To find GRV:





To find STOIIP or GIIP (if STOIIP enter So & Bo; if GIIP enter Sg & Bg):

 

Petroleum Engineering Equations & Formulas

Oil & gas volumes

STOIIP is a term which normalises volumes of oil contained under high pressure and temperature in the subsurface conditions.

GIIP is the equivilant expression for gas initially in place.

GRV is the Gross Rock Volume of the hydrocarbon-bearing interval and is the priduct of the area (A) containing hydrocarbons and interval thickness (H).

      STOIIP = GRV * (N/V) * Φ * So * (1/Bo) [stb]

      GIIP = GRV * (N/V) * Φ * Sg * (1/Bg) [stb]

      GRV = A * H

      Ultimate recovery = HCIIP * Recovery Factor [stb] or [scf]

      Reserves = Ultimate Recovery - Cumulative Production [stb] or [scf]


            
 

$$ STOIIP = GRV * \frac{N}{G} * \Phi * S_{o} * \frac{1}{B_{o}} [stb] $$

$$ GIIP = GRV * \frac{N}{G} * \Phi * S_{g} * \frac{1}{B_{g}} [stb] $$

$$ GRV = A * H $$

$$ UR = HCIIP * RF\;[stb] \;or \;[scf] $$

$$ Reserves = UR * CP \;[stb]\; or \;[scf] $$

Where:

  • $GRV$ is Gross rock volume
  • $UR$ is Ultimate recovery
  • $RF$ is Recovery factor
  • $CP$ is Cumulative production
  • $A$ is Product of the area
  • $H$ is Interval thickness