Richard Luff shares an overview on what’s happening offshore west Africa, discussing common challenges and potential solutions operators can implement to avoid pitfalls. Hint: local content is key.

1. www.intecsea.com
September 2017
Challenges to deepwater
developments in West Africa

2. Riser systems Flow assuranceMetOcean
Conditions and
mooring systems
Seabed
Geotechnical
conditions
There are 4 technical considerations
pertinent to West African developments…

3. MetOcean considerations
Location
Significant wave
height
Peak Period
West Africa 3.14 19.2
North Sea 13.2 18.4
Gulf of Mexico 16.7 15.6
Uni-directional wave
Wind speed
Considering metocean conditions is important in selecting
the headings of moored FPSO vessels and offtake tankers.
The table above demonstrates that the wave height in West
Africa is small in comparison to other areas, though it has a
long period swell which can affect topside operations.

4. Two types of mooring systems
Turret Type Mooring Spread Mooring
Risers enter the vessel via the geo-stationary turret with the
ship able to weathervane around it and head into the wind
to reduce motions, as well as ease offtake tanker issues.
The moored tanker is aligned with the prevailing weather
and risers can be brought up over the vessel sides. It is
cheaper but may require a separate offloading buoy.

5. • Heave motion similar to TLPs
• Enables SCR system
• Eliminates need for a turret and swivel
Introduction to ‘Low Motion technology’

6. Producing oil from deep waters can provide many
challenges when it comes to ensuring the flow of
the fluid:
• Pressures can be boosted by gas injection
or pumping
• Temperatures need to be maintained in
many cases to avoid waxing
• Efficient pipeline design and insulation
becomes crucial
In extreme cases, Pipe-in-Pipe
designs are used to provide
maximum insulation…

7. Inner pipe wall thickness
25mm, D/t ~ 10-15
Aerogel insulation around
the inner pipe and spacers
every 4m
Outer pipe wall thickness
21mm, D/t ~ 15-20
Pipe-in-Pipe

8. All of the projects in Ghana that have been installed to date
have used flexible risers to bring production to the surface.
Though, as water depths increase, alternative systems
become more attractive, particularly if insulation is required.
Hybrid riser towers have been used in other West African
areas such as Angola. Steel catenary risers can offer
advantages in installation and material cost.

9. The Hybrid Riser Tower
• Uses vertical steel pipes with a
buoyancy can and flexible jumpers
to the FPSO.
• Flex joints and connections
add complexity and cost.
The Hybrid Riser Tower vs. The Steel Catenary Riser
The Steel Catenary Riser
• Can take wave form and is laid as an
extension of the pipeline

10. Moving from technical issues to commercial
Traditional offshore field development
EXPLORATION APPRAISAL
RESERVOIR
EVALUATION
FIELD DEVELOPMENT
STUDIES
PROJECT
IMPLEMENTATION
DISCOVERY AFE FIRST
PRODUCTION

11. Fast-tracked offshore field development
PROJECT
IMPLEMENTATION
PRELIMINARY
ENGINEERING
FIELD DEVELOPMENT
DEFINTION
EXPLORATION
APPRAISAL & RESERVOIR
EVALUATION
DISCOVERY AFE
FIRST
PRODUCTION
Moving from technical issues to commercial

12. Fast-track developments look attractive from an NPV
perspective. Though working on assumptions - because
of lack of definition - has the potential to cost a company
a lot more money than the time saving they can expect
to achieve.

13. Some areas that can cause this lack of
definition include:
• Number of wells, top hole locations and
drilling programme
• Completion design
• Flow assurance – chemical injection
requirements, pressure ratings, temperature
issues etc.
• Infield flowline and pipeline routing, and
loadings to structures.
• Operation and commissioning philosophies
• Interface definitions between the subsea
production system and drilling, floating
production system, installation,
commissioning and operations

14. GAS EXPORT
Many West African countries don’t have infrastructure to use the gas
produced from offshore fields. A large investment will be needed to
develop the electricity national grids, power generation, LNG or
chemical plants that use produced gas.
Development options are being restricted by the desire to prevent
offshore flaring of associated gas. All four of Ghana’s offshore
developments have export of gas to shore via pipelines of 60 to 80km.

15. LOCAL CONTENT
• Ghana, like other West African countries, has
expressed a strong desire to learn the skills
necessary to develop its people
• The Ghana Government has worked with oil
companies and contractors to ensure that local
companies are involved in each of the offshore
developments
• There has been strong cooperation between
international companies and local contactors
• As a result, Ghana has a growing capability for
engineering, fabrication, testing and offshore
support

16. TECHNOLOGY TRANSFER
• Send selected indigenous staff to other locations in the
world to gain exposure and experience on similar
projects
• Graduate development programs - recruitment and
development of graduates from local universities and
nationals being educated overseas
• Scholarships - sponsorship of selected students to
pursue engineering programs

17. There is enormous potential for deepwater developments in West Africa.
There are also significant challenges which need to be addressed and
overcome. These are not only technical but involve development of local
infrastructure, skills base and resources.
In today’s low oil price market, these challenges are even more important.
Ghana has made good progress in tackling some of these challenges.
SUMMARY

18. DISCLAIMER
This presentation has been prepared by a representative of INTECSEA.
The presentation contains the professional and personal opinions of the presenter, which are given in good faith. As such, opinions presented herein may not always necessarily reflect the position of
INTECSEA as a whole, its officers or executive.
Any forward-looking statements included in this presentation will involve subjective judgment and analysis and are subject to uncertainties, risks and contingencies—many of which are outside the
control of, and may be unknown to, INTECSEA.
INTECSEA and all associated entities and representatives make no representation or warranty as to the accuracy, reliability or completeness of information in this document and do not take responsibility
for updating any information or correcting any error or omission that may become apparent after this document has been issued.
To the extent permitted by law, INTECSEA and its officers, employees, related bodies and agents disclaim all liability—direct, indirect or consequential (and whether or not arising out of the negligence,
default or lack of care of INTECSEA and/or any of its agents)—for any loss or damage suffered by a recipient or other persons arising out of, or in connection with, any use or reliance on this presentation
or information.
FOR MORE INFORMATION, CONTACT:
Richard Luff | Business Consultant
P +441483795342
E richard.luff@intecsea.com