Influence of Frictional or Rotational Kinetic Energy on Wellbore-Fluid/Temperature Profiles During Drilling Operations

Abstract

Summary Temperature-profile distributions in a wellbore during drilling operations might take different forms when applying the energy balance in the overall system. For steady-state conditions, wherein the wellbore is considered a closed system, adding any source of additional energy to this system can influence the predicted temperature profiles. This study presents a new analytical model to investigate the influence of rotational energy arising from the drillstring operation on the wellbore-temperature behavior. A significant part of the drilling operation is rotation of the drillstring. Depending on the drilling rig, various equipment provides this kind of energy, such as the rotary table or topdrive. In addition, downhole motors or turbines can add additional rotation to the drill bit. This type of energy source can be construed as a supplemental heat source that could be added to the formulations of drillpipe- and annular-temperature profiles. Overall, this study presents two models involving frictional and rotational energy. These models yield the same solution if we do not include the energy source, and they can apply equally well for any energy-balance system. The proposed mathematical models provide new insights into different energy terms that can be included to compute the temperature profiles in the drillpipe and annulus.