What is the relationship between the magnetic field density and the distance from the surface of a magnet halfway between the poles?

There is an inverse relationship between the magnetic field density and the distance from the surface of a magnet halfway between the poles in that as distance increases intensity decreases. 

“other instruments such as gravimeters and magnetometers are also used in the search for petroleum. extracting crude oil normally starts with drilling wells into an underground reservoir. when an oil well has been tapped, a geologist (known on the rig as the "mudlogger") will note its presence. “ this is what i found on google i hope it

English can you write this in english do we can you