German to English Science Geology wells/ oil drilling/sands

I have a series of questions that all strem from my lack of knowledge of this well/drill hole diagram. There is also fairly little word context to pull from so it might be somewhat of a stretch.

Heading: Verrohrung
it's subcategories (in a measurement table) are as follows:
Wandstoesse (previous entry)
Guete
Gewindeverbinder

Later, there are three grouped words in one category (still the measurement section):
Oberes Lager
Unteres Lager
GESCHLITZT

On the diagram itself, some words pointing out different sections of depth are as follows:
Alb
Alt
Polyptichiten (not Polyptychon)

For this entry, please help me identify geschlitzt. (I know this means slotted but cannot translate it well in the context.)