Abstarct: Drilling operations in the oil industry have a high value and is one of the most costly parts of this industry, so reducing costs and increasing efficiency in this industry has received a lot of attention. Drilling penetration rate is considered to be the main and important key in drilling operations. Drilling penetration rate is usually calculated in Cost Per Foot, which is affected by several factors, including bit, a drilling bit other than the direct cost, which is the price of the drill itself. Directly on other costs as well. This research has been done in one of the oilfield in the southwest of the country. In this research, the methods of calculating the cost per Foot drilling are mentioned and calculated. Since the method of calculating the cost per Foot drilling for selection bit is not a complete method, other complementary methods such as special energy method and drilling drillability have been discussed and a suitable drill with the most desirable parameters for drilling has been proposed. Various field parameters along with specific energy and drillability for drilling this formation were plotted and compared in logs by LogPlot software and drill performance and possible problems (Loss) in the well were analyzed and then field parameters in the baxse well by LogPlot software is drawn and baxsed on the selected bit, the best and most desirable parameters for drilling this formation are suggested. The results obtained from the cost per Foot in the most efficient bit in drilling operations and the most suitable and economical combination of drilling these drills with the reasons for selection and for the selected formation of this field has been proposed. Also, determining the optimal drilling parameters for the study formation in this area is mentioned, and finally, using the results of graphs and numerical comparisons, wells as baxse wells and bits as baxse bits, from both groups of synthetic diamond bits and rolling cone Button bits have been selected and the optimal drilling parameters have been proposed from the mentioned method to achieve the optimal drilling speed.