Estupiñán Letamendi, JennyMarfil, Rafaela2023-06-202023-06-2020041576-5172https://hdl.handle.net/20.500.14352/52496The Napo Formation of the Cenomaniense age is an importan reservoir-sandstone in the Oriente basin of Ecuador. It displays higher porosity values (average 2 1%) compared to other reservoir in the region. The sandstone are fine to coarse grained and moderately to well sorted quartz arenites (average Qt932 F6.1 L0.7). Quartz cement is the dominant porosity reducing agent in this reservoir but o ther factors such as the glaucon ite, other clay in traclastos, grain-coating chlorite, pyrite, early siderite, mesodiagenetic Fedolomite-ankerite, kaolin, and pyrrhotite also playa critical role. Intergranular volume IGV vs cement percentage, indicates that cementation is the predominant contributor to porosity loss in all the reservoir. Some intervals shows secondary porosity but it is of minore effect on the enhancement of porosity.spajournal articlehttp://www.sociedadgeologica.es/publicaciones_geotemas_realizadas.htmlopen access552.1Reservoir sandstonediagenesiscementationLower Creta ceousEcuadorPetrología