Deep and ultra-deep wells, HPHT environments, offshore and deepwater completions, and corrosive environments requiring high torque and fatigue resistance.
This repeat order to a Nigerian operator combined two casing strings in a single shipment: 13⅜″ L-80 with ZC-3 connection for the intermediate string and 9⅝″ P-110 with ZC-31 for the production string. Packaging both strings in one shipment reduces mobilisation costs and synchronises delivery to the rig site.
ZC-3 connection — 13⅜″ 68 ppf L-80: ZC-3 is ZC Steel Pipe's semi-flush to full-flush premium connection with a metal-to-metal taper seal and torque shoulder. On 13⅜″ intermediate casing, the full-flush design maximises annular clearance against the 20″ conductor above, critical in tight-clearance deepwater wells where annular flow resistance must be controlled during cementing.
ZC-31 connection — 9⅝″ 53.5 ppf P-110: ZC-31 is ZC's full-flush connection engineered for P-110 mechanical properties and the higher torque requirements of horizontal wells and HPHT production strings. P-110 at 9⅝″ × 53.5 ppf is a standard deep-well production casing specification: the 110 ksi minimum yield handles the high burst and collapse loads of deepwater or HPHT production, and the full-flush OD permits running through the 13⅜″ intermediate string without contact at connections.
Packing: Isolation rings and wooden shelf packing were specified to prevent connection face damage during ocean transit — standard practice for flush-joint premium connections where the thread runs to the pipe end face.
ZC Steel Pipe has supplied this Nigerian operator on repeat cycles since 2023, demonstrating consistent dimensional compliance with the customer's own thread gauge calibration requirements and third-party mill inspection protocol.