Fig. 8

Porosity distribution within different lithology and facies groups. a Data set subdivided by lithology shows a rather skewed distribution for each group. b Grouping by facies for limestone results in rather unimodal distribution for each type. Arrows point to reduced porosity due to sparitic cementation of pore space between particles in grainstones. c Facies groups of dolomitic limestone show a unimodal distribution of porosity, with exception of the grainstone group, which is more bimodally distributed. Some samples of dolomitic wackestone show abnormal high porosity due to intense bioturbation and dolomitized burrows. d Distribution of dolostone, grouped by crystal size, is still skewed in the fine and medium crystalline groups. Porosity is mainly controlled by crystal morphology and secondary porosity (vugs), which increases porosity