Modeling of Pipe Friction and Smear Effect in Drilling Operations

The increased complexity of drilling programs has led to the development of new drilling techniques and has resulted in problems that were not encountered before. This study focuses on two such issues: 1) to model the influence of wellbore friction on downhole temperatures of the drilling fluid, 2) to understand the smear effect mechanism observed in a casing while drilling operation through mathematical studies.

An analytical model has been proposed to estimate the increase in downhole wellbore temperatures during a drilling activity and subsequently validated for a deviated and a horizontal well using real-time data measured in the field. The contribution of wellbore temperatures and plugging of micro-fractures towards improving the fracture gradient of the formation has then been analyzed using quantitative studies aiming to provide a physical insight into the smear effect mechanism. Various parametric analyses have also been presented to help optimize future drilling programs.