in the hydrophilic main chain Structural unit B The molar ratio is 10:3; the structural unit D in the end-capping structure Structural unit E The molar ratio of P1 is 1:2.5; the weight average molecular weight of P1 is 26×10 4 g / mol.

[0266] Comparative Example 5

[0267] (I) Methyl isobutyl ketone is divided into two parts, a first solvent-i and a first solvent-ii (the molar ratio of the first solvent-i to the first solvent-ii is 1:1.5), and monomer A' (2-acrylamide-2-methylpropanesulfonic acid), monomer B' (itaconic acid), monomer C' (N,N-dimethylacrylamide), and initiator G-1 are added to the first solvent-i and mixed uniformly to obtain a mixed solution;

[0268] The molar ratio of monomer A':monomer B':monomer C':initiator G-1:first solvent-i is 10:10:7:3:40;

[0269] (II) adding the first solvent-ii into a reactor, heating the temperature to 80° C., then uniformly adding the mixed solution dropwise to the first solvent-ii at 80° C. for 4 hours, and then maintaining the temperature for 4 hours to carry out a polymerization reaction to obtain a reaction product system;

[0270] (III) The reaction product system was subjected to vacuum distillation to separate and remove methyl isobutyl ketone to obtain a polymer (denoted as D5).

[0271] In D5, the structural unit A in the hydrophilic main chain Structural unit B Structural unit C The molar ratio is 10:10:7; the structural unit D in the end-capping structure Structural unit E The molar ratio of D5 is 1:2.5; the weight average molecular weight of D5 is 47×10 4 g / mol.

[0272] Test Case

[0273] The polymers P1-P9 and D1-D5 prepared in Examples 1-9 and Comparative Examples 1-5 were respectively mixed with anhydrous ethanol and deionized water at a weight ratio of 10:1:30 to prepare oil well cement retarders (respectively designated as S1-S9 and DS1-DS5);

[0274] The experimental oil well cement slurry was prepared using the above-mentioned retarders S1-S9 and DS1-DS5. The cement slurry was prepared and tested for thickening time, water loss, free liquid and compressive strength in accordance with GB / T 19139-2012 "Test Methods for Oil Well Cement".

[0275] 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 reducer BXF-200L + 2.8g retarder + 2.5g drag reducer CF40L + 0.1g defoamer G603);

[0276] Among them, microsilicon: silicon content ≥5%, specific surface area 15-25m 2 / g;

[0277] Hollow glass microspheres: density 0.6g / cm 3 , diameter 5-30 μm;

[0278] Suspension concentrate BCJ-300S: purchased from Tianjin PetroChina Boxing Engineering Technology Co., Ltd.

[0279] Fluid loss additive BXF-200L: purchased from Tianjin PetroChina Boxing Engineering Technology Co., Ltd.

[0280] Drag reducer CF40L: purchased from Tianjin PetroChina Boxing Engineering Technology Co., Ltd.

[0281] Defoaming agent G603: purchased from Tianjin PetroChina Boxing Engineering Technology Co., Ltd.

[0282] The results are shown in Table 1.

[0283] Table 1

[0284] Note: In Table 1, the thickening temperature is 125°C, the test pressure is 90 MPa, and the top temperature is 80°C.

[0285] As can be seen from Table 1, the oil well cement retarders S1-S9 prepared using the polymers P1-P9 provided by the present invention have an excellent retarding effect on the experimental oil well cement slurries. The thickening time of the oil well cement slurries can reach more than 350 minutes, and the top compressive strength after 48 hours is greater than 7 MPa (Figure 2 shows the thickening curve of the experimental cement slurry using retarder S1 at 125°C, with a thickening time of 432 minutes; Figure 3 shows the compressive strength development curve of the experimental cement slurry using retarder S1 at 80°C, with hardening and strength development starting at 13.5 hours and a compressive strength of 17.2 MPa after 48 hours). The top strength develops rapidly, and no over-retardation occurs. The water loss is no more than 45 mL, meeting the requirements of deep well cementing construction. Among them, retarders S1 and S2 exhibit particularly excellent overall performance, with the oil well cement slurries having a thickening time of more than 430 minutes, a top compressive strength of more than 12 MPa after 48 hours, and a water loss of no more than 40 mL.

[0286] In addition, the ultra-long sealing section was simulated to be returned to the ground once, and the strength development of the cement slurry was tested under the condition of a top temperature of 30°C. Figure 4 shows the compressive strength development curve of the experimental cement slurry using retarder S1 at 30°C. The cement slurry began to harden after 36 hours, and the compressive strength reached 3.2 MPa after 48 hours. There was no super-retardation phenomenon, which can meet the requirements of cementing construction in long sealing sections.

[0287] The above effects indicate that the polymer and oil well cement retarder provided by the present invention can solve the problem of ultra-retarded setting of cement slurry at the top of a long sealing section in deep wells. The top strength develops rapidly, has no effect on the water loss of the cement slurry, and contains no free liquid, thus having good engineering application prospects.

[0288] In particular, retarders D1-D5 do not contain the polymer of the present invention and cannot solve the problem of super-slow setting of cement slurry at the top of the long sealing section (Figure 5 shows the thickening curve of the experimental cement slurry using retarder DS1 at 125°C, with a thickening time of 406 minutes; Figure 6 shows the compressive strength development curve of the experimental cement slurry using retarder DS1 at 80°C, showing no strength after 48 hours and starting to harden after 130 hours, maintaining a low compressive strength and exhibiting super-slow setting, which cannot meet the requirements of cementing construction in the long sealing section).

[0289] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

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

2. The polymer according to claim 1, wherein R1, R2, R3, R4, R5 are each independently selected from -H or -CH3; R6 is -CH2-; R 11 , R 12 , R 13 , R 14 , R 15 are each independently selected from -H or -CH3; R 16 , R 17 , R 18 , R 19 , R 20 , R 21 and R 22 For -H, R 23 is -CH3; and / or, the molar ratio of the structural unit A: structural unit B: structural unit C is 10:(1-6):(1-3); And / or, the molar ratio of the structural unit D: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, monomer A', monomer B', monomer C' and initiator G are polymerized to obtain a polymer; Wherein, the monomer A' has a structure shown in formula (7); the monomer B' has a structure shown in formula (8); and the monomer C' has a structure shown in formula (9); Wherein, R1, R2, R3, R4, R5 are each independently selected from -H or C1-C2 alkyl; R6 is selected from C1-C3 alkylene; Z is selected from H + , K + 、Na + or NH4 + ; R7, R8, R9, R 10 Each independently selected from -H, -CH3, -COOM 1 or -CH2COOM 2 , and R7, R8, R9, R 10 are not simultaneously selected from -H or -CH3; wherein 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 C1-C2 alkyl; The initiator G has a structure shown in formula (10): Wherein, Q1, Q2, Q3, Q4, Q5, Q6 are polymer segments, and Q1, Q2, Q3, Q4, Q5, Q6 each independently contain a structural unit D and a structural unit E; wherein the structural unit D has a structure shown in formula (11); and the structural unit E has a structure shown in formula (12); Among them, R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 Each is independently selected from -H or -CH3; The molar ratio of the structural unit D: structural unit E is 1: (0.5-5); The molar ratio of the 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, R5 are each independently selected from -H or -CH3; R6 is -CH2-; R 11 , R 12 , R 13 , R 14 , R 15 are each independently selected from -H or -CH3; R 16 , R 17 , R 18 , R 19 , R 20 , R 21 and R 22 For -H, R 23 is -CH3; and / or, the molar ratio of the structural unit D: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 polymerization reaction conditions include: temperature of 60-90° C. and time of 2-4 h.

7. The method according to claim 4 or 5, wherein: The preparation method of the initiator G comprises: (1) in the presence of a first catalyst, subjecting 5-bromo-1,2,3-pyrogallol to a first reaction with monomer D' and monomer E' to obtain a first product; Wherein, the monomer D' has a structure shown in formula (13); the monomer E' has a structure shown in formula (14); Among them, R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 Each is independently selected from -H or -CH3; (2) in the presence of a second solvent, subjecting the first product to a second reaction with metal powder L to obtain a second product; subjecting the second product to a third reaction with carbon dioxide to obtain a third product; and subjecting the third product to a fourth reaction in the presence of an acid, and separating the resulting product system to obtain a fourth product; (3) in the presence of a third solvent, subjecting the fourth product to a fifth reaction with thionyl chloride to obtain a fifth product; (4) subjecting the fifth product to a sixth reaction 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-ether complex, sodium hydroxide and potassium hydroxide; and / or, the molar ratio of 5-bromo-1,2,3-pyrogallol: first catalyst: monomer D': monomer E' is 1: (0.01-0.05): (1-3): (3-9); And / or, the conditions of the first reaction include: temperature of 100-150° C., pressure of 2.5-3 MPa, and 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 gold 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 of the second reaction include: temperature of -5-0°C, time of 3-5h; And / or, the conditions of the third reaction include: temperature of -5-0°C, time of 2-8h; And / or, the conditions of the fourth reaction include: temperature of 0-10°C, pH of 2-4, and time of 4-5h.

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

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 of the sixth reaction include: temperature of 30-40° C. and time of 2-4 h.

12. A polymer obtained by the preparation method according to any one of claims 4 to 11.

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

14. The oil well cement retarder according to claim 13, wherein: The co-solvent is alcohol and / or ketone.

15. An oil well cement slurry comprising the retarder according to claim 13 or 14.

Images