Hi,
I will give it a shot....
This novel is well written – passive, “well” modifies “written”.
This is a well-written novel- "Well-written" now is used as adjective to describe the novel. Note it that a hyphen is typically used in this form.
This is a piece of "badly-damaged" furiture. No one will buy it.- hyphenated as adj.
The piece of furiture is "badly damaged". No one will buy it.- adverb modifying verb