English: Schematic illustration of a subsea blowout preventer stack installed on the seabed with kill and choke lines shown connected ready for a top kill operation.

Legend:

• red represents the blowout preventer stack
• grey represents the oil flow passage
• white tubing represents the kill (left) and choke (right) lines
• light brown represents the larger diameter kill and choke line sections
• dark brown represents the top of the subsea well casing
• the five grey rectangles within the lower red shape represent ram-type blowout preventers
• the two grey rectangles within the upper red shape represent annular-type blowout preventers
• the dark grey line to the left represents a bent riser