According to Devon Canada exploration geologist Peter Graham, the hiatus in northern exploration resulted in the disappearance of northern infrastructure -- icebreaking and dredging capabilities and support vehicles. Even some of the harbors are no longer navigable.
For northern operators, only two options exist to economically transport equipment:
- Barging up the Mackenzie River during the summer and fall.
- Sailing ice-breaking vessels through the Northwest Passage.
"In a sense, were having to recreate the infrastructure," Graham explained.
Devon is currently assessing how best to drill its first offshore well -- whether to construct a subsea drilling caisson or to utilize an ice island that takes advantage of the fact that the shallow Beaufort Sea freezes down to the seafloor.
The technological innovations required for Arctic exploration are designed to meet the challenges of the harsh environment; theyre also designed to decrease time drilling time, increase environmental and personnel safety and significantly reduce operational costs.
Devon has placed its heli-portable, Arctic class rigs on ice pads poured over the tundra. A refrigerated coil inside the ice pad keeps the ice pad cold, even as temperatures climb during the spring months.
"Its basically like having a hockey rink on the ground," Graham said. During the summer, the ice pad melts, leaving a minimal footprint on the tundra.
Mud systems must be refrigerated when drilling through permafrost and the underlying gas hydrate zones, which could potentially liquefy when exposed to changes in temperature and pressure. Devon has used an "encapsulated mud pit" in its northern operations. Essentially, the drilling mud goes into a big bladder that is buried within the permafrost layer (a layer that is permanently frozen). Permafrost occurs within a few feet of the grounds surface.
According to Berquist, there are no leakage problems as with mud pits or sump pits.
Finally, Devon is developing what it calls second generation Blow Out Preventers (BOPs) or "Shear and Seal" BOPs. Because environmental issues are of paramount importance in the North, this technology enables drillers to quickly cut the pipe, casing and drill collars, sealing off the well, if required.
-- SUSAN EATON