Emulsion thickening main agent, preparation method thereof and emulsion thickening agent

Abstract

The invention relates to an emulsion thickening main agent, a preparation method thereof and an emulsion thickening agent, and belongs to the field of emulsion thickening agents. The preparation method of the emulsion thickening main agent comprises the following steps: carrying out polymerization reaction on sulfonate acryloyl triquaternary ammonium salt, 4-acryloyl morpholine and a substance A to obtain the emulsion thickening main agent, the substance A is one or two of dimethyl hexadecyl acryloyl quaternary ammonium salt and acrylamide. The preparation method provided by the invention is simple and easy to operate, and the obtained S, M and B type emulsion thickening main agent has moderate molecular weight of the thickening agent corresponding to the S, M and B type emulsion thickening main agent, and has excellent salt resistance, temperature resistance and shear resistance.

Description

Technical Field

[0001] This invention relates to an emulsion thickener, its preparation method, and emulsion thickeners, belonging to the field of emulsion thickeners. Background Technology

[0002] The geological background of a certain reservoir in the Ordos Basin is complex. For example, the reservoir has high water mineralization, an average reservoir temperature of 20.2-79.7℃, an average permeability of 0.19mD, an average porosity of 7%, an average sand body thickness of 17m, and a sandstone reservoir clay mineral content of 14-28%. It is located in a mid-latitude semi-arid region with a continental warm temperate monsoon climate. Spring and winter are windy, dry, and cold with large climate fluctuations and frequent droughts. Summer and autumn are hot and rainy, with frequent intermittent rainfall and alternating droughts and floods. The average annual temperature is 9.6℃, the highest temperature is 39.3℃, and the lowest temperature is -26.5℃. The average annual sunshine duration is 2405.7 hours, the annual precipitation is 561 mm, and the frost-free period is 175 days.

[0003] Based on geological background analysis and combined with the climatic characteristics of the block, the fracturing fluid system for reservoir fracturing in this area needs to meet the following requirements: low friction, low residue, strong proppant carrying capacity, strong permeation and displacement, easy flowback, low-temperature gel breaking, low damage, strong compatibility with reservoir rocks and fluids, moderate molecular weight of fracturing fluid thickener (bulk viscosity η≤350mPa·s), strong salt resistance and shear resistance, simple preparation and high preparation rate.

[0004] Currently, the fracturing fluid system used in this reservoir is a cross-linked gel fracturing fluid system with guar gum as a thickener. However, the following problems exist: First, the sand addition compliance rate is low, only 87.5%. Specifically, of the 24 wells using the fracturing fluid system, 3 wells failed to reach the designed sand volume. Second, the highest sand ratio is low, only 35%. Specifically, in 2022, of the 15 fracturing operations using the integrated emulsion fracturing fluid system, the highest sand ratio was met in 9 out of 15 sections, resulting in a highest sand ratio compliance rate of only 60%. Third, near-wellbore zone permeation is weak. After the permeation pressure exceeds 8 MPa, the permeation efficiency decreases significantly, and the displacement velocity is too high, further reducing permeation efficiency (e.g., ...). Figure 1 (As shown); Moreover, during fracturing, as the fracturing fluid diffuses to the distal end, the pressure inside the fracture gradually decreases, and then the seepage begins to take effect. This is because the existing fracturing fluid system has weak proppant-carrying capacity and weak salt resistance, as well as weak shear resistance when forming a complex network fracture system dominated by the "main fracture" and extending outwards. Summary of the Invention

[0005] The first objective of this invention is to provide a method for preparing an emulsion thickening agent to solve the problems of weak sand-carrying capacity, weak salt resistance, and weak shear resistance in existing fracturing fluid systems.

[0006] The second objective of this invention is to provide an emulsion thickening agent to solve the problems of weak sand-carrying capacity, weak salt resistance, and weak shear resistance in existing fracturing fluid systems.

[0007] The third objective of this invention is to provide an emulsion thickener to address the problems of weak proppant carrying capacity, weak salt resistance, and weak shear resistance in existing fracturing fluid systems.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] A method for preparing an emulsion thickener includes the following steps: polymerizing sulfonate acryloyl triquaternary ammonium salt, 4-acryloylmorpholine and substance A to obtain the emulsion thickener; wherein substance A is one or two of dimethylhexadecylacryloyl quaternary ammonium salt and acrylamide.

[0010] The preparation method of the emulsion thickener of the present invention is a pioneering invention. The present invention obtains an S-type emulsion thickener by polymerizing sulfonate acryloyl triquaternary ammonium salt, 4-acryloylmorpholine, dimethylhexadecylacryloyl quaternary ammonium salt, and acrylamide; an M-type emulsion thickener by polymerizing sulfonate acryloyl triquaternary ammonium salt, 4-acryloylmorpholine, and dimethylhexadecylacryloyl quaternary ammonium salt; and a B-type emulsion thickener by polymerizing sulfonate acryloyl triquaternary ammonium salt, 4-acryloylmorpholine, and acrylamide.

[0011] The preparation method of this invention is simple and easy to operate. The solidification point, dissolution time, thickening rate, gel breaking performance, and drag reduction rate of the obtained S, M, and B type emulsion thickeners all meet the fracturing construction requirements of a reservoir in the Ordos Basin. Moreover, these three emulsion thickeners have moderate molecular weights and bulk viscosity η≤324.9mPa·s, resulting in fracturing fluid systems with low surface tension, low damage, and low residue properties in aqueous solution. The apparent viscosity in standard brine is η≥76.5mPa·s, indicating its salt resistance. The temperature and shear resistance η≥60mPa·s gives the fracturing fluid a high sand ratio and strong sand carrying capacity.

[0012] Preferably, when substance A is dimethylhexadecylacrylamide quaternary ammonium salt or acrylamide, the mass ratio of sulfonate acrylamide triquaternary ammonium salt, 4-acryloylmorpholine to substance A is (2-4):(2-4):(6-9); more preferably, it is 3:3:(7-8). Under these mass ratio conditions, the reaction efficiency is high and the reactants react more completely.

[0013] More preferably, when substance A is dimethylhexadecylacryl quaternary ammonium salt, the mass ratio of sulfonate acryl triquaternary ammonium salt, 4-acryloylmorpholine to substance A is (2-4):(2-4):(7-9); more preferably 3:3:8; when substance A is acrylamide, the mass ratio of sulfonate acryl triquaternary ammonium salt, 4-acryloylmorpholine to substance A is (2-4):(2-4):(6-8); more preferably 3:3:7.

[0014] To improve reaction efficiency, preferably, when substance A is dimethylhexadecylacryl quaternary ammonium salt and acrylamide, the mass ratio of sulfonate acryl triquaternary ammonium salt, 4-acryloylmorpholine to substance A is (1-3):(1-3):(10-12); more preferably 2:2:11.

[0015] Preferably, the mass ratio of the dimethylhexadecylacrylamide quaternary ammonium salt to acrylamide is 5:6.

[0016] Preferably, the polymerization reaction is carried out at a temperature of 45–55°C for 5–6 hours. Within this temperature range, the reactants react more effectively, resulting in a higher yield of the products. The 5–6 hour duration ensures a more complete and efficient polymerization reaction.

[0017] Preferably, the dimethylhexadecylacryl quaternary ammonium salt is dimethylhexadecylallylammonium chloride. Preferably, the sulfonate acrylyl triquaternary ammonium salt has the following structural formula:

[0018] More preferably, the sulfonate acryloyl triquaternary ammonium salt is generated by reacting dilute sulfuric acid, hydroxyacetamide, n-hexadecyl primary alcohol, ethylene glycol, and allyl alcohol.

[0019] Preferably, the reaction temperature is 65–75°C and the reaction time is 4–10 h.

[0020] Preferably, the mass ratio of the dilute sulfuric acid, hydroxyacetamide, n-hexadecyl primary alcohol, ethylene glycol, and allyl alcohol is (3-4):(15-16):(25-26):(30-31):(10-11).

[0021] Preferably, the catalyst for the reaction is dilute hydrochloric acid and ammonium persulfate. The mass ratio of the dilute hydrochloric acid to ammonium persulfate is (1-1.5):(0.01-0.02). The mass ratio of the dilute hydrochloric acid to hydroxyacetamide is (1-1.5):(3-3.5).

[0022] Preferably, the mass fraction of the dilute sulfuric acid is 15-25%, and the mass fraction of the dilute hydrochloric acid is 20-31%.

[0023] Preferably, the solvent for the polymerization reaction is water, and the mass ratio of water to 4-acryloylmorpholine is (5-7):(2-3).

[0024] The second technical solution of the present invention is:

[0025] An emulsion thickener, wherein the emulsion thickener is prepared by the above-mentioned method for preparing emulsion thickener.

[0026] The thickening agent of the present invention is an S, M, or B type emulsion thickening agent with a moderate molecular weight, and has excellent salt resistance and temperature and shear resistance.

[0027] The third technical solution of the present invention is:

[0028] An emulsion thickener is made of an emulsion thickener, nonylphenol polyoxyethylene ether, and white oil, wherein the mass ratio of the emulsion thickener, nonylphenol polyoxyethylene ether, and white oil is (53-57):(0.5-1.5):(42-46).

[0029] The emulsion thickener of the present invention is made from S, M, and B type emulsion thickeners, nonylphenol polyoxyethylene ether, and white oil, respectively. It belongs to the W / O type emulsion thickener. The emulsion thickener has strong sand-carrying capacity, excellent salt resistance, and temperature and shear resistance, which meets the requirements of a reservoir in the Ordos Basin.

[0030] Preferably, the mass ratio of the emulsion thickener, nonylphenol polyoxyethylene ether, and white oil is 55:1:44. Attached Figure Description

[0031] Figure 1 The diagram shows the percolation efficiency of fracturing fluid systems using guar gum as a thickener under different percolation pressures in the background technology.

[0032] Figure 2 This is a synthetic route diagram of the emulsion thickener of Example 1 of the present invention;

[0033] Figure 3 This is a synthetic route diagram of the emulsion thickener of Example 2 of the present invention;

[0034] Figure 4 This is a synthetic route diagram of the emulsion thickener of Example 3 of the present invention;

[0035] Figure 5 This is a synthetic route diagram of the emulsion thickener of Comparative Example 1 of the present invention;

[0036] Figure 6 This is a synthetic route diagram of the emulsion thickener of Comparative Example 2 of the present invention;

[0037] Figure 7This is a graph showing the results of the thickener pour point test in Experimental Example 1 of the present invention;

[0038] Figure 8 This is a bulk viscosity curve of the thickener in Experimental Example 2 of the present invention;

[0039] Figure 9 This is a graph showing the dissolution time of the thickener in Experimental Example 3 of the present invention.

[0040] Figure 10 This is a graph showing the thickening rate of the thickener in Experimental Example 4 of the present invention.

[0041] Figure 11 This is a graph showing the apparent viscosity of the thickener in Experimental Example 5 of the present invention.

[0042] Figure 12 This is a graph showing the temperature and shear resistance properties of the thickener in Experimental Example 6 of this invention.

[0043] Figure 13 This is a graph showing the thickener's gel breaking performance in Experimental Example 7 of the present invention;

[0044] Figure 14 This is a graph showing the drag reduction rate of the thickener in Experimental Example 8 of the present invention. Detailed Implementation

[0045] The method for preparing the emulsion thickener of the present invention involves polymerizing one or two of sulfonate acryloyl triquaternary ammonium salt, 4-acryloylmorpholine, dimethylhexadecylacryloyl quaternary ammonium salt, and acrylamide to obtain the emulsion thickener.

[0046] Emulsion thickeners are prepared using emulsion thickeners as the main agent. When used in conjunction with percolation and anti-swelling agents, different concentrations of these thickeners can create novel emulsion fracturing fluid systems that meet the requirements of high-flow-rate, high-sand-ratio, and strong percolation displacement fracturing in water-sensitive and salt-sensitive tight and shale oil reservoirs. When used in conjunction with low-temperature and conventional breaker agents, different concentrations of these thickeners can create fracturing fluid systems that meet the requirements of fracturing in tight, shale oil, and gas reservoirs within the 20-80℃ temperature range. When used alone, different concentrations of these thickeners can create fracturing fluid systems that meet the requirements of low viscosity drag reduction, high viscosity and high sand-ratio proppant carrying capacity in fracturing operations, and are suitable for ordinary tight, shale oil, and gas reservoirs.

[0047] In practical applications, the integrated emulsion fracturing fluid used combines multiple agents such as drag reduction, drainage assistance, and anti-swelling. By adjusting the concentration, it is possible to switch between low-viscosity drag-reducing hydraulic fracturing fluid, medium-viscosity fluid, and high-viscosity linear gel fracturing fluid in a timely manner, meeting the requirements for large-scale online mixing.

[0048] The sulfonate acetylated triquaternary ammonium salt in the following examples was synthesized by reacting 3% dilute sulfuric acid, 15% hydroxyacetamide, 25% n-hexadecyl primary alcohol, 30% ethylene glycol, and 10% allyl alcohol in an aqueous solution at 70°C for 6 hours with 5% dilute hydrochloric acid and 0.05% ammonium persulfate as catalysts. The product was then filtered and dried to obtain the final product. All mass fractions mentioned above refer to the final concentrations of each substance in the system. It appears as a white solid powder with a light jasmine fragrance and a density of 0.87 × 10⁻⁶. 3 Kg / m 3 The dilute sulfuric acid is 15% sulfuric acid by mass, and the dilute hydrochloric acid is 30% hydrochloric acid by mass. Here, it is sufficient to ensure that the final concentration of the dilute sulfuric acid in the system is 3% and the final concentration of the dilute hydrochloric acid is 5%. The specific reaction formula is shown below:

[0049]

[0050] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0051] I. Specific embodiments of the preparation method of the emulsion thickener of the present invention are as follows:

[0052] Example 1

[0053] The preparation method and synthetic route of the emulsion thickener in this embodiment are as follows: Figure 2 As shown, the specific steps are as follows:

[0054] 25% dimethylhexadecylallylammonium chloride, 10% sulfonate acryloyl triquaternary ammonium salt, 10% 4-acryloylmorpholine, 30% acrylamide, and 0.1% potassium persulfate were added sequentially to deionized water, and the deionized water was replenished to make up the system to 100%. The polymerization reaction was carried out at 55°C and normal pressure for 6 hours to obtain the emulsion thickener.

[0055] Example 2

[0056] The preparation method and synthetic route of the emulsion thickener in this embodiment are as follows: Figure 3 As shown, the specific steps are as follows:

[0057] 40% dimethylhexadecylallylammonium chloride, 15% sulfonate acryloyl triquaternary ammonium salt, 15% 4-acryloylmorpholine, and 0.1% ammonium persulfate were added sequentially to deionized water, and the deionized water was replenished to make up the system to 100%. The polymerization reaction was carried out at 50°C and normal pressure for 5.5 h to obtain the emulsion thickener.

[0058] Example 3

[0059] The preparation method and synthetic route of the emulsion thickener in this embodiment are as follows: Figure 4 As shown, the specific steps are as follows:

[0060] 15% sulfonate acryloyl triquaternary ammonium salt, 15% 4-acryloylmorpholine, 35% acrylamide, and 0.1% potassium persulfate were added sequentially to deionized water, and the deionized water was replenished to make up the system to 100%. The polymerization reaction was carried out at 45°C and normal pressure for 5 hours to obtain the emulsion thickener.

[0061] II. Specific embodiments of the emulsion thickener of the present invention are as follows:

[0062] Example 4

[0063] The emulsion thickener in this embodiment is an S-type emulsion thickener, which is prepared using the preparation method of Example 1.

[0064] Example 5

[0065] The emulsion thickener in this embodiment is an M-type emulsion thickener, which was prepared using the preparation method of Example 2.

[0066] Example 6

[0067] The emulsion thickener in this embodiment is a type B emulsion thickener, which was prepared using the preparation method of Example 3.

[0068] III. Specific embodiments of the emulsion thickener of the present invention are as follows:

[0069] Example 7

[0070] The emulsion thickener of this embodiment is composed of the S-type emulsion thickener of Example 4, nonylphenol polyoxyethylene ether, and white oil, wherein the mass ratio of the emulsion thickener, nonylphenol polyoxyethylene ether, and white oil is 55:1:44.

[0071] Example 8

[0072] The emulsion thickener of this embodiment is composed of the M-type emulsion thickener of Example 5, nonylphenol polyoxyethylene ether, and white oil, wherein the mass ratio of the emulsion thickener, nonylphenol polyoxyethylene ether, and white oil is 55:1:44.

[0073] Example 9

[0074] The emulsion thickener of this embodiment is composed of the type B emulsion thickener of Example 6, nonylphenol polyoxyethylene ether, and white oil, wherein the mass ratio of the emulsion thickener, nonylphenol polyoxyethylene ether, and white oil is 55:1:44.

[0075] IV. Comparative Example

[0076] Comparative Example 1

[0077] The preparation method and synthetic route of the emulsion thickener in this comparative example are as follows: Figure 5 As shown, the specific steps are as follows:

[0078] 23% dimethylhexadecylallylammonium chloride, 15% 4-acryloylmorpholine, 30% acrylamide, and 0.1% potassium persulfate were added sequentially to deionized water, and the deionized water was replenished to make up the system to 100%. The polymerization reaction was carried out at 40°C and normal pressure for 4.5 h to obtain the Z-type emulsion thickener.

[0079] The emulsion thickener of this comparative example is composed of the Z-type emulsion thickener, nonylphenol polyoxyethylene ether, and white oil, wherein the mass ratio of the emulsion thickener, nonylphenol polyoxyethylene ether, and white oil is 55:1:44.

[0080] Comparative Example 2

[0081] The preparation method and synthetic route of the emulsion thickener in this comparative example are as follows: Figure 6 As shown, the specific steps are as follows:

[0082] 13% dimethylhexadecylallylammonium chloride, 15% sulfonate acryloyl triquaternary ammonium salt, 30% acrylamide, and 0.1% ammonium persulfate were added sequentially to deionized water, and the deionized water was replenished to make the system 100%. The polymerization reaction was carried out at 35°C and normal pressure for 4 hours to obtain the F-type emulsion thickener.

[0083] The emulsion thickener of this comparative example is composed of the F-type emulsion thickener, nonylphenol polyoxyethylene ether, and white oil, wherein the mass ratio of the emulsion thickener, nonylphenol polyoxyethylene ether, and white oil is 55:1:44.

[0084] V. Experimental Examples

[0085] Experimental Example 1: Thickener Freezing Point

[0086] This experiment measured the freezing point of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2. The method was as follows: 100 mL of the emulsion thickener was placed in a freezing point tester, and its freezing point was measured. The results are as follows. Figure 7 As shown.

[0087] Depend on Figure 7 It can be seen that the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2 have a freezing point between -30℃≤Sp≤-18℃, which is a low freezing point and has good fluidity at low temperatures, all of which meet the requirements of a reservoir in the Ordos Basin.

[0088] Experimental Example 2: Bulk Viscosity of Thickener

[0089] This experiment measured the bulk viscosity of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2. The measurement method was as follows: 400 mL of the emulsion thickener was placed in a test cup, and its viscosity was measured using a six-speed viscometer. The results are as follows. Figure 8 As shown.

[0090] Depend on Figure 8 It can be seen that the bulk viscosity η of the emulsion thickeners obtained in Examples 7-9 is ≤324.9 mPa·s, while the bulk viscosities of the emulsion thickeners obtained in Comparative Examples 1 and 2 are 241 mPa·s and 393.8 mPa·s, respectively. However, a certain reservoir in the Ordos Basin requires the fracturing fluid system to have low surface tension, low damage, and low residue properties. This necessitates that the fracturing fluid thickener have a moderate molecular weight and a bulk viscosity η ≤350 mPa·s. Therefore, the bulk viscosities of the emulsion thickeners obtained in Examples 7-9 and Comparative Example 1 meet the requirements.

[0091] Dissolution time in Experiment Example 3

[0092] This experiment measured the dissolution time of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2. The method was as follows: 5g of each of the five emulsion thickeners was placed in a beaker containing 500mL of water, stirred with a glass rod, and the complete dissolution time was recorded. The results are as follows. Figure 9 As shown.

[0093] As shown in Table 9, the dissolution time of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2 is 25-35 seconds. The dissolution time determines the speed of fracturing fluid preparation, and is generally suitable at 20-40 seconds. Therefore, all five emulsion thickeners meet the requirements.

[0094] Experimental Example 4: Thickening Rate

[0095] This experiment measured the thickening rate of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2. The measurement method was as follows: the emulsion thickener was dissolved in water to make the mass fraction of the emulsion thickener 1.2%, and the viscosity of the solution was measured after 3 min and 240 min. The thickening rate was calculated based on the viscosity of the two solutions. The results are as follows. Figure 10 As shown.

[0096] The viscosity-increasing rate is the percentage of the viscosity ratio after dissolving a 1.2% (by mass) emulsion thickener in water for 3 min and 240 min. It characterizes the initial viscosity and viscosity-increasing potential of the fracturing fluid, and determines its proppant-carrying capacity. Figure 10 It can be seen that the thickening rate v of these five emulsion thickeners is ≥93.5%, and the requirement for the thickening rate of a certain reservoir in the Ordos Basin is v≥90%. Therefore, the thickening rate of these five emulsion thickeners all meet the requirements.

[0097] Experimental Example 5: Apparent Viscosity

[0098] This experiment measured the apparent viscosity of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2. The method was as follows: five emulsion thickeners were dissolved in water and a NaCl solution with a mineralization of 50,000 mg / L, respectively. The apparent viscosity of the solutions after dissolving in water for 3 min and 240 min, and the apparent viscosity after dissolving in NaCl solution for 3 min, were measured using a six-speed rotational viscometer. The mass fraction of the emulsion thickeners was 1.2% for all solutions. The results are as follows: Figure 11 As shown.

[0099] As shown in Table 11, the apparent viscosity of the emulsion thickeners obtained in Examples 7-9 in NaCl solution is η≥76.5mPa·s, while the apparent viscosities of the emulsion thickeners obtained in Comparative Examples 1 and 2 in NaCl solution are 82mPa·s and 63.2mPa·s, respectively.

[0100] The apparent viscosity after dissolving in a NaCl solution with a salinity of 50,000 mg / L for 3 minutes characterizes the salt resistance of the emulsion thickener. Based on the water quality requirements for solution preparation in a reservoir block in the Ordos Basin, the apparent viscosity of the standard brine, η ≥ 75 mPa·s, is preferably appropriate. Therefore, the apparent viscosities of the emulsion thickeners obtained in Examples 7-9 and Comparative Example 1 meet the requirements.

[0101] Experimental Example 6: Temperature and Shear Resistance

[0102] This experiment tested the temperature and shear resistance of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2. The testing method was as follows: five emulsion thickeners were dissolved in water to prepare fracturing fluid, and the fluid was subjected to fracturing at 100°C for 170 seconds. -1 Its temperature and shear resistance were determined using a rheometer under conditions of 120 min, with the mass fraction of emulsion thickener being 1.2%. The results are as follows: Figure 12 As shown.

[0103] Depend on Figure 12 It can be seen that the viscosity of the emulsion thickeners obtained in Examples 7-9 is η≥60mPa·s, while the viscosities of the emulsion thickeners obtained in Comparative Examples 1 and 2 are 54mPa·s and 80mPa·s, respectively. The temperature and shear resistance of the emulsion thickener reflects the sand-carrying capacity of the fracturing fluid. A certain reservoir in the Ordos Basin requires the fracturing fluid to have a high sand ratio and strong sand-carrying capacity, which means that the temperature and shear resistance of the emulsion thickener is required to be η≥55mPa·s. Therefore, the temperature and shear resistance of the emulsion thickeners obtained in Examples 7-9 and Comparative Example 2 meet the requirements.

[0104] Experimental Example 7: Degradation Performance

[0105] This experiment tested the breaking performance of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2, specifically involving breaking time, surface tension, breaking liquid viscosity, anti-swelling rate, and residue content. The testing method was as follows: 0.1% ammonium persulfate was added to a 1.2% emulsion fracturing solution and placed in a water bath at a constant temperature of 90°C for 4 hours. The viscosity was measured using a six-speed viscometer, which was the breaking liquid viscosity. The time required for the breaking liquid viscosity to reach 3 mPa·s was the breaking time. The breaking liquid was centrifuged and dried, and the percentage of solid residue by mass was the residue content. The surface tension of the supernatant was measured using a surface tension meter, and the swelling rate was measured using an anti-swelling meter. The results are as follows: Figure 13 As shown.

[0106] Depend on Figure 13 It is known that the breaking time of the five emulsion thickeners should be ≤230 min, surface tension ≤26 mN / m, breaking fluid viscosity ≤5 mPa·s, anti-swelling rate ≥80%, and residue content ≤98 mg / L. According to the protection requirements for low-porosity and low-permeability reservoirs in a certain reservoir in the Ordos Basin, the breaking time should be ≤2400 s, surface tension ≤26 mN / m, breaking fluid viscosity ≤5 mPa·s, anti-swelling rate ≥80%, and residue content ≤100 mg / L. Therefore, the breaking performance of this emulsion thickener meets the requirements.

[0107] Experimental Example 8: Drag Reduction

[0108] This experiment measured the drag reduction rate of the emulsion thickeners obtained in Examples 7-9 and Comparative Examples 1 and 2. The measurement method was as follows: 1 mL of emulsion thickener was dissolved in water to prepare a 1000 mL solution, and the drag reduction rate was measured using a drag meter. The results are as follows: Figure 14 As shown.

[0109] The drag reduction rate refers to the percentage difference between the frictional resistance (or pressure difference) of clean water and drag-reduced water flowing through pipes of the same material, diameter, and length, under the same temperature and flow rate conditions, and the frictional resistance (or pressure difference) of the clean water.

[0110] Depend on Figure 14 It can be seen that the drag reduction rate of the five emulsion thickeners is ≥70%, which meets the fracturing construction requirements of a reservoir in the Ordos Basin.

[0111] Based on the conclusions of Experiment Examples 1-8, it can be seen that the solidification point, bulk viscosity, dissolution time, thickening rate, apparent viscosity, temperature and shear resistance, gel breaking performance, and drag reduction rate of the emulsion thickener prepared according to Examples 1-3 all meet the requirements for fracturing construction of a reservoir in the Ordos Basin.

[0112] Example 9: Application of Thickening Agent in Ninggu 1 Well

[0113] Ninggu 1 Well High-Viscosity Novel Emulsion Fracturing Fluid: The main component is the S-type emulsion thickener of Example 7 with a mass fraction of 1.2-1.5%;

[0114] The low-viscosity novel emulsion fracturing fluid of Ninggu 1 well contains 0.1% by mass of the S-type emulsion thickener from Example 7;

[0115] In field applications, the integrated fracturing fluid system used comprises 825.4 m³. 3 High-viscosity novel emulsion fracturing fluid, 226.6m 3 The performance evaluation of the low-viscosity novel emulsion fracturing fluid, including the high-viscosity novel emulsion fracturing fluid system, is shown in Table 1.

[0116] Table 1 Performance evaluation of the integrated fracturing fluid system in Ninggu 1 well (high viscosity)

[0117]

[0118] As shown in Table 1, the performance of the integrated fracturing fluid system in Ninggu 1 well meets the fracturing requirements of a reservoir in the Ordos Basin.

[0119] Example 10: Application of Thickening Agent in Open-Flange 1H Well

[0120] Low-viscosity slickwater from well 1H: The main component is the S-type emulsion thickener of Example 7 with a mass fraction of 0.1-0.15%, and it also contains an oil displacement agent with a mass fraction of 0.3% and an anti-swelling and drainage aid with a mass fraction of 0.3%; the oil displacement agent and the anti-swelling and drainage aid are both from Dongying Shipuri Petroleum Engineering Technology Co., Ltd.;

[0121] The permeation displacement agent can greatly change the wettability of the reservoir rock surface, making capillary force the displacement force, reducing the adsorption force of the rock surface, reducing the oil-water interfacial tension, increasing the oil washing effect, and improving the crude oil recovery rate; the anti-swelling and drainage aid is used in oil and gas well production enhancement fracturing and acidizing operations to prevent reservoir clay minerals from swelling and migrating when exposed to water, thus preventing damage to the oil and gas reservoir, improving the return efficiency of the working fluid in the well, and protecting the oil and gas reservoir.

[0122] In field application, the fracturing fluid was 1143m³. 3 The performance evaluation of this fracturing fluid system, which uses low-viscosity, absorbent slickwater, is shown in Table 2.

[0123] Table 2 Performance Evaluation of the Integrated Seepage and Slippery Water System for Well 1H with Open Edge

[0124]

[0125] As shown in Table 2, the performance of the integrated seepage and slickwater system in the Kaibian 1H well meets the fracturing requirements of a reservoir in the Ordos Basin.

[0126] Example 11: Application of Thickening Agent in Well Fuye 1H

[0127] Low-viscosity slickwater from Well Fuye 1H: The main component is the S-type emulsion thickener of Example 7 with a mass fraction of 0.1-0.15%, and it also contains an oil displacement agent with a mass fraction of 0.3% and an anti-swelling and drainage integrated agent with a mass fraction of 0.3%.

[0128] The novel emulsion fracturing fluid for the Fuye 1H well consists of a main component of 0.25-0.3% by mass of the S-type emulsion thickener from Example 7, and also contains 0.3% by mass of an adsorption oil displacement agent and 0.3% by mass of an anti-swelling and drainage integrated agent.

[0129] The high-viscosity novel emulsion fracturing fluid for the Fuye 1H well consists of a main component of 0.4-0.6% by mass of the S-type emulsion thickener from Example 7, and also contains 0.3% by mass of an oil displacement agent and 0.3% by mass of an anti-swelling and drainage integrated agent.

[0130] The dosage of low-temperature breaker in the Fuye 1H well is as follows: 0.03% by mass in low-viscosity permeable slickwater, 0.06% by mass in medium-viscosity novel emulsion fracturing fluid, and 0.13% by mass in high-viscosity novel emulsion fracturing fluid. The breaker is a composite material composed of a strong oxidant, injected simultaneously with the fracturing fluid. After fracturing, it breaks the polymer chains of the thickener, thereby reducing the viscosity of the fracturing fluid, decreasing flow resistance, and facilitating flowback. The low-temperature breaker is sourced from Dongying Shipuri Petroleum Engineering Technology Co., Ltd.

[0131] In field applications, the integrated permeation fracturing fluid system comprises 5700.6m³. 3 Low viscosity, absorbent slippery water, 9818.4m 3 Medium-viscosity novel emulsion fracturing fluid, 589m 3 A novel high-viscosity emulsion fracturing fluid and 245 temporary plugging knots were developed. The plugging knots are a polyester polymer sourced from Dongying Sperry Petroleum Engineering Technology Co., Ltd. These knots are used to temporarily seal dominant high-permeability channels during reservoir stimulation, thereby completing the stimulation of low-permeability reservoirs. The performance evaluation of this novel high-viscosity emulsion fracturing fluid system is shown in Table 3.

[0132] Table 3 Performance Evaluation of the Integrated Permeate Fracturing Fluid System in Well Fuye 1H (High Viscosity)

[0133]

[0134] As shown in Table 3, the performance of the integrated permeation fracturing fluid system in the Fuye 1H well meets the fracturing requirements of a reservoir in the Ordos Basin.

[0135] Example 12: Application of Thickening Agent in Ninggu 2 Well

[0136] Ninggu 2 Well High-Viscosity Novel Emulsion Fracturing Fluid: The main component is the M-type emulsion thickener of Example 8 with a mass fraction of 1.0-1.2%;

[0137] The low-viscosity novel emulsion fracturing fluid for Ninggu 2 well: the main component is the M-type emulsion thickener of Example 8 with a mass fraction of 0.1%;

[0138] In field applications, the integrated fracturing fluid system includes 1020m³ 3 High-viscosity novel emulsion fracturing fluid, 5m 3 The performance evaluation of the low-viscosity novel emulsion fracturing fluid and the high-viscosity novel emulsion fracturing fluid system is shown in Table 4.

[0139] Table 4 Performance evaluation of the integrated emulsion fracturing fluid system in Ninggu 2 well (high viscosity)

[0140]

[0141]

[0142] As shown in Table 4, the performance of the integrated fracturing fluid system in Ninggu 2 well meets the fracturing requirements of a reservoir in the Ordos Basin.

[0143] Example 13: Application of Thickening Agent in Well J30-5-P18

[0144] J30-5-P18 Well High-Viscosity Novel Emulsion Fracturing Fluid: The main component is the Type B emulsion thickener of Example 9 with a mass fraction of 1.2-1.5%;

[0145] J30-5-P18 well low-viscosity novel emulsion fracturing fluid: the main component is the type B emulsion thickener of Example 9 with a mass fraction of 0.1%;

[0146] In field applications, the integrated fracturing fluid system comprises 4794.6 m³. 3 High-viscosity novel emulsion fracturing fluid, 609m 3 The performance evaluation of the low-viscosity novel emulsion fracturing fluid and the high-viscosity novel emulsion fracturing fluid system is shown in Table 5.

[0147] Table 5 Performance Evaluation of Integrated Emulsion Fracturing Fluid System in Wells J30-5-P18 and J30-5-P19 (High Viscosity)

[0148]

[0149] As shown in Table 5, the performance of the integrated fracturing fluid system in wells J30-5-P18 and J30-5-P19 both meet the fracturing requirements of a reservoir in the Ordos Basin.

[0150] Example 14: Application of Thickening Agent in Well J30-5-P19

[0151] J30-5-P19 Well High-Viscosity Novel Emulsion Fracturing Fluid: The main component is the Type B emulsion thickener of Example 9 with a mass fraction of 1.2-1.5%;

[0152] J30-5-P19 well low-viscosity novel emulsion fracturing fluid: the main component is the type B emulsion thickener of Example 9 with a mass fraction of 0.1%;

[0153] In field applications, the integrated fracturing fluid system comprises 4473.1m³. 3 High-viscosity novel emulsion fracturing fluid, 824.2m 3 The performance evaluation of the novel low-viscosity emulsion fracturing fluid system is shown in Table 5.

[0154] The specific application of fracturing fluid in Experiment Examples 9-14 is shown in Table 6. Wells 2 and 3 are oil wells, and wells 1 and 4-6 are gas wells.

[0155] Table 6. Application of fracturing fluid

[0156]

[0157] The fracturing fluid injection volume, sand volume, construction discharge volume, and maximum sand ratio of the above six wells all met the design requirements. Among them, the sand addition compliance rate and the maximum sand ratio compliance rate both reached 100%. Moreover, the production output after the modification was higher than that of the adjacent well, indicating that the problem of weak permeability in the near-wellbore zone has been solved.

Claims

1. A method for preparing an emulsion thickener, characterized in that, Includes the following steps: The sulfonate acryloyl triquaternary ammonium salt, 4-acryloylmorpholine and substance A are polymerized to obtain the emulsion thickener; the substance A is one or two of dimethylhexadecylacryloyl quaternary ammonium salt and acrylamide.

2. The method for preparing the emulsion thickener according to claim 1, characterized in that, When substance A is dimethylhexadecylacryl quaternary ammonium salt or acrylamide, the mass ratio of sulfonate acryl triquaternary ammonium salt, 4-acryloylmorpholine to substance A is (2-4):(2-4):(6-9).

3. The method for preparing the emulsion thickener according to claim 1, characterized in that, When substance A is dimethylhexadecylacryl quaternary ammonium salt and acrylamide, the mass ratio of sulfonate acryl triquaternary ammonium salt, 4-acryloylmorpholine to substance A is (1-3):(1-3):(10-12).

4. The method for preparing the emulsion thickener according to claim 3, characterized in that, The mass ratio of the dimethylhexadecylacryl quaternary ammonium salt to acrylamide is 5:

6.

5. The method for preparing the emulsion thickener according to any one of claims 1-4, characterized in that, The polymerization reaction is carried out at a temperature of 45–55°C for 5–6 hours.

6. The method for preparing the emulsion thickener according to any one of claims 1-4, characterized in that, The dimethylhexadecylacryl quaternary ammonium salt is dimethylhexadecylallylammonium chloride.

7. The method for preparing the emulsion thickener according to any one of claims 1-4, characterized in that, The solvent for the polymerization reaction is water, and the mass ratio of water to 4-acryloylmorpholine is (5-7):(2-3).

8. An emulsion thickener, characterized in that, The emulsion thickening agent is prepared by the method described in any one of claims 1-7.

9. An emulsion thickener, characterized in that, It is made of emulsion thickener, nonylphenol polyoxyethylene ether and white oil, wherein the emulsion thickener is the emulsion thickener according to claim 8, and the mass ratio of the emulsion thickener, nonylphenol polyoxyethylene ether and white oil is (53-57):(0.5-1.5):(42-46).

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