Polymer, preparation method thereof and thickening composition containing polymer

Abstract

The invention provides a polymer, a preparation method thereof and a thickening composition containing the polymer. Monomers of the polymer comprise acrylamide, allyl-beta-cyclodextrin, (2-methyl-3-acrylamide propyl) butyl dimethyl ammonium chloride and styrene; the thickening composition comprises the polymer provided by the invention, a suspending agent, an activating agent, an emulsifying agent and a solvent, is relatively high in viscosity, good in sedimentation stability, good in dispersity in 20wt% hydrochloric acid and strong in temperature resistance and shearing resistance, and can meet the requirement of deep acidification at high temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield development, and particularly relates to a polymer, a preparation method thereof, and a thickening composition containing the same. Background Art

[0002] In the prior art, the viscosity of the high-temperature gel acid system decreases rapidly during the heating process, and its shear resistance at high temperatures is poor. It is not suitable for use as a high-temperature on-line variable-viscosity acid for acidizing marine oil and gas reservoirs with temperatures exceeding 150°C. To improve the temperature resistance of the acid solution, it is necessary to improve the performance of the thickening agent. At present, most of the thickening agents used in on-site acidizing are prepared with powders, and the emulsion system is only simply emulsified on the basis of conventional cationic polymers, resulting in a temperature resistance that cannot reach 150°C.

[0003] Therefore, in view of the above deficiencies, it is urgent to develop a new type of thickening agent for acidizing to improve its stability and viscosity at high temperatures and achieve the instant preparation of acid solutions. Summary of the Invention

[0004] One aspect of the present invention provides a polymer, the monomers of which include acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride, and styrene.

[0005] According to a specific embodiment of the present invention, taking the total mass of the monomers as 100%, the content of acrylamide is 0.75 to 1 wt%, the content of allyl-β-cyclodextrin is 68 to 69 wt%, the content of (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride is 9 to 11.2 wt%, and the content of styrene is 20 to 22 wt%.

[0006] According to a specific embodiment of the present invention, the weight-average molecular weight of the polymer is 2.698×10 6 to 2.989×10 6 ; and / or

[0007] the particle size of the polymer is 80 to 200 mesh;

[0008] Preferably, the weight-average molecular weight of the polymer is 2.721×10 6 .

[0009] Another aspect of the present invention provides a method for preparing the polymer as described in one aspect of the present invention, which includes the following steps:

[0010] React acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride, and styrene under the action of an initiator to obtain the polymer.

[0011] According to a specific embodiment of the present invention, the total mass of the acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride and styrene is counted as 100%, the dosage of the acrylamide is 0.75 to 1 wt%, the dosage of the allyl-β-cyclodextrin is 68 to 69 wt%, the dosage of the (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride is 9 to 11.2 wt% and the dosage of the styrene is 20 to 22 wt%; and / or

[0012] The dosage of the initiator is 0.4 wt% of the total mass of the acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride and styrene.

[0013] According to a specific embodiment of the present invention, the initiator is a mixture of persulfate and bisulfite;

[0014] Preferably, the mass ratio of the persulfate to the bisulfite is 2:1;

[0015] Preferably, the persulfate is ammonium persulfate; and / or

[0016] The bisulfite is sodium bisulfite.

[0017] According to a specific embodiment of the present invention, the reaction is carried out in water;

[0018] Preferably, the acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride and water are mixed, and then the initiator and styrene are added to carry out the reaction;

[0019] Preferably, the dosage of the water is sufficient to dissolve the acrylamide, allyl-β-cyclodextrin and (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride;

[0020] Preferably, the conditions of the reaction are to react at 40 °C for 10 h; and / or

[0021] The reaction product obtained from the reaction is purified, dried and pulverized to obtain the polymer;

[0022] Preferably, the purification is carried out by washing with absolute ethanol; and / or

[0023] The conditions of the drying are to dry at 40 °C for 12 h.

[0024] According to a specific embodiment of the present invention, the (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride is prepared by the following steps:

[0025] React methylacrylamidopropyldimethylamine with chlorobutane to obtain the said (2-methyl-3-acrylamidopropyl)butyldimethylammonium chloride;

[0026] Preferably, mix the said methylacrylamidopropyldimethylamine, chlorobutane and a solvent, and then carry out the said reaction;

[0027] Preferably, the said solvent is anhydrous ethanol and / or acetone; and / or

[0028] The amount of the said solvent used is sufficient to dissolve the methylacrylamidopropyldimethylamine and chlorobutane;

[0029] Preferably, the molar ratio of the said solvent, methylacrylamidopropyldimethylamine and chlorobutane is 2.8:1.8:1;

[0030] Preferably, distill the reaction product obtained from the said reaction to remove the solvent and unreacted chlorobutane to obtain the purified (2-methyl-3-acrylamidopropyl)butyldimethylammonium chloride;

[0031] Preferably, the conditions of the said reaction are to react at 75 °C for 6.5 h.

[0032] According to a specific embodiment of the present invention, the allyl-β-cyclodextrin is prepared by the following method:

[0033] React β-cyclodextrin with allyl bromide under the action of a catalyst to obtain the said allyl-β-cyclodextrin;

[0034] Preferably, the mass ratio of the said β-cyclodextrin to allyl bromide is 1:1.23; and / or

[0035] Taking the mass of the said β-cyclodextrin as 100%, the amount of the said catalyst used is 35.2 wt%;

[0036] Preferably, the said reaction is carried out in a solvent;

[0037] Preferably, first mix the said β-cyclodextrin, catalyst and solvent, and then dropwise add the said allyl bromide to carry out the said reaction;

[0038] Preferably, the said solvent is dimethyl sulfoxide and / or N,N-dimethylformamide; and / or

[0039] The amount of the said solvent used is sufficient to dissolve the β-cyclodextrin;

[0040] Preferably, the said catalyst is an inorganic base;

[0041] Preferably, the said catalyst is sodium hydroxide;

[0042] Preferably, the reaction product obtained from the reaction is vacuum filtered, and the filter residue is collected and washed with acetone and dried to obtain the purified allyl-β-cyclodextrin;

[0043] Preferably, the drying condition is drying at 50 °C for 12 h;

[0044] Preferably, the reaction condition is reacting for 1 to 8 h under an ice bath condition of 0 to 10 °C.

[0045] The third aspect of the present invention provides a thickening composition, which includes a polymer, a suspending agent, an activator, an emulsifier and a solvent;

[0046] The polymer is the polymer described in the first aspect of the present invention or the polymer prepared by the method described in the second aspect of the present invention.

[0047] According to a specific embodiment of the present invention, taking the mass of the thickening composition as 100%, the thickening composition includes 39 wt% to 45 wt% of the polymer, 1.5 wt% to 2.2 wt% of the suspending agent, 0.5 wt% to 1.1 wt% of the activator, 2.4 wt% to 2.8 wt% of the emulsifier and 50 wt% to 55 wt% of the solvent.

[0048] According to a specific embodiment of the present invention, the suspending agent is organic bentonite; and / or

[0049] The activator is a lower alcohol; and / or

[0050] The emulsifier is an isomeric tridecanol nonionic surfactant; and / or

[0051] The solvent is white oil;

[0052] Preferably, the HLB value of the emulsifier is 7 to 13;

[0053] Preferably, the HLB value of the emulsifier is 9 to 12.

[0054] According to a specific embodiment of the present invention, the organic bentonite is quaternary ammonium salt organic bentonite; and / or

[0055] The lower alcohol is methanol and / or ethanol; and / or

[0056] The emulsifier is selected from at least two of isomeric tridecanol polyoxyethylene ether 1303, isomeric tridecanol polyoxyethylene ether 1305 and isomeric tridecanol polyoxyethylene ether 1307; and / or

[0057] The white oil is selected from at least two of 3# white oil, 5# white oil and 26# white oil and / or 15# white oil;

[0058] Preferably, the white oil is a mixture of 3# white oil and 26# white oil or 15# white oil;

[0059] Preferably, the mass ratio of the 3# white oil to the 26# white oil is (25 to 31):(24 to 28);

[0060] Preferably, the white oil is 15# white oil.

[0061] According to a specific embodiment of the present invention, the emulsifier is selected from a mixture of isomeric tridecyl alcohol polyoxyethylene ether 1303 and isomeric tridecyl alcohol polyoxyethylene ether 1307 with a mass ratio of 0.7:2, a mixture of isomeric tridecyl alcohol polyoxyethylene ether 1303, isomeric tridecyl alcohol polyoxyethylene ether 1305, and isomeric tridecyl alcohol polyoxyethylene ether 1307 with a mass ratio of 0.9:0.2:1.7, a mixture of isomeric tridecyl alcohol polyoxyethylene ether 1303 and isomeric tridecyl alcohol polyoxyethylene ether 1305 with a mass ratio of 0.8:2, a mixture of isomeric tridecyl alcohol polyoxyethylene ether 1303 and isomeric tridecyl alcohol polyoxyethylene ether 1307 with a mass ratio of 0.7:1.9, or a mixture of isomeric tridecyl alcohol polyoxyethylene ether 1303, isomeric tridecyl alcohol polyoxyethylene ether 1305, and isomeric tridecyl alcohol polyoxyethylene ether 1307 with a mass ratio of 0.6:1.2:0.6.

[0062] The fourth aspect of the present invention provides a method for preparing the thickening composition as described in the second aspect of the present invention, which includes the following steps:

[0063] 1) Mix the solvent and the suspending agent to obtain a first mixture;

[0064] 2) Mix the first mixture and the activator to obtain a second mixture;

[0065] 3) Mix the second mixture and the emulsifier to obtain a third mixture;

[0066] 4) Mix the polymer and the third mixture to obtain the thickening composition.

[0067] According to a specific embodiment of the present invention, steps 1) to 4) are all carried out by stirring and mixing;

[0068] Preferably, the stirring speed in steps 1) and 2) is independently 8000 to 11000 rpm; and / or

[0069] the stirring speed in steps 3) and 4) is 400 to 600 rpm.

[0070] According to a specific embodiment of the present invention, steps 1) to 4) are all carried out at room temperature (i.e., the ambient temperature without additional heating);

[0071] Preferably, in step 4), the polymer and the third mixture are mixed by stirring until no further stratification occurs to obtain the thickened composition.

[0072] Use of the polymer according to one of the present inventions, the polymer prepared by the method according to the second invention, the thickened composition according to the third invention, and the thickened composition prepared by the method according to the fourth invention in acidizing high-temperature carbonate rock reservoirs, particularly as a thickening agent for acidizing;

[0073] Preferably, the high temperature is not lower than 150 °C.

[0074] Advantages of the present invention:

[0075] Aiming at the problems of poor stability and insufficient temperature resistance of the thickening agent for acidizing in the prior art, the present invention provides a polymer, a preparation method thereof, and a thickened composition containing the same. The monomers of the polymer include acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride, and styrene; the thickened composition includes the polymer, a suspending agent, an activator, an emulsifier, and a solvent. The properties of the thickened composition provided by the present invention are as follows: at room temperature, the bulk viscosity is 369 to 414 mPa·s, the apparent viscosity is 51 to 58.5 mPa·s, the height of the supernatant after standing for 15 minutes is 0, and no stratification occurs. It has good dispersibility in 20 wt% hydrochloric acid for 8 minutes, and no obvious undissolved particles, precipitates, or floating substances appear; the gel acid prepared from the thickened composition, 20 wt% hydrochloric acid, and 5.5 wt% imidazoline corrosion inhibitor has a viscosity of 17.98 to 20.35 mPa·s after being sheared at a constant shear rate of 150 °C for 120 minutes. The above data prove that the thickened composition provided by the present invention has a high viscosity, good sedimentation stability, good dispersibility in 20 wt% hydrochloric acid, and strong temperature and shear resistance, and can meet the requirements for deep acidizing at a high temperature of not lower than 150 °C. -1 The viscosity after shearing at a constant shear rate of 150 °C for 120 minutes is 17.98 to 20.35 mPa·s. The above data prove that the thickened composition provided by the present invention has a high viscosity, good sedimentation stability, good dispersibility in 20 wt% hydrochloric acid, and strong temperature and shear resistance, and can meet the requirements for deep acidizing at a high temperature of not lower than 150 °C. Description of the Drawings

[0076] Figure 1 Infrared spectrum of the polymer prepared in Example 1;

[0077] Figure 2 Reaction equation for preparing allyl-β-cyclodextrin;

[0078] Figure 3 Reaction equation for preparing (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride. Detailed Embodiments

[0079] The present invention will be further described below in conjunction with embodiments. However, the embodiments of the present invention are only exemplary descriptions, and this implementation manner does not constitute a limitation to the present invention under any circumstances.

[0080] Preparation of polymer

[0081] The β-cyclodextrin, dimethyl sulfoxide, sodium hydroxide, allyl bromide, acetone, absolute ethanol, methacrylamidopropyl dimethylamine, chlorobutane, acrylamide, styrene, ammonium persulfate, and sodium bisulfite used in Example 1 are all of analytical grade.

[0082] Hereinafter, room temperature refers to 25 °C.

[0083] Example 1

[0084] According to Figure 2 the reaction equation shown below, allyl-β-cyclodextrin was prepared: Weigh 4.54 g of β-cyclodextrin and add it to a 150 mL beaker. Then slowly add dimethyl sulfoxide as a solvent until the β-cyclodextrin is completely dissolved. Subsequently, add 1.60 g of sodium hydroxide as a catalyst and stir evenly. Then, in an ice-water bath (temperature 0 to 10 °C), slowly add 4 mL of allyl bromide (i.e., 5.592 g) dropwise in two portions for reaction. After 1 h of full reaction, a large amount of yellow precipitate is obtained. Vacuum filter to remove the solvent, collect the filter residue, wash it with acetone, and dry it at 50 °C for 12 h to obtain white powdery allyl-β-cyclodextrin, which is stored in a sealed dry environment.

[0085] According to Figure 3 the reaction equation shown below, (2-methyl-3-methacrylamidopropyl) butyl dimethyl ammonium chloride was prepared: Add 5 mL of absolute ethanol as a solvent to a three-necked flask. At room temperature, add methacrylamidopropyl dimethylamine, and then slowly add chlorobutane under stirring (the molar ratio of absolute ethanol, methacrylamidopropyl dimethylamine, and chlorobutane is 2.8:1.8:1). After stirring evenly, heat the system to raise the temperature to 75 °C and react at a constant temperature for 6.5 h. Then use a rotary evaporator to distill off the solvent and unreacted chlorobutane to obtain a pale yellow viscous liquid, namely (2-methyl-3-methacrylamidopropyl) butyl dimethyl ammonium chloride.

[0086] Preparation of polymer: First, the styrene product was pretreated, specifically by washing it 3 times with a 10 wt% aqueous sodium hydroxide solution, washing it several times with pure water until neutral to remove the inhibitor therein, drying it, and subjecting it to vacuum distillation to collect the fraction at 59 to 60 °C and 53.3 kPa to obtain pretreated styrene.

[0087] Then, 0.08 g of acrylamide, 6.87 g of allyl-β-cyclodextrin, and 0.91 g of (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride were weighed separately and placed in a beaker. 85 mL of deionized water was added and stirred. After the three monomers were completely dissolved, they were poured into a three-necked flask containing a rotor. 0.04 g of initiator (a mixture of ammonium persulfate and sodium bisulfite with a mass ratio of 2:1) was added at one time. At the same time, 2.4 mL of styrene (i.e., 2.1648 g) was added dropwise. The reaction was carried out at 40 °C for 10 h to obtain a transparent gel; the obtained gel was washed with anhydrous ethanol 3 to 5 times, cut into pieces, and dried in an oven at 40 °C for 12 h to obtain a purified polymer with a weight-average molecular weight of 2.721×10 6 and it was a white solid. After being crushed and sieved, a fine powder of the polymer with a particle size of 80 to 200 mesh was obtained.

[0088] Test Example 1 - Polymer Structure Characterization

[0089] The fine powder of the polymer prepared in Example 1 was used to prepare a sample by KBr pressing. Infrared analysis was performed on it using a Shimadzu IRPrestige-21 Fourier transform infrared spectrometer, and the infrared spectrum was measured as Figure 1 shown.

[0090] Figure 1 It was shown that the stretching vibration peaks of N-H and C=O in -CONH of acrylamide appeared at 3350 cm 2 and 1645 cm -1 respectively, indicating that the polymer contained acrylamide structure; at the same time, the O-H stretching vibration peak of -OH in β-CD (i.e., β-cyclodextrin) appeared at 3350 cm -1 , and the skeletal vibration of β-CD appeared at 560 cm -1 , indicating that A-β-CD (i.e., allyl-β-cyclodextrin) structure existed in the polymer; in addition, the C-H stretching vibration peaks of methyl and methylene in (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride appeared at 2923 cm -1 , and the stretching vibration peak of the quaternary ammonium group (-(CH -1 )N(CH -1 ) 2 ) 3 ) 2 Cl) in (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride appeared at 948 cm -1 ; the stretching vibration of -CH=CH 2 in the benzene ring was at 3092, 3027, 3005 cm -1 and the stretching vibrations at 1500, 1474, 1447, 1421 cm -1It is the bending vibration peak of -CH=CH- in the benzene ring. It is proved that allyl-β-cyclodextrin and (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride were first prepared in Example 1, and the finally prepared polymer is a polymer product of styrene-cyclodextrin type polyacrylamide.

[0091] Preparation of thickening composition

[0092] The HLB values of isomeric tridecyl alcohol polyoxyethylene ether 1303, isomeric tridecyl alcohol polyoxyethylene ether 1305, and isomeric tridecyl alcohol polyoxyethylene ether 1307 used in the following examples and comparative examples are 9, 10, and 12 respectively;

[0093] The 806 organic bentonite rheological aid and 801-B organic bentonite rheological aid used in the following examples and comparative examples were both purchased from Zhejiang Qinghong New Materials Co., Ltd.;

[0094] The following normal temperature refers to the ambient temperature without additional heating.

[0095] Example 2

[0096] 1) Add 55 g of solvent 15# white oil to a reaction kettle equipped with a stirring device, stir at a speed of 11000 rpm, and uniformly add 2.2 g of a suspending agent (i.e., 806 organic bentonite rheological aid) to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain a first mixed liquid;

[0097] 2) Add 1.1 g of an activator (i.e., ethanol) to the reaction kettle in step 1) at a speed of 11000 rpm and stir evenly to obtain a second mixed liquid;

[0098] 3) Add 2.7 g of an emulsifier (i.e., a mixture of 0.7 g of isomeric tridecyl alcohol polyoxyethylene ether 1303 and 2 g of isomeric tridecyl alcohol polyoxyethylene ether 1307) to the reaction kettle in step 2) at a speed of 400 rpm and stir evenly to obtain a third mixed liquid;

[0099] 4) Uniformly add 39 g of the polymer prepared in Example 1 to the third mixed liquid until it is stirred evenly and no longer layers, and then the thickening composition is obtained.

[0100] Example 3

[0101] Preparation of thickening composition:

[0102] 1) Add 54 g of solvent 15# white oil to a reaction kettle equipped with a stirring device, stir at a speed of 10000 rpm, and uniformly add 1.5 g of a suspending agent (i.e., 801-B organic bentonite rheological aid) to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain a first mixed liquid;

[0103] 2) Add 0.7 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a rotational speed of 8000 rpm, stir evenly to obtain a second mixed solution;

[0104] 3) Add 2.8 g of emulsifier (i.e., a mixture of 0.9 g of isomeric tridecyl alcohol polyoxyethylene ether 1303, 0.2 g of isomeric tridecyl alcohol polyoxyethylene ether 1305, and 1.7 g of isomeric tridecyl alcohol polyoxyethylene ether 1307) to the reaction kettle in step 2) at a rotational speed of 400 rpm, stir evenly to obtain a third mixed solution;

[0105] 4) Add 41 g of the polymer prepared in Example 1 to the third mixed solution at a constant speed until it is stirred evenly and no longer layers, then the thickening composition is obtained.

[0106] Example 4

[0107] Preparation of thickening composition:

[0108] 1) Add 50 g of solvent 15# white oil to a reaction kettle equipped with a stirring device, stir at a rotational speed of 10000 rpm, and add 1.7 g of suspending agent (806 organobentonite rheology aid) at a constant speed to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain a first mixed solution;

[0109] 2) Add 0.5 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a rotational speed of 8000 rpm, stir evenly to obtain a second mixed solution;

[0110] 3) Add 2.8 g of emulsifier (i.e., a mixture of 0.8 g of isomeric tridecyl alcohol polyoxyethylene ether 1303 and 2 g of isomeric tridecyl alcohol polyoxyethylene ether 1305) to the reaction kettle in step 2) at a rotational speed of 400 rpm, stir evenly to obtain a third mixed solution;

[0111] 4) Add 45 g of the polymer prepared in Example 1 to the third mixed solution at a constant speed until it is stirred evenly and no longer layers, then the thickening composition is obtained.

[0112] Example 5

[0113] Preparation of thickening composition:

[0114] 1) Add 53 g of solvent 15# white oil to a reaction kettle equipped with a stirring device, stir at a rotational speed of 10000 rpm, and add 1.8 g of suspending agent (806 organobentonite rheology aid) at a constant speed to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain a first mixed solution;

[0115] 2) Add 0.6 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a rotational speed of 8000 rpm, stir evenly to obtain a second mixed solution;

[0116] 3) Add 2.6 g of emulsifier (i.e., a mixture of 0.7 g of isomeric tridecyl alcohol polyoxyethylene ether 1303 and 1.9 g of isomeric tridecyl alcohol polyoxyethylene ether 1307) to the reaction kettle in step 2), stir evenly, and obtain the third mixed liquid;

[0117] 4) Add 42 g of the polymer prepared in Example 1 to the third mixed liquid at a constant speed until it is stirred evenly and no longer separates into layers, then the thickening composition is obtained.

[0118] Example 6

[0119] Preparation of thickening composition:

[0120] 1) Add 52 g of solvent 15# white oil to the reaction kettle with a stirring device, stir at a speed of 10,000 rpm, and add 1.7 g of suspending agent (i.e., 806 organobentonite rheological aid) at a constant speed to prevent the suspending agent from caking during stirring until it is stirred evenly, and obtain the first mixed liquid;

[0121] 2) Add 0.9 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a speed of 8,000 rpm, stir evenly, and obtain the second mixed liquid;

[0122] 3) Add 2.4 g of emulsifier (i.e., a mixture of 0.6 g of isomeric tridecyl alcohol polyoxyethylene ether 1303, 0.6 g of isomeric tridecyl alcohol polyoxyethylene ether 1305, and 1.2 g of isomeric tridecyl alcohol polyoxyethylene ether 1307) to the reaction kettle in step 2) at a speed of 400 rpm, stir evenly, and obtain the third mixed liquid;

[0123] 4) Add 43 g of the polymer prepared in Example 1 to the third mixed liquid at a constant speed until it is stirred evenly and no longer separates into layers, then the thickening composition is obtained.

[0124] Example 7

[0125] Preparation of thickening composition:

[0126] 1) Add 25 g of solvent 3# white oil and 28 g of 26# white oil to the reaction kettle with a stirring device, stir at a speed of 10,000 rpm, and add 1.6 g of suspending agent (i.e., 801-B organobentonite rheological aid) at a constant speed to prevent the suspending agent from caking during stirring until it is stirred evenly, and obtain the first mixed liquid;

[0127] 2) Add 0.8 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a speed of 8,000 rpm, stir evenly, and obtain the second mixed liquid;

[0128] 3) Add 2.6 g of emulsifier (i.e., a mixture of 0.7 g of isomeric tridecanol polyoxyethylene ether 1303 and 1.9 g of isomeric tridecanol polyoxyethylene ether 1307) to the reaction kettle in step 2), and stir evenly to obtain a third mixed solution;

[0129] 4) Add 42 g of the polymer prepared in Example 1 to the third mixed solution at a constant speed until it is stirred evenly and no longer layers, then the thickening composition is obtained.

[0130] Example 8

[0131] Preparation of thickening composition:

[0132] 1) Add 31 g of solvent 3# white oil and 24 g of 26# white oil to the reaction kettle with a stirring device, stir at a speed of 10,000 rpm, and add 1.6 g of suspending agent (i.e., 806 organic bentonite rheology aid) at a constant speed to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain a first mixed solution;

[0133] 2) Add 0.8 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a speed of 8,000 rpm, and stir evenly to obtain a second mixed solution;

[0134] 3) Add 2.7 g of emulsifier (i.e., a mixture of 0.7 g of isomeric tridecanol polyoxyethylene ether 1303 and 2 g of isomeric tridecanol polyoxyethylene ether 1307) to the reaction kettle in step 2) at a speed of 400 rpm, and stir evenly to obtain a third mixed solution;

[0135] 4) Add 40 g of the polymer prepared in Example 1 to the third mixed solution at a constant speed until it is stirred evenly and no longer layers, then the thickening composition is obtained.

[0136] Comparative Example 1

[0137] Preparation of thickening composition:

[0138] 1) Add 53 g of solvent 15# white oil to the reaction kettle with a stirring device, stir at a speed of 10,000 rpm, and add 1.8 g of suspending agent (i.e., 806 organic bentonite rheology aid) at a constant speed to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain a first mixed solution;

[0139] 2) Add 0.6 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a speed of 8,000 rpm, and stir evenly to obtain a second mixed solution;

[0140] 3) Add 2.6 g of emulsifier (i.e., a mixture of 0.7 g of isomeric tridecanol polyoxyethylene ether 1303 and 1.9 g of isomeric tridecanol polyoxyethylene ether 1307) to the reaction kettle in step 2) at a speed of 400 rpm, and stir evenly to obtain a third mixed solution;

[0141] 4) Add 42 g of cationic polyacrylamide to the third mixed solution at a constant speed until it is stirred evenly and no longer stratified, thus obtaining the thickening composition.

[0142] Comparative Example 2

[0143] Prepare the thickening composition:

[0144] 1) Add 52 g of solvent 15# white oil to a reaction kettle equipped with a stirring device, stir at a speed of 10,000 rpm, and add 1.7 g of suspending agent (i.e., 806 organic bentonite rheology aid) at a constant speed to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain the first mixed solution;

[0145] 2) Add 0.9 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a speed of 8,000 rpm and stir evenly to obtain the second mixed solution;

[0146] 3) Add 2.4 g of emulsifier (i.e., a mixture of 0.6 g of isomeric tridecyl alcohol polyoxyethylene ether 1303, 0.6 g of isomeric tridecyl alcohol polyoxyethylene ether 1305, and 1.2 g of isomeric tridecyl alcohol polyoxyethylene ether 1307) to the reaction kettle in step 2) at a speed of 400 rpm and stir evenly to obtain the third mixed solution;

[0147] 4) Add 43 g of cationic polyacrylamide to the third mixed solution at a constant speed until it is stirred evenly and no longer stratified, thus obtaining the thickening composition.

[0148] Comparative Example 3

[0149] Prepare the thickening composition:

[0150] 1) Add 53 g of solvent 15# white oil to a reaction kettle equipped with a stirring device, stir at a speed of 10,000 rpm, and add 1.8 g of suspending agent (806 organic bentonite rheology aid) at a constant speed to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain the first mixed solution;

[0151] 2) Add 0.6 g of activator (i.e., ethanol) to the reaction kettle in step 1) at a speed of 8,000 rpm and stir evenly to obtain the second mixed solution;

[0152] 3) Add 2.6 g of emulsifier (i.e., isomeric tridecyl alcohol polyoxyethylene ether 1307) to the reaction kettle in step 2) at a speed of 400 rpm and stir evenly to obtain the third mixed solution;

[0153] 4) Add 42 g of the polymer prepared in Example 1 to the third mixed solution at a constant speed until it is stirred evenly and no longer stratified, thus obtaining the thickening composition.

[0154] Comparative Example 4

[0155] Preparation of thickening composition:

[0156] 1) Add 53 g of solvent 3# white oil into a reaction kettle equipped with a stirring device, stir at a speed of 10,000 rpm, and uniformly add 1.6 g of suspending agent (801-B organobentonite rheology aid) to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain a first mixed liquid;

[0157] 2) Add 0.8 g of activator (i.e., ethanol) into the reaction kettle in step 1) at a speed of 8,000 rpm, stir evenly to obtain a second mixed liquid;

[0158] 3) Add 2.6 g of emulsifier (i.e., a mixture of 0.7 g of isomeric tridecyl alcohol polyoxyethylene ether 1303 and 1.9 g of isomeric tridecyl alcohol polyoxyethylene ether 1307) into the reaction kettle in step 2) at a speed of 400 rpm, stir evenly to obtain a third mixed liquid;

[0159] 4) Uniformly add 42 g of the polymer prepared in Example 1 to the third mixed liquid until it is stirred evenly and no longer layers, then the thickening composition is obtained.

[0160] Comparative Example 5

[0161] Preparation of thickening composition:

[0162] 1) Add 53 g of solvent 15# white oil into a reaction kettle equipped with a stirring device, stir at a speed of 10,000 rpm, and uniformly add 1.8 g of suspending agent (806 organobentonite rheology aid) to prevent the suspending agent from caking during stirring until it is stirred evenly to obtain a first mixed liquid;

[0163] 2) Add 0.6 g of activator (i.e., ethylene glycol) into the reaction kettle in step 1) at a speed of 8,000 rpm, stir evenly to obtain a second mixed liquid;

[0164] 3) Add 2.6 g of emulsifier (i.e., a mixture of 0.7 g of isomeric tridecyl alcohol polyoxyethylene ether 1303 and 1.9 g of isomeric tridecyl alcohol polyoxyethylene ether 1307) into the reaction kettle in step 2) at a speed of 400 rpm, stir evenly to obtain a third mixed liquid;

[0165] 4) Uniformly add 42 g of the polymer prepared in Example 1 to the third mixed liquid until it is stirred evenly and no longer layers, then the thickening composition is obtained.

[0166] Test Example 2

[0167] Viscosity measurement, sedimentation stability measurement, dispersibility measurement at 8 min in acid, apparent viscosity measurement, and temperature and shear resistance measurement were carried out on the thickening compositions prepared in Examples 2 to 8 and Comparative Examples 1 to 5. The specific measurement methods for each index are as follows:

[0168] A. Determination of the bulk viscosity of the thickening composition

[0169] Use a six-speed rotational viscometer to measure the bulk viscosity of the thickening compositions prepared in Examples 2 to 8 and Comparative Examples 1 to 5, and read the pointer reading θ of the viscometer under the condition of a rotational speed of 100 r / min 100 .

[0170] The bulk viscosity (AV 本体 ) is calculated according to the following formula (1):

[0171] AV 本体 = θ 100 × 3 (1)

[0172] The results of the bulk viscosity determination are shown in Table 1.

[0173] B. Determination of the sedimentation stability of the thickening composition

[0174] At room temperature (25 °C), directly pour all the thickening compositions prepared in Examples 2 to 8 and Comparative Examples 1 to 5 into 12 50-mL graduated cylinders, let stand for 15 min, and record the height of the supernatant in each graduated cylinder. The lower the height of the supernatant, the better the sedimentation stability. The specific results are shown in Table 1.

[0175] C. Determination of the dispersibility of the thickening composition in acid at 8 min

[0176] ⅰ Determination of the acid injection time into the well:

[0177] The target well is a pipe string with a diameter of 76 mm and a well depth of 5000 m. Gelled acid (obtained by mixing the thickening composition and 20 wt% hydrochloric acid in a volume ratio of 0.009:1) is used as the main acid, and the displacement is 4 m 3 / min. It can be calculated that:

[0178] The wellbore volume is (76 mm / 1000 / 2) 2 × 3.14 × 5000 m = 22.67 m 3 ;

[0179] The gelled acid injection time into the well is 22.67 m 3 ÷ 4 m 3 / min = 5.67 min;

[0180] Because there is a process of increasing the displacement speed, the injection time into the well is estimated to be 8 min;

[0181] ⅱ Place 500 mL of 20 wt% hydrochloric acid (i.e., an aqueous HCl solution with an HCl mass fraction of 20 wt%) in a beaker, stir the hydrochloric acid at a rotation speed of 400 r / min ± 5 r / min, add 4.5 mL of the thickening composition prepared in any one of Examples 2 to 8 and Comparative Examples 1 to 5 to the beaker, start timing when stirring begins, stir for 8 min, let it stand at room temperature (25 °C) and record the dispersion of the thickening composition in the acid solution, and observe whether there are obvious undissolved particles, precipitates, and floating substances in the acid solution;

[0182] According to the method in ⅱ, measure the dispersibility of the thickening compositions prepared in Examples 2 to 8 and Comparative Examples 1 to 5 in hydrochloric acid at 8 min. The specific results are shown in Table 1.

[0183] D. Determination of the apparent viscosity of the thickening composition

[0184] Add the thickening compositions prepared in Examples 2 to 8 and Comparative Examples 1 to 5 to 300 mL of 20 wt% hydrochloric acid at an addition amount of 4.5 mL each, and measure the reading θ at 100 r / min 100 '.

[0185] The apparent viscosity (AV 表观 ) is calculated according to the following formula (2):

[0186] AV 表观 = θ 100 '×3 (2)

[0187] The measurement results of the apparent viscosity are shown in Table 1.

[0188] E. Determination of the temperature and shear resistance of the thickening composition

[0189] Prepare 300 mL of 20 wt% hydrochloric acid and place it in a beaker, stir the hydrochloric acid at a rotation speed of 400 r / min ± 5 r / min, add an imidazoline corrosion inhibitor (a 150 °C corrosion inhibitor purchased from Dongying Shiprui Petroleum Engineering Technology Co., Ltd., with a dosage of 5.5 wt% of the mass of 20% hydrochloric acid), stir evenly, then add 4.5 mL of the thickening composition prepared in any one of Examples 2 to 8 and Comparative Examples 1 to 5. After the thickening composition is completely dissolved, place it in a water bath at 25 °C ± 1 °C for 2 h to obtain a gelled acid; take 50 mL of the prepared gelled acid, put it into an acid-resistant rheometer, pressurize it with nitrogen to 0.7 MPa, and test the viscosity of the gelled acid after shearing at a constant shear rate of 150 °C and 170 s -1 for 120 min;

[0190] According to the above method, measure the temperature and shear resistance of the thickening compositions prepared in Examples 2 to 8 and Comparative Examples 1 to 5. The specific results are shown in Table 1.

[0191] Table 1. Performance evaluation of the thickening composition

[0192]

[0193] The data in Table 1 show that: at room temperature, the thickening compositions prepared in Examples 2 to 8 have high viscosity, good sedimentation stability, and good dispersibility in 20 wt% hydrochloric acid. Specifically, at room temperature: the bulk viscosity of the thickening compositions prepared in Examples 2 to 8 is 369 to 414 mPa·s, and the apparent viscosity is 51 to 58.5 mPa·s; the height of the supernatant after standing at room temperature for 15 minutes is 0, and there is no layering phenomenon; the dispersibility in 20 wt% hydrochloric acid is good within 8 min, and there are no obvious undissolved particles, precipitates, or floating substances. At a high temperature of 150 °C, the thickening compositions prepared in Examples 2 to 8 have strong shear resistance: the viscosity of the gel acid prepared from the thickening composition, 20 wt% hydrochloric acid, and 5.5 wt% imidazoline corrosion inhibitor after shearing at a constant shear rate of 170 s at 150 °C for 120 min is 17.98 to 20.35 mPa·s. Compared with Example 5, in Comparative Example 1, the polymer prepared in Example 1 in Example 5 was replaced with an equal mass of cationic polyacrylamide. Although the bulk viscosity of Comparative Example 1 is not much different from that of Example 5, its apparent viscosity decreased to 61% of that of Example 5, and its temperature and shear resistance decreased significantly. Compared with Example 5, the shear resistance performance of Comparative Example 1 decreased by 54%; compared with Example 6, in Comparative Example 2, the polymer prepared in Example 1 was also replaced with an equal amount of cationic polyacrylamide. Its bulk viscosity decreased by 18.7% compared with Example 6, and the sedimentation stability at room temperature also deteriorated significantly (layering occurred after standing at room temperature for 15 min, and the height of the supernatant reached 10 mL), and the dispersibility in acid became poor and it was easy to form clusters, so the temperature and shear resistance performance could not be measured. Comparing Comparative Example 1 with Example 5 and Comparative Example 2 with Example 6, it can be proved that the thickening composition prepared from the polymer of the present invention has better high temperature and shear resistance performance; -1 Compared with Example 5, in Comparative Example 3, the emulsifier in Example 5 (specifically, a mixture of isomeric tridecanol polyoxyethylene ether 1303 and isomeric tridecanol polyoxyethylene ether 1307) was replaced with an equal mass of isomeric tridecanol polyoxyethylene ether 1307. It was shown that the bulk viscosity of Comparative Example 3 at room temperature was 18.5% higher than that of Example 5, and the sedimentation stability decreased (specifically, layering occurred after standing at room temperature for 15 min, and the height of the supernatant reached 5 mL), and the dispersibility in 20 wt% hydrochloric acid was poor and it was easy to form clusters, so the temperature and shear resistance performance could not be measured, indicating that the type of emulsifier will affect the bulk viscosity, sedimentation stability, and dispersibility in acid of the thickening composition, and ultimately affect the temperature and shear resistance performance;

[0194]

[0195] ​Compared with Example 5, in Comparative Example 5, the activator ethanol was replaced with an equal mass of ethylene glycol, which significantly increased the bulk viscosity of the thickening composition. Specifically, it was 1.4 times the bulk viscosity of Example 5. The sedimentation stability also deteriorated, and stratification occurred after standing at room temperature for 15 minutes. The height of the supernatant liquid reached 7 mL. The dispersibility in acid became poor, and it was easy to form clusters, indicating that the activator would affect the bulk viscosity, sedimentation stability, and dispersibility in acid of the thickening composition, and ultimately affect the temperature and shear resistance performance;

[0196] Compared with Example 7, in Comparative Example 4, the solvents in Example 7 (specifically, No. 26 white oil and No. 3 white oil) were replaced with an equal mass of No. 3 white oil. Although its dispersibility in acid was good, it caused the bulk viscosity of the thickening composition to drop below 100 mPa·s, and the sedimentation stability also deteriorated (stratification occurred after standing at room temperature for 15 minutes, and the height of the supernatant liquid was 12 mL);

[0197] In summary, the types of polymer, solvent, activator, and emulsifier will all affect the viscosity, sedimentation stability, acid dispersibility, and temperature and shear resistance of the thickening composition. The thickening composition prepared by using the formula provided by the present invention can maintain a stable dispersion state for a long time, can be quickly dispersed in the acid solution, is not easy to agglomerate, and has good temperature and shear resistance, and can meet the requirements of deep acidification.

[0198] Although the present invention has been described with reference to specific embodiments, those skilled in the art should understand that various changes can be made without departing from the true spirit and scope of the present invention. In addition, various changes can be made to the main body, spirit, and scope of the present invention to adapt to specific situations, materials, material compositions, and methods. All such changes are included within the scope of the claims of the present invention.

Claims

1. A polymer, the monomers of which include acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride, and styrene.

2. The polymer according to claim 1, wherein, taking the total mass of the monomers as 100%, the content of acrylamide is 0.75 to 1 wt%, the content of allyl-β-cyclodextrin is 68 to 69 wt%, the content of (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride is 9 to 11.2 wt%, and the content of styrene is 20 to 22 wt%.

3. The polymer according to claim 1 or 2, wherein, The weight-average molecular weight of the polymer is 2.698×10 6 to 2.989×10 6 ; and / or the particle size of the polymer is 80 to 200 mesh.

4. A method for preparing the polymer according to any one of claims 1 to 3, which comprises the following steps: reacting the acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride, and styrene under the action of an initiator to obtain the polymer.

5. The method according to claim 4, wherein, taking the total mass of the acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride, and styrene as 100%, the dosage of acrylamide is 0.75 to 1 wt%, the dosage of allyl-β-cyclodextrin is 68 to 69 wt%, the dosage of (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride is 9 to 11.2 wt%, and the dosage of styrene is 20 to 22 wt%; and / or the dosage of the initiator is 0.4 wt% of the total mass of the acrylamide, allyl-β-cyclodextrin, (2-methyl-3-acrylamidopropyl) butyldimethylammonium chloride, and styrene.

6. The method according to claim 4 or 5, wherein, the initiator is a mixture of persulfate and bisulfite; preferably, the mass ratio of the persulfate to the bisulfite is 2:

1.

7. The method according to any one of claims 4 to 6, wherein, the reaction is carried out in water; and / or the reaction conditions are to react at 40°C for 10 h; and / or purifying, drying, and pulverizing the reaction product obtained from the reaction to obtain the polymer.

8. A thickening composition, which comprises a polymer, a suspending agent, an activator, an emulsifier, and a solvent; the polymer is the polymer according to any one of claims 1 to 3 or the polymer prepared by the method according to any one of claims 4 to 7.

9. The thickening composition according to claim 8, wherein, taking the mass of the thickening composition as 100%, the thickening composition comprises 39 wt% to 45 wt% of the polymer, 1.5 wt% to 2.2 wt% of the suspending agent, 0.5 wt% to 1.1 wt% of the activator, 2.4 wt% to 2.8 wt% of the emulsifier, and 50 wt% to 55 wt% of the solvent.

10. The thickening composition according to claim 8 or 9, wherein, The suspending agent is organic bentonite; and / or The activator is a lower alcohol; The emulsifier is an isomeric tridecanol nonionic surfactant; The solvent is white oil; Preferably, the HLB value of the emulsifier is 7 to 13.

11. The thickening composition according to claim 10, characterized in that the organic bentonite is a quaternary ammonium salt organic bentonite; and / or the emulsifier is selected from at least two of isomeric tridecanol polyoxyethylene ether 1303, isomeric tridecanol polyoxyethylene ether 1305, and isomeric tridecanol polyoxyethylene ether 1307; the white oil is selected from at least two of 3# white oil, 5# white oil, and 26# white oil and / or 15# white oil; Preferably, the white oil is a mixture of 3# white oil and 26# white oil or 15# white oil.

12. A method for preparing the thickening composition according to any one of claims 8 to 11, which comprises the following steps: 1) Mix the solvent and the suspending agent to obtain a first mixture; 2) Mix the first mixture and the activator to obtain a second mixture; 3) Mix the second mixture and the emulsifier to obtain a third mixture; 4) Mix the polymer and the third mixture to obtain the thickening composition.

13. The application of any one of the polymer according to any one of claims 1 to 3, the polymer prepared by the method according to any one of claims 4 to 7, the thickening composition according to any one of claims 8 to 11, and the thickening composition prepared by the method according to claim 12 in the acidification of high-temperature carbonate rock reservoirs, particularly as a thickening agent for acidification; Preferably, the high temperature is not lower than 150°C.

Images