Well structures

A well's structure describes how it accesses hydrocarbon zones—whether it targets a single layer or multiple formations simultaneously. This affects drilling complexity, production strategy, and regulatory requirements.

Single Zone

Single Zone wells target one hydrocarbon-bearing formation. This is the simplest configuration—one wellbore accessing one reservoir. Most conventional wells in Alberta use this structure.

Dual Zone

Dual Zone wells produce from two separate formations through the same wellbore. This requires careful engineering to isolate each zone and manage different reservoir pressures. Reduces surface footprint compared to drilling two separate wells.

Triple Zone

Triple Zone wells access three formations. More complex than dual zone, requiring additional completion equipment and monitoring to manage production from each layer independently.

Four Zone

Four Zone wells target four separate formations—the practical limit for most multi-zone completions. Maximizes resource recovery from a single surface location but requires sophisticated well management.

Commingled

Commingled wells produce from multiple zones mixed together in the same tubing string, rather than keeping each zone's production separate. Simpler equipment but makes it harder to track which zone is contributing what—requires regulatory approval and careful reservoir management.

Drain

Drain refers to a wellbore specifically designed to drain a targeted area of a reservoir, often a horizontal leg extending from a vertical well. Used to maximize contact with the pay zone and improve recovery rates.