dual completion

1. n. [Well Completions]
A single wellbore having tubulars and equipment that enable production from two segregated zones. In most cases, two tubing strings will be used to provide the necessary level of control and safety for the fluids from both zones. However, in some simple dual completions, the second or upper zone is produced up the tubing-casing annulus.
2. n. [Well Testing]
A wellbore with simultaneous production of hydrocarbons, water or both from more than one producing zone. Although the term refers to cases in which only two separate zones are present, in actuality there may be multiple zones involved. This completion technique avoids backflow from one reservoir zone to another in the wellbore.