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O
O
O: Oil.
O&G: Oil and gas.
O&M Manual: See Operation and maintenance manual.
O
3
: See Ozone.
OA (Logging): Oxygen activation.
OAP: Outer annulus pressure.
OA (Well Design): Outer annulus.
OBA5: See Operational balancing agreements.
Obligate Aerobes: Bacteria that must have molecular (dissolved) oxygen
(DO) to reproduce.
OBR: Oil/brine ratio.
OBS: Ocean bottom seismic.
Observation Well: (1) A well with primary purpose of monitoring uid
movement or other reservoir function. (2) Wells used for instrumentation or
mechanical observations of a reservoir.
Obsidian: Dark, volcanic glass.
OC: Operating center.
OC: Outer casing.
OCS: See Outer ...