## 3 Results
### Physics-Based Simulation Results
#### 3.1.2 Result 2  
The second computer simulation results were based on the drilling fluids shown in Figure 4. The examples displayed in Figure 13a,b are for the 80:20 and 90:10 OBMs filled in a deviated well, respectively. The 80:20 OBM results show that BP and RS swabbing and surging speed predictions were nearly equal and differed from the power law model for both fluid systems. However, deviations of the power law for swabbing were not consistent. Another observation was that for the 90:10 OBM, the surging speed for the flow  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Swabbing**} & \multicolumn{2}{c}{**Surging**} \\ \cline{2-5}
**OBM/Well/Density** & \% BP to PL** & \% BP to RS** & \% BP to PL** & \% BP to RS** \\  & **Change** & **Change** & **Change** & **Change** \\ \hline
90:10 Inclined 1.96 sg & 0.14 & \(-\)1.58 & \(-\)3.09 & \(-\)2.84 \\
80:20 Inclined 1.96 sg & 2.73 & \(-\)2.10 & 1.34 & \(-\)0.15 \\
90:10 Vertical 1.96 sg & 1.16 & \(-\)1.60 & \(-\)2.36 & \(-\)2.80 \\
80:20 Vertical 1.96 sg & \(-\)0.61 & \(-\)3.53 & \(-\)1.49 & \(-\)0.23 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Comparisons of 80:20 and 90:10 OBMs (from Figures 11 and 12, respectively) with 1.96 sg density in vertical and inclined wells.  
Figure 12: Surging comparisons of 1.96 sg 80:20 and 90:10 OBMs filled in deviated and vertical wells.  
rate increments up to 300-400 lpm exhibited unexpected increases. For analysis purposes, the swabbing speeds (at 600 lpm) and surging speeds (no circulation) were considered; the results are displayed in Figures 14-17.  
Similarly, the percentile deviations of the swabbing and surging speed predicted by the PL and RS models (i.e., Figures 14-17) were compared with the BP model. The comparisons are provided in Tables 7 and 8. In the deviated well filled with 2.0 sg 80:20 and 90:10 OBM, the results showed that the swab and surge speed predictions of the BP and RS is quite similar, recording less than 0.7% deviation. However, in the well filled with 80:20 OBM, the BP model's swab and surge percentile deviations from PL records were 14% and 18.8%, respectively. Similarly, the results obtained from the 90:10 OBM fluid showed \(-\)4.8% and 9.3% deviations, respectively. Table 8 also shows the results obtained from the 1.96 sg drilling fluids (80:20 and 90:10 OBM) filled in vertical and inclined wells. The results also show that the deviation of the BP from the RS was relatively lower than from the PL model.  
Figure 14: Swabbing comparisons of 2.0 sg 80:20 and 90:10 OBMs filled in deviated and vertical wells.  
Figure 13: (**a**) Example of swabbing and surging effects of 2.0 sg 80:20 OBM filled in a deviated well. (**b**) Example of swabbing and surging effects of 2.0 sg 90:10 OBM filled in a deviated well.  
Figure 16: Swabbing comparisons of 2.0 sg 80:20 and 90:10 OBMs filled in deviated and vertical wells.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Swabbing**} & \multicolumn{2}{c}{**Surging**} \\ \cline{2-5}
**OBM/Well/Density** & \multicolumn{1}{c}{**\% BP to PL**} & \multicolumn{1}{c}{**\% BP to RS**} & \multicolumn{1}{c}{**\% BP to PL**} & \multicolumn{1}{c}{**\% BP to RS**} \\  & **Change** & **Change** & **Change** & **Change** \\ \hline
90:10 Inclined 2.0 sg & \(-4.77\) & \(0.30\) & \(9.28\) & \(-0.70\) \\
80:20 Inclined 2.0 sg & \(14.00\) & \(0.00\) & \(18.83\) & \(-0.65\) \\
90:10 Vertical 2.0 sg & \(1.97\) & \(4.82\) & \(-3.06\) & \(-2.97\) \\
80:20 Vertical 2.0 sg & \(13.12\) & \(-0.50\) & \(-0.76\) & \(0.30\) \\ \hline \hline \end{tabular}
\end{table}
Table 7: Comparisons of 80:20 and 90:10 OBMs (from Figures 14 and 15, respectively) with 2.0 sg density in vertical and inclined wells.  
Figure 15: Surging comparisons of 2.0 sg 80:20 and 90:10 OBMs filled in deviated and vertical wells.