[57] Abstract
The invention provides a protective coating for oil pipes and wellheads and downhole equipment used in oil and gas drilling, oil recovery and transportation. The protective coating comprises, by weight percentage, 55 to 95% of polyphenylene sulfide, 3 to 30% of adhesion enhancer, and 1 to 20% of abrasion resistant enhancer. A surface wettability converting agent may also be included in the range of 1 to 15%. It can prevent or reduce the high temperature, high pressure, high hydrogen sulfide and carbon dioxide, high salt content and other strong corrosive media on the erosion, corrosion and waxing, scaling and hydrate blockage, reduce friction and reduce production costs. Improve the overall performance and service life of oil pipes. The present invention also provides a method of preparing such a protective coating and a method of constructing the same.
1. Protective coating for petroleum pipes, characterized in that the weight percentage comprises the following components:
55~95%, 3~30%,
1 to 20%.
Polyphenylene sulfide adhesion enhancer
2. The protective coating for petroleum pipes according to claim 1, wherein the adhesion enhancer is at least one of micron or nanometer titanium dioxide, chromium trioxide, cobalt sulphate, and carbon fiber. The wear-resistant enhancer is at least one of micron or nano-sized aluminum oxide, copper sulfide, silicon carbide, molybdenum disulfide, carbon fiber, and silicon dioxide.
A protective coating for petroleum pipes according to claim 1 or 2, which comprises the following components in percentage by weight:
Polyphenylene sulfide 55~95%,
Adhesion enhancer 3~30%,
Wear-resistant enhancer 1~20%,
Surface wettability conversion agent 1~15%.
A protective coating for petroleum pipes according to claim 3, wherein the surface wettability converter is at least one of fluorine tetrahexa, polytetrafluoroethylene, polyvinyl alcohol, and molybdenum disulfide.
5. A protective coating for petroleum pipes according to claim 3, characterized in that the following components are included by weight:
Polyphenylene sulfide 55~95%,
Adhesion enhancer 3~30%,
Wear-resistant enhancer 1~20%,
Surface wettability conversion agent 1~15%,
Surface leveling agent 0• 5~5%.
A protective coating for petroleum pipes according to claim 5, wherein the surface leveling agent is at least one of titanium oxide, silane, and octyl acrylate copolymer of the order of micrometers or nanometers.
A protective coating for petroleum pipes according to claim 1 or 2, characterized in that the following components are included in percentage by weight:
Polyphenylene sulfide 55~95%,
Adhesion enhancer 3~30%,
Wear-resistant enhancer 1~20%,
Surface leveling agent 0. 5~5%.
A protective coating for petroleum pipes according to claim 7, wherein the surface leveling agent is at least one of micron- or nano-sized titanium dioxide, silane, and octyl acrylate copolymer.
9. A method for preparing a protective coating for a petroleum pipe, characterized in that the method comprises ball-milling polyphenylene sulfide powder with other components and ethanol of 3 to 5 times the weight of polyphenylene sulfide in a ball mill, time For 4~24 hours, after ball milling, the particle size is controlled at 0.074~0.096 mm, and the suspension of protective coating is prepared for use; then the suspension is dried at 11 CTC ~ 160 ° C for 4-6 hours, ie A dry powder of protective coating is obtained.
10. A method of constructing a protective coating for a petroleum pipe, characterized in that the method comprises the following steps:
1), the surface of the workpiece is pretreated: the cover on the surface of the workpiece is removed;
2), spraying with high pressure airless spraying or electrostatic powder spraying process;
a ) High pressure airless spraying with a suspension of protective coating: spraying on the workpiece in a high pressure and airless manner or spraying the bottom layer, the top layer and/or the intermediate layer on the workpiece: first spraying the bottom layer on the workpiece, the spraying ends after the workpiece into [deg.] 60~80 C oven for 20 to 30 minutes of pre-baked in full removal of solvent the bottom, and then into the plasticized workpiece plasticizing furnace, plasticizing temperature is [deg.] 300~350 C , The plasticizing time is 15~60 minutes; the thermal spraying process is adopted for the middle layer and the surface layer, that is, the workpiece is taken out from the plasticizing furnace, and the upper layer or the surface layer is quickly sprayed, respectively, and then plasticized in a plasticizing furnace. The plasticizing temperature is 320 ° C ~ 400 ° C , the plasticizing time is 30 ~ 120 minutes, and finally the plasticized workpiece coated with the surface layer is taken out of the furnace and immediately placed in water to be cooled and quenched;
b ), using dry powder of protective coating on the workpiece once or on the bottom layer, the surface layer and / or the intermediate layer for electrostatic powder coating. • Is the use of high-voltage electric field effect, the coating powder is negatively charged, the workpiece is grounded, so that the paint is absorbed into the workpiece On the surface, the workpiece is attached with powder coating and then sent to the plasticizing furnace. The powder is melted by heat and leveled and solidified into a film. The thickness of the bottom layer is 30~100^〇1, and the plasticizing temperature is 300!:~350°(: The plasticizing time is 15~60 minutes, the plasticizing temperature of the middle layer or the surface layer is 320° C ~400° C , the plasticizing time is 30 ~ 120 minutes, and finally the plasticized workpiece is quickly taken out from the furnace. Put in water to cool and quench.
Protective coating for petroleum pipe, preparation method and construction method thereof
Technical field:
The invention relates to a petroleum pipe used in oil and gas drilling, oil recovery and transportation, a protective coating for a wellhead and a downhole equipment, a preparation method thereof and a construction method.
Background technique:
Oil pipes include drill pipes, tubing, casing and oil and gas pipelines and sucker rods. Downhole and wellhead equipment includes wellhead high pressure control systems, station equipment and downhole pumps and packers. The working environment of oil pipelines and wellheads and downhole equipment is very harsh (such as oil and gas wells may be as high as 180 ° C , pressures may be as high as 100 MPa , high concentrations of hydrogen sulfide and carbon dioxide, high chloride content and other highly corrosive media), and their service life and Performance has seriously affected exploration and development and oil and gas field operations. For sulfur-containing gas fields, it may cause environmental problems and major safety accidents.
At present, the methods used in the protection of petroleum pipelines are mainly: stainless steel pipes are used in harsh corrosive environments, but stainless steel is expensive, and its use conditions are also limited. It is necessary to adapt to the temperature, carbon dioxide, hydrogen sulfide and chloride content. Steel type. For oil and gas wells with temperatures below 100 ° C , epoxy phenolic series coatings or linings are mainly used at home and abroad. The main problem with these coatings is temperature sensitivity, and their overall performance is reduced at temperatures above 100 ° C. The applicant entrusted the authoritative organization of China’s petroleum industry to conduct high-temperature and high-pressure harsh environmental corrosion evaluation test (the test standard adopts the American Society of Corrosion Engineers Standard NACE TM 0185-93 “Test Method for Autoclave Evaluation of Tube Plastic Internal Coating Anticorrosion”), and found the above. The coating is soaked in a harsh corrosive environment of the oil pipe (ie, high temperature (140 ° C ), high pressure (35 MPa ), high hydrogen sulfide and carbon dioxide, high chloride content, high salt content and other strong corrosive media) The coating is bubbling and delaminating. Analysis of the reason found that: when implemented by the method described above, the adhesion of the coating to the petroleum pipe matrix is poor, and the coating becomes brittle. When the temperature is higher than 14 ( TC) , the reliability of the overall performance is lowered, and the range of use is limited.
Chinese Patent Application Publication No. 1100124 A “High-temperature anti-stick anti-corrosion coating” discloses a coating based on polyphenylene sulfide, which can be used in a rubber mold and a reaction kettle, and has a certain non-stickiness. China Patent Application Publication No. 1100123 A “Abrasion Resistant Coating” discloses a wear-resistant anti-wear coating which has good thermal stability, chemical resistance, mechanical properties, adhesion, self-lubricity and resistance. Grindability can be applied to parts of various mechanical products in mining, metallurgy, building materials, energy, agricultural machinery, transportation and other departments. in
National Patent Application Publication No. 1133331 A “Polyphenylene sulfide resin anticorrosive coating” discloses a polyphenylene sulfide resin anticorrosive coating for use in a coal tar kettle of a coking plant, which is used for spraying on carbon due to acid and alkali resistance. On the inner surface of the coal tar kettle made of steel plate, plasticized to form a protective layer to meet the process requirements of the kettle. China Patent Application Publication No. 1 253 979 A “A heat-resistant, acid-resistant coating for the surface of a metal material” discloses a heat-resistant and acid-resistant coating for the surface of a metal material, and the metal material treated by the invention is at a high temperature and a high concentration. Sulfuric acid has good corrosion resistance in the harsh environment.
At present, the anti-corrosion coatings for petroleum pipes (sweat, oil pipes, etc.) of China’s petroleum industry are mainly imported, and the coatings are epoxy phenolic.
Summary of the invention:
The object of the present invention is to provide a method for preventing or reducing high temperature, high pressure, high hydrogen sulfide and carbon dioxide, high salt and other strong corrosive media to corrode and wax, scale and hydrate the pipeline, and improve the oil pipe. Anti-corrosion, anti-wear, anti-erosion, anti-foling, anti-fouling, anti-friction, reduce production costs, improve the overall performance and service life of oil pipes, protective coatings for oil pipes and wellheads or downhole equipment . Another object of the invention is to provide a process for the preparation of such protective coatings. Still another object of the present invention is to provide a method of construction of such a protective coating.
The object of the invention is achieved in this way:
The protective coating for petroleum pipes of the present invention is characterized by comprising the following components in percentage by weight:
Polyphenylene sulfide 55~95%,
Adhesion enhancer 3~30%,
Wear-resistant enhancer 1~20%.
The above adhesion enhancer is at least one of micron or nanometer titanium dioxide ( Ti 0 2 ), chromium oxide ( Cr 2 0,), cobalt oxychloride ( C 〇2 0 3 ), carbon fiber, and is resistant to The abrasive enhancer is at least micron or nanometer aluminum oxide ( A 1 2 0 3 ), copper sulfide ( CuS ), silicon carbide ( SiC ), molybdenum disulfide ( MoS 2 ), carbon fiber, silica Alternatively, other adhesion enhancers or abrasion enhancers may be employed.
The above protective coatings include the following components by weight.
