Shallow Water Subsea Drilling and Production Structure to Resist Sand and Ice Keel Intrusion in Arctic Environments

Prescott, Neal (Fluor Corporation) | Mejia, Felipe (Fluor Corporation) | Erford, John (Fluor Corporation) | Bhardwaj, Ruchika (Fluor Corporation)

OnePetro 

Abstract

In certain offshore shallow water production areas in cold regions the sea conditions are characterized by first year and potentially multi-year ice features. Unlike some other arctic regions, which are characterized by icebergs, there are regions where no icebergs occur. However, gouges are formed by rafted ice, pressure ridges, and multi-year ice from the polar pack that forms deep keels. Ice gouging of the seabed in these areas is caused by winds, currents and waves driving the ice sheet containing these ice keels.

As more reserves are being found in shallow water arctic and sub-arctic environments, there is a need to determine how best to develop these resources cost effectively. See Figure 1. Recent interest has been raised for installing typical shallow water subsea drilling templates on the seabed to be drilled by jackup drilling rigs. However, these templates would be at risk of damage from sand intrusion and ice keel penetration.

This paper discusses a novel design to best protect the subsea template and its mechanical equipment. Furthermore, this paper outlines the process undertaken for designing a subsea drilling and production template and protective structure by encasing the template within a protective structure that is placed in an armored excavation, or "Glory Hole", to prevent sand intrusion and ice keel penetration.

To protect a drilling and production template in shallow water, an enclosed structure was required to be embedded in the soil at the bottom of a Glory Hole with a full-time domed protection cover to protect from ice and soil entrance. Slotted doors allow jackup access to the template during drilling. Operation of the Wellheads contained within the Subsea Template is remotely controlled by a subsea cable containing electrical, hydraulic and fiber optic cables and tubes. The operation of the facilities can be monitored and controlled at the Command and Control Center located onshore and connected to the offshore template by the control cable.

  Country: North America (0.94)
  Industry: Energy > Oil & Gas > Upstream (1.00)
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  Technology: Information Technology (1.00)