terms used in petroleum evaluation

Terms used in petroleum evaluation


# Chance of Success - An estimate of the chance of all the elements within a prospect working, described as a probability. High risk prospects have a less than 10% chance of working, medium risk prospects 10-20%, low risk prospects over 20%. Typically about 40% of wells recently drilled find commercial hydrocarbons.
# Hydrocarbon in Place - amount of hydrocarbon likely to be contained in the prospect. This is calculated using the volumetric equation - GRV x N/G x Porosity x Sh x FVF

* GRV - Gross Rock volume - amount of rock in the trap above the hydrocarbon water contact
* N/G - net/gross ratio - percentage of the GRV formed by the reservoir rock ( range is 0 to 1)
* Porosity - percentage of the net reservoir rock occupied by pores (typically 5-35%)
* Sh - hydrocarbon saturation - some of the pore space is filled with water - this must be discounted
* FVF - formation volume factor - oil shrinks and gas expands when brought to the surface. The FVF converts volumes at reservoir conditions (high pressure and high temperature) to storage and sale conditions