From Shipyard Backlog to Operational Readiness: The Jacking System Story

Introduction: The Challenge

A LeTourneau design jack-up rig, faced a critical operational hurdle. A series of planned overhauls from a shipyard project (Phase 3) remained incomplete as the rig transitioned to an offshore location. Furthermore, additional damage was sustained during subsequent jacking operations. The result was a growing list of compromised units across the Forward, Starboard, and Port legs. Issues ranged from excessive gear uplift and worn bearings to severe component damage, including a final drive with 26mm warpage and multiple 7T ½" pinions with severe plastic deformation. Without immediate and expert remedial action, the rig's ability to safely position itself for drilling operations was at significant risk.

Project Scope & Objectives

Formura Offshore Services was tasked with executing a comprehensive remedial campaign to complete the pending Phase 3 work and address newly identified damage. The project scope was extensive, covering multiple drive systems across 16 individual units.

The primary objectives were:

• Complete Phase 3 Scope: Execute all pending overhauls and repairs that were planned during the shipyard project but left unfinished.

Challenge - Incomplete Shipyard Work & New Damage: The project began with a backlog of pending overhauls, compounded by fresh damage from rig movements, creating a moving target for the scope of work.

Formura's Solution - Phased & Adaptive Execution: The team systematically worked through the Phase 3 list while remaining vigilant for new issues. When excessive uplift and warpage were discovered on Final Drives (e.g., Unit D1, F1, H4) outside the original scope, they promptly got client approval and executed the necessary overhauls on the spot.

Challenge - Severe & Widespread Component Wear: Many components were found in "poor condition" with severe wear, pitting, and plastic deformation. Units like A3, F1, and H3 required complete replacement of the 7T ½" pinion and inboard hubs.

Formura's Solution - Precision Diagnostics & Replacement: The team conducted thorough inspections of every disassembled unit. Severely worn components were systematically replaced with spare parts. For example, Unit A3's inboard hub and pinion were replaced, reducing uplift from 1.10mm to just 0.25mm.

Challenge - Critical Final Drive Distortion: Several final drives exhibited warpage and uplift far beyond tolerance (e.g., Unit F1: 26mm warpage, 4.47mm uplift). This level of distortion can lead to catastrophic failure if not corrected.

Formura's Solution - Expert Realignment & Reassembly: The team meticulously rebuilt these critical drives. On Unit F1, the outboard hub, inboard hub, and 7T ¼" P pinion were all replaced with spares. The results were dramatic: warpage was reduced from 26mm to 5mm, and uplift from 4.47mm to 0.70mm, bringing the unit back into safe operational parameters.

Challenge - Managing Sparse & Strategic Spares: With a limited inventory of spare parts offshore, the team had to make critical decisions about component reuse versus replacement.

Formura's Solution - Strategic Component Management: The team expertly balanced the use of available spares with the refurbishment of existing components. In Unit C2, they reused the pinion but replaced the worn inboard hub. In Unit I3, they reused the pinion and seals while replacing only the bearings and hub insert, ensuring reliability while conserving critical spares.

• Address Operational Damage:Repair components damaged during recent jacking operations, restoring full mechanical integrity.
• Expand Scope as Needed:Identify and rectify issues on units not originally included in the work scope, such as the Final Drives on Units D1, F1, and H4, which were found to have excessive warpage and uplift.
• Restore OEM Specifications:Dismantle, inspect, and rebuild units to LeTourneau OEM methods and standards, replacing worn gears, pinions, bearings, and seals.
• Ensure Long-Term Reliability:Utilize spare components strategically and perform precision reassembly to guarantee extended operational life.

Key Challenges & Solutions

The Formura team, executed this complex campaign over a 10-week period (December 10 to February 17) in an offshore environment.

Project Results

Formura Offshore Services successfully delivered a comprehensive remedial campaign, completing the Phase 3 scope and addressing critical emergent issues within the offshore schedule.

Key Results:

• 16 Units Restored: All primary, secondary, and final drive systems on the identified units were successfully overhauled, including emergent work on final drives not in the original plan.
• Operational Integrity Achieved: Critical parameters like gear uplift and housing warpage were corrected across the board.
  • Unit A3 secondary drive uplift reduced from 1.10mm to 0.25mm.
  • Unit F1 final drive warpage reduced from 26mm to 5mm (uplift from 4.47mm to 0.70mm).
  • Unit H4 final drive warpage corrected to 6mm with uplift reduced to 0.20mm.
• Rig Readiness Restored: By completing the shipyard backlog and repairing new damage, the rig was returned to a fully operational status, ready for safe and reliable jacking operations.
• Future-Proofed Performance: The strategic replacement of worn gears, pinions, and bearings, combined with precision reassembly, has significantly extended the operational life of the jacking system.

Conclusion

This project exemplifies Formura Offshore Services' capability to handle complex, multi-phase remedial campaigns in an offshore setting. Faced with a combination of pending work, unexpected damage, and limited spares, the team delivered technically superb solutions that prioritized the client's operational and financial priorities. The successful restoration of the Rig jacking system underscores Formura's position as a trusted partner for ensuring the safety, reliability, and longevity of critical offshore assets.