Temperature-resistant salt-resistant viscosity-reducing oil-washing plugging agent for offshore oilfield heavy oil thermal recovery and preparation method of temperature-resistant salt-resistant viscosity-reducing oil-washing plugging agent
By preparing a temperature- and salt-resistant viscosity-reducing and plugging-regulating agent for washing oil, the problems of high viscosity and uneven steam absorption in heavy oil thermal recovery in offshore oilfields were solved. This achieved efficient viscosity reduction and foam plugging regulation in high-temperature and high-salt environments, thus improving the thermal recovery effect.
Patent Information
- Application Number
- CN202511438350.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-10
- Publication Date
- 2025-11-21
AI Technical Summary
In the process of heavy oil thermal recovery in offshore oilfields, there are problems such as high viscosity of heavy oil and uneven steam absorption profile. Existing reagents are difficult to meet the requirements of high temperature and salt resistance for viscosity reduction and foam plugging control at the same time.
A temperature- and salt-resistant viscosity-reducing cleaning oil conditioning agent was prepared by using a compounding method containing components such as anionic, nonionic, natural, and salt-resistant stabilizers. The solution with high foaming and high viscosity-reducing properties was formed by low-speed stirring.
It effectively reduces the viscosity of heavy oil and adjusts the steam absorption profile in high-temperature and high-salt environments, improving thermal recovery without damaging the formation. It has a high viscosity reduction rate and good temperature and salt resistance.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical enhancement technology for heavy oil thermal recovery, specifically to a temperature- and salt-resistant viscosity-reducing and blockage-regulating agent for heavy oil thermal recovery in offshore oilfields and its preparation method. Background Technology
[0002] In the development of heavy oil thermal recovery steam huff and puff in offshore oilfields, the problems of high heavy oil viscosity and uneven steam absorption profile are faced simultaneously. The high viscosity of heavy oil in the formation leads to the retention of heavy components in the formation due to the extraction of heat mass after the hot fluid enters, exacerbating the difficulty of hot fluid injection and heavy oil recovery, severely impacting the effectiveness of heavy oil thermal recovery. Furthermore, in the later stages of offshore oilfield steam huff and puff development, factors such as formation heterogeneity, differences in mobility ratios, and steam overlap can easily lead to uneven steam absorption or steam channeling. Steam channeling affects both the steam huff and puffing effect of injection wells and the normal production of channeled wells, and also results in low thermal energy utilization, severely impacting thermal recovery efficiency. Using a temperature- and salt-resistant viscosity-reducing wash oil plugging agent to lower the viscosity of heavy oil in the formation and utilizing the selective plugging properties of foam for profile adjustment can effectively solve the dual problems of high heavy oil viscosity and uneven steam absorption profile. At the same time, the wash oil plugging agent also has advantages such as minimal reservoir damage, good temperature resistance, and simple process.
[0003] Domestic research on wash oil plugging agents for offshore oilfields rarely yields agents that simultaneously meet the dual requirements of viscosity reduction and foam plugging in heavy oil; only agents targeting a single function of viscosity reduction and foaming are available. Some researchers, considering the high formation water salinity, high condensate content, and high formation temperature of gas wells in the Zhongyuan Oilfield, have developed a novel organic amine derivative surfactant, CT5-7. Other researchers have synthesized the anionic surfactant AGES from dodecanol in the presence of a TBE catalyst. AGES exhibits strong foaming ability and good foam stability in the presence of Ca... 2+ In mixed brine with a concentration of 5000 mg / L and a salinity of 50000 mg / L, or in the presence of 20% kerosene, the foaming performance is superior to SDS and ABS, and it shows little decomposition even after heating at 250℃ for 6 hours. Current research on reverse emulsifying viscosity reducers mainly targets the need for viscosity reduction in produced fluids under low-temperature, low-salinity conditions in onshore oilfields. These are mainly ionic and nonionic, and can be categorized into three main types based on the main agent: 1. Primarily anionic surfactants, including carboxylate, sulfonate, and sulfate types; 2. Primarily low-molecular-weight nonionic surfactants, such as the TWEEN series and OP series; 3. Primarily high-molecular-weight nonionic surfactants, while also developing amphoteric surfactants.
[0004] There are currently no reports on the application of temperature- and salt-resistant viscosity-reducing and blockage-regulating agents for heavy oil in offshore oil fields. Summary of the Invention
[0005] This invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a temperature- and salt-resistant viscosity-reducing and blockage-regulating agent for heavy oil in offshore oil fields and its preparation method.
[0006] This invention is achieved through the following technical solution: A high-temperature and salt-resistant viscosity-reducing wash oil blockage regulator for heavy oil in offshore oil fields, wherein the components and mass percentages of the viscosity-reducing wash oil blockage regulator are as follows: Anionic surfactants 10%~15%; Nonionic surfactants: 10%~20%; 10%~20% natural surfactants; Salt stabilizer 5%~10%; Temperature stabilizer 1%~3%; Complexing agent 1%~2%; Additives 0.5%~1%; Water balance.
[0007] In the above technical solution, the anionic surfactant is at least one of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecylbenzene sulfonate, α-olefin sulfonate, or internal olefin sulfonate.
[0008] In the above technical solution, the nonionic surfactant is at least one of C12~18 fatty alcohol polyoxyethylene (15) ether, C12~18 fatty alcohol polyoxyethylene (20) ether, C12~18 fatty alcohol polyoxyethylene (25) ether or C12~18 fatty alcohol polyoxyethylene (35) ether.
[0009] In the above technical solution, the natural surfactant is at least one of decyl glucoside, lauryl glucoside, tetradecyl glucoside, polyol glucoside, or alkyl polyglycoside.
[0010] In the above technical solution, the salt-resistant stabilizer is at least one of coconut oleamidopropyl betaine, hexadecylamide hydroxysulfonate betaine, erucamide propyl hydroxysulfonate betaine, or oleamidopropyl hydroxysulfonate betaine.
[0011] In the above technical solution, the temperature stabilizer is at least one of sodium perfluorododecyl sulfonate, partially fluorinated sodium dodecyl sulfonate, or sodium perfluorotetradecyl sulfonate.
[0012] In the above technical solution, the complexing agent is at least one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediaminetetraacetic acid, or hydroxyethylenediaminetriacetic acid.
[0013] In the above technical solution, the auxiliary agent is at least one selected from methanol, ethanol, ethylene glycol, isopropanol, or glycerol.
[0014] A method for preparing the aforementioned viscosity-reducing and anti-blocking agent for heavy oil in offshore oilfields involves the following steps: Anionic surfactants, nonionic surfactants, and natural surfactants are added to a mixing tank and mixed with tap water. The mixture is stirred at low speed until the solution becomes clear and transparent. Then, a salt-resistant stabilizer, a temperature-resistant stabilizer, a complexing agent, and additives are added to the mixing tank. After stirring at low speed, the mixture is removed from the tank. Once the foam has completely subsided, the viscosity-reducing and anti-blocking agent is obtained.
[0015] In the above technical solution, the anionic surfactant, nonionic surfactant, and natural surfactant are added to the compounding vessel and stirred at a low speed with tap water at a speed of 10 rpm to 30 rpm.
[0016] The beneficial effects of this invention are: This invention addresses the high-temperature and high-salinity application conditions of heavy oil thermal recovery in offshore oilfields and the needs for viscosity reduction and foam plugging control during the extraction process. It provides a temperature- and salt-resistant viscosity-reducing and plugging-control agent for heavy oil thermal recovery in offshore oilfields, along with its preparation method. This agent combines high foaming performance, high viscosity-reducing performance, and temperature and salt resistance to achieve multiple functions in one agent. In terms of formulation, it uses high-foaming and high-viscosity-reducing agents as main agents, supplemented by auxiliary agents that improve temperature and salinity tolerance and enhance miscibility, thus forming a temperature- and salt-resistant viscosity-reducing and plugging-control agent for heavy oil thermal recovery in offshore oilfields. Detailed Implementation
[0017] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below through specific embodiments.
[0018] Example 1 A method for preparing a temperature- and salt-resistant viscosity-reducing and blockage-regulating agent for heavy oil in offshore oil fields includes the following steps: According to the requirements of the formulation process, 14% of anionic surfactant (α-olefin sulfonate), 12% of nonionic surfactant (C12~18 fatty alcohol polyoxyethylene (35) ether), and 15% of natural surfactant (dodecyl glucoside) are added to the compounding kettle and slowly mixed with tap water. The stirring speed should be kept at low speed. After stirring for 20 minutes, observe the state of the aqueous solution. The requirement is that no white crystals are precipitated, there is no precipitate, no suspended matter, and the solution is transparent and clear. At the same time, the foam height of the semi-finished solution should not exceed two-thirds of the compounding kettle. Then, add 5% of salt-resistant stabilizer (cocamidopropyl betaine), 1.5% of temperature-resistant stabilizer (sodium perfluorododecyl sulfonate), 0.5% of complexing agent (ethylenediaminetetraacetic acid), and 0.5% of auxiliary agent (ethanol) to the compounding kettle. Stir at low speed for 20 minutes and then remove from the kettle. During the stirring process, the foam height of the solution should not exceed two-thirds of the compounding kettle. After the foam disappears, transfer the finished product to the finished product container.
[0019] The product obtained in Example 1 was prepared into a solution with a mass concentration of 1.0% for performance testing. The specific test conditions were as follows: 1. Testing instruments: Waring shearing machine, high-temperature displacement device, etc.; 2. Experimental temperature: room temperature, 250℃; 3. Experimental materials: heavy oil from an offshore oil field, artificially filled sand core from an offshore oil field (permeability 2000 mD), distilled water, etc. The experimental results are shown in the table below: This invention can withstand operating environments at 300°C, and can withstand reservoir produced water with a total mineralization of less than or equal to 20,000 mg / L and a sum of calcium and magnesium ion concentrations of less than or equal to 2,000 mg / L, without damaging the formation and protecting the environment. The viscosity-reducing wash oil blockage-regulating agent of this invention was tested according to the standards of "Q / SH1020 1967-2020 General Technical Conditions for High-Temperature Foaming Agents for Steam Injection" and "Q / SH1020 2193-2013 General Technical Conditions for High-Temperature Heavy Oil Viscosity Reducers". At room temperature, the foaming height is greater than 600 mL, and the half-life of the precipitate reaches more than 8 minutes. For artificial cores of 2000~3000 mD, the resistance factor can reach more than 43 at 250℃. The viscosity reduction rate of this viscosity-reducing wash oil blockage-regulating agent for produced liquids with a viscosity less than or equal to 20000 mPa·s is more than 98.1%; the viscosity reduction rate for produced liquids with a viscosity greater than 20000 mPa·s and less than or equal to 40000 mPa·s is more than 96.7%.
[0020] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.
Claims
1. A temperature- and salt-resistant viscosity-reducing and blockage-regulating agent for heavy oil in offshore oil fields, characterized in that: The viscosity-reducing wash oil blockage-regulating agent comprises the following components and their mass percentages: Anionic surfactants 10%~15%; Nonionic surfactants: 10%~20%; 10%~20% natural surfactants; Salt stabilizer 5%~10%; Temperature stabilizer 1%~3%; Complexing agent 1%~2%; Additives 0.5%~1%; Water balance.
2. The offshore oilfield heavy oil thermal resistance temperature and salt resistance viscosity reducing and blockage regulating agent according to claim 1, characterized in that: The anionic surfactant is at least one of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecylbenzene sulfonate, α-olefin sulfonate, or internal olefin sulfonate.
3. The offshore oilfield heavy oil thermal resistance temperature and salt resistance viscosity reducing and blockage regulating agent according to claim 1, characterized in that: The nonionic surfactant is at least one of C12-18 fatty alcohol polyoxyethylene (15) ether, C12-18 fatty alcohol polyoxyethylene (20) ether, C12-18 fatty alcohol polyoxyethylene (25) ether or C12-18 fatty alcohol polyoxyethylene (35) ether.
4. The offshore oilfield heavy oil thermal resistance temperature and salt resistance viscosity reducing and blockage regulating agent according to claim 1, characterized in that: The natural surfactant is at least one of decyl glucoside, lauryl glucoside, tetradecyl glucoside, polyol glucoside, or alkyl polyglycoside.
5. The offshore oilfield heavy oil thermal resistance temperature and salt resistance viscosity reducing and blockage regulating agent according to claim 1, characterized in that: The salt-resistant stabilizer is at least one of coconut oleamidopropyl betaine, hexadecylamide hydroxysulfonate betaine, erucamide propyl hydroxysulfonate betaine, or oleamidopropyl hydroxysulfonate betaine.
6. The offshore oilfield heavy oil thermal resistance temperature and salt resistance viscosity reducing and blockage regulating agent according to claim 1, characterized in that: The temperature stabilizer is at least one of sodium perfluorododecyl sulfonate or sodium perfluorotetradecyl sulfonate.
7. The offshore oilfield heavy oil thermal resistance temperature and salt resistance viscosity reducing and blockage regulating agent according to claim 1, characterized in that: The complexing agent is at least one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediaminetetraacetic acid, or hydroxyethylenediaminetriacetic acid.
8. The offshore oilfield heavy oil thermal resistance temperature and salt resistance viscosity reducing and blockage regulating agent according to claim 1, characterized in that: The additive is at least one of methanol, ethanol, ethylene glycol, isopropanol, or glycerol.
9. A method for preparing a temperature- and salt-resistant viscosity-reducing and blockage-regulating agent for heavy oil in offshore oilfields as described in any one of claims 1 to 8, characterized in that: The preparation method is specifically as follows: Anionic surfactants, nonionic surfactants, and natural surfactants are added to a compounding vessel and mixed with tap water. The mixture is stirred at low speed until the solution is clear and transparent. Then, salt-resistant stabilizers, temperature-resistant stabilizers, complexing agents, and additives are added to the compounding vessel. After stirring at low speed, the mixture is removed from the vessel. Once the foam has completely subsided, the viscosity-reducing and blockage-regulating washing oil agent is obtained.
10. The preparation method of the temperature- and salt-resistant viscosity-reducing and blockage-regulating agent for heavy oil in offshore oilfields according to claim 9, characterized in that: The anionic surfactant, nonionic surfactant, and natural surfactant are added to the compounding vessel and stirred at a low speed of 10 rpm to 30 rpm with tap water.