Well logging is like taking a picture of the inside of a pipe that goes deep into the ground. But instead of using a normal camera, we use a special tool called a logging tool that measures different things like how thick the pipe is, what type of rock or soil the pipe is going through, and how much water or oil is in the pipe. We put the logging tool into the pipe and it sends us all this information so we can better understand what is going on under the ground. This helps us know if there is oil or water that we can use, or if the ground is strong enough to build something like a building or a bridge on top of it.