After a well has been drilled, the data collected needs to be interpreted in order to identify any hydrocarbons that may have been encountered. This evaluation is done using the following methods:
Petrophysical rock parameters (resistivity, self-potential, natural radioactivity, density, sonic-velocity, bedding dips, temperature, formation pressure, etc.) are recorded and interpreted to gain information on depth, lithology, thickness, orientation and porosity of the reservoir. They may also characterise any fluid types (Gas, Oil, Brine) and the pore space saturation.