A seamless product line for minimising waste and for safe and efficient transport of drill cuttings developed by StatoilHydro has been installed on the Eirik Raude drilling rig for field testing.
This technology is needed to satisfy the most stringent requirement for drilling waste, which calls for none of it to be discharged.
The zero-discharge standard represents an important condition for opening new acreage to oil and gas exploration in environmentally hypersensitive areas, such as the waters around Norway’s northern Lofoten islands and in the Barents Sea.
The main challenges on the rig are to:
- minimise the amount of chemical waste
- deal with the large volumes of cuttings (rock chips removed from a well during drilling), bearing in mind that these will have to be transported to land for further treatment rather than being discharged at sea
- offload cuttings onto a service vessel without the use of cranes.
Chemical residues and slop water will be cleaned using the best available techniques on the market which yield environmental gains. This will provide more drilling chemicals for reuse and acceptable discharge of purified water directly to the sea.
Cuttings will be mechanically dried as they come off the shale shakers, and temporarily stored in specially-designed buffer tanks.
Pneumatic systems will then transfer the cuttings to receiving tanks on the deck of a service vessel by blowing them from rig to vessel in a continuous stream. This is the key to reducing the number of containers required on the rig and eliminating crane lifts.
Drying the cuttings on the rig also minimises handling on land and permits their potential conversion into useful products, such as soil enhancers and geological membranes beneath waste disposal sites.
