Sedimentology And Petrophysics Of Turonian-Coniacian Rudist Rich-Reservoir Rocks, Offshore Tunisia

The Turonian-Coniacian rudist-bearing carbonates are characterized by their good quality as reservoir rocks. They produce oil and gas in several fields in eastern onshore and offshore of Tunisia. These rudist-rich facies are featured by a developed porosity (intragranular, intergranular, intercrystalline and matrix porosity especially between micritic grains). In terms of reservoir properties, the highest values of helium-porosity (reaching 24%) and nitrogen-permeability (reaching 1200 mD) were measured in rudist-rich carbonates. In addition, some diagenetic features such as dolomitisation and dissolution have created additional pores and have clearly enhanced the reservoir potential of these rudist-rich carbonates. On the other side, some diagenetic processes such as cementation, silicification and compaction have led to the destruction of the pore system and the decrease of porosity and permeability values.