Main Article Content
Drilling is an important and expensive operation necessary for the exploration and exploitation of oil resources. One of the important goals of drilling operations is to achieve higher drilling speeds at a lower cost while maintaining safety. In drilling operations, the time and efficiency of the operation are of great importance as factors that are directly related to drilling costs. One of the criteria for the efficiency of drilling operations is the penetration rate of the drilling rig. Estimating this parameter and knowing it when planning to drill a well can help to more accurately assess the drilling time and estimate its cost. Also, a reasonable knowledge of the physical and mechanical properties of the rock and the proper selection of drilling operation parameters will help a lot in reducing drilling and production costs. In this study, in order to investigate the factors affecting the penetration rate, the most important effective factors were two categories of controllable (operational) and uncontrollable (environmental) factors. Obtaining a model that can find the relationship between these factors and the penetration rate has always been of particular importance. However, the mathematical modes presented in this regard have focused more on controllable and operational factors. The complexity of the drill-rock interaction as well as the combined effect of the factors affecting the penetration rate has made that conventional methods are not able to fully analyze and predict the penetration rate. The main reason for this can be related to the numerous factors affecting the penetration rate and on the other hand the interaction between these factors. To overcome this problem, the Rock engineering systems (RES) approach has been used. In order to investigate the effect of factors affecting the infiltration rate, the information of one of the wells in Majnoon oil field has been used. In this regard, first the factors affecting the penetration rate are identified and then using the approach of Rock engineering systems (RES) an index called the penetration index (PI) is predicted. The results show that in the study area, depths of 2728 and 3574 meters have the highest and lowest penetration indices, respectively. Also, among the factors affecting the penetration rate, the porosity factor was recognized as the most influential factor on the penetration rate.