SPE Drilling & Completion
Volume 26, Number 1, March 2011, pp. 124-132

SPE-124233-PA

Magnus: Utilization of Conductor Sharing Wellhead Technology To Access Additional Hydrocarbons With a Slot-Constrained Platform

View full textPDF ( 1,719 KB )

DOI  More information 10.2118/124233-PA http://dx.doi.org/10.2118/124233-PA

Citation

  • Hicks, S.E., Moore, A., Honey, M., Farmer, I.R., Smart, B., Ekseth, R., and Brown, D. 2011. Magnus: Utilization of Conductor Sharing Wellhead Technology To Access Additional Hydrocarbons With a Slot-Constrained Platform. SPE Drill & Compl  26 (1): 124-132. SPE-124233-PA. doi: 10.2118/124233-PA.

Discipline Categories

  • 1.4 Drilling Equipment and Operations
  • 1.3 Wellbore Design/Construction
  • 1.2.4 Trajectory Design, Survey Calculation, Collision Checking

Keywords

  • Conductor Sharing, Slot Splitting, Unguided conductor , Gyro

Summary

The Magnus platform, UK northern North Sea, has been producing since 1983 with all 20 original slots now occupied. Additional infill and extend-reach-drilling (ERD) production targets were identified and a means of access was required while maintaining base field production. Platform modification was selected because of significant commercial advantage over alternative developments. The Magnus jacket was modified to permit running of four additional large conductors into which two smaller casings could be installed respectively.

A tapered jacket profile necessitated preinstalled conductor guide frames to build to 4° inclination at seabed, requiring initial use of the large conductor as a conduit for drilling assemblies. Custom-manufactured and specialist equipment was designed and procured to enable successful underreaming to 54 in. and installation of 46-in. conductor. Drilling-assembly design and initial pilot-hole profile were deemed critical to subsequent success in running rigid open-ended 46-in. conductor. Well-critical structural cement was pumped to seabed by use of a 16-in. inflatable packer and inner string. Unguided installation of two 18 5/8-in. casing strings inside 46-in. conductor was then achieved. The 18 5/8-in. casing strings were cemented in place using light cement to preserve (shallow) casing-shoe integrity. High-resolution multishot gyro surveys and a newly developed "gamma-wipe" survey technique were used to obtain critical 18 5/8-in. relative-shoe-orientation information before subsequent kickoff.

Two wells were batch set successfully to the 13 3/8-in. casing shoe by means of one conductor. Modification of existing wellhead technology for close proximity has proved successful. Access to additional Magnus resources by means of an otherwise full template has been delivered by this conductor-sharing-wellhead (CSW) technology.

© 2010. Society of Petroleum Engineers

View full textPDF ( 1,719 KB )

History

  • Original manuscript received: 19 August 2009
  • Meeting paper published: 8 September 2009
  • Revised manuscript received: 18 July 2010
  • Manuscript approved: 20 July 2010
  • Published online: 3 January 2011
  • Version of record: 11 March 2011