Bai giang pttkk drilling rigs

Drilling Rigs 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Broad Classification of Drilling Rigs 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Types of Drilling Rigs 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Semi-submersible ✓ Parts / Features: ➢ Subsea wellhead ➢ Submerged pontoon keeps it afloat ➢ Bottled or column stabilized ➢ Connected to deck by columns ➢ Moonpool below the derrick ➢ Less cross-sectional area in the water line ➢ High degree of stability ➢ Dynamic positioning / anchor mooring 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Semi-submersible Specificity ✓ Transportation: Towed / self propelled ✓ Spudding the Rig: Temporary and permanent guide base adopted ✓ Stability: Tolerates harsh conditions as a result of space between the columns; compensate vertical motion using telescopic joint; tensioner system; wave motion compensator system ✓ Anchoring: use of conventional mooring / dynamic positioning with thrusters {short baseline system (4 hydrophones and at least one transponder) or Long baseline system (4 transducers and transponders)} ✓ Functionality: Utilized in drilling exploratory and development wells 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Semi-submersible ✓ Capacity Ranges 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Semi-submersible ✓ Pros and Cons Cons Pros ➢ Mobile with high transit speed (~10kts) ➢ Highly stable with minimal response to wave action ➢ Large deck area ➢ High initial and operating costs ➢ Limited deck load (due to buoyancy) ➢ Structural fatigue ➢ Expensive to move over large distances ➢ Limited dry-docking facilities available ➢ Difficulty in handling mooring systems and landing BOP stack in rough seas 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Semi-submersible 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Semi-submersible 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com Drill Ship ✓ Parts / Features: ➢ Subsea wellhead ➢ Self propelled ➢ High storage capacity ➢ Capacity for dual derrick ➢ Dynamic positioning / anchor mooring 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 10 Tension Leg Platform Specificity ✓ Transportation: Topsides lift / modular installed (foundation is built onshore and towed to site) ✓ Spudding the Rig: Foundation set using concrete piles (hammered), structure follows ✓ Stability: Provided by the tendons in tension Ballasting to control tension Use of hydraulic tensioners ✓ Anchoring: Anchored using the tendons ✓ Functionality: Utilized mainly for development wells 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 24 Tension Leg Platform ✓ Capacity Ranges 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 25 Tension Leg Platform ✓ Pros and Cons Pros Cons ➢ Mobile and reusable ➢ Initial cost is high ➢ Good stability with minimal vertical motion ➢ High subsea cost ➢ Low incremental cost with increasing depth ➢ Low maintenance cost ➢ Possible in deep water 01/2018 ➢ Tension leg fatigue with time ➢ Difficulty in maintaining subsea systems ➢ Little storage capacity Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 26 Tension Leg Platform 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 27 Spar Platform ✓ Parts / Features: ➢ SPAR: Single Point Anchor Reservoir ➢ Drilling / Production ➢ Catenary or taut mooring system ➢ designs available: Classic, truss and cell spar ➢ Drilling through the center of the cylinder ➢ Drilled with subsea/surface wellhead ➢ Buoyancy cans adopted for stability 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 28 Spar Specificity ✓ Transportation: Towed; Topside installed on site ✓ Spudding the Rig: Rig is towed to location and ballasted upright ✓ Stability: Deep draft hull (90% submerged)/ buoyancy cans Use of spiral fins / truss frame reduced vortex induced vibrations (VIV) ✓ Anchoring: Anchored using catenary or taut mooring system ✓ Functionality: Utilized mainly for development wells 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 29 Spar ✓ Capacity Ranges 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 30 Spar ✓ Pros and Cons Pros Cons ➢ Good degree of stability ➢ Use of surface wellhead possible with reduced heave ➢ Lower costs with truss spar ➢ Mobile 01/2018 ➢ Susceptible vortex induced vibration (classic spar) ➢ Cost intensive with increasing water depth ➢ Requires large facilities for manufacturing Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 31 Spar Platform 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 32 Spar Platform 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 33 Concrete Platform ✓ Parts / Features: ➢Gravity based, seat on seabed ➢Drilling / Production ➢No mooring required ➢Drilling through the center of the structure ➢High storage capacity ➢Variation: monopod and multi-pod 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 34 Concrete Platform Specificity ✓ Transportation: bottom section constructed in dry dock; towed to site and lowered to seabed; Topside installed on site ✓ Spudding the Rig: Platform is towed to location and ballasted to seabed ✓ Stability: stabilized by the weight of the structure (up to 850,000 T) resting on seabed ✓ Anchoring: No anchoring system required ✓ Functionality: Utilized for development wells (drilling and production) 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 35 Concrete Platform ✓ Capacity Ranges 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 36 Concrete Platform ✓ Pros and Cons Pros Cons ➢ Cheap and easy installation ➢ Expensive capital cost ➢ Low maintenance required ➢ Challenges with decommissioning ➢ High storage capacity ➢ Can withstand severe ➢ No reduction in load carrying capacity with time 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 37 Concrete Platform 01/2018 Đinh Công Vĩnh Luân – MSc in Offshore Engineering Email: luandcv@gmail.com 38