Abstract
Expandable Sand Screens (ESS®) were deployed successfully in two gas-condensate subsea production wells on the Scoter field, in the UK sector of the North Sea in May 2003. The Shell UK operated 22/30a-S1 (Scoter P1) and 22/30a-S2 (Scoter P2) wells are near-vertical, drilled from the semi-submersible rig, Ocean Guardian, and penetrate the Forties sandstone. Well clean-up performance to the rig (June 2003) and first production to the Shearwater processing platform (December 2003) exceeded original expectations.
The success of the Scoter 4" ESS installation has been due, in part, to the multi-disciplinary approach taken by both Shell and Weatherford, from concept selection to after-action review. This paper details learnings on the extensive ESS design and execution including:
Torque and drag analysis for screen running in and expansion to minimize damage.
Determination of rig-heave effects on screen expansion from an Axial Compliant Expansion (ACE) tool.
Use of long-term, synthetic core baking-tests (at temperature) to estimate the effect of completion-to-clean-up time on reservoir return permeability: initial production data showed no evidence of skin (no wellbore damage or screen plugging for both wells).
Erosion and collapse modeling of the screens.
Well clean-up and bean-up, including offshore petroleum engineering support.
Sand control contingency planning (e.g. external gravel pack sand control design, including mud selection testing).
Simplified completion including use of a Formation Isolation Valve (FIV)
This technical knowledge can be adopted elsewhere for future sand control applications, including:
Any design and installation of ESS, especially from a semi-submersible rig.
Any return permeability testing, especially to assess the effect of delayed clean-up on reservoir return permeability.
Any clean-up of a gas-condensate ESS well.
