Drilling of exploration and production wells creates large quanitites of waste in the form of drill cuttings and used drilling mud. We can now re-use 67 percent of oil-based and 50 percent of water-based drilling mud.
Drilling exploration and production wells yields large volumes of waste in the form of drill cuttings (rock spoil) and used drilling mud.
Drill cuttings will always be coated in used mud. The best solution in environmental terms is to reduce the volume of waste as much as possible, followed by various forms of recycling. Acceptable deposition is a last resort.
The challenges presented by such waste management differ depending on whether the drilling is conducted offshore, on land, in deserts or in Arctic regions. A case-by-case approach is needed to find the best solution in terms of the environment, safety and project economics.
When oil-based drilling muds are used on the Norwegian continental shelf, the waste is either injected into a well or shipped ashore for acceptable disposal.
Water-based muds are largely recycled, and discharges of these substances have been substantially reduced in recent years.
The group is now recycling 67% of oil-based and 50% of water-based drilling fluid.
All waste from drilling on land must be dealt with in an acceptable manner on site.
Statoil therefore needs various technologies for handling such waste as well as methods for assessing the best overall solution in each case.