Clear Cut Interventions – HWU Onshore Support Base

The Challenge:

CCI own a Hydraulic Workover Unit (HWU) which they deploy offshore onto production platforms for cost effective down-hole intervention.  Upcoming onshore contracts required an Onshore Support Base to be designed & fabricated to support the HWU on land over the well head.

The Solution:

Cube Offshore were engaged to develop the concept and carry out detailed structural design of the Substructure.

The arrangement comprised the following components:

  • 4no. corner Support Pods to transfer loads into the ground
  • 2no. Spreader beams to span between the Support Pods and provide support for the loads above
  • 1no. Sub-Base Module sitting atop the Spreader Beams:
    • Supporting the 191t jacking loads
    • Supporting a 35t BOP
    • Support the HWU tower above c/w all dead, personnel & functional loading
  • All components were configured to be road transportable throughout WA without the need for a pilot
  • All components were liftable in accordance with DNV 2.7-3 R00 requirements
  • Ease of assembly with minimal use of bolting, instead adopting clamped, bearing and turnbuckle connections
  • Design compliance with API Spe. 4F – Drilling & Well Servicing Structures

The Scope:

The following was delivered as part of an integrated project approach & full collaboration between design engineering, fabrication and client:

  • Basis of Design & Functional Specification
  • Concept development
  • Detailed engineering design & 3D modelling
  • Fabrication drawings, dxf files and NC files
  • Fabrication support
  • Assembly procedures



1. Staad.Pro structural analysis                                                                  2. Staad.Pro 3D model



3. AutoCad 3D model exported to Navisworks                4. Completed structure assembled for operation



5. BOP suspended under Sub-Base Module