ABSTRACT
This chapter summarizes the exploration part of the oil field life cycle and the part that geoscientists play in discovery and extraction of hydrocarbons. This involvement includes the mapping of what is below the surface using seismic technology, the building of geologic models of the reservoir, the interpretation of well-logging results, which chronicle observations made during drilling, and the depths at which the observations are made, as well as the analysis of rock and fluid samples to provide a complete picture of the reservoirs. Decisions can then be made about whether to develop oil and gas fields. The difference between the various geoscience disciplines is explained. Different types of well logging are presented and explanations are given of the outputs of each logging method, and how the methods can be combined to provide complete information about the fluids and rock types in the well, and the depths at which they may be found. Finally, the chapter ends with the methods used by geoscientists to estimate the quantity of hydrocarbons in the reservoir.
