Abstract
This paper sets out the development of a cantilever system for a self-propelled, self-elevating support vessels (SESVs) also known as jack/up barge or lift boat to support well intervention and workover.
Historically, vessels have been designed to operate within a limited segment of the well field life cycle. With Well intervention, a variety of vessels from service boats to drilling rigs have been utilised depending on water death and scope of required operations.
In areas such as MENA, well intervention is conducted either utilising jack up drilling units or jack up barges. Despite their inherent capability for workover, drilling rigs tend to be expensive in terms of both day rate and cost of moving between platform locations as they require mobilisation of tugs to tow them. Drilling rigs are designed to drill wells and are overkill for most Intervention scopes.
Jack up barges particularly self-propelled ones, offer greater efficiencies, quicker servicing times and lower costs. The barges can deploy sooner in a shorter weather window and do not require tugs. This is because such vessels do not require a marine spread to tow them between locations.
Previously, the workover capability of a drilling jack up unit has meant barges have been limited to supporting light well intervention scopes such as Coil Tubing, pumping and Wireline or used only in tender assist mode where heavier work over scopes including P&A and ESP replacement are required.
A study was conducted to establish what modifications could be made to the SESV (Self-propelled jack up barge) to:
Improve efficiency and safety of light well intervention (LWI)
Incorporate capability to handle heavier work over scope requiring pipe handling
The result was the development of two distinct cantilever systems for installation on the SESV's
| Cantilever Type | Cantilever Capability | |
|---|---|---|
| 1 | Work Over Capable | Cantilever complete with automated work over unit (rig) to conduct scopes including P&A, ESP and Completion Change out |
| 2 | Light Well Intervention | Cantilever with interface for a tower to support coil tubing Injector head and wireline sheaves |
| Cantilever Type | Cantilever Capability | |
|---|---|---|
| 1 | Work Over Capable | Cantilever complete with automated work over unit (rig) to conduct scopes including P&A, ESP and Completion Change out |
| 2 | Light Well Intervention | Cantilever with interface for a tower to support coil tubing Injector head and wireline sheaves |
In this era of low oil prices and cost saving, using a gap analysis approach, separate proven, reliable and efficient solutions have been brought together to offer a safe, highly efficient and economical solution to reduce operational cost in well intervention and work over. In this case it was the development of an innovative cantilever design to align the marine benefits of a 4 legged self-propelled jack up barge and a proven work over rig.
