Technical Limits of Long Wells Presented at ONS 2006

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Technical Limits of Long WellsPresented at ONS
2006

• Bernt S. Aadnoy, PhD
• Professor of Drilling Engineering
• University of Stavanger

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This presentation

• 1. Some applications
• 2. Technical limitations
• 3. Present well limit
• 4. Ultra ERD 15 km stepout
• 5. Stepout statistics
• 6. Summary

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1. Some applications

• Extended reach
• 1980 limit 3km 3 platforms
• 2000 limit 10 km 1 platform
• Important for Recovery Factor
• Environmental drilling
• Mittelplatte land marsh offshore
• California shores drilling rigs appear as
  buildings

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2. Technical limitations

• Present ERD stepout 10.6 km
• Some technical challenges
• Well friction
• Hydraulics
• Stuck pipe
• Hole cleaning,
• Circulation losses,
• Borehole stability,
• Entire process upgraded, must use novel
  technology

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3. Present well limit
 

• 10 km stepout

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4. Ultra ERD 15 km stepout

• Friction
• Steel DP Composite DP

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Ultra ERD 15 km stepout

• Hoist requirements
• 2300 kN with steel DP
• 1200 kN composite DP
• Top drive requirements
• 50 kNm steel DP
• 30 kNm composite DP
• Modern drilling units satisfies this
• 15 km stepouts feasible with modern rigs

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5. Stepout Statistics
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6. Summary

• 15 km stepout wells can be drilled with modern
  rigs.
• Novel technology will allow for even longer wells
• Expandable casing
• Casing drilling
• Hydraulic boosters
• Drilling technology should not be seen as a
  limiting factor