Organic geochemical and petrological evaluation to assess the remaining hydrocarbon potential and depositional conditions: a case study of the Paleozoic shales of west Perlis region, northern Peninsular Malaysia - Muhammad Nadzmi Abdul Ghofur; Jasmi Hafiz Abdul Aziz; Yousif M. Makeen; Wan Hasiah Abdullah; Mohammed Hail Hakimi (Arabian Journal of Geosciences, 2022)