Concentric riser will reduce mud weight margins, improve gas-handling safety

A high-pressure concentric riser, consisting of a surface casing string run within the riser, will have the potential to use a dual-density mud system to reduce mud weight margins, allowing operators to set fewer casing strings in deepwater environments. An additional benefit includes improved gas-h...

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Bibliographic Details
Published in:The Oil & gas journal 1998-11, Vol.96 (44), p.54-62
Main Authors: SHAUGHNESSY, J.M, HERRMAN, R.P
Format: Magazinearticle
Language:English
Subjects:
Applied sciences
Crude oil, natural gas and petroleum products
Custom design
Drilling
Energy
Exact sciences and technology
Fuels
Mud
Natural gas
Ocean floor
Offshore drilling
Offshore drilling and production
Process engineering
Prospecting and production of crude oil, natural gas, oil shales and tar sands
Safety
Technology
Test wells
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Summary:A high-pressure concentric riser, consisting of a surface casing string run within the riser, will have the potential to use a dual-density mud system to reduce mud weight margins, allowing operators to set fewer casing strings in deepwater environments. An additional benefit includes improved gas-handling safety above the seafloor. In comparison with the concentric riser system, conventional marine risers are not designed to contain pressure; instead, they serve primarily as a conduit between the seafloor blowout preventer (BOP) and the rig floor. Issues with well control, gas handling, and well testing are much more easily handled with a pressure riser and a surface BOP. Furthermore, such a setup allows underbalanced or near-balanced drilling from a deepwater floater, which until now, has been restricted by the lack of reliable subsea rotating BOPs. The concentric riser system is described in detail.
ISSN:0030-1388
1944-9151