Glossary
barrel: a unit of measurement for oil. One
barrel is 42 gallons or nearly 159 liters.
darcy: a non-SI unit for measuring permeability.
derrick: the metal tower that supports the weight of
the drill stem in a drilling rig.
downhole: in the drill hole. In the ground.
drill stem: the thick, hollow pipes that are used to
drill into the ground.
fault: a fracture in the earth's crust,
usually involving a shift in the position of one or both
of the sides.
newton: a measurement of force. One newton is
the same as a kilogram-meter per
second squared.
pascal: a measurement of pressure. One pascal
is equal to a newton per meter squared.
permeability: how easy it is for a liquid or gas to
pass through the tiny spaces within the
rock. This is usually expressed in darcys.
porosity: the amount of empty pore space within the
rock. This is usually expressed as a
percentage of empty space within the
rock.
pressure: the amount of force exerted over an
area. Pressure is usually expressed in
pascals, which is one
newton per meter.
sedimentary rock: organic and inorganic particles
which are buried and then moved deep into
the earth. Exposed to high temperatures and pressures,
they become rock.
Sandstone is a common example of a
sedimentary rock.
tension: a contact force we see when a string or wire
pulls on an object. This is usually
expressed in newtons.
torque: a force that rotates around a central pivot
point. Torque is usually expressed in
newton-meters.
viscosity: a measure of how "sticky" a liquid
is. Honey has a higher viscosity than water.