Evaluation of under balance drilling using an intelligent system

Under balance drilling often in order to reduce formation damage, lost circulation reduction and increase the rate of penetration is investigated. Wellbore instability due to high expenses and personnel likely to endanger the drilling, a major concern in the oil and gas industry will be created. Wellbore instability with under balance drilling has a direct relationship, so that the main requirement for Evaluation of under balance drilling wellbore stability, is wellbore stability.in this paper, the wellbore stability in one of oil fields of Iran by Adaptive Neural Fuzzy Inference System for Evaluation of under balance drilling has been evaluated. The results showed that to achieve this goal, using this system is well suited and could predict valuable and accurate results. Finally, it was concluded that there is a mean square error between experimental data and predicted model which are 0.002136 and 0.00006038 for training data and test data, respectively.