PETE 406

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PETE 406

• Lesson 8
• Offshore Drilling

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Content

• Inland barges (submersible)
• Jackup rigs
• Wildcats
• Shallow water templates
• Cantilevered over platform
• Platform rigs
• Floaters - semis and drillships

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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.

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Jackup rigs
Noble Drillings Cecil ForbesA Jack-Up Rig
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Jackup rigs

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

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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

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Jackup rigs

• Used for both wildcat and development
• Shallow water up to 350-400 WD
• Derrick may be fixed or cantilevered

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Platform rigs

• Tendered

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Platform Rig

• Self contained

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Platform Rig

• Operations similar to land except
• Limited storage space
• Crew lives on location
• Cementing operations simpler

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Floating rigs

• Semi-submersible
• Drill ships

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Sonats George Washington
A Semi-Submersible Rig
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Zapatas TraderA Drillship
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Semi-submersible Marine Riser Subsea BOP stack
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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

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Drilling from Floating Vessel

• Water depth at new location verified
• Tide tables obtained
• Choke manifold inspected and tested
• Site surveyed and marked with buoys

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Drilling from Floating Vessel

• Anchor boats on location
• Heading adjusted and anchor setting begins

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Drilling from Floating Vessel
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Drilling from Floating Vessel

• Anchor lines tensioned

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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

C
B
A
21
k

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

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lling

• Wellhead installed with conductor casing

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While WOC riser and stack are N/U and latched
onto the wellhead
Control pods
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Surface hole drilled to 3000 to 5000
BML Surface casing is run and cemented through
riser and BOPs
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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

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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
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Production hole drilled to TD and
logged Production casing or liner run and
cemented Well completed and tested
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Floating Drilling

• After testing, hole prepared for abandonment
• PA, PNA
• TA, TA, TNA
• Perfs squeezed, and cement plugs set according to
  regulatore rules and regulations

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Floating Drilling

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