Unformatted text preview: ncreasing the mechanical energy (axial and torsional) trying to improve
the drilling performance. It was until the DSE tool was used to evaluate the drilling efficiency that the “abnormal” situation
was illuminated and correction were implemented.
The field data also suggest a good correlation between the DSE, calculated with downhole data, and the rock confined
strength while drilling at-balance. Recent published experimental data shows that the mud density affects the MSE by
increasing its values, even when the bit seems to be drilling efficiently.9 It is expected that this phenomenon would also be
true when using DSE to evaluate the drilling efficiency at overbalance conditions.
A novel correlation for Drilling Specific Energy (DSE) is presented. DSE can be defined as the work done to excavate and
remove underneath the bit a unit volume of rock. Teale’s original MSE equation was modified to include a particular bit
hydraulic-related term on the specific energy concept.
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- Spring '13