Removal of OEM Drilling Equipment

1. Introduction

Allrig was contracted to remove OEM drilling equipment from a jackup drilling unit undergoing refurbishment in shipyard. The scope included the removal of the Drilling Line, Top Drive, Travelling Block, Top Drive Dolly, Travelling Block Dolly, Crown Cluster, Deadline Sheave, and Deadline Anchor.

The unavailability of the Drawworks, a critical heavy lifting system often utilised for this scope, introduced significant challenges to the project. Without this primary hoisting equipment, Allrig had to engineer and implement alternative heavy lifting solutions, to safely manage the removal of large and heavy components. Despite these constraints, Allrig successfully completed the full scope safely, efficiently and without damage to the asset.

2. Project Work Scope

The Client requested the removal of the following equipment for future overhauling:

• Travelling Block (23ton)
• Top Drive (30ton)
• Top Drive Dolly
• Travelling Block Dolly
• Crown Cluster Assembly (7ton)
• Deadline Sheave
• Deadline Anchor

All work was performed using Rope Access and advanced rigging techniques.

Derrick / Equipment Layout

3. Engineering Approach

With the Drawworks unavailable, Allrig engineered a lifting solutions enabling safe removal of all major components without the primary hoisting system. The key element of this approach was utilising the Crown Cluster as the main hangoff point, providing a structurally verified anchor point for all temporary lifting equipment.

A temporary lifting arrangement was rigged directly from the Crown Cluster, allowing controlled vertical movement of the Travelling Block and Top Drive using an airoperated chain hoist. This ensured:

• Loads followed a validated structural path
• Precise control during lowering operations
• Full independence from the Drawworks

3.1 Additional rigging elements included:

• Highcapacity chain hoists and pulllifts
• Rigfloor Air Hoists for lowering the Crown Cluster, Deadline Sheave, and Deadline Anchor
• Dropped objects prevention techniques
• Quayside yard crane for the final lifts of all removed equipment.

Temporary Lifting Arrangement

4. Execution Summary

4.1 DeStringing of Drilling Line

• Drill line spooled off and safe cable connector kit installed.
• Messenger line connected to a spooling unit.
• Drill line removed by pulling from the deadline spooling unit.
• Area cleared for Travelling Block removal tasks.

4.2 Travelling Block Removal

• Travelling Block disconnected from Drawworks load path.
• Travelling Block raised and controlled using an airoperated chain hoist.
• Travelling Block lowered to the drill floor in controlled stages.
• Travelling Block transferred to quayside crane for final lift.

4.3 Top Drive Removal (with no transit frame)

• All services disconnected and removed - electric, air, hydraulic, and mud hose.
• The Top Drive was topandtailed inside the derrick using chain hoists and tuggers rigged from the crown cluster and quayside crane.
• Required continuous rigging adjustments, precise load balancing, controlled rotation, and close coordination between Allrig and the yard rigging teams.
• Lowered in stages using the air hoist and crane.
• Once at drill floor level, rerigged and lowered to the pipe deck using a tandem lift.
• Transferred to quayside.

4.4 Top Drive Dolly Removal

• All services disconnected and removed - electric, hydraulic.
• Dolly secured using chain hoists.
• Mechanical connections removed.
• Lowered to drill floor using chain hoists and air hoists.
• Transferred to quayside.

4.5 Travelling Block Dolly Removal

• All services disconnected and removed - electric, hydraulic.
• Dolly isolated and secured.
• Lowered using chain hoists.
• Transferred to quayside.

4.6 Crown Cluster Removal

• Rigfloor air hoists rigged through predetermined guide points.
• Chain blocks and pulllifts used to remove securing bolts.
• Crown cluster lowered in controlled stages.
• Transferred to quayside crane for removal.

4.7 Deadline Sheave Removal

• Air Hoist lines rigged to sheave housing.
• Sheave disconnected and lowered using air hoists.
• Transferred to quayside crane for removal.

4.8 Deadline Anchor Removal

• Anchor isolated and rigged with chain hoists.
• Lowered using rigfloor air hoists.
• Transferred to quayside crane for removal.

Heavy Lift Operations

5. Safety Performance

• Zero incidents recorded
• Strict droppedobject prevention measures
• Rope Access technician management for reduced exposure at height
• Daily coordination and toolbox talks ensured alignment between Allrig, the yard, and the rig crew.

6. Project Outcomes

• All planned equipment removed on schedule
• No impact on the owner or the shipyard’s critical path
• Engineered lifting methodology applied to work around Drawworks unavailability
• Strong collaboration between Allrig and other stakeholders.

Client Feedback: “The Allrig crew performed exceptionally well in this scope of work. Their combination of safety, efficiency, professionalism, and technical competence is commendable. I would confidently recommend this team for similar scopes in any operational environment.”

Overall Rating: Outstanding

— Client Representative

7. Lessons Learned

• Crown Cluster hangoff method proved highly effective.
• Absence of a lifting frame for the Top Drive required bespoke rigging and increased coordination.
• The air hoist specification provided excellent control
• Rigfloor Air Hoists were highly effective for controlled handling of equipment exiting the Vdoor.
• A premobilization survey would have further reduced the overall schedule.

8. Conclusion

When the Drawworks was removed from the plan, the challenge didn’t stop us, it defined us.

Through rigorous planning, proactive change-management, and seamless coordination across all teams, Allrig completed a complex heavy-lift removal with zero incidents and zero schedule impact.

Engineered solutions. Disciplined execution. Industry-leading performance.

That’s the Allrig difference.

Final Equipment Removal