Round Thread Casing
Overview
Round Thread Casing is a standardized tubular product used in oil and gas well drilling and completion. Manufactured under API Specification 5CT, it serves as the primary barrier against formation pressures and subsurface contaminants. Its round thread profile (API Thread Form) ensures reliable connections even in high-stress environments. The product is typically supplied in lengths of 8-14 meters, with outer diameters ranging from 4.5 to 20 inches to accommodate various well designs.
Structure and Working Principle
The casing consists of precision-machined steel pipes with male (pin) and female (box) threaded ends. The round thread geometry combines trapezoidal threads with rounded roots to distribute stress evenly. During installation, threaded connections are torqued to create metal-to-metal seals. The casing string supports borehole walls while withstanding axial loads from the weight of subsequent casing strings and external pressure from surrounding formations.
Key Features
API-certified round threads provide 20-30% better fatigue resistance compared to square threads. The design includes thread compounds for galling prevention and improved sealing. Modern variants feature premium connections with elastomeric seals or metal-to-metal secondary seals for high-pressure applications. Anti-corrosion treatments like epoxy coatings or CRAs (Corrosion Resistant Alloys) extend service life in sour gas environments.
Application Areas
Primarily used as surface casing (protecting freshwater zones) and intermediate casing (isolating unstable formations). Also employed in directional drilling where bending stresses demand durable threading. Specialized grades like L80 13Cr are specified for CO2 injection wells, while P110 finds use in deep shale gas extraction. Offshore platforms commonly require heavy-weight casings with enhanced collapse resistance.
Maintenance and Precautions
Thread protectors must remain installed until rig-site use. Damaged threads require re-cutting per API RP 5B1 standards. Storage should prevent moisture accumulation to avoid pitting corrosion. Critical inspection points include thread concentricity (max 0.13mm deviation) and lack-of-fusion defects in the pipe body. Hydrostatic testing at 1.5x working pressure is mandatory before deployment.
B2B Procurement Guide
Verify mill test reports for chemical composition, mechanical properties, and NDT results. Leading manufacturers include Tenaris, Vallourec, and TPCO. Bulk orders (500+ tons) typically secure 8-12% discounts. Consider Incoterms carefully—FOB pricing excludes rising ocean freight costs. Third-party inspection by SGS or BV is recommended for international shipments.
Related Manufacturers
- 主营：精密管、镀锌管、精密钢管、K55石油套管、无缝管、20Cr精密钢管、40Cr精密无缝管、冷拔无缝钢管、精密光亮钢管、薄壁精密钢管、20号精轧管、45号精密无缝钢管、厚壁精密管、45号精密钢管、20#精密无缝管、桥式滤水管、镀锌无缝管、热镀锌无缝钢管、Q235B镀锌管、40Cr精轧无缝管、堆焊耐磨板、Q355B热镀锌钢管、Q235B镀锌钢管、Q355B镀锌无缝管、高精度精密钢管
- 主营：--
- 主营：石油套管
- 主营：油管短接、密封电泵、双公油管、石油套管、圆螺纹套管、螺纹连接套管、套管变扣、油田井口、油管接箍、高压管件、石油接箍、高压管道、管头油管、套管接箍、地热井套管、石油专用管、耐磨性接箍、不锈钢油管、不锈钢套管、铝合金高压、定制特殊扣、耐磨油管短节、不锈钢石油管、饮用水井套管、套管转换接头
- 主营：涂塑复合钢管、聚氨酯保温管、钢套钢蒸汽保温管、石油套管、热浸塑管、给排水涂塑复合钢管、防腐钢管、衬塑管道
- 主营：保温钢管、声测管、衬塑钢管、石油套管、K55表层石油套管、绝缘接头、防腐钢管、钢塑复合管、包覆式3PE防腐钢管、涂塑钢管、环氧煤沥青防腐钢管、地埋管道环氧煤沥青防、IPN8710环氧树、水泥砂浆衬里防腐钢管、聚氨酯保温钢管、黑夹克聚氨脂发泡保温、钢套钢保温钢管、钢制法兰、硅酸铝保温钢管
- 主营：石油套管壁厚、L80-13Cr石油
- 主营：N80石油套管价格、16mn方通钢管、q345bcde无缝方管、大口径厚壁钢管
- 主营：石油管、温泉井地热井套管、油套管、石油套管、高压锅管、石油钢管、直缝钢管、钻探套管、无缝钢管、外加厚油管、地热井套管、地热井石油、偏题口套管、表套定制管、石油钻探管、钻杆密封套管、套管接箍油管、高压合金钢管
- 主营：螺旋钢管、防腐钢管、复合钢管、石油套管、保温钢管、法兰、弯头、管件
- 主营：直缝管、直焊管、专用管、无缝圆管、锅炉管、结构管、流体管、无缝管、镀锌管、油套管、地质管、碳钢焊管、薄壁钢管、合金钢管、定制焊管、保温钢管、镀锌钢管、石油钢管、直缝钢管、无缝钢管、非标钢管、无缝方管、石油钻管、连接套筒、精密钢管、地热井管
- 主营：无缝钢管、焊接钢管、直缝钢管、供应石油套管、批发石油套管、K55石油套管、不锈钢管、无缝方管切割、20#石油裂化管、GB9948无缝钢管、地热井套管、L245N无缝管、不锈钢无缝钢管、5310无缝钢管、35CrMo合金钢管、16Mn无缝方管、45#大口径无缝钢管、N80无缝钢管、J55无缝管、P110无缝钢管、L80石油管材、大口径厚壁无缝钢管、厚壁合金无缝钢管、高压无缝钢管、高压锅炉无缝管
- 主营：石油管、油管、石油设备、石油套管、套管、接箍、套管短接、油管短接
- 主营：气密扣、缩径管、石油管、石油套管、扣油管、无缝管、扶正器、特别扣、特殊扣、护丝帽、油套管、替代扣、由壬接头、丝堵定制、油管短接、过渡接头、油管浮鞋、油管接箍、套管短接、隔热油管、套管接箍、钻杆变扣、油管定制、加厚短接、转换接头
- 主营：不锈钢圆钢、不锈钢板、不锈钢管
- 主营：5ct套管、接箍料、eue耐磨、无缝石油套管、短接帽、石油管、l80油管、tbg油管、大无缝、无缝钢、油管接、套管平、钢管扣、抗油管、高压管、127套管、api套管、9-5套管、内衬管、5-1套管、油套管、j55套管、中石油、vam油管、eue油管、8-5套管
- 主营：石油油管套管、抗硫80S油管、抗硫80S套管接箍、石油套管短接、镀铜13Cr油管接箍、耐磨油管短接、转换接头、油管试压堵、浮鞋、钻杆提升短接、钻杆循环接头、油管旋塞阀、油套管、钻杆护丝帽、油管接箍、浮箍