Phase change microcapsule suitable for cooling drilling fluid and preparation method of phase change microcapsule

Abstract

The invention relates to the technical field of drilling fluid cooling, and discloses a phase change microcapsule suitable for drilling fluid cooling and a preparation method thereof.The phase change microcapsule comprises a capsule wall stabilizing material and a capsule core phase change material, and the capsule wall stabilizing material comprises polyurethane, polyurea, polyamide, polyimide, polystyrene and a first organic solvent; the capsule core phase change material comprises paraffin, fatty acid, polyol, inorganic hydrated salt, polymer gel, expanded graphite, carbon nanotubes, metal nanoparticles and a second organic solvent, and the first organic solvent is at least one of toluene, xylene, cyclohexanone and the like. The temperature of the drilling fluid is kept at a relatively low level, the cooling of the drilling fluid is realized, so that the drilling efficiency is improved, harmful solvents and additives are not used in the preparation process of the phase-change microcapsules, the phase-change microcapsules are pollution-free to the environment, and the requirements of greenness and environmental protection are met.

Description

Technical Field

[0001] The invention relates to the technical field of drilling fluid cooling, and in particular to a phase change microcapsule suitable for drilling fluid cooling and a preparation method thereof. Background Art

[0002] Drilling fluid plays an important role in the drilling process. Its main functions include carrying drill cuttings, cooling the drill bit, balancing formation pressure, etc. However, as the drilling depth increases, the underground temperature gradually rises, and the temperature of the drilling fluid will also rise accordingly, which will not only affect the drilling efficiency, but may also cause a series of safety issues. Therefore, a cooling device is used to cool the drilling fluid.

[0003] Traditional methods of cooling drilling fluid mainly include the use of coolants or coolants, but these methods have problems such as unstable cooling effect and serious environmental pollution, which causes the drilling fluid to become high temperature after long-term use. This will not only cause a series of safety problems, but also seriously affect the drilling efficiency and cannot meet the drilling needs.

[0004] Therefore, we propose a phase change microcapsule suitable for cooling drilling fluid and a preparation method thereof. Summary of the invention

[0005] The present invention mainly solves the technical problems existing in the above-mentioned prior art and provides a phase change microcapsule suitable for cooling drilling fluid and a preparation method thereof.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a phase change microcapsule suitable for cooling drilling fluid, comprising a capsule wall stabilizing material and a capsule core phase change material, the capsule wall stabilizing material comprising polyurethane, polyurea, polyamide, polyimide, polystyrene and a first organic solvent, the capsule core phase change material comprising paraffin, fatty acid, polyol, inorganic hydrated salt, polymer gel, expanded graphite, carbon nanotube, metal nanoparticles and a second organic solvent, the first organic solvent is at least one of toluene, xylene, cyclohexanone, etc., and the second organic solvent is at least one of ethanol, acetone, acetonitrile, etc.

[0007] Preferably, the polyurethane is obtained by the reaction of isocyanate and polyol, the polyurea is obtained by the reaction of isocyanate and amines, the polyamide is obtained by the reaction of a dibasic acid or a diamine with a diamine or a dibasic acid, the polyimide is obtained by the reaction of a dibasic acid anhydride with a diamine, and the polystyrene is obtained by the polymerization of styrene monomers.

[0008] Preferably, the paraffin is a straight-chain alkane paraffin, the fatty acid is at least one of saturated fatty acids such as stearic acid and palmitic acid, the polyol is at least one of low molecular weight polyols such as ethylene glycol and glycerol, the inorganic hydrated salt is at least one of sodium sulfate decahydrate, magnesium chloride hexahydrate, etc., the polymer gel is at least one of polyacrylamide, polyethylene glycol, etc., the expanded graphite is expanded graphite with modified surface, the carbon nanotubes are single-walled carbon nanotubes or multi-walled carbon nanotubes, and the metal nanoparticles are at least one of silver nanoparticles, copper nanoparticles, etc.

[0009] Preferably, the mass ratio of the capsule wall stabilizing material to the capsule core phase change material is 1:5, and the mass ratio of the first organic solvent to the second organic solvent is 1:1.

[0010] A method for preparing phase change microcapsules suitable for cooling drilling fluids comprises the following steps:

[0011] The first step: dissolving polyurethane, polyurea, polyamide, polyimide and polystyrene in the capsule wall stabilizing material in a first organic solvent to obtain a capsule wall stabilizing material solution;

[0012] Step 2: dissolving the paraffin wax, fatty acid, polyol, inorganic hydrated salt, polymer gel, expanded graphite, carbon nanotubes and metal nanoparticles in the core phase change material in a second organic solvent to obtain a core phase change material solution;

[0013] Step 3: Add the core phase change material solution dropwise to the wall stabilizing material solution, and obtain a phase change microcapsule suspension through stirring, emulsification, and solidification.

[0014] Step 4: Centrifuge, wash and dry the phase change microcapsule suspension to obtain phase change microcapsules suitable for cooling the drilling fluid.

[0015] Preferably, in the third step, the stirring speed is 500-2000 rpm, the emulsification time is 10-60 min, the curing temperature is 20-80° C., and the curing time is 1-6 h.

[0016] Preferably, in the fourth step, the centrifugal separation speed is 2000-5000 rpm, the centrifugal time is 5-30 min, the washing liquid is at least one of ethanol, acetone, acetonitrile, etc., the drying temperature is 40-100° C., and the drying time is 2-12 h.

[0017] Beneficial Effects

[0018] The present invention provides a phase change microcapsule suitable for cooling drilling fluid and a preparation method thereof. It has the following beneficial effects:

[0019] (1) A phase change microcapsule suitable for cooling drilling fluid and a preparation method thereof. The phase change microcapsule of the present invention can stably release heat within a specific temperature range, so that the temperature of the drilling fluid is maintained at a relatively low level, thereby achieving cooling of the drilling fluid and improving drilling efficiency. In addition, no harmful solvents and additives are used in the preparation process of the phase change microcapsule, so there is no pollution to the environment, which meets the requirements of green environmental protection.

[0020] (2) The phase change microcapsules suitable for cooling drilling fluid and the preparation method thereof. The phase change microcapsules of the present invention have good dispersibility and stability, can be evenly dispersed in the drilling fluid, and are not easy to flocculate or float, thereby ensuring the uniformity and stability of the cooling effect.

[0021] (3) The phase change microcapsules suitable for cooling drilling fluid and the preparation method thereof are simple and easy to implement, do not require special equipment and technology, and are easy to realize industrial production. The prepared phase change microcapsules have uniform particle size, good dispersibility and high stability. The phase change microcapsules can be applied to different types of drilling fluids and different drilling environments, and have broad application prospects. DETAILED DESCRIPTION

[0022] Embodiment 1: A phase-change microcapsule suitable for cooling drilling fluid, comprising a capsule wall stabilizing material and a capsule core phase-change material, wherein the capsule wall stabilizing material comprises polyurethane, polyurea, polyamide, polyimide, polystyrene and a first organic solvent, and the capsule core phase-change material comprises paraffin, fatty acid, polyol, inorganic hydrated salt, polymer gel, expanded graphite, carbon nanotube, metal nanoparticles and a second organic solvent, wherein the first organic solvent is at least one of toluene, xylene, cyclohexanone and the like, and the second organic solvent is at least one of ethanol, acetone, acetonitrile and the like, polyurethane is obtained by reacting isocyanate and polyol, polyurea is obtained by reacting isocyanate and amines, polyamide is obtained by reacting dibasic acid or diamine with diamine or dibasic acid, polyimide is obtained by reacting dibasic acid anhydride with diamine, polystyrene is obtained by polymerizing styrene monomer, paraffin is straight-chain alkane paraffin, and fatty acid is stearic acid, brown At least one of saturated fatty acids such as palmitic acid, the polyol is at least one of low molecular polyols such as ethylene glycol and propylene glycol, the inorganic hydrated salt is at least one of sodium sulfate decahydrate, magnesium chloride hexahydrate, etc., the polymer gel is at least one of polyacrylamide, polyethylene glycol, etc., the expanded graphite is surface-modified expanded graphite, the carbon nanotube is a single-walled carbon nanotube or a multi-walled carbon nanotube, the metal nanoparticle is at least one of silver nanoparticles, copper nanoparticles, etc., the mass ratio of the capsule wall stabilizing material to the capsule core phase change material is 1:5, the mass ratio of the first organic solvent to the second organic solvent is 1:1, the phase change microcapsule of the present invention can stably release heat within a specific temperature range, so that the temperature of the drilling fluid is maintained at a relatively low level, the cooling of the drilling fluid is achieved, and the drilling efficiency is improved. In addition, no harmful solvents and additives are used in the preparation process of the phase change microcapsule, and there is no pollution to the environment, which meets the requirements of green environmental protection.

[0023] Embodiment 2: On the basis of embodiment 1, the capsule wall stabilizing material includes polyurethane, polyurea, polyamide, polyimide, polystyrene and a first organic solvent, the capsule core phase change material includes paraffin, fatty acid, polyol, inorganic hydrated salt, polymer gel, expanded graphite, carbon nanotube, metal nanoparticles and a second organic solvent, the first organic solvent is at least one of toluene, xylene, cyclohexanone, etc., the second organic solvent is at least one of ethanol, acetone, acetonitrile, etc., polyurethane is obtained by reacting isocyanate and polyol, polyurea is obtained by reacting isocyanate and amines, polyamide is obtained by reacting dibasic acid or diamine with diamine or dibasic acid, polyimide is obtained by reacting dibasic acid anhydride with diamine, polystyrene is obtained by polymerizing styrene monomer, paraffin is a straight-chain alkane petroleum The phase change microcapsules of the present invention have good dispersibility and stability, can be evenly dispersed in drilling fluid, are not easy to flocculate or float, thereby ensuring the uniformity and stability of the cooling effect.

[0024] Example 3: Based on Example 1 and Example 2, polyurethane is obtained by reacting isocyanate and polyol, polyurea is obtained by reacting isocyanate and amines, polyamide is obtained by reacting dibasic acid or diamine with diamine or dibasic acid, polyimide is obtained by reacting dibasic acid anhydride with diamine, polystyrene is obtained by polymerizing styrene monomer, paraffin is straight-chain alkane paraffin, fatty acid is at least one of saturated fatty acids such as stearic acid and palmitic acid, polyol is at least one of low molecular weight polyols such as ethylene glycol and glycerol, inorganic hydrated salt is at least one of sodium sulfate decahydrate, magnesium chloride hexahydrate, etc., and polymer gel is polyacrylamide At least one of amine, polyethylene glycol, etc., the expanded graphite is expanded graphite with modified surface, the carbon nanotube is a single-walled carbon nanotube or a multi-walled carbon nanotube, the metal nanoparticle is at least one of silver nanoparticles, copper nanoparticles, etc., the mass ratio of the capsule wall stabilizing material to the capsule core phase change material is 1:5, the mass ratio of the first organic solvent to the second organic solvent is 1:1. The preparation method of the invention is simple and easy, does not require special equipment and technology, is easy to realize industrial production, and the prepared phase change microcapsules have uniform particle size, good dispersibility and high stability. The phase change microcapsules can be applied to different types of drilling fluids and different drilling environments, and have broad application prospects.

[0025] Embodiment 4: On the basis of Embodiment 1, Embodiment 2 and Embodiment 3, the paraffin is a straight-chain alkane paraffin, the fatty acid is at least one of saturated fatty acids such as stearic acid and palmitic acid, the polyol is at least one of low molecular weight polyols such as ethylene glycol and glycerol, the inorganic hydrated salt is at least one of sodium sulfate decahydrate, magnesium chloride hexahydrate, etc., the polymer gel is at least one of polyacrylamide, polyethylene glycol, etc., the expanded graphite is expanded graphite with modified surface, the carbon nanotube is a single-walled carbon nanotube or a multi-walled carbon nanotube, the metal nanoparticle is at least one of silver nanoparticles, copper nanoparticles, etc., the mass ratio of the capsule wall stabilizing material to the capsule core phase change material is 1:5, and the mass ratio of the first organic solvent to the second organic solvent is 1:1.

[0026] Example 5: Based on Example 1, Example 2, Example 3 and Example 4, the first organic solvent is at least one of toluene, xylene, cyclohexanone, etc., the second organic solvent is at least one of ethanol, acetone, acetonitrile, etc., polyurethane is obtained by reacting isocyanate and polyol, polyurea is obtained by reacting isocyanate and amines, polyamide is obtained by reacting dibasic acid or diamine with diamine or dibasic acid, polyimide is obtained by reacting dibasic acid anhydride with diamine, polystyrene is obtained by polymerizing styrene monomer, paraffin is straight-chain alkane paraffin, and fatty acid is stearic acid , palmitic acid and other saturated fatty acids, the polyol is at least one of ethylene glycol, propylene glycol and other low molecular weight polyols, the inorganic hydrated salt is at least one of sodium sulfate decahydrate, magnesium chloride hexahydrate and the like, the polymer gel is at least one of polyacrylamide, polyethylene glycol and the like, the expanded graphite is surface-modified expanded graphite, the carbon nanotube is a single-walled carbon nanotube or a multi-walled carbon nanotube, the metal nanoparticle is at least one of silver nanoparticles, copper nanoparticles and the like, the mass ratio of the capsule wall stabilizing material to the capsule core phase change material is 1:5, and the mass ratio of the first organic solvent to the second organic solvent is 1:1.

[0027] A method for preparing phase change microcapsules suitable for cooling drilling fluids comprises the following steps:

[0028] The first step: dissolving polyurethane, polyurea, polyamide, polyimide and polystyrene in the capsule wall stabilizing material in a first organic solvent to obtain a capsule wall stabilizing material solution;

[0029] Step 2: dissolving the paraffin wax, fatty acid, polyol, inorganic hydrated salt, polymer gel, expanded graphite, carbon nanotubes and metal nanoparticles in the core phase change material in a second organic solvent to obtain a core phase change material solution;

[0030] Step 3: Add the core phase change material solution dropwise to the wall stabilizing material solution, and obtain a phase change microcapsule suspension through stirring, emulsification, and solidification.

[0031] Step 4: Centrifuge, wash and dry the phase change microcapsule suspension to obtain phase change microcapsules suitable for cooling the drilling fluid.

[0032] In the third step, the stirring speed is 500-2000rpm, the emulsification time is 10-60min, the curing temperature is 20-80°C, and the curing time is 1-6h. In the fourth step, the centrifugal separation speed is 2000-5000rpm, the centrifugation time is 5-30min, the washing liquid is at least one of ethanol, acetone, acetonitrile, etc., the drying temperature is 40-100°C, and the drying time is 2-12h.

[0033] Working principle of the present invention: The preparation method of the phase change microcapsule encapsulates the core phase change material in a tiny capsule formed by the capsule wall stabilizing material through a specific chemical reaction and physical process. These microcapsules can undergo phase change within a specific temperature range, absorb or release heat, and thus achieve a cooling effect on the drilling fluid. In the first step, capsule wall stabilizing materials such as polyurethane, polyurea, polyamide, polyimide and polystyrene are dissolved in a first organic solvent to form a capsule wall stabilizing material solution. These polymer materials have good stability and film-forming properties and can form the wall material of the capsule in subsequent steps. In the second step, capsule core phase change materials such as paraffin, fatty acids, polyols, inorganic hydrated salts, polymer gels, expanded graphite, carbon nanotubes and metal nanoparticles are dissolved in a second organic solvent to form a capsule core phase change material solution. These materials have good phase change properties and thermal stability and can absorb or release heat when the temperature changes. In the third step, the core phase change material solution is added dropwise to the wall stabilizing material solution, and the core phase change material is wrapped by the wall stabilizing material through stirring, emulsification, curing and other steps to form a phase change microcapsule suspension. In this process, the control of parameters such as stirring speed, emulsification time and curing temperature has an important influence on the formation and performance of microcapsules. In the fourth step, the phase change microcapsule suspension is centrifuged, washed and dried to obtain phase change microcapsules suitable for cooling drilling fluid. In this process, the centrifugal speed and centrifugal time determine the separation effect of the microcapsules, the selection of washing liquid can remove impurities on the surface of the microcapsules, and the drying temperature and drying time affect the drying degree and stability of the microcapsules. When the temperature in the drilling fluid rises, the phase change material in the microcapsule will absorb heat and undergo a phase change, from solid to liquid or gas, thereby reducing the temperature of the drilling fluid. When the temperature drops, the phase change material will release heat and return to its original state, thereby achieving temperature regulation and stabilization. This phase change process can be repeated within a certain temperature range, so that the microcapsule has a good cooling effect and stability. In addition, the capsule wall stabilizing material of the microcapsule can protect the capsule core phase change material from the influence of the external environment and improve the stability and durability of the microcapsule. At the same time, the selection and design of the capsule wall material can also affect the performance and application range of the microcapsule. For example, by selecting different polymer materials and organic solvents, microcapsules with different shapes, sizes and properties can be prepared to meet different drilling fluid cooling requirements.

[0034] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A phase change microcapsule suitable for cooling drilling fluid, characterized in that: It includes a capsule wall stabilizing material and a capsule core phase change material. The capsule wall stabilizing material includes polyurethane, polyurea, polyamide, polyimide, polystyrene and a first organic solvent. The capsule core phase change material includes paraffin, fatty acid, polyol, inorganic hydrated salt, polymer gel, expanded graphite, carbon nanotube, metal nanoparticles and a second organic solvent. The first organic solvent is at least one of toluene, xylene, cyclohexanone, etc., and the second organic solvent is at least one of ethanol, acetone, acetonitrile, etc.

2. The phase change microcapsule suitable for cooling drilling fluid according to claim 1, characterized in that: The polyurethane is obtained by the reaction of isocyanate and polyol, the polyurea is obtained by the reaction of isocyanate and amines, the polyamide is obtained by the reaction of a dibasic acid or a diamine with a diamine or a dibasic acid, the polyimide is obtained by the reaction of a dibasic acid anhydride with a diamine, and the polystyrene is obtained by the polymerization of styrene monomers.

3. The phase change microcapsule suitable for cooling drilling fluid according to claim 1, characterized in that: The paraffin wax is a straight-chain alkane paraffin wax, the fatty acid is at least one of saturated fatty acids such as stearic acid and palmitic acid, the polyol is at least one of low molecular weight polyols such as ethylene glycol and glycerol, the inorganic hydrated salt is at least one of sodium sulfate decahydrate and magnesium chloride hexahydrate, the polymer gel is at least one of polyacrylamide and polyethylene glycol, the expanded graphite is expanded graphite with modified surface, the carbon nanotube is a single-walled carbon nanotube or a multi-walled carbon nanotube, and the metal nanoparticle is at least one of silver nanoparticles, copper nanoparticles, etc.

4. The phase change microcapsule suitable for cooling drilling fluid according to claim 1, characterized in that: The mass ratio of the capsule wall stabilizing material to the capsule core phase change material is 1:5, and the mass ratio of the first organic solvent to the second organic solvent is 1:

1.

5. A method for preparing phase change microcapsules suitable for cooling drilling fluid, characterized in that: The specific steps include: The first step: dissolving polyurethane, polyurea, polyamide, polyimide and polystyrene in the capsule wall stabilizing material in a first organic solvent to obtain a capsule wall stabilizing material solution; Step 2: dissolving the paraffin wax, fatty acid, polyol, inorganic hydrated salt, polymer gel, expanded graphite, carbon nanotubes and metal nanoparticles in the core phase change material in a second organic solvent to obtain a core phase change material solution; Step 3: Add the core phase change material solution dropwise to the wall stabilizing material solution, and obtain a phase change microcapsule suspension through stirring, emulsification, and solidification. Step 4: Centrifuge, wash and dry the phase change microcapsule suspension to obtain phase change microcapsules suitable for cooling the drilling fluid.

6. The method for preparing phase change microcapsules suitable for cooling drilling fluid according to claim 5, characterized in that: In the third step, the stirring speed is 500-2000 rpm, the emulsification time is 10-60 min, the curing temperature is 20-80° C., and the curing time is 1-6 h.

7. The method for preparing phase change microcapsules suitable for cooling drilling fluid according to claim 5, characterized in that: In the fourth step, the centrifugal separation speed is 2000-5000 rpm, the centrifugal time is 5-30 min, the washing liquid is at least one of ethanol, acetone, acetonitrile, etc., the drying temperature is 40-100° C., and the drying time is 2-12 h.