Challenges and Considerations in A Tripping Operation: The Need for An Advanced Control

The operation of oil well drilling is essential for the production of oil and gas, it is the key process in oil and gas production and exploration industry. The drilling activity is challenging due to many uncertainties in the geological aspect and unknown behavior of the drill string while interacting with a downhole formation. In tripping operation, the axial speed of the drill string can be critical since it generates pressure surge or swab. Surge and swab pressures become very critical in wells having small window pressure between pore and fracture pressure. This surge or swab pressure must be controlled to prevent drilling problems such as lost circulation, wellbore damage, gas kick, and blowout. In order to control the axial velocity of a drill string, an accurate drill string dynamic model is necessary. This model must be able to represent the main dynamics of the real drill string. Another model that is also important is a pressure dynamic model that describes the dynamic of mud pressure changes in a wellbore due to axial movement of the drill string. The challenges and considerations in tripping operations are mentioned. This study will enhance the understanding of drilling problems due to surge or swab pressures and its corresponding mathematical model representation. Simulation and its results are presented in the final section of this paper. It shows the possibility to estimate the downhole pressure by using surface data and shows that there is a coupling between an axial movement of the drill string and pressure changes in the bottom hole.