1. Exploration drilling – The search for hydrocarbons by drilling a hole (well) into the seabed to determine reservoir location and estimate its size. See also Mobile Offshore Drilling Units.
2. Production well testing – It is carried out to measure production rates of flow from an exploratory well and estimate its field life.
3. Development drilling – Drilling of a large number of wells through which hydrocarbons flow to a production facility for processing, transportation and sale.
4. Early production – The production of hydrocarbons soon after discovery and prior to full development of the production field.
5. Production – The process of receiving hydrocarbons from subsea wells, separating out water, oil and gas to make sellable product suitable for export by pipeline or tanker. See also Offshore Production Units.
6. Workover – A maintenance procedure involving the re-entry of a producing well for the purpose of restoring or improving production.