Regional and well established carbonate geological and diagenetic processes are re-examined in<br>Jurassic carbonate reservoirs using the large amount of quantitative mercury injection capillary<br>pressure (MICP) pore system data acquired by Saudi Aramco in the last eight years. An extensive Berri<br>field data set included petrographic data and MICP pore system data obtained by Thomeer analysis.<br>The Berri data from four Jurassic carbonate reservoirs is compared to other data, and specifically the<br>Ghawar Rosetta Stone data using a regional depositional context. The anticipated increase of Jurassic<br>carbonate-rim cement to the North of Ghawar is evident. Much more important from a pore system<br>perspective are the amounts of syntaxial overgrowth cement and the correlative increase of<br>echinoderms and foraminifera in the Hadriya and Fadhili. These latter increases necessitate a fifth<br>porositon (F-ESO), an additional maximum pore-throat diameter mode in the Hadriya and Fadhili pore<br>system models, as compared to the four porositions that describe the pore systems of the Ghawar<br>Arab D limestone and the Berri Arab and Hanifa. Review of the Abqaiq petrographic and MICP data of<br>Ross et al. (1995) provide independent support for the four porositons of Clerke et al. (2008) and also<br>indicate the presence of a fifth (F-ESO) porositon in the Abqaiq Arab D.<br>The pore system effect of the predicted and present carbonate rim cements is imperceptible.<br>Echinoderm and foraminifera are very abundant in the Berri Fadhili and show a steady decrease in<br>abundance upward through the Berri Jurassic section, i.e., the Fadhili, Hadriya, Hanifa and the Arab.<br>Echinoderm abundance is closely linked to marine salinities and high magnesium calcite. Quantitative<br>determinations of echinoderm and foraminifera abundance are shown to be correlative to and useful as<br>a predictor of the pore destructive syntaxial overgrowth cement. Regional models of reservoir quality<br>distribution could potentially be improved using maps of high precision Ca/Mg ratio relating to the high<br>magnesium calcite of echinoderms and syntaxial overgrowth cements and maps of echinoderm<br>abundances and habitats. These regional maps could relate broadly and inversely to reservoir quality<br>and depositional salinity.


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