ΔE 19.9, loose: different enough that you should pick on purpose. Petroleum Brown is noticeably darker, warmer than Karak Stone.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Petroleum Brown is noticeably darker, warmer than Karak Stone.
The same difference applies the other way round: Karak Stone is noticeably lighter, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Karak Stone on the colour wheel See Petroleum Brown on the colour wheel
All matches: Karak Stone equivalents · Petroleum Brown equivalents