Glossary of Terms
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- Abnormal Formation Pressure: a formation pressure greater than the hydrostatic pressure exerted by vertical column of water with salinity normal for that geographic area.
- Abnormal pressure is therefore something higher than is normal for that area.
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- Accumulator Bottle: a vessel for storing the hydraulic energy that is used to perform BOP functions
- Accumulator Drawdown Test: a test to verify the accumulator system is able to support the fluid volume and pressure require-ments of the BOP in use and to be capable of securing the well in the event of a total loss of power
- Acoustical Backup System: used to actuate up to sixteen different preselected critical functions if the primary system were to fail
- Active Barrier: a barrier designed to be actuated either manually (e.g. by a diver or ROV) or by some form of remote control
- Adjustable Choke: a choke that can be used to vary the rate of flow through its orifice
- Aerosol: the suspension of fine solid particles or liquid droplets, in air or another gas.
- Air Pump System (Accumulator): pneumatic pumps that should be capable of charging the accumulators to the system working pressures
- Anhydrite: a form of calcium sulphate
- Anhydrite: an evaporate with the chemical formula CaSO4 + H2O
- Annular BOP: a blowout preventer that uses a donut-shaped elastomeric sealing element to seal the space between the tubular and the wellbore or an open hole.
- Annular Capacity: the volume capacity of the annulus in units of bbl/ft
- Annulus: the is donut-shaped space between the wall of the hole and the drill string
- Anticline: although not strictly true, for our purpose we can think of an anticline as a fold in the rock that points up like the crest of a wave
- API Connection: a flange, hub, or studded connection that meets the API standards of manufacture
- Aquifer: a water-bearing rock or reservoir
- Arrested Compaction: similar to undercompaction
- Artesian Pressure: a well where the potentiometric surface is above the rig floor, causing the well to flow
- Atmospheric Pressure: the pressure exerted on the surface of the earth by the weight of the atmosphere. Normal atmospheric pressure at sea level is about 14.7psi
- Atoll: a circular coral island with central lagoon that usually formed around an ancient submerged volcano
- Auto-Shear System: a system to automatically shutdown the wellbore by activating the shear-blind rams in the event of total loss of control from the pods or the LMRP becomes unexpectedly disconnected
- Auto Fill Casing Valve: a self-filling casing shoe valve run to reduce the surging pressures while running casing.
- AX Ring Gasket: a Cameron gasket used in the subsea wellhead and LMRP hydraulic connector
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- Back-reaming: a procedure for tripping out of the hole through tight spots and involves a combination of pumping and rotating Back Pressure: the pressure resulting from resisting flow
- Ball/flex Joint: designed to deflect the bending stresses imposed on the riser system by tides and sea currents
- Ball Joint: consists of a ball and socket arrangement where pressurized hydraulic fluid (from a pilot line) provides the lubrication and a pin mechanism to prevents excessive movement
- Ballooning Formations: a phenomenon that can exist when weak formations have been exposed to annular pressures losses that are able to open up the micro-fractures along the wellbore face, allowing mud seepages into these formations. This mud is then returned to the wellbore when the pumps are stopped
- Barge Drilling Rig: submersible rig that sits on the bottom and is used in sheltered, shallow coastal waters , inland waterways or other wetlands
- Barite: a heavy rock (barium sulfate) with a SG of 4.2 to 4.3 that has been ground into a powder which is used to weight up drill-ing mud and cement.
- Barite sag: barite slipping either down the hole or to the low side of a horizontal well creating density differences and affecting the hydrostatic pressure
- Barrel: an oilfield barrel is a unit of liquid volume and is equal to 42 American galleons or 158.97 liters
- Barrier Influencing Factor: something that influences how a barrier performs