We're harmonizing science with the Bible. How can this be possible if, superficially, science and the Bible look completely different? We have to know what's real science and what's not.
Sheol refers to life beyond the grave, quite literally an underworld realm of the dead. It's also modified in a variety of ways which can be grouped to correspond to the main regions of the interior of the Earth.
Tehom was Wet. Sheol is Dry
The space in the interior of the Earth formerly occupied by the great deep is now a great gulf (chasm) of open space that Jesus spoke of in Luke 16:26. The open space is no longer referred to as tehom, it's now sheol.
The Antediluvian World
A word that ties together a developing theory for the interior of the Earth is tehom, the deep. The deep is first mentioned in Genesis 1:2 as a body of water which predates creation.
We (that's me and the Holy spirit) make a contextual connection between tehom and sheol because they're both used to refer to the underworld realm of the dead, also known as the grave.
After Noah's flood the region in the interior of the Earth, formerly occupied by the great deep (tehom), is now a great gulf or mega chasm of open space that Jesus spoke of in Luke 16:26 (sheol).