TY - JOUR IS - 2 TI - Petrographic and microtextural analyses of miocene sandstones of onshore West Baram delta province, Sarawak basin: Implications for porosity and reservoir rock quality SN - 13377027 N2 - The Miocene Miri Formation of West Baram delta is the most prolific formation of Onshore Sarawak Basin in terms of hydrocarbon accumulation. Despite their similarity in age and arenaceous composition, the prolific hydrocarbon occurrence in Miri Formation has not been reflected in the adjacent Belait and Lambir formations likely due to failure to identify discrete reservoir units in the formations. Thus, this study attempts to augment exploration in onshore West Baram Delta by analyzing petrographic and microtextural variations in Belait and Lambir formations using thin sections and Field emission scanning electron microscopy (FESEM) images. Organic content and anoxic condition of deposition, Iron and carbonate precipitation, tangential and floating rock fabric were shown to define the texture of the Lambir sandstones, while the Belait rocks are characterized by sutured and deformed quartz grains. The Belait conglomerates reveal euhedral quartz crystals characterized by mechanical weathering defects (fractures and striations), which are potential nucleation sites that promote the growth of quartz cement which subsequently limits compaction. Conversely, the chemical weathering features (etchings, pitting, solution pits and notches) in Lambir sandstones provide sites for pore growth, while the carbonate intraclasts, pyrite frambroids and iron oxides inhibits quartz cementation, but infill pore spaces. In all, the study showed that the Lambir are comparatively a more porous formation. EP - 184 ID - scholars7877 AV - none SP - 162 PB - Slovnaft VURUP a.s Y1 - 2016/// N1 - cited By 5 UR - https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976472287&partnerID=40&md5=30100b1878a27a5291be52fe39353fa6 A1 - Ali, A.M. A1 - Padmanabhan, E. A1 - Baioumy, H. JF - Petroleum and Coal VL - 58 ER -