The text you quote deals with extraction of organic compounds from different parts (sections, if you will) of the formation/well system.

Wellbore = the actual cylindrical "hole in the ground" that was originally drilled. Also called "open borehole" or "uncased wellbore" - i.e. without casing.

When you put in casing this wellbore becomes "cased wellbore".

And there (usually) are no square wellbores, you are right.

"Wellbore Tubulars" are the pipes you put into the well. These are both large-diameter pipes (about an inch less than diameter of the open borehole - this tubular, naturally, is the casing) and thin pipes - e.g. production tubing.

The general name for all these pipes and tubes is "tubular goods", so "wellbore tubulars" in plain simple English means "pipes lowered/installed in the well".

Fracture system - probably artificial fractures made in a hydraulic fracturing operation or similar type of operation. These fractures go from the well outside into the productive formation.


Matrix of the formation - system of pre-existing fractures (both vertical and horizontal) going in various directions and containing hydrocarbons in a productive formation (oil&gas are either stored between grains of sand (in sandstone-typ formations etc.) or in fractures (in limestone-type formations)

Hope this helps.

Good luck!