## 3 Results
### Determination of the Quantities of KL, PAM, and XC  
The parameters of the Herschel-Bulkley model (apparent viscosity, yield stress, flow behavior indices, and consistency coefficient), were used here to characterize the rheological properties of SFPDF. Table 3 shows the rheological characterization of different concentrations of the three types of polymer drilling fluids.  
The yield stress parameter of the Herschel-Bulkley model, which represents the actual yield stress of the fluid, is represented here as the minimum shear stress required for the fluid to flow. Since yield stress is not extrapolated, the meaning of the yield stress in the Bingham model is different from that of the Herschel-Bulkley model parameter. The size of the yield stress value is primarily associated with the type and concentration of polymer treatment agent. In addition, the solids content of the fluid certainly influences the yield stress. The KL drilling fluid and PAM drilling fluid exhibited similar yield stress, while yield stress of the XC drilling fluid system was much greater than that of the other two fluids, and it increased with increasing concentration (Table 3).  
Flow behavior indices (n) show that, within the scope of a certain shear rate, fluid behavior can be expressed by the strength of non-Newtonian forces. A smaller flow behavior index indicates a stronger Newton diagram of the drilling fluid and better performance of shear thinning. The value of the consistency coefficient (K) is associated with drilling fluid viscosity and yield stress. A larger consistency coefficient indicates greater viscosity. Excessively large consistency coefficients can cause problems in the opening of a pump; if the consistency coefficient is too small, the fluid may carry rocky debris, creating a disadvantage. The values of flow behavior indices are mainly influenced by the formation of space truss structures. The consistency coefficient value is influenced by the solid phase content of the system and the viscosity of the liquid, it is also influenced by the strength of the fluid space grid structure. The flow behavior indices of the three kinds of system drilling fluids analyzed in the present study are comparatively high, and the consistency coefficient increases with an increasing concentration of the fluid's active ingredient (Table 3).  
Suitable polymer concentrations [17] were determined as described in the analysis above, while considering the requirements of drilling in permafrost regions of the Qinghai Tibet Plateau for natural gas hydrate. That is, low-temperature SFPDF should be considered based on the findings of previous  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Fluid** & **Concentration** & **AV 1 (mPa*s)** & **YP 2 (Pa)** & \(n\)3 ** & **\(R^{2}\)5** & **SSE 6 (Pa2)** \\ \hline KL  & **SSE 6 (Pa2)** \\ \hline KL  & 0.2\% & 3.3 & 0.1 & 0.9 & 0.1 & 0.9958 & 0.039 \\ KL & 0.4\% & 6.0 & 0.1 & 0.9 & 0.1 & 0.9995 & 0.013 \\ KL & 0.6\% & 13.5 & 0.3 & 0.9 & 0.1 & 0.9989 & 0.127 \\ KL & 0.8\% & 38.0 & 0.3 & 0.6 & 0.7 & 0.9993 & 0.257 \\ PAM  & 0.2\% & 2.0 & 0.1 & 0.7 & 0.1 & 0.9958 & 0.038 \\ PAM & 0.4\% & 2.8 & 0.1 & 0.9 & 0.1 & 0.9985 & 0.026 \\ PAM & 0.6\% & 3.5 & 0.3 & 0.9 & 0.1 & 0.9975 & 0.013 \\ PAM & 0.8\% & 3.8 & 0.3 & 1.0 & 0.1 & 0.9983 & 0.007 \\ XC  & 0.2\% & 3.5 & 0.3 & 0.9 & 0.1 & 0.9979 & 0.01 \\ XC & 0.4\% & 10.5 & 0.5 & 0.7 & 0.1 & 0.9978 & 1.03 \\ XC & 0.6\% & 18.5 & 1.0 & 0.9 & 0.1 & 0.9926 & 1.015 \\ XC & 0.8\% & 28.8 & 3.6 & 0.6 & 0.4 & 0.9972 & 0.657 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Rheological parameters of different concentrations of polymer drilling fluid.  
studies. The amounts of added KL, PAM, and XC should be 0.8%, 0.4% and 0.8%, respectively, to create optimal drilling conditions; that is, drilling fluids showed suitable viscosities at these concentrations.