Initials after well names (Texas)

What do the initials stand for at the of a well name? e.g., H, LA, ULA, etc. I would guess that “H” is horizontal, but what about the other letter combinations you see?

This is in Texas.

Without the full name and area of the well, I can only guess that those letter designate the formation being targeted. In Oklahoma, for example HMX means horizontal Mississippi multi-unit. HWX means horizontal Woodford multi-unit.