Abstract

This paper documents the omnipresence of low resistivity sandstones occurring within the Lower Cretaceous Pariwar Formation, typically in order of 2-6 ohm-m. The formation conformably overlies the Baisakhi-Bhadasar Formation while its upper contact with overlying Lower Goru Formation represents an unconformity and is known to be hydrocarbon producing, albeit having low resistivity values. Thickly developed Pariwar Formation (ca. 650m-thick) consists mainly of sandstone with coarsening and thickening up trend intervening with thin shale layers. Sandstone is characterized as dirty white, light grey, hard and compact, fine to coarse grained occasionally very coarse, poorly sorted, glauconitic and calcareous at places. Intervening shale is grey to dark grey, occasionally greenish and brownish grey, hard, silty, fissile and calcareous in nature. The lower and middle part of Pariwar Formation show aggradational box-type to fining-up electrolog motifs representing distributary channels and inter distributary tidal flats of lower delta plain. The sands of distributary channels are poorly sorted, matrix rich quartz wacke with rip-up clasts. The interdistributary plains are characterized by alternations of sandstone-shale (heterolithic facies) of tidal origin with medium to fine grained, moderately sorted quartz arenite. The top part of Pariwar Formation is characterized by coarsening-up electrolog motifs. Petrographic study reveals dominant quartz wacke in the lower part of the coarsening-up sands while the top part of each cycle represents relatively better sorted quartz arenite. This progradational coarsening-up sandstone in the top part represents mouth bars in the delta front environment.