The document provides an overview of deepwater riser design, detailing various riser types, selection factors, and design procedures. It emphasizes the complexity of riser design, highlighting the importance of analyzing multiple factors such as material types, environmental conditions, and operational requirements. The summary concludes that while technical considerations are crucial, non-technical factors can sometimes supersede them in the design process.

1. GENERAL
OVERVIEW
OF
DEEPWATER
RISER
DESIGN
Alberto
Alvino

3. Overview
Introduc>on
Riser
Types
Main
Selec>on
Factors
Design
Procedure
Dynamic
Example
of
Riser
Modeling
Summary

4. INTRODUCTION

5. Introduc>on
• What
is
Riser?
A
riser
is
a
pipe
that
connects
and
surface
facility
to
a
subsea
system
• What
is
Deepwater?
Above
1000L
depth
• What
is
Riser
Design?
It
means
to
achieve
the
func>onal
requirements

6. RISER
TYPES

7. Riser
Types
• Material
Type:
Steel,
Flexible,
Titanium
and
Composite
• BOP
(X-­‐Tree)
LocaDon:
Subsea
and
Surface
(Dry
and
Wet)
• ConfiguraDon
Type:
SCR,
SLWR,
Hybrid
Riser,
TTR
• FuncDonal
Type:
Drilling,
Produc>on,
Injec>on,
Export,
Comple>on/Workover

8. Material
Type:
Steel
Pipe
Failure
types
very
well
known,
proven
technology,
more
suppliers

9. Material
Type:
Unbonded
Flexible
Pipe
The
main
advantage
of
using
flexible
pipes
is
their
ability
to
work
under
extreme
dynamic
condiDon
compared
with
rigid
carbon
steel
pipes
Only
3
suppliers:
GE
Oil
&
Gas,
NOV,
and
Technip
Complex
mechanism
of
failures
Heavier
&
expensive
than
steel

10. Material
Type:
Titanium
Titanium
alloys
have
a
unique
combina>on
of
proper>es,
such
as
high
strength,
low
elasDc
modulus
and
density,
which
make
them
a[rac>ve
for
use
in
offshore
riser
systems.

11. Current
Applica>on
of
Titanium
in
Offshore
Riser
Systems

12. Material
Type:
Composite
Material
Carbon
Fiber

13. Material
Type:
Composite
Pipe

14. Material
Type:
Composite
Material
• Weight
• Strength
• Corrosion
• Fa>gue
• Less
expensive
to
build
complex
component
• Thermal
proper>es
§ Orthotropic
material
§ More
bri[le
§ More
expensive
than
steel
§ Complex
repair
procedure
Advantage
Disadvantage

15. Surface
x
Subsea
BOP
The
comparison
of
a
conven>onal
subsea
BOP
drilling
system
and
a
surface
BOP
drilling
system
clearly
shows
the
reduc>on
in
size,
weight,
loads,
and
physical
deck
area
required
to
drill
a
well
using
surface
BOP.

16. Surface
x
Subsea
BOP
Dry
x
Wet
Tree

17. Func>onal
Riser
Types
• Drilling
• Produc>on
• Injec>on
• Export
• Comple>on
• Workover

18. Riser
Configura>on
Type:
SCR

19. Advantage
/
Disadvantage
• Simple
in
design
with
few
complicated
component
• Economically
a[rac>ve
in
terms
of
both
installa>on
and
construc>on
• High
top
tension
• Low
fa>gue
performance
at
riser
top
and
TDZ

20. Riser
Configura>on
Type:
Lazy
Wave

21. Advantage
/
Disadvantage
• Reduce
Top
Tension
• Decouples
(par>ally)
floater
and
TDP
• Increase
design
complexity
• Increase
hardware
and
installa>on
cost

22. Riser
Configura>on
Type:
Top
Tension
Riser

23. Advantage
/
Disadvantage
• Field
proven
• Efficient
drilling
• Fast
access
to
wellbore
• Riser
weight
• Interference
problem

24. Riser
Configura>on
Type:
Hybrid
Riser

25. Advantage
/
Disadvantage
• Pre-­‐installable
• Low
vessel
payload
• Decoupled
from
vessel
mo>on
• Increased
design
complexity
• High
CAPEX
compared
to
other
riser
types
• Interference
issues

26. MAIN
SELECTION
FACTORS

27. Key
Selec>on
Factors
• Water
depth
• Environmental
condiDons
• Geographical
locaDon
• Reservoir
pressure
and
temperature
• Corrosive
fluids
• Number
of
wellheads
• Wellhead
type
• Cost
and
schedule
• Operator

28. Water
depth
–
SCR
Applica>on

29. Water
depth
–
Flexible
Applica>on

30. Environmental
condi>ons

31. Environmental
condi>ons

32. Geographical
loca>on
/
Operator
Preference
Geographical
breakdown
flexible
riser
pipe.

33. DESIGN
PROCEDURE

34. Overview
• Pre-­‐FEED
§ Determine
technically
feasible
riser
solu>ons
§ Determine
cost
comparison
between
riser
solu>ons
§ Iden>fy
risks
associated
with
riser
system
§ Concept
selec>on

35. Overview
• FEED
§ Further
develop
selected
concept
(or
concepts)
to
enable
Operator
to
commence
the
Execu>on
Phase
with
high
degree
of
confidence
and
low
level
of
risk
§ Develop
documenta>on
to
enable
an
ITT
(invita>on
to
tender)
package
to
be
issued
to
Execu>on
Phase
contractors
• Detail
Design
§ Detailed
design
of
the
riser
system
to
enable
fabrica>on
and
installa>on

36. Design
Procedure:
Design
Basis
• Required
informaDon:
Riser
pipe
proper>es,
riser
system
data
(flex
joint,
bending
s>ffener,
buoyancy
modules,
etc.),
wellhead
data,
subsea
equipment
(BOP,
LMRP,
Lower
flex
joint),
water
depth,
environmental
condi>on,
conductor
data,
soil
proper>es,
vessel
data,
fa>gue
details,
hydrodynamic
proper>es,
pressure,
temperature,
etc.

37. Design
Procedure:
Methodology
• Define
the
TTR
stack-­‐up

38. Design
Procedure:
Methodology
• Define
the
compliant
riser
profile

39. Modeling
Considera>ons
• Built
the
FE
global
model;
• Most
components
can
be
modeled
as
pipe
elements
with
the
key
proper>es
defined:
– Bending
s>ffness
– Axial
s>ffness
– Mass
– Drag
diameter
– Buoyancy
diameter

40. Commercial
SoLware
• Riser
Global
FEA:
• Flexcom
• Orcaflex
• DeepRiser
• Ansys
• Abaqus
• Riser
VIV
soLware
• Shear
7
• VIVA
• VIVANA

41. Global
FE
Model
Example
of
SRC
Global
Model
of
FE
created
in
Orcaflex
soLware.

42. Riser
Analysis
Type
• Collapse,
Burst
and
buckling
checks
• Top
tension
determina>on
• Operability
analysis
• DriL-­‐off
analysis
• Recoil
analysis
• Hang-­‐off
analysis
• Riser
installa>on
analysis
• Fa>gue
analysis
(VIV,
VIM
and
wave
fa>gue)

43. Design
Criteria
&
Standards
Code
• Drilling
Riser
(API
RP
16Q)
Envelope
Parameter
API
RP
16Q
Limit
AMJIG
Limit
Drilling
Mean
Flex-­‐Joint
Angle
2
2
Maximum
Flex-­‐Joint
Angle
4
4
von
Mises/Yield
Stress
0.67
0.67
Extreme,
Non-­‐
Drilling
Maximum
Flex-­‐Joint
Angle
90%
of
Max
90%
of
Max
von
Mises/Yield
Stress
0.67
0.80
Survival,
Non-­‐
Drilling
Maximum
Flex-­‐Joint
Angle
90%
of
Max
90%
of
Max
von
Mises/Yield
Stress
0.67
1.00

44. Design
Criteria
&
Standards
Code
• Produc>on
Riser
(API
RP
2RD)

45. DYNAMIC
EXAMPLE
OF
RISER
MODELING

46. SOME
EXAMPLES
Flexcom
Models
h[ps://www.woodgroup.com/what-­‐we-­‐do/view-­‐by-­‐products-­‐
and-­‐services/digital-­‐solu>ons/flexcom
Deep
Riser
Models
h[ps://www.woodgroup.com/what-­‐we-­‐do/view-­‐by-­‐products-­‐
and-­‐services/digital-­‐solu>ons/riser
Orcaflex
Models
h[ps://www.orcina.com/SoLwareProducts/OrcaFlex/Examples/
index.php

47. SUMMARY

48. Summary
• There
are
diverse
riser
types
• Riser
design
is
complex
task
that
involve
several
itera>on
analysis,
involving
inter-­‐
discipline
itera>on;
• Some
>me,
technical
factor
are
overpassed
by
not
technical
factor;