**2.2 Comparing corrected MSE from surface drilling data to downhole measured MSE**

**Figure 1** shows an example from the Gulf of Mexico data set where Majidi et al. [7] emphasized the importance of using the downhole torque measurements as the torque term in the MSE often dominates the WOB term (see Eq. (1)). The discrepancy between MSE from uncorrected surface data and from the use of downhole measurements is clear in **Figure 1**. Using all the available drilling information, the frictional losses are estimated in order to compute the CMSE. The similarity between Majidi et al. [7] MSE from downhole measurements and the results computed from corrected surface drilling data is illustrated in **Figure 1**. Using the CMSE approach where surface drilling data are corrected for friction losses, results qualitatively comparable to measured downhole MSE can be derived. This opportunity leads to a reasonable estimation of mechanical rock properties at any well using commonly available surface drilling data thus circumventing the major problem of lack of well data in unconventional reservoirs.
