The gas-tight threaded oil casing (also known as a gas-sealed special threaded oil casing) is a high-performance well casing specifically designed for harsh oil and gas well environments characterized by high pressure, elevated temperatures, and corrosive conditions. Its key feature lies in the use of specialized gas-tight threaded joints that enable high-strength, highly airtight metal-to-metal connections.
To meet diverse market demands, Gaoyuan Company has developed a range of non-API-standard oil casing tubes, establishing its proprietary GY product series that includes various steel grades and thread types. This expands the specification portfolio of domestically produced oil casing tubes and offers flexible options tailored to different application requirements.
Product Specifications: 2-3/8″ to 13-3/8″
Steel grades: J55, K55, N80, L80, P110
The gas-tight snap-on oil casing consists of a tube body and a gas-tight snap-on joint (external thread end/inside thread collar), with the following key sealing structure:
| Model | GY-1 | GY-2 | GY-3 | GY-2C | GY-3B |
| Sealing Method | Conic Surface/Conical Surface | Conic Surface/Conical Surface | Spherical/Cone Surface | Conic Surface/Conical Surface | Conic Surface/Conical Surface |
| Thread Profile | Partial Trapezoid | Improve the Partial Step Function | Upgrade to Partial Trapezoidal | Improve the Partial Step Function | Improve the Partial Step Function |
| Torque Shoulder | Right Angle | Negative Angle | Negative Angle | Negative Angle | Negative Angle |
| Applicable Well Conditions | Conventional, high-pressure oil and gas wells | Conventional wells, high-pressure wells, deep wells, inclined wells, horizontal wells | Well conditions including deep wells, inclined wells, horizontal wells, and wells subjected to high composite loads | Conventional, high-pressure oil wells | Well conditions including deep wells, inclined wells, horizontal wells, and wells subjected to high composite loads |
It maintains excellent gas sealing performance even under tensile, compressive, and bending loads.
It facilitates precise control of the screwing position and reduces circumferential stress at the connection interface; the negative-angle torque shoulder surface enhances the self-locking effect after joint screwing.
Rationally designing the thread profile ensures excellent connection strength; optimizing the thread diameter enhances the thread's resistance to slippage.
After the coupling is screwed onto the pipe body, the inner bore becomes smooth, effectively eliminating turbulence in the fluid flow within the pipe.
The optimized thread structure prevents slip failure of the oil casing under tensile loads, providing excellent connection and sealing performance.
Optimize the thread diameter to prevent adhesion between the threaded surface and sealing surfaces during repeated tightening and loosening operations.
The company operates four DMG MORI lathes, whose advanced manufacturing capabilities are epitomized in five key areas: ultra-precision machining, proprietary core technologies, high-rigidity structures, intelligent and integrated systems, and comprehensive quality control throughout the entire production process, representing the pinnacle of global high-end CNC lathe technology.
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