Pipelay

Installation

We do end to end engineering required for a pipelay project. This comprises of mainly-

Determining the appropriate stinger and barge rollerbox settings
Stinger rotation and barge trim along the route
Required Tension levels at various water depths
Offshore Procedures to be followed during execution

Dynamic simulations performed to determine the above parameters while keeping in mind several constraints such as:

Barge/Vessel Tensioner and Thrust Capacity
Existing environmental conditions – Wave/Current etc
Pipelay in curves
Seabed clearance for shallow waters

Software Employed:

Offpipe: S-lay
Orcaflex: J-lay

These are industry recognized software packages used widely all over the world.

How do we add Value?

Our engineering aims to deliver the most efficient solution, both technically and commercially, using our company QSHE standard. For example, for pipelay with a DP vessel we will try to work towards a low thrust level for fuel savings. This is done by a high level clearly laid-out step by step plan.

Key Deliverables:

Analyses document
Procedure Document

Pre-commissioning

When pipelay is finished and the final connection has been made, the pipeline has to be tested. We can develop a pre-commissioning plan for the installed pipeline. This typically incorporates:

Developing a Pipeline Testing Plan and Schematic
Developing Schematics for Pig Receiver/Pig Launcher - Start-up/Laydown and A&R heads
Flooding/Cleaning & Gauge Pigging Operation
Hydrotest (Complete System).

Contingency/Repair

Failure can occur during installation or during service.

Contingency – Failure during Installation:

The failures during installation can be due to equipment, material, human or third party failures or environmental conditions. We create Contingency Operations to be implemented in case of a failure. For example:

Flooding Prevention Study
Emergency Repair/Remedial work due to dry or wet buckle

Repair – Failure during Service:

When the pipeline is in service the failures which can occur are material degradations, environmental conditions, risks and blockage. To mitigate these threats, Emergency Response Plans have to be developed before any such situations occur. These include:

Pre-failure Analyses and Procedures
Inspection, Repair and Maintenance Plans

Midline Tie-in

Midline Tie-in or Above Water Tie-in (AWTI) is an operation where two laid down pipelines on the seabed are welded together after being lifted above water using vessel davits. For AWTI we determine/provide:

Steps for recovering the pipelines
Welded Configuration for recovered pipes
Steps for lowering the completed pipeline
Weld excavation analysis
Minimum weld thickness assessment for removal of the welding clamp
Offshore Procedures to be followed during execution

Static Code checks (pipeline integrity) are performed for every static loadcase. Dynamic Analysis is performed for the respective worst case in Pipe Recovery, Welded configuration and Laydown. DNV buckle checks are used to ascertain pipe integrity during dynamics.

Software Employed: Orcaflex

End Deliverables:

Analysis Document
Procedure Document

Steel Cantenary Riser (SCR) Hang-Off

A Steel Catenary Riser (SCR) can be installed and be hung-off against a FPSO or directly to a platform.

For installation on platform, the SCR is either lifted or made buoyant to bring it to the Platform. Then it is handed-over and hung-off.

For installation on FPSO, the SCR can be lifted, handed-over and directly hung-off if FPSO is in position. Otherwise it can be pre-laid on the seabed. Once the FPSO is anchored on location, the pre-laid SCR(s) will be recovered, keel-hauled, handed-over and hung-off to the FPSO.

We can perform the analysis to ensure SCR is safely installated in all the aforementioned operations. We are also adept at writing procedures to be followed offshore for a safe and efficient installation.