Topside Cooler Replacement

Introduction

This production cooler replacement project was initiated to address the deteriorated condition of the existing production coolers, which had been in continuous service since 1996. These coolers are critical for regulating the temperature of production fluids received from wellhead platforms via subsea pipelines. After nearly 30 years of operation in a harsh offshore environment, the equipment had suffered extensive corrosion and structural degradation. While temporary repairs had been applied over time, the units had reached the end of their reliable service life, prompting a full replacement to safeguard production continuity and platform integrity.

The cooler bundle replacement works required the temporary installation of Thunder Cranes modular offshore crane.  This was due to the existing platform crane having insufficient reach to provide lifting support over the work area.

In this project Thunder Cranes supported the client and EPC contractors.  Thunder Cranes’ scope involved performing reaction force calculations, developing lifting plans, installation of our TC70 modular crane, and executing the lifting of the cooler bundles using the TC70 crane.  The planning and preparation by the client, Thunder Cranes and various EPC contractors included:

• Platform structural analysis and customized rig up plan for a Thunder Cranes TC70 installation.
• Lifting plans for cooler replacement.
• Deck extension design and fabrication.
• Removal of obstructions & installation of the deck extension and support scaffolding.
• Removal of the old coolers and installation and commissioning of the new coolers.

Challenges & Solutions

• Replacement of cooler units located on offshore platform at topside (northeast corner).
• Precise, safe, stable lifting device is needed to install coolers in a congested location with sensitive equipment, high above sea level on the platform upper deck.
• Cooler location is outside of the reach of the existing platform crane which is located at the topside (southwest corner).
• Crane barge option was ruled out due to crane reach, cost considerations, and the need for stable, precise lifting.  The client therefore requested a modular crane provided by Thunder Cranes.
• Thunder Cranes proposed TC70 modular pedestal to be temporarily installed at topside (southeast corner) where it can carry out the lifting needed to support the EPC contractors.
• Modular crane option by Thunder Cranes is feasible, however installation will be in constrained space, requiring a modified and customized modular crane setup.
• TC70 customized setup, including installation of extension deck to overcome space constraints.
• Production shut down makes this a highly time-sensitive project. Requires high level of efficiency and organization by all project teams to ensure successful timely completion.
• Items Lifted by TC70: Cooler Plenum Structures & Cooler Tube Bundles.
• Maximum weight lifted by TC70: 77 tons (Cooler Tube Bundles).

Project Steps

Installation of TC70 Modular Crane:

• Modular crane customised to include a swing limiter/stopper. Swing limiter is required as safety device to make sure the crane is not accidentally operating on any area above production equipment no go zone.
• TC70 crane counterweight is removed due to space constraints, the load chart is therefore re-engineered and limited for this operation.
• Space constraints mean crane powerpack located at laydown area at upper deck. The common practice for pedestal crane is to place the power pack on the top of the crane beam. For this project the power pack placed away from the crane. However, no extension hose required, and fluid parameter is not affected.
• TC70 installation required small modifications to platform, including removal of some temporary structures, and addition of a small deck extension to the platform which was fabricated and installed prior to the TC70 installation.
• TC70 modular crane installation was carried out by a Thunder Cranes crew of 6 persons, supported by the client platform crane and a scaffolding team. The platform crane lifted the TC70 components from supply vessel, and then supported Thunder Cranes’ crew to perform the installation of the TC70
• The installation process was supervised by a Thunder Cranes superintendent and witnessed by a 3^rd party inspector.
• Once installation is complete a dynamic load test was performed with a 16,953 Lbs waterbag at an 80ft radius to prove the crane can handle the required loads, verify the structural integrity of the crane, the performance of its mechanical and hydraulic systems, the effectiveness of safety devices such as brakes and limit switches. This confirms that the crane has been correctly installed before being put into service.

Cooler Removal Works:

• Disconnection of inlet/outlet lines, fusible loop, mechanical components, and structural elements. Existing cooler bundles and plenum were lifted, backloaded, and transported to PSB Jetty.

Logistics and Load-out:

• Transfer of the new cooler from fabrication yard to PSB Jetty, followed by offshore transportation to ERPB using dedicated supply vessels.

Installation and Alignment:

• Precision alignment and base plate adjustment to ensure geometric compatibility with existing piping. Installation of the new cooler structure and bundle with tie-in completed without piping modifications.

Mechanical, Electrical & Instrumentation Works:

• Installation and adjustment of fan blades, belt tensioning, and verification against FAT requirements. Power and instrumentation cabling completed, vibration transmitters installed, and fusible loop reinstated into the platform safety shutdown system.

Testing and Handover:

• • Dry run testing conducted with comprehensive checks on vibration, airflow, temperature, alignment, and electrical load. Pre-Start-Up and Safety Review (PSSR) completed and spare parts handed over to operations.

Project Timeline

• Sept 2025: Installation of Extension Beams
• 12–15 Jan 2026: Thunder Cranes TC70 mobilization, rig-up, and load testing.
• 15–18 Jan 2026: Disconnection and removal of existing cooler bundles and plenum.
• 18–19 Jan 2026: Backload of old equipment to PSB Jetty.
• 19–20 Jan 2026: Load-out and offshore transportation of new production cooler to ERPB.
• 21–24 Jan 2026: Installation, alignment, mechanical completion, E&I works, dry run testing.
• 25 Jan 2026: Thunder Cranes TC70 rig-down and backload.
• 26 Jan 2026: PSSR completion and readiness for start-up.