High-pressure gas environments requiring gas-tight sealing; sour service capability for H₂S / CO₂ environments.
S-95 is not one of the API 5CT 11th edition grades. It is a mill grade designation with a 95 ksi minimum yield, sitting between L-80 and P-110 in strength. Because API 5CT does not define it, its chemistry, hardness and testing come from the purchase specification — so a buyer using S-95 in sour service writes those requirements, and the NACE MR0175 / ISO 15156 basis, into the PO.
11¾″ is a less common casing size, typically specified in high-clearance deepwater well designs where the operator wants more annular volume between the 13⅜″ intermediate and 9⅝″ production strings, or where the 11¾″ × 13⅜″ annulus is used for managed-pressure cementing access.
ZC-2 connection — gas-tight performance: ZC-2 delivers a two-step metal-to-metal seal (nose seal and torque shoulder) equivalent in gas-tightness to VAMTOP. For high-pressure gas wells where BTC thread compound degradation under thermal cycling cannot be tolerated, ZC-2 eliminates the reliance on dope for sealing and achieves ISO 13679 CAL III gas-tightness by metal contact alone.
Pup joints included: The shipment included full-length R3 joints plus 10 ft and 5 ft pup joints. Pup joints allow the driller to fine-tune casing string depth — landing the shoe precisely at the target formation top regardless of the whole-joint depth increment.
ZC Steel Pipe supplied MTC per EN 10204 3.1, ZC-2 thread gauge calibration certificates, and third-party dimensional inspection for this order. Sour service documentation (hardness test results, NACE MR0175 compliance letter) provided at shipment.