Oilfield maths: hydrostatic pressure, mud weight, API gravity, buoyancy, ECD and production decline
Bottom-hole pressure from mud weight and depth in oilfield units.
Standard measure of how light or heavy a crude oil is relative to water.
Reduction in a steel pipe string's weight when submerged in drilling mud.
Effective mud density while circulating, including friction pressure.
Speed of mud returning up the annulus, key to carrying cuttings out.
Mud volume per minute from a triplex pump's bore, stroke and speed.
Volume of oil originally in a reservoir (in stock-tank barrels).
Percentage of oil in place that can actually be produced.
Falling production rate of a well over time at a constant decline rate.
Volume of gas produced per barrel of oil.
Rate at which fluid pressure rises with depth (psi per foot).
Mud weight needed to just balance formation pore pressure.
Internal volume of pipe per foot of length (barrels per foot).
Pore pressure of a formation from its gradient and depth.
Steady oil flow rate into a well from radial Darcy flow.
Fraction of annular velocity effectively lifting cuttings out of the hole.