Foam stabilizer as well as preparation method and application thereof
By modifying the combination of xanthan gum and nanoparticles, a foam stabilizer is formed, which solves the problem of insufficient stability of water-based recyclable microfoam drilling fluid at high temperatures. This achieves efficient configuration and enhanced temperature resistance of the drilling fluid, thereby improving drilling efficiency and effectiveness.
Patent Information
- Application Number
- CN202411544466.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2026-05-01
AI Technical Summary
Existing foam stabilizers are easily soluble at high temperatures, resulting in insufficient stability and temperature resistance of water-based recyclable microfoam drilling fluids, which affects drilling efficiency and effectiveness.
A combination of xanthan gum, nanoparticles, polyethylene glycol disuccinate, and N-vinylpyrrolidone is used to modify and form a foam stabilizer, which enhances the stability and temperature resistance of the foam. The nanoparticles form a solid film at the gas-liquid interface, which improves the half-life and self-healing ability of the foam.
It significantly improves the temperature stability and viscosity of water-based drilling fluids, shortens preparation time, enhances suspension and carrying capacity, reduces filtration loss, and meets the needs of on-site drilling operations.
Smart Images
Figure BDA0005113449430000121 
Figure BDA0005113449430000131
Abstract
Description
Technical Field
[0001] This invention relates to the field of drilling fluid technology, and in particular to a foam stabilizer, its preparation method, and its application. Background Technology
[0002] Water-based recyclable microfoam drilling fluid is a mature, novel low-density drilling fluid system developed jointly by MI Drilling Fluids and Acti-Systems in the United States. This system has been applied in hundreds of wells in low-pressure formations of old oilfields in the North Sea, northwestern Venezuela, and the Gulf of Mexico. Results show that water-based recyclable microfoam drilling fluid is the optimal system for low-pressure and multi-pressure formations prone to leakage and differential sticking. Water-based recyclable microfoam drilling fluid generates multi-layered microfoams encapsulated by foaming agents and foam stabilizers, with a spherical air core inside each microfoam. The high strength and low gas permeability of the microfoam allow it to withstand bottomhole pressure. Water-based recyclable microfoam drilling fluid offers advantages such as low density, reusability unaffected by downhole tools like MWD and drilling fluid motors, no need for on-site gas injection equipment (compressors and gas production and injection equipment), effective prevention of leakage in low-pressure fractured, high-permeability sandstone and fractured formations, protection of oil and gas reservoirs, and reduced drilling costs.
[0003] Water-based recirculating microfoam drilling fluid is beneficial for increasing the rate of penetration (ROP). During drilling operations, the reduced fluid column pressure decreases the "pressure holding effect" of the fractured rock at the bottom of the well. Furthermore, drilling with water-based recirculating microfoam drilling fluid creates a vibrating fluid layer in the rock fractures at the bottom of the well, similar to a boiling layer, producing a "cavitation" effect. Water-based recirculating microfoam drilling fluid is also beneficial for reducing reservoir contamination. Due to its lower fluid column pressure, the depth of fluid penetration into the formation and the degree of reservoir contamination are significantly reduced, which is beneficial for protecting oil and gas reservoirs.
[0004] Microfoams are beneficial in preventing well leakage. This is because foam fluids have a low density, and the density is adjustable (0.4-0.9 g / cm³). 3 The resulting liquid column pressure is also lower, which may cause the density of the foam fluid during drilling to be lower than the formation pressure coefficient, or the equivalent circulating density to be lower than the critical leakage pressure of easily leaky formations, thus greatly reducing the probability and extent of well leakage. Water-based recirculating microfoam drilling fluid has a strong sand-carrying capacity. Because the viscosity of the foam fluid base fluid is generally high, the viscosity of the foam system is also correspondingly increased, resulting in a strong ability to carry drill cuttings, greatly avoiding repeated cutting of rock, and improving wellbore cleaning capabilities.
[0005] Water-based recyclable microfoam drilling fluid is mainly composed of foaming agents, stabilizers, and other treatment agents. Foam, as a thermodynamically unstable system, is stabilized under certain conditions by adding foam stabilizers. Foam stabilizers are mostly water-soluble polymers and surfactants; most are susceptible to temperature and salinity, which reduces their foam-stabilizing effect. Xanthan gum, as a water-soluble macromolecular polymer, is a viscosity-enhancing agent for drilling fluid and has a good foam-stabilizing effect. However, it has a long dissolution time, is prone to clumping, and is relatively cumbersome to use. Increased viscosity also leads to decreased foaming performance. Furthermore, viscosity decreases at high temperatures, reducing foam stability.
[0006] Therefore, how to provide a foam stabilizer with excellent temperature resistance and solubility, as well as a long liquid half-life and good stability has become an urgent problem to be solved. Summary of the Invention
[0007] To address the aforementioned technical problems, this invention provides a foam stabilizer, its preparation method, and its application. Through modification, the synergistic effect of xanthan gum and specific nanoparticles is utilized, significantly increasing the half-life of the water-based drilling fluid containing it and improving the overall temperature stability of the water-based drilling fluid. At the same time, the resulting liquid foam stabilizer is easy to use, has good solubility, can shorten the preparation cycle of water-based drilling fluid, and meets the application requirements of field operations.
[0008] To achieve this objective, the present invention adopts the following technical solution:
[0009] In a first aspect, the present invention provides a foam stabilizer, wherein the raw materials for preparing the foam stabilizer include the following components: xanthan gum, nanoparticles, polyethylene glycol disuccinate, and N-vinylpyrrolidone;
[0010] The nanoparticles include nano-silica and / or nano-calcium carbonate.
[0011] The foam stabilizer provided by this invention includes nanoparticles, which can be adsorbed on the gas-liquid interface to form a solid film, effectively preventing the liquid film from draining out, thereby extending the half-life of the foam and improving its stability. The nanoparticles show little change in performance after long-term aging at high temperatures, exhibiting better long-term foam stabilization effect. By grafting and modifying the nanoparticles, hydrophilic groups can be introduced, giving them an "active" structure, which is conducive to the movement of particles to the gas-liquid interface and enhances the stability of the foam. The modified nanoparticles can enhance the "self-healing" ability of the foam within a certain concentration range, further enhancing the stability of the foam.
[0012] The foam stabilizer provided by this invention uses nanoparticles including nano-silica and / or nano-calcium carbonate. The nano-sized silica particles can have a synergistic effect with xanthan gum, improving the foaming volume and stability. Supercalcium carbonate is an important inorganic chemical product with advantages such as wide availability of raw materials and low price. As a drilling fluid treatment agent, it can improve the stability and temperature resistance of foam, while effectively sealing the formation and reducing filtration loss.
[0013] The polyethylene glycol disuccinate in the foam stabilizer preparation raw materials provided by this invention has a strong bonding ability with guest molecules and is more hydrophilic than materials such as polyester polyols. N-vinylpyrrolidone acts as a catalyst and reinforcing agent, making the reaction easier and more complete. Modifying xanthan gum and nanoparticles with polyethylene glycol disuccinate and N-vinylpyrrolidone improves the hydrophilicity and solubility of the resulting foam stabilizer, shortening the preparation time of water-based drilling fluids. Furthermore, combining xanthan gum and specific nanoparticles maximizes their synergistic effect, improves its temperature resistance, and increases the half-life of the exudate, making it more suitable for use in water-based drilling fluids.
[0014] Preferably, the raw materials for preparing the foam stabilizer, by weight, include the following components: 35-65 parts xanthan gum (e.g., 38, 40, 45, 50, 55, or 60 parts, etc.), 3-5 parts nanoparticles (e.g., 3.2, 3.5, 3.8, 4, 4.2, 4.5, or 4.8 parts, etc.), 35-65 parts polyethylene glycol disuccinate (e.g., 38, 40, 45, 50, 55, or 60 parts, etc.), and 2-10 parts N-vinylpyrrolidone (e.g., 3, 4, 5, 6, 7, 8, or 9 parts, etc.).
[0015] Preferably, the xanthan gum has a weight-average molecular weight of 3.5 × 10⁻⁶. 5 -6.6×10 6 g / mol, for example, could be 4.15 × 10⁻⁶ g / mol. 5 g / mol, 6×10 5 g / mol, 8.72×10 5 g / mol, 1×10 6 g / mol, 2.34×10 6 g / mol or 5.81×10 6 g / mol, etc.
[0016] Preferably, the nanoparticles have a particle size of 20-100 nm, such as 30 nm, 37 nm, 40 nm, 50 nm, 60 nm, 76 nm, or 96 nm.
[0017] Preferably, the raw materials for preparing the foam stabilizer further include 2-10 parts by weight of chain transfer agent, for example, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts or 9 parts, etc.
[0018] Preferably, the chain transfer agent comprises sodium formate.
[0019] Preferably, the raw materials for preparing the foam stabilizer further include 4-8 parts of initiator by weight, for example, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts or 7.5 parts, etc.
[0020] Preferably, the initiator includes any one or a combination of at least two of azo initiators, persulfate initiators, or bisulfite initiators.
[0021] Preferably, the azo initiator includes azobisisobutyramidine hydrochloride and / or azobisisobutyramidine imidazoline hydrochloride.
[0022] Preferably, the persulfate initiator includes potassium persulfate and / or sodium persulfate.
[0023] Preferably, the bisulfite initiator includes sodium bisulfite and / or potassium bisulfite.
[0024] In a second aspect, the present invention provides a method for preparing a foam stabilizer as described in the first aspect, the method comprising the following steps:
[0025] (1) Polyethylene glycol disuccinate, N-vinylpyrrolidone and optional chain transfer agent and optional first initiator are reacted to obtain a grafting intermediate solution;
[0026] (2) The grafting intermediate solution obtained in step (1) is mixed with xanthan gum and nanoparticles to obtain a reaction solution, and polymerization is initiated by a second initiator to obtain the foam stabilizer.
[0027] The foam stabilizer preparation method provided by this invention can directly obtain the product after polymerization without further processing. The preparation method is relatively simple, has low equipment requirements, low cost, and controllable product quality, which is conducive to its widespread application.
[0028] Preferably, the reaction in step (1) includes the following steps: dissolving polyethylene glycol disuccinate in a first alkaline solution, mixing it with N-vinylpyrrolidone and a chain transfer agent, adding a first initiator to obtain a mixed solution, initiating the reaction, and obtaining the grafting intermediate solution.
[0029] Preferably, the first alkaline solution comprises a sodium hydroxide solution.
[0030] Preferably, the pH of the first alkaline solution is 7-9, for example, it can be 7.2, 7.5, 7.8, 8, 8.2, 8.5 or 8.8.
[0031] Preferably, the polyethylene glycol disuccinate in the first alkaline solution has a mass content of 35-65%, for example, it can be 38%, 40%, 45%, 50%, 55% or 60%, etc.
[0032] Preferably, the temperature at which the solution is dissolved in the first alkaline solution is 45-50°C, for example, 45.5°C, 46°C, 46.5°C, 47°C, 48°C, or 49°C.
[0033] Preferably, the time for dissolving in the first alkaline solution is 2-3 hours, for example, 2.1 hours, 2.3 hours, 2.5 hours, 2.7 hours or 2.9 hours.
[0034] Preferably, the N-vinylpyrrolidone content in the mixed solution is 2-10% by mass, for example, it can be 3%, 4%, 5%, 6% or 8%, etc.
[0035] Preferably, the chain transfer agent is a sodium formate solution of 0.05-0.15 mol / L, such as 0.06 mol / L, 0.08 mol / L, 0.1 mol / L, 0.12 mol / L, or 0.14 mol / L.
[0036] Preferably, the chain transfer agent has a mass content of 2-10% in the mixed solution, for example, it can be 3%, 4%, 5%, 6% or 8%, etc.
[0037] Preferably, the mixing time is 10-30 min, for example, it can be 12 min, 15 min, 18 min, 20 min, 22 min, 25 min or 28 min.
[0038] Preferably, the mass content of the first initiator in the mixed solution is 2-4%, for example, it can be 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5% or 3.8%, etc.
[0039] Preferably, the first initiator includes an azo initiator.
[0040] Preferably, the reaction temperature is 75-90°C, for example, 78°C, 80°C, 82°C, 85°C or 88°C.
[0041] Preferably, the reaction time is 2-4 hours, for example, 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours or 3.8 hours.
[0042] Preferably, the xanthan gum is mixed with the grafting intermediate solution and nanoparticles in the form of a xanthan gum solution.
[0043] Preferably, the xanthan gum solution is obtained by dissolving xanthan gum in a second alkaline solution.
[0044] Preferably, the xanthan gum solution contains 35-65% xanthan gum by mass, for example, 38%, 40%, 45%, 50%, 55%, or 60%.
[0045] Preferably, the second alkaline solution comprises a sodium hydroxide solution.
[0046] Preferably, the pH of the second alkaline solution is 7-9, for example, it can be 7.2, 7.5, 7.8, 8, 8.2, 8.5 or 8.8.
[0047] Preferably, the temperature at which the solution is dissolved in the second alkaline solution is 45-50°C, for example, 45.5°C, 46°C, 46.5°C, 47°C, 48°C, or 49°C.
[0048] Preferably, the time for dissolving in the second alkaline solution is 2-3 hours, for example, 2.1 hours, 2.3 hours, 2.5 hours, 2.7 hours or 2.9 hours.
[0049] Preferably, the volume ratio of the grafting intermediate solution to the xanthan gum solution is 1:(0.8-1.2), wherein the specific value of (0.8-1.2) can be, for example, 0.85, 0.9, 0.95, 1, 1.05, 1.1 or 1.15.
[0050] Preferably, the amount of nanoparticles used is 3-5% of the mass of the reaction solution, for example, it can be 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5% or 4.8%, etc.
[0051] Preferably, the second initiator includes a persulfate initiator and / or a bisulfite initiator.
[0052] Preferably, the concentration of the persulfate initiator or bisulfite initiator in the second initiator is 0.05-0.15 mol / L, for example, it can be 0.06 mol / L, 0.08 mol / L, 0.1 mol / L, 0.12 mol / L or 0.14 mol / L, etc.
[0053] Preferably, the amount of the second initiator is 2-4% of the mass of the reaction solution, for example, it can be 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5% or 3.8%, etc.
[0054] Preferably, the polymerization temperature is 80-85℃, for example, it can be 80.5℃, 81℃, 82℃, 83℃ or 84℃, etc.
[0055] Preferably, the polymerization time is 4-8 hours, for example, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours or 7.5 hours.
[0056] Preferably, the mixing and blending method includes stirring.
[0057] Preferably, the stirring rate is 2000-3000 rpm, for example, 2100 rpm, 2300 rpm, 2500 rpm, 2700 rpm, or 2900 rpm.
[0058] Thirdly, the present invention provides a water-based drilling fluid, the water-based drilling fluid comprising a water-based polymer drilling fluid, a foaming agent, and a foam stabilizer as described in the first aspect.
[0059] Preferably, the foaming agent content in the water-based drilling fluid is 0.05-0.5% by mass, for example, it can be 0.08%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3% or 0.4%, etc.
[0060] Preferably, the mass content of the foam stabilizer in the water-based drilling fluid is 0.05-0.5%, for example, it can be 0.08%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3% or 0.4%, etc.
[0061] The water-based drilling fluid provided by the present invention significantly improves its viscosity and dynamic shear force by adding the foam stabilizer as described in the first aspect. The resulting drilling fluid has better suspension and carrying capacity. At the same time, due to the good solubility of the foam stabilizer, the preparation time of the water-based drilling fluid is short, which is convenient for on-site construction operations.
[0062] Fourthly, the present invention provides the application of the foam stabilizer as described in the first aspect and the water-based drilling fluid as described in the third aspect in drilling operations.
[0063] Compared with the prior art, the present invention has at least the following beneficial effects:
[0064] The foam stabilizer provided by this invention improves the solubility of the obtained foam stabilizer in water-based recyclable microfoam drilling fluid by using a combination of xanthan gum, specific nanoparticles, polyethylene glycol disuccinate and N-vinylpyrrolidone, shortens the preparation time of water-based drilling fluid, and the half-life of water-based drilling fluid containing this foam stabilizer can reach more than 480 minutes. At the same time, it has excellent overall stability and temperature resistance, and significantly improved viscosity and dynamic shear force, giving the drilling fluid better suspension and carrying capacity. It can also effectively seal the formation and reduce filtration loss, meeting the application requirements of field drilling operations. Detailed Implementation
[0065] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.
[0066] The materials used in the following examples are shown below:
[0067] Xanthan gum, Erdos Zhongxuan Biochemical Co., Ltd.;
[0068] Nano-silica, Liaoning Quanrui Reagent Co., Ltd., 60nm;
[0069] Nanoscale ultrafine calcium carbonate, Liaoning Quanrui Reagent Co., Ltd., 60nm;
[0070] Polyethylene glycol disuccinate, Liaoning Quanrui Reagent Co., Ltd.;
[0071] Foaming agent, alkyl betaine, Liaoning Oilfield Fenghua Petroleum Machinery Manufacturing Co., Ltd., FH-II.
[0072] Example 1
[0073] A foam stabilizer, said foam stabilizer being prepared by the following method:
[0074] (1) Add sodium hydroxide to 200 mL of distilled water until the pH is 8. Add 70 g of polyethylene glycol dibutyl ester to the above alkaline solution with a pH of 8 at 45 °C and continue stirring for 2 h to obtain a polyethylene glycol dibutyl ester solution.
[0075] Add 4g of N-vinylpyrrolidone and 4g of 0.05mol / L sodium formate solution to the above polyethylene glycol disuccinate solution, stir for 20min, add 4g of azobisisobutyramidine hydrochloride, heat to 75℃ for reaction, maintain 75℃ and stir for 2h to obtain grafting intermediate solution.
[0076] (2) Add 0.6g sodium hydroxide to 200mL distilled water and stir for 5min to obtain an alkaline solution. The pH value is measured to be 8 using pH test paper. Heat the alkaline solution to 45℃, add 70g xanthan gum, keep the solution temperature at 45℃, and stir for 2h to obtain xanthan gum aqueous solution.
[0077] Mix 150 mL of the above grafting intermediate solution with 150 mL of the above xanthan gum aqueous solution, add 15 g of nano-sized ultrafine calcium carbonate, heat to 80 °C, maintain the temperature, add 4 g of 0.05 mol / L potassium persulfate aqueous solution to react, stir the reaction for 4 h, cool to room temperature, and obtain the foam stabilizer.
[0078] Example 2
[0079] A foam stabilizer, the only difference between the foam stabilizer and Example 1 is that the amount of nano-sized ultrafine calcium carbonate is 9g, that is, 9g of nano-sized ultrafine calcium carbonate is added in step (2) of the preparation method, and the other materials, amounts and preparation methods are the same as in Example 1.
[0080] Example 3
[0081] A foam stabilizer, said foam stabilizer being prepared by the following method:
[0082] (1) Add sodium hydroxide to 200 mL of distilled water until the pH is 9. Add 100 g of polyethylene glycol dibutyl ester to the above alkaline solution with a pH of 9 at 48 °C and continue stirring for 2.5 h to obtain a polyethylene glycol dibutyl ester solution.
[0083] Add 10g of N-vinylpyrrolidone and 10g of 0.1mol / L sodium formate solution to the above polyethylene glycol disuccinate solution, stir for 20min, add 6g of azobisisobutyramidine hydrochloride, heat to 85℃ for reaction, maintain temperature and stir for 3h to obtain grafting intermediate solution.
[0084] (2) Add 0.8g of sodium hydroxide to 200mL of distilled water and stir for 5min to obtain an alkaline solution. The pH value is 9 when measured with pH test paper. Heat the alkaline solution to 48℃, add 100g of xanthan gum, maintain the temperature and stir for 2.5h to obtain xanthan gum aqueous solution.
[0085] Mix 150 mL of the above grafting intermediate solution with 150 mL of the above xanthan gum aqueous solution, add 15 g of nano-sized ultrafine calcium carbonate, heat to 82 °C, maintain the temperature, add 6 g of 0.05 mol / L sodium bisulfite aqueous solution to react, stir the reaction for 6 h, cool to room temperature, and obtain the foam stabilizer.
[0086] Example 4
[0087] A foam stabilizer, the only difference between the foam stabilizer and Example 3 is that the amount of nano-sized ultrafine calcium carbonate is 9g, that is, 9g of nano-sized ultrafine calcium carbonate is added in step (2) of the preparation method, and the other materials, amounts and preparation methods are the same as in Example 3.
[0088] Example 5
[0089] A foam stabilizer, said foam stabilizer being prepared by the following method:
[0090] (1) Add sodium hydroxide to 200 mL of distilled water until the pH is 9. Add 130 g of polyethylene glycol dibutyl ester to the above alkaline solution with a pH of 9 at 50 °C and continue stirring for 2.5 h to obtain a polyethylene glycol dibutyl ester solution.
[0091] Add 20g of N-vinylpyrrolidone and 20g of 0.15mol / L sodium formate solution to the above polyethylene glycol disuccinate solution, stir for 20min, add 8g of azobisisobutyramidine hydrochloride, heat to 90℃ for reaction, maintain temperature and stir for 4h to obtain grafting intermediate solution.
[0092] (2) Add 0.8g sodium hydroxide to 200mL distilled water and stir for 5min to obtain an alkaline solution. The pH value is 9 when measured with pH test paper. Heat the alkaline solution to 50℃, add 130g xanthan gum, maintain the temperature and stir for 3h to obtain xanthan gum aqueous solution.
[0093] Mix 150 mL of the above grafting intermediate solution with 150 mL of the above xanthan gum aqueous solution, add 15 g of nano-sized ultrafine calcium carbonate, heat to 85 °C, maintain the temperature, add 8 g of 0.05 mol / L sodium bisulfite aqueous solution to react, stir the reaction for 6 h, cool to room temperature, and obtain the foam stabilizer.
[0094] Example 6
[0095] A foam stabilizer, the only difference between the foam stabilizer and Example 5 is that the amount of nano-sized ultrafine calcium carbonate used is 9g, that is, 9g of nano-sized ultrafine calcium carbonate is added in step (2) of the preparation method, and the other materials, amounts and preparation methods are the same as in Example 5.
[0096] The water-based polymer drilling fluids described in the following application examples, by weight, comprise the following components:
[0097] 5% sodium bentonite (Jianping County Wanxing Bentonite Co., Ltd.), 0.2% soda ash, 0.2% caustic soda, 0.2% thickener (high-viscosity polyanionic cellulose, Wen'an County Zhongde Chemical Co., Ltd.), 1% filtration loss reducer (low-viscosity polyanionic cellulose, Jingzhou Xuecheng Industrial Co., Ltd.), balance: water.
[0098] Application Example 1
[0099] A water-based drilling fluid comprising 200 mL of water-based polymer drilling fluid, 4 mL of the foam stabilizer obtained in Example 1, and 4 mL of foaming agent (alkyl betaine, Liaoning Oilfield Fenghua Petroleum Machinery Manufacturing Co., Ltd.).
[0100] Application Example 2-6
[0101] A water-based drilling fluid, differing from Application Example 1 only in that the foam stabilizer obtained in Example 1 is replaced with the foam stabilizer obtained in Examples 2-6.
[0102] Comparative Application Example 1
[0103] A water-based drilling fluid, which is a water-based polymer drilling fluid.
[0104] Comparative Application Example 2
[0105] A water-based drilling fluid, comprising 200 mL of water-based polymer drilling fluid and 4 mL of foaming agent (alkyl betaine, Hebei Oilfield Fenghua Petroleum Machinery Manufacturing Co., Ltd.).
[0106] The density, apparent viscosity, plastic viscosity, dynamic shear force, and medium-pressure filtration loss of the above-mentioned water-based drilling fluid were determined using the methods and instruments specified in "GB / T 16783.1-2014 Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry - Part 1: Water-based Drilling Fluids". The medium-pressure filtration loss was determined at 150°C and 3.5 MPa.
[0107] The half-life was tested using the following method:
[0108] 1) Before hot rolling
[0109] Pour 200 mL of water-based polymer drilling fluid into a mixing cup and adjust the speed of the mixer to stabilize it at 3000 rpm. Measure 0.4 mL of foam stabilizer and add it to the mixing cup. After stirring for 5 minutes, measure 0.4 mL of foaming agent and add it to the mixing cup. Stir for 5 minutes to obtain the water-based drilling fluid. Transfer the water-based drilling fluid in the mixing cup to a 1000 mL graduated cylinder and record the time required for the drilling fluid to precipitate to 100 mL. This is the pre-heat rolling half-life.
[0110] 2) After hot rolling
[0111] After hot rolling, once the aging tank has cooled down, pour out the water-based drilling fluid. Stir at 3000 rpm for 10 minutes, then transfer the water-based drilling fluid from the stirring cup to a 1000 mL graduated cylinder. Record the time required for the drilling fluid to precipitate down to 100 mL, which is the half-life after hot rolling.
[0112] The hot rolling conditions in the above tests were 120℃ for 16 hours, and the test results are summarized in Table 1.
[0113] Table 1
[0114]
[0115]
[0116] Test results show that, before and after hot rolling, the water-based recyclable microfoam drilling fluid with added foam stabilizer exhibits excellent viscosity-enhancing and shear-lifting capabilities, and its performance remains stable, with a half-life exceeding 480 minutes. The foam stabilizer provided by this invention possesses unique foam-stabilizing properties, making it well-suited for use in water-based recyclable microfoam drilling fluids. It improves the half-life, effectively enhances the drilling fluid's structural strength and suspension capacity, shortens maintenance and treatment time, and increases drilling efficiency.
[0117] 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 foam stabilizer, characterized in that, The raw materials for preparing the foam stabilizer include the following components: xanthan gum, nanoparticles, polyethylene glycol disuccinate, and N-vinylpyrrolidone. The nanoparticles include nano-silica and / or nano-calcium carbonate.
2. The foam stabilizer according to claim 1, characterized in that, The raw materials for preparing the foam stabilizer, by weight, include the following components: 35-65 parts xanthan gum, 3-5 parts nanoparticles, 35-65 parts polyethylene glycol disuccinate, and 2-10 parts N-vinylpyrrolidone.
3. The foam stabilizer according to claim 1 or 2, characterized in that, The xanthan gum has a weight-average molecular weight of 3.5 × 10⁻⁶. 5 -6.6×10 6 g / mol; Preferably, the nanoparticles have a particle size of 20-100 nm.
4. The foam stabilizer according to any one of claims 1-3, characterized in that, The raw materials for preparing the foam stabilizer also include 2-10 parts by weight of chain transfer agent; Preferably, the chain transfer agent comprises sodium formate; Preferably, the raw materials for preparing the foam stabilizer further include 4-8 parts by weight of an initiator; Preferably, the initiator includes any one or a combination of at least two of azo initiators, persulfate initiators, or bisulfite initiators; Preferably, the azo initiator includes azobisisobutyramidine hydrochloride and / or azobisisobutyramidine imidazoline hydrochloride; Preferably, the persulfate initiator includes potassium persulfate and / or sodium persulfate; Preferably, the bisulfite initiator includes sodium bisulfite and / or potassium bisulfite.
5. A method for preparing a foam stabilizer as described in any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) Polyethylene glycol disuccinate, N-vinylpyrrolidone and optional chain transfer agent and optional first initiator are reacted to obtain a grafting intermediate solution; (2) The grafting intermediate solution obtained in step (1) is mixed with xanthan gum and nanoparticles to obtain a reaction solution, and polymerization is initiated by a second initiator to obtain the foam stabilizer.
6. The preparation method according to claim 5, characterized in that, The reaction in step (1) includes the following steps: dissolving polyethylene glycol disuccinate in a first alkaline solution, mixing it with N-vinylpyrrolidone and a chain transfer agent, adding a first initiator to obtain a mixed solution, initiating the reaction, and obtaining the grafting intermediate solution; Preferably, the first alkaline solution comprises a sodium hydroxide solution; Preferably, the pH of the first alkaline solution is 7-9; Preferably, the polyethylene glycol disuccinate has a mass content of 35-65% in the first alkaline solution; Preferably, the temperature at which the solution dissolves in the first alkaline solution is 45-50°C; Preferably, the time for dissolving in the first alkaline solution is 2-3 hours; Preferably, the N-vinylpyrrolidone content in the mixed solution is 2-10% by mass; Preferably, the chain transfer agent is a 0.05-0.15 mol / L sodium formate solution; Preferably, the chain transfer agent has a mass content of 2-10% in the mixed solution; Preferably, the mixing time is 10-30 minutes; Preferably, the mass content of the first initiator in the mixed solution is 2-4%; Preferably, the first initiator includes an azo initiator; Preferably, the reaction temperature is 75-90°C; Preferably, the reaction time is 2-4 hours.
7. The preparation method according to claim 5 or 6, characterized in that, The xanthan gum is mixed with grafting intermediate solution and nanoparticles in the form of xanthan gum solution; Preferably, the xanthan gum solution is obtained by dissolving xanthan gum in a second alkaline solution; Preferably, the xanthan gum solution contains 35-65% xanthan gum by mass. Preferably, the second alkaline solution comprises a sodium hydroxide solution; Preferably, the pH of the second alkaline solution is 7-9; Preferably, the temperature at which the solution dissolves in the second alkaline solution is 45-50°C; Preferably, the time for dissolving in the second alkaline solution is 2-3 hours; Preferably, the volume ratio of the grafting intermediate solution to the xanthan gum solution is 1:(0.8-1.2); Preferably, the amount of nanoparticles used is 3-5% of the mass of the reaction solution; Preferably, the second initiator includes a persulfate initiator and / or a bisulfite initiator; Preferably, the concentration of the persulfate initiator or bisulfite initiator in the second initiator is 0.05-0.15 mol / L; Preferably, the amount of the second initiator is 2-4% of the mass of the reaction solution; Preferably, the polymerization temperature is 80-85°C; Preferably, the polymerization time is 4-8 hours.
8. A water-based drilling fluid, characterized in that, The water-based recyclable microfoam drilling fluid includes a water-based polymer drilling fluid, a foaming agent, and a foam stabilizer as described in any one of claims 1-4.
9. The water-based drilling fluid according to claim 8, characterized in that, The foaming agent content in the water-based drilling fluid is 0.05-0.5% by mass; Preferably, the mass content of the foam stabilizer in the water-based drilling fluid is 0.05-0.5%.
10. The application of a foam stabilizer as described in any one of claims 1-4, or a water-based drilling fluid as described in claim 8 or 9, in drilling operations.