Modeling and Control Evaluation of Manage Pressure Drilling of Oil Wells

Andre Alonso Fernandes¹; Marco Antonio Meggiolaro¹

¹ PUC-Rio

doi:10.20906/CPS/COB-2015-0822

Resumo

The drilling of oil wells involves basically the same technology since the 19th century. Drilling consists of running in hole a series of connected drillpipes (DPs) and to pump fluid (mud) through the DP, while weight and rotation are transmitted to the drillstring. The fluid pumped through the interior of the DPs not only is responsible for bringing the cuttings to the surface, but it also consists of the primary barrier against influxes from the well, being also responsible for stabilizing the walls of the open hole. The stabilization of the open hole and hindering influxes from the fluid are due to the density property. The fluid density is responsible for the hydrostatic pressure within the wellbore. The difference between the minimum and maximum pressure allowable for a given depth is called the operating window. Being the pressure in the well within the operating window, problems with influxes and hole stabilization are not expected. Some new oilfields as well as some depleted fields are experiencing severe operational restrictions due to small operational windows. The open hole pressure variation due to friction losses on the annular in some cases is greater than the operational window, inhibiting the perforation of the well. Manage Pressure Drilling (MPD) is an alternative technology to conventional drilling. The annular of the well is sealed while pressure is contained within it. By adjusting annular pressure it is possible to compensate for friction loss variation on the annular and drill well sections with close operational windows. In order to achieve proper control of surface pressure and downhole pressure, the modeling and control of the MPD system must be accurate and fast enough to face operational needs. Therefore, their evaluation is important to identify key points of this new technology, as detailed in this work.

Palavras-chave: Drilling; MPD; Modeling; Control