Page 11 - Well Logging and Formation Evaluation

CHAPTER 1

BASICS

1.1 TERMINOLOGY

Like most professions, petroleum engineering is beset with jargon.
Therefore, it will make things simpler if I first go through some of the
basic terms that will be used throughout this book. Petroleum engineer-
ing is principally concerned with building static and dynamic models of
oil and gas reservoirs.
Static models are concerned with characterizing and quantifying the
structure prior to any production from the field. Hence, key parameters
that the models aim to determine are:

• STOIIP = stock tank oil initially in place; usually measured in stock
tank barrels (stb)
• GIIP = gas initially in place; usually measured in billion standard cubic
feet (Bcf)
• GBV = gross bulk volume; the total rock volume of the reservoir
containing hydrocarbon
• NPV = net pore volume; the porespace of the reservoir
• HCPV = hydrocarbon pore volume; the porespace actually containing
hydrocarbon
• f= porosity; the proportion of the formation that contains fluids
• k = permeability; usually expressed in millidarcies (md)
• S w = water saturation; the proportion of the porosity that contains water
• S h = hydrocarbon saturation; the proportion of the porosity that contains
hydrocarbon
• FWL = free water level; the depth at which the capillary pressure in the
reservoir is zero; effectively the depth below which no producible
hydrocarbons will be found

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