Cross-linked polymer fracturing fluid system capable of being continuously mixed on line and preparation method of cross-linked polymer fracturing fluid system
Through the combination of thickener and compound A modified xanthan gum, the high temperature stability of the crosslinked polymer fracturing liquid can be improved online continuously mixing, solving the problem of decreasing viscosity of the fracturing liquid in high-temperature environments, and achieving efficient fracturing effect and oil and gas mining efficiency.
Patent Information
- Application Number
- CN202510539929.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2025-07-18
AI Technical Summary
The crosslinked polymer fracturing liquid can be continuously mixed online and has insufficient stability in high-temperature environments, resulting in poor fracturing effect, limiting its application in deep high-temperature formations.
The thickener water-soluble polymer and cocoayl apple sodium amino acid ratio are used to modify xanthan gum, and the intermolecular interaction is improved through compound A, forming a crosslinking network structure, and enhancing the high temperature stability of the fracturing fluid.
Maintain good viscosity and rheological performance under high temperature conditions, ensure smooth fracturing construction, improve oil and gas extraction efficiency, and reduce resource waste.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of fracturing fluids, and in particular to an online continuously mixed cross-linked polymer fracturing fluid system and a preparation method thereof. Background Art
[0002] In the field of oil and gas extraction, fracturing technology is one of the key means to increase the production of oil and gas wells. By injecting fracturing fluid into the formation, cracks are formed in the formation, thereby improving the flow channel of oil and gas and increasing the recovery rate. The performance of the fracturing fluid plays a decisive role in the fracturing effect.
[0003] In recent years, online continuous mixing cross-linked polymer fracturing fluid has been widely used in fracturing operations because it can be prepared in real time according to on-site needs, has the advantages of high flexibility and reduced storage space. However, as oil and gas production gradually expands to deep high-temperature formations, this type of fracturing fluid faces severe challenges. Under high temperature environment, the high-temperature stability of online continuous mixing cross-linked polymer fracturing fluid is poor. Specifically, high temperature will accelerate the degradation of polymer molecules, reduce the viscosity of the fracturing fluid, and cannot effectively support the cracks, resulting in a significant reduction in the fracturing effect. In addition, high temperature may also cause an imbalance in the reaction between the cross-linking agent and the polymer, destroy the cross-linking structure, and further weaken the performance of the fracturing fluid. This high-temperature stability problem limits the large-scale application of this type of fracturing fluid in high-temperature formations, and increases the cost and difficulty of oil and gas production. Therefore, it is urgent to develop an online continuous mixing cross-linked polymer fracturing fluid with high-temperature stability. Summary of the invention
[0004] The present invention provides an online continuously mixed cross-linked polymer fracturing fluid system and a preparation method thereof, which solves the problem of insufficient high temperature stability of the online continuously mixed cross-linked polymer fracturing fluid in the related art.
[0005] The technical solution of the present invention is as follows: The present invention provides an online continuous mixing cross-linked polymer fracturing fluid system, comprising the following components in parts by weight: Thickener 0.8~1.6 parts, stabilizer 0.1~0.5 parts, breaker 0.2~0.4 parts, cross-linking agent 0.6~1.2 parts, drainage aid 0.05~0.08 parts, water 100 parts; The thickener comprises a water-soluble polymer and sodium cocoyl apple amino acid in a mass ratio of 20:1-8.
[0006] As a further technical solution, the stabilizer includes one or both of ammonium thiosulfate and sodium thiosulfate; The degumming agent includes one or both of ammonium persulfate and sodium persulfate; The drainage aid includes one or two of fluorocarbon surfactants and quaternary ammonium salt surfactants.
[0007] As a further technical solution, the raw materials of the crosslinking agent include organic zirconium and organic aluminum in a mass ratio of 1:1 to 3.
[0008] As a further technical solution, the raw materials of the crosslinking agent further include compound A-modified xanthan gum; the compound A includes 2-acrylamide-2-methylpropanesulfonic acid.
[0009] As a further technical solution, the preparation method of the compound A-modified xanthan gum includes the following steps: A1. After dissolving xanthan gum, a xanthan gum solution is obtained; A2. Add compound A to the xanthan gum solution and stir to mix. After adding an initiator and reacting, a reaction product is obtained; wash the reaction product, dry it, and crush it to obtain compound A-modified xanthan gum.
[0010] Xanthan gum is a biopolymer with good water solubility, thickening property, pseudoplasticity, and stability. In the fracturing fluid, it can increase the viscosity of the fracturing fluid. By using compound A to modify xanthan gum, the xanthan gum is dissolved to form a solution, then compound A is added and reacted under the action of an initiator to introduce new functional groups or chain segments on the xanthan gum molecular chain. These new structures can enhance the intermolecular interaction and improve the rigidity of the molecule, making xanthan gum not easily undergo molecular chain breakage or degradation at high temperatures, thereby improving the high-temperature stability of the fracturing fluid. The crosslinking reaction forms a crosslinked network structure between xanthan gum molecules, restricting the movement of molecular chains and improving the heat resistance and shear resistance of xanthan gum, thus improving the performance of the fracturing fluid under high-temperature conditions.
[0011] In step A1, dissolving xanthan gum to obtain a xanthan gum solution is to make xanthan gum molecules fully dispersed in the solvent so that they can be uniformly mixed with compound A and react subsequently.
[0012] In step A2, adding compound A to the xanthan gum solution and stirring to mix enables the two to come into full contact, creating conditions for the reaction. After adding the initiator, the initiator will initiate the chemical reaction between compound A and xanthan gum, thereby achieving the modification of xanthan gum. The reaction product obtained after the reaction is washed to remove impurities such as unreacted compound A, initiator, and by-products generated during the reaction. The drying process is to remove the solvent in the reaction product to obtain a solid product. Crushing is to further refine the dried product so that it can be better applied to the fracturing fluid and improve its dispersibility and solubility in the fracturing fluid.
[0013] By the method of adding Compound A to the fracturing fluid to modify xanthan gum, the high-temperature stability of the fracturing fluid can be effectively improved, meeting the fracturing construction requirements in high-temperature formation conditions in fields such as oil and gas exploitation.
[0014] As a further technical solution, in the xanthan gum solution, the mass ratio of xanthan gum to water is 1:8 - 12; The mass of Compound A is 4% - 8% of the mass of xanthan gum; The mass ratio of the initiator to Compound A is 1 - 3:4.
[0015] As a further technical solution, the temperature of the reaction is 53 - 58 °C, and the time is 2.5 - 3.5 h; The initiator includes one or both of potassium persulfate and ammonium persulfate.
[0016] As a further technical solution, the mass ratio of the organic zirconium, organic aluminum, and modified xanthan gum is 1:1:0.5 - 1.
[0017] The present invention also provides a preparation method for an on-line continuous mixing crosslinked polymer fracturing fluid system for preparing the on-line continuous mixing crosslinked polymer fracturing fluid system, comprising the following steps: S1. Mix water, a stabilizer, a breaker, and a flowback aid to obtain a mixed liquid; S2. Sequentially add a thickening agent and a crosslinking agent to the mixed liquid and mix to obtain an on-line continuous mixing crosslinked polymer fracturing fluid.
[0018] As a further technical solution, in step S1, the mixing time is 10 - 15 min, and the rotation speed is 800 - 1000 rpm; In step S2, the mixing time is 15 - 20 min, and the rotation speed is 500 - 600 rpm.
[0019] The working principle and beneficial effects of the present invention are as follows: In the present invention, the fracturing fluid uses a water-soluble polymer and sodium cocoyl apple amino acid with a unique ratio as a thickening agent, greatly improving the stability of the fracturing fluid in a high-temperature environment. In deep oil and gas exploitation, the formation temperature is often relatively high, and ordinary fracturing fluids are prone to problems such as viscosity decrease and performance deterioration at high temperatures, affecting the fracturing effect. However, the fracturing fluid of the present invention can always maintain good viscosity and rheological properties in a high-temperature formation due to its excellent high-temperature stability, ensuring the smooth progress of the fracturing construction and effectively improving the oil and gas exploitation efficiency.
[0020] The characteristic of online continuous mixing enables the real-time adjustment of the fracturing fluid formula according to actual needs under different mining conditions. This precise mixing avoids performance deviation or waste phenomena caused by large-scale pre-preparation and improper storage of traditional fracturing fluids. When facing complex and variable formation conditions, it can quickly adapt to the most suitable fracturing fluid, thus more effectively opening the oil and gas channels, improving the recovery rate of oil and gas resources, and reducing resource waste. Detailed implementation manners
[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.
[0022] Embodiment 1 An online continuously mixable crosslinked polymer fracturing fluid, comprising the following components in parts by weight: 0.8 part of thickening agent, 0.1 part of ammonium thiosulfate, 0.2 part of ammonium persulfate, 0.6 part of crosslinking agent (organic zirconium and organic aluminum with a mass ratio of 1:1), 0.05 part of fluid loss additive, 100 parts of water; the thickening agent is polyethyleneimine and sodium cocoyl apple amino acid with a mass ratio of 20:1; A preparation method of the online continuously mixable crosslinked polymer fracturing fluid, comprising the following steps: S1. Mix water, ammonium thiosulfate, ammonium persulfate, and fluid loss additive at 800 rpm for 15 minutes to obtain a mixed solution; S2. Sequentially add the thickening agent to the mixed solution and mix at 500 rpm for 10 minutes, then add the crosslinking agent and continue to mix for 10 minutes to obtain the online continuously mixable crosslinked polymer fracturing fluid.
[0023] Embodiment 2 An online continuously mixable crosslinked polymer fracturing fluid, comprising the following components in parts by weight: 1.6 parts of thickening agent, 0.5 part of ammonium thiosulfate, 0.4 part of ammonium persulfate, 1.2 parts of crosslinking agent (organic zirconium and organic aluminum with a mass ratio of 1:3), 0.08 part of fluid loss additive, 100 parts of water; the thickening agent is polyethyleneimine and sodium cocoyl apple amino acid with a mass ratio of 20:8; A preparation method of the online continuously mixable crosslinked polymer fracturing fluid, comprising the following steps: S1. Mix water, ammonium thiosulfate, ammonium persulfate, and fluid loss additive at 1000 rpm for 10 minutes to obtain a mixed solution; S2. Add a thickening agent to the mixed solution and mix at 600 rpm for 10 min, then add a crosslinking agent and continue mixing for 5 min to obtain an online continuously mixable crosslinked polymer fracturing fluid.
[0024] Example 3 An online continuously mixable crosslinked polymer fracturing fluid comprises the following components in parts by weight: 1.5 parts of thickening agent, 0.3 part of ammonium thiosulfate, 0.3 part of ammonium persulfate, 1 part of crosslinking agent (organic zirconium and organic aluminum with a mass ratio of 1:1), 0.06 part of flowback aid, and 100 parts of water; the thickening agent is polyethyleneimine and sodium cocoyl apple amino acid with a mass ratio of 20:3; A preparation method of an online continuously mixable crosslinked polymer fracturing fluid comprises the following steps: S1. Mix water, ammonium thiosulfate, ammonium persulfate, and flowback aid at 900 rpm for 13 min to obtain a mixed solution; S2. Add a thickening agent to the mixed solution and mix at 600 rpm for 10 min, then add a crosslinking agent and continue mixing for 10 min to obtain an online continuously mixable crosslinked polymer fracturing fluid.
[0025] Example 4 The difference between this example and Example 3 is only that the crosslinking agent is xanthan gum modified with compound A; compound A is 2-acrylamido-2-methylpropanesulfonic acid; A preparation method of xanthan gum modified with compound A comprises the following steps: A1. Mix xanthan gum and water at a mass ratio of 1:8 to obtain a xanthan gum solution; A2. Add compound A to the xanthan gum solution and stir to mix, add ammonium persulfate and react at 58 °C for 2.5 h to obtain a reaction product; wash, dry, and pulverize the reaction product to obtain xanthan gum modified with compound A; the mass of compound A is 4% of the mass of xanthan gum; the mass ratio of ammonium persulfate to compound A is 1:4.
[0026] Example 5 The difference between this example and Example 3 is only that the crosslinking agent is organic zirconium, organic aluminum, and xanthan gum modified with compound A with a mass ratio of 1:1:0.5; compound A is 2-acrylamido-2-methylpropanesulfonic acid; A preparation method of xanthan gum modified with compound A comprises the following steps: A1. Mix xanthan gum and water at a mass ratio of 1:8 to obtain a xanthan gum solution; A2. Add compound A to the xanthan gum solution, stir and mix. After adding ammonium persulfate and reacting at 58 °C for 2.5 h, a reaction product is obtained. Wash, dry and crush the reaction product to obtain compound A-modified xanthan gum. The mass of compound A is 4% of the mass of xanthan gum. The mass ratio of ammonium persulfate to compound A is 1:4.
[0027] Example 6 The difference between this example and Example 3 is only that the crosslinking agent is an organic zirconium, an organic aluminum and a compound A-modified xanthan gum with a mass ratio of 1:1:1; compound A is 2-acrylamido-2-methylpropanesulfonic acid. The preparation method of the compound A-modified xanthan gum comprises the following steps: A1. Mix xanthan gum and water at a mass ratio of 1:8 to obtain a xanthan gum solution. A2. Add compound A to the xanthan gum solution, stir and mix. After adding ammonium persulfate and reacting at 58 °C for 2.5 h, a reaction product is obtained. Wash, dry and crush the reaction product to obtain compound A-modified xanthan gum. The mass of compound A is 4% of the mass of xanthan gum. The mass ratio of ammonium persulfate to compound A is 1:4.
[0028] Example 7 The difference between this example and Example 6 is only that the preparation method of the compound A-modified xanthan gum comprises the following steps: A1. Mix xanthan gum and water at a mass ratio of 1:12 to obtain a xanthan gum solution. A2. Add compound A to the xanthan gum solution, stir and mix. After adding ammonium persulfate and reacting at 53 °C for 3.5 h, a reaction product is obtained. Wash, dry and crush the reaction product to obtain compound A-modified xanthan gum. The mass of compound A is 8% of the mass of xanthan gum. The mass ratio of ammonium persulfate to compound A is 3:4.
[0029] Example 8 The difference between this example and Example 5 is only that compound A is 2-acrylamido-2-methylpropanesulfonic acid.
[0030] Comparative Example 1 The difference between this comparative example and Example 3 is only that the thickening agent is polyethyleneimine.
[0031] Comparative Example 2 The difference between this comparative example and Example 3 is only that the thickening agent is a mixture of polyethyleneimine and sodium lignosulfonate with a mass ratio of 20:3.
[0032] Comparative Example 3 The difference between this comparative example and Example 3 is only that the thickening agent is a mixture of polyethyleneimine and sodium cocoyl isethionate with a mass ratio of 20:3.
[0033] Experimental Example 1 According to the SY / T 376-2008 "General Technical Conditions for Fracturing Fluids" standard, the apparent viscosities of the fracturing fluids prepared in Examples 1-8 and Comparative Examples 1-3 were tested. Then, the pressure of the autoclave was set to 10 MPa and the temperature was set to 100 °C. The samples were maintained under the set conditions for 24 hours, and the apparent viscosities after high temperature resistance were tested again. The change rate of the apparent viscosity of the fracturing fluid under high temperature and high pressure was calculated. The results are shown in Table 1 below.
[0034] Table 1 Performance Test Results
[0035] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. An online continuous mixing crosslinkable polymer fracturing fluid system, characterized in that, It comprises components in the following parts by weight: 0.8 - 1.6 parts of thickening agent, 0.1 - 0.5 parts of stabilizer, 0.2 - 0.4 parts of breaker, 0.6 - 1.2 parts of crosslinking agent, 0.05 - 0.08 parts of flowback aid, and 100 parts of water; The thickening agent comprises a water-soluble polymer and sodium cocoyl apple amino acid in a mass ratio of 20:1 - 8.
2. The online continuously mixable crosslinkable polymer fracturing fluid system according to claim 1, characterized in that, The stabilizer comprises one or both of ammonium thiosulfate and sodium thiosulfate; The breaker comprises one or both of ammonium persulfate and sodium persulfate; The flowback aid comprises one or both of fluorocarbon surfactant and quaternary ammonium salt surfactant.
3. The online continuously mixable crosslinkable polymer fracturing fluid system according to claim 2, wherein The raw materials of the crosslinking agent comprise organic zirconium and organic aluminum in a mass ratio of 1:1 - 3.
4. The online continuously mixable crosslinkable polymer fracturing fluid system according to claim 1, wherein The raw materials of the crosslinking agent further comprise compound A modified xanthan gum; compound A comprises 2 - acrylamide - 2 - methylpropanesulfonic acid.
5. The online continuously mixable crosslinkable polymer fracturing fluid system according to claim 1, wherein The preparation method of the compound A modified xanthan gum comprises the following steps: A1. Dissolve xanthan gum to obtain a xanthan gum solution; A2. Add compound A to the xanthan gum solution, stir and mix, add an initiator to react, and then wash, dry, and pulverize the reactant to obtain compound A modified xanthan gum.
6. The online continuously mixable crosslinkable polymer fracturing fluid system according to claim 1, wherein In the xanthan gum solution, the mass ratio of xanthan gum to water is 1:8 - 12; The mass of compound A is 4% - 8% of the mass of xanthan gum; The mass ratio of the initiator to compound A is 1 - 3:
4.
7. The online continuously mixable crosslinkable polymer fracturing fluid system according to claim 1, wherein The temperature of the reaction is 53 - 58 °C, and the time is 2.5 - 3.5 h; The initiator comprises one or both of potassium persulfate and ammonium persulfate.
8. The online continuously mixable crosslinkable polymer fracturing fluid system according to claim 1, characterized in that, The mass ratio of the organic zirconium, organic aluminum, and modified xanthan gum is 1:1:0.5 - 1.
9. A preparation method of an online continuously mixable crosslinkable polymer fracturing fluid system for preparing the online continuously mixable crosslinkable polymer fracturing fluid system according to any one of claims 1 to 8, characterized in that, It comprises the following steps: S1. Mix water, stabilizer, breaker, and flowback aid to obtain a mixed solution; S2. Sequentially add the thickening agent and crosslinking agent to the mixed solution and mix to obtain an on-line continuously mixed and crosslinked polymer fracturing fluid.
10. The preparation method of the online continuously mixable crosslinkable polymer fracturing fluid system according to claim 9, characterized in that, In step S1, the mixing time is 10 - 15 min, and the rotation speed is 800 - 1000 rpm; In step S2, the mixing time is 15 - 20 min, and the rotation speed is 500 - 600 rpm.