Intro to offshore drilling
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This document discusses various types of offshore drilling rigs and operations. It describes inland barges, jackup rigs, platform rigs, and floating rigs like semi-submersibles and drillships. The key systems involved in offshore drilling are also summarized, including well design, mud systems, cementing, blowout preventers, and riser systems. Offshore drilling processes like running casing and conductor pipes are also outlined.
Intro to 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
- 6. High pressure circulating 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
- 13. Drilling Instrumentation • Drilling • Tripping • Well control – Kicks – Loss circulation • Wellbore difficulties – Hole cleaning – Instability – Stuck pipe
- 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
- 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.
- 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’
- 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.
- 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
- 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