Wellhead (Surface valves) control pressure, production flow, and safety (like the master, wing, and kill valves).
Cellar is a pit around the wellhead for easier access and safety.
Wellbore (below ground) has multiple steel casings cemented in place for stability and zonal isolation.
Tubing carries hydrocarbons from the reservoir to the surface.
Packer seals space between tubing and casing.
Perforations let hydrocarbons enter the wellbore.
Hydrocarbons flow from the reservoir, through perforations, up the tubing, and out via the flowline.
Main purpose: Safely control and transport oil & gas from the reservoir to surface facilities.