Reservoir Characteristics and Geomechanical Parameters Derived from Dipole Sonic log in the Asmari Formation, Ramshir Oil field, SW Iran

The present paper is an attempt to characterize the reservoir properties and calculate geomechanical parameters using dipole sonic log of the Asmari Formation, Ramshir oil field, SW Iran, as well as predict bit selection. The Asmari Formation is divided to 8 zones based on reservoir parameters. Moreover, zones 1, 2, and 3 (individual zone 2) are in production stage. To understand lithological changes of the reservoir, 300 thin sections were studied. It was defined 8 lithological facies including dolostone, clayey limestone, wackestone/packstone, grainstone, anhydrite, sandstone, shale/marl, and pyritic shale. These variations indicated that sedimentary environment changes from shallow marine, tidal flat, to lagoon. Dolomitization, recrystallization, micritization, pyritization and solution are dominant diagenetic processes. The variation of geomechanical parameters, which is proportional to lithofacies changes, can be considered as a key to determine possible reservoir properties changes and drilling potential as well. These parameters are coincided, indicating that the presence of heterogeneity and reservoir potential of upper part is higher than lower part of the Asmari Formation.