Cost optimization, is a procedure, which its final goal is to reduce the cost by making the interfering parameters to the optimum level. In drilling operation, a large amount of saving in time and money will be achieved, by reducing the drilling time, since; some of the costs are time-dependent. Drilling time is reduced by increasing the rate of penetration. Rate of penetration is affected by many parameters such as hydraulics, weight on bit, rotary speed, bit type, mud properties, formation characteristics, etc. In this research, nine wells from Khangiran gas field were selected and by comparing drilling parameters in these wells, a primary optimization by comparison has been performed. Then, secondary optimization using mathematical techniques was applied to make drilling variables to the optimum level and give a computational optimized well. Finally, primary and secondary optimizations were combined together to reduce drilling rate and cost as much as possible.
An optimal well, which can improve drilling time 30 % to 180 % in relation to the wells, drilled and save a considerable amount of drilling cost was designed for Khangiran field after applying optimization techniques.
The significance of this research is to reduce the time and cost for drilling the next wells in Khangiran field. In addition, the same techniques can be applied in other hydrocarbon fields to reduce costs and time of drilling operation.