Reservoir potential and heterogeneity are critical important factors for exploring shallow marine sandstone reservoirs. Shallow marine sandstones are crucial hydrocarbon bearing reservoirs around the globe and in Southeast Asia. The integrated analysis consisting of petrographic characteristics and reservoir properties for Nyalau Formation from Bintulu area have been discussed in this case study. The field observations, helium porosimetry on core plugs, thin sections study and petrographic approach provides insight into the factors responsible for variations in porosity and permeability in shallow marine sandstone. The results indicate that Nyalau Formation is comprised of five different facies well exposed in Bintulu area, Sarawak basin, Malaysia. The identified facies based on sedimentary structures and lithology are, trough cross-bedded sandstone, laminated sandstone, bioturbated sandstone and massive sandstone facies. It is analyzed that total clay content, grain size, grain shape and grain sorting impact the reservoir in different ways. The trough cross-bedded and massive sandstone facies have low clay content and medium grained, subrounded and well sorted having porosity around 20-25 and permeability 15-20 millidarcies. The laminated and heterolithic sandstone facies are fine grained, poor to moderately sorted, high clay amount and subangular are comprised of low porosity (8-12 ) and low permeability (0.5-2 millidarcies). The bioturbated sandstone facies is highly disturbed due to burrow activity and having very low porosity (5 ) and low permeability (0.5-1 millidarcies). By integrating these parameters, it is concluded that trough cross bedded and massive sandstone facies have best reservoir quality among all facies of Nyalau Formation. © 2006-2017 Asian Research Publishing Network (ARPN).