Abstarct: Hydraulic fracturing Treatment (HFT) is a common stimulation technology which is being used to enhance hydrocarbon production and recovery factor consequently. Selecting a target well/ laxyer is considered the first stage for a successful HFT and is regarded as a critical decision in the whole process of the execution of HFT. Through candidate well/laxyer selection, identification and selection of suitable well/ laxyer will be done considering enough chance of higher production after stimulation job. However, generally no comprehensive method which is reliable for different situations and geological settings has been defined so far. In addition, for fracturing carbonate formations, the possibility of the existence of natural fractures and rock stiffness can be challenging. In this research three wells in the one of Iranian carbonate reservoir have been studied. Mechanical earth model (MEM) consist of elastic moduli, magnitude and direction of stresses, pore pressure profile has been made. Also in order to assess the validity of the MEM, a failure analysis was performed by using image logs. The MEM failure prediction was compared to actual events identified throughout the wells and accuracy of the model was confirmed. For constructing of MEM, having shear velocity data is necessary. However, in practice the shear sonic is not included in the set of acquired logs for cost saving purposes. Hence, lots of methods have been developed to estimate these data using other available informations of reservoir. In this study, petrophysical properties affecting shear wave velocity was determined. Then by using multiple regression and considering compressive wave velocity, neutron porosity (NPHI) and density (RHOB) as independent variables, shear wave velocity was estimated. Moreover coefficients of regression was optimized by using particle swarm optimization (PSO) algorithm. In this study, at first a new definition of fracability index, the Total Fracability Index (TFI), has been proposed. The TFI is a function of Young’s modulus, mineralogical brittleness, internal friction angle, minimum horizontal stress, and horizontal stress contrast. Then according to previous researches and field experiences four main criteria consist of the TFI, Natural Fracture Index (NFI), laxyer thickness, and fracture containment capability considered for selecting candidate laxyers. At the end, by using these criteria and baxsed on analytic hierarchy process (AHP) mathematical modelling, candidate laxyers in three wells in Bangestan reservoir of Ahwaz oilfield are selected. Results shows that laxyers C1 and C2 in Ilam formation and laxyers E1 and E2 in Sarvak formation are best candidates for hydraulic fracturing.