Modal analyses of thin sections from the Guadalupe and Palmichal Groups, and from the Arenisca El Morro Formation, has revealed the petrographic differences between them. Particularly the sandstones from the latter unit bear metamorphic rock fragments that indicate changes in the source area. The textural features enabled calculations of porosity loss for each lithological unit studied. Values of compactional and cementational porosity loss together with the compaction index point towards compaction as the main proxy in obliteration of primary porosity. Significant cementation occurred only locally, except in the Arenisca Dura Formation, where high cement percentages are not unusual. The arenita intermedia of the Palmichal Group and the Arenisca de El Morro Formation exhibit the best petrophysical attributes to be viewed as potential hydrocarbon reservoirs or aquifers.