Final answer:
A Repeat Formation Test (RFT) is used to determine the pressure and permeability of formations, key for understanding reservoir characteristics in petroleum engineering.
Step-by-step explanation:
The Repeat Formation Test (RFT) is an important tool in the field of petroleum engineering and geoscience. It is specifically designed to determine the pressure and permeability of formations. The RFT involves lowering a probe into a well at a specific depth to measure the formation pressure directly. This information can be vital for understanding the reservoir's characteristics, including its ability to produce fluids like oil or gas. This is contrasted with other well-logging tools that may measure natural gamma radiation to determine lithology, use neutron logging to evaluate porosity, or analyze the lithology and composition of formations with a variety of well-logging instruments.