Intro to offshore drilling

1. Drilling Operations
Offshore Drilling

2. Content
• Inland barges (submersible)
• Jackup rigs
– Wildcats
– Shallow water templates
– Cantilevered over platform
• Platform rigs
• Floaters - semi’s and drillships
• Science programs

3. Rotary drilling process
• Time is money!
• Not about performance
but loss reduction.
• People, tools, equipment
& systems processes are
the key elements.

4. Pipe handling
• Conventional typically
replaced by
– Iron roughnecks
– Top drives, Derrick
drilling machines
– Auto systems
• Auto slips
• Casing while drilling
• Pipe racking systems

5. Key drilling systems

6. High pressure circulating system

7. Mud circulating system

8. Cementing System

9. Cementing
Full String Cementing
Steel
Casing
Borehole
Cement
Steel Liner
Liner Cementing

10. Well design

11. Basic well control
• Primary well control
– Flow in/out
– Pressure
– Volumes
• Pumping
• Displacement
– Drilling parameters
– Mud logging

12. Blow out preventers

13. Drilling Instrumentation
• Drilling
• Tripping
• Well control
– Kicks
– Loss circulation
• Wellbore difficulties
– Hole cleaning
– Instability
– Stuck pipe

14. Offshore Rig Types

15. An offshore well?
• Type of well?
– Exploration, appraisal development?
• Drilling environment
– West Africa, SE Asia, North Atlantic
• Wellbore design
• Wellbore Volumes, how many casing strings?
– Casing capacities, weights?
• Deck space, handling running issues?
• Drilling Tools & equipment needed?
• Mud chemicals volumes
• Cementing, fluids, storage?
• Other 3rd party operations to be conducted?
– Coring, well testing?
– Where will all the equipment go?
– Deck plan design? management?
• People logistics?
• Drilling Contingencies?

16. Inland barge
• Used in swamps, bays, inland water,
shallow offshore.
• Floated and towed to location
• On location these rigs are submerged
• Well is drilled
• Personnel and supplies are brought in by
boat.

17. Jackup rigs
• A Jack-up MODU.
– Mobile Offshore
Drilling Unit.

18. Jackup rigs
• Independent legs or mat
supported
• Some are self propelled to
location, but most moved
by tugs
• On location survey boat
surveys location

19. Jackup rigs
• Legs jacked down to sea
floor
• Hull picked up above water
• Rig “pre-loaded”
• Seawater pumped out
• Jacked up to working “air
gap”
• Well drilled

20. Jackup rigs
• Used for both wildcat
and development
• Shallow water up to
350-500’ WD
• Derrick may be fixed
or cantilevered

21. Platform rigs
• Tendered

22. Platform Rig
• Self contained
• Operations similar to
land except:
– Limited storage space
– Crew lives on location
– Cementing operations
simpler

23. Floating rigs
• Semi-submersible
• Drill ships
Subsea BOP
RISER JOINTS
Kill, choke and/or
riser boost lines
Slip joint outer barrel
Upper ball ‘flex’ joint
Slip joint inner barrel
Riser tensioners
Lower ball ‘flex’ joint
Mud line
Marine riser = drilling riser, allows returns to surface,
well control, communications link
Subsea BOP
RISER JOINTS
Kill, choke and/or
riser boost lines
Slip joint outer barrel
Upper ball ‘flex’ joint
Slip joint inner barrel
Riser tensioners
Lower ball ‘flex’ joint
Mud line
Marine riser = drilling riser, allows returns to surface,
well control, communications link
Subsea BOP
RISER JOINTS
Kill, choke and/or
riser boost lines
Slip joint outer barrel
Upper ball ‘flex’ joint
Slip joint inner barrel
Riser tensioners
Lower ball ‘flex’ joint
Mud line
Marine riser = drilling riser, allows returns to surface,
well control, communications link

24. Floating rig systems.
• Wellhead & conductor
• Subsea BOP’s
• Flexjoint
• Lower marine riser
package ‘LMRP’
• Marine riser system
• Telescopic or slip joint

25. Wellhead system design
• System Objective:
– Solution for drilling in ultra
deepwater drilling
• BOP Flange
• Wellhead Connector
• Subsea Wellhead System
• Conductor Sizing (Analysis)
• Conductor/Casing Connectors
– 15,000 psi to 20,000 psi rated
pressure
– 7,000,000 ft.-lbs.
• Bending @ 15,000 psi
F
~6.6 MM ft-lbs
~7 MM ft-lbs
~7.7 MM ft-lbs
~14 MM ft-lbs
(40' Below Mudline)
~8.4 MM ft-lbs

BOP Flange
Wellhead
Connector
Wellhead
System
Conductor/
Casing
Connectors
F
~6.6 MM ft-lbs
~7 MM ft-lbs
~7.7 MM ft-lbs
~14 MM ft-lbs
(40' Below Mudline)
~8.4 MM ft-lbs

BOP Flange
Wellhead
Connector
Wellhead
System
Conductor/
Casing
Connectors
BOP Flange
Wellhead
Connector
Wellhead
System
Conductor/
Casing
Connectors

26. k
• 26” Conductor hole
drilled to approx.
1000’ BML
– Can be drilled with
or without riser
– 20” conductor
casing run and
cemented.

27. • Wellhead
installed
with
conductor
casing

28. While WOC riser
and stack are N/U
and latched onto
the wellhead
Control pods

29. Surface hole drilled to
3000’ to 5000’ BML
Surface casing is run
and cemented
through riser and
BOP’s

30. Floating Drilling
• Float collar drilled out and casing tested
• Float shoe drilled out and 5’ to 15 feet of
new formation drilled
• Hole is circulated and conditioned
• Casing seat is tested

31. Intermediate hole drilled to
just above target zone and
logged
Intermediate casing set,
cemented and tested
Intermediate casing drilled
out
Hole circulated and
conditioned
Casing seat tested

32. Production hole drilled
to TD and logged
Production casing or
liner run and
cemented
Well completed and
tested

33. Subsea BOP Stack issues
• Height and weight
• Pressures and bending loads
• Intervention
• Operating considerations
• Time savings
• LMRP & wellhead connectors
• Choke and kill line, id’s!

34. Marine Riser
• Riser spider
• Gimbal
• Telescopic joint
• Marine riser
• Fill up valve
• Termination spool
• Flex (ball) joint

35. Riser tensioning issues
• Loading and dynamic considerations
– Riser handling & running
– Connections
– Riser, wellhead & mooring analysis
– Tensioning system
– Disconnect, volumes, recoil
– Redundancy

36. Marine Riser

37. Sub Sea Capital equipment
1. Diverter
2. Spider / Gimbal
3. Riser Coupling
4. Upper Flex Joint
5. Telescopic Joint
6. Tensioning Ring
7. Intermediate Flex Joint
8. Termination Joint
9. Riser Adapter
10. Single Flex Joint
11. BOP Connector
12. Wellhead Connector
13. Wellhead
3
1
2
6
4
7
9
13
5
8
10
11
12
3
1
2
6
4
7
9
13
5
8
10
11
12

38. Heave Compensation
• Required to
– Maintains constant weight on the bit
when drilling, running tools &
equipment
• - when the vessel heaves?
– Maintain constant tension on the
marine riser
• - when the vessel heaves?

39. Deepwater work?
• No diver
intervention
possible
• Diver-less
operations
– Remote Operated
Vehicles ‘ROV’

40. Remote operated vehicles

41. Subsea concepts
Wellheads &
Tree Systems
Connection
Systems
Control
Systems
Manifolds
Templates
Intervention
Systems
Downhole
Systems
Subsea
Processing
Flow Assurance
Riser Systems
Flowlines &
Umbilicals
What subsea tools and equipment will your rigs require
To be able to manage faster, cheaper, safer operations?

42. Drilling from Floating Vessel
• Rig move
– Hole opener pulled
from storage and
prepared for use
– Structural casing is
measured and brought
on deck
– Inspect and test riser
and BOP system

43. Drilling from Floating Vessel
• Well prepared for
spudding
– Temporary guide base
(A) set
– 36” Structural hole
drilled to 80’ to 200’
BML
– 30” Structural casing
(B) run and cemented
with permanent guide
base (C) attached
A
B
C

44. Drilling from Floating Vessel
– Water depth at new location verified
– Tide tables obtained
– Choke manifold inspected and tested
• Site surveyed and marked with buoys

45. Drilling from Floating Vessel
• Anchor boats on location
• Heading adjusted and anchor setting begins

46. Drilling from Floating Vessel

47. Drilling from Floating Vessel
• Anchor lines tensioned

48. Floating Drilling
• After testing, hole prepared for
abandonment
– P&A, PNA
– TA, T&A, TNA
• Perfs squeezed, and cement plugs set
according to regulatore rules and
regulations

49. CHIKYU: Dynamic positioning
• GPS satellites and
acoustic positioning
system communicate with
transponders on the ocean
floor
• Propulsion systems
counteract the forces
acting on the ship e.g.
– wind, wave, and current
direction and speed.

50. CHIKYU: DP systems

51. CHIKYU
• First riser equipped
science drill ship to
reach the deeper
waters environments
of the Earth.

52. Riser benefits
• Circulate drilling fluid,
mud,
• Re-enter drilling pipe
easily,
• Lower large diameter of
measuring/monitoring
devices, not limited to the
inner diameter of the
drilling pipe.

53. Circulating system
• Increase mud water weight, to counter-balance the
formation pressure,
• reinforce wall of the borehole by mud ingredients
(mud cake),
• exploit viscosity of mud to displace drilling
cuttings (scraped formation particles) smoothly
• sample drilling cuttings (scraped formation
particles) on board to evaluate formation layers

54. Scientific drilling programs

56. Floating Drilling
• Riser and BOP retrieved
• Casing cut approx. 10’ BML if PNA
• Temporary and permanent guide base
retrieved
• Anchors pulled
• Vessel under way to next location

57. End of presentation
Offshore Drilling