## 3 Results
### Rheological Properties with Temperature Response Characteristics of SFPDF
3.2 Addition of GC Treatment Agent and the Rheological Properties with Temperature Response Characteristics of SFPDF  
Several research units cooperated to develop GC with the goal of solving problems inherent in drilling fluid systems used in permafrost regions in the Qinghai-Tibetan Plateau involving cryogenic technology to extract natural gas hydrate. The GC treatment agent (Based on the previous research foundation, the amount of 0.6% was identified) was combined with the three types of polymer drilling fluid described above to produce particular samples. These samples were adjusted to optimize the overall performance of the polymer drilling fluid. The results of adding GC polymer to drilling fluid samples were as follows:  
Sample 4: 1 L H\({}_{2}\)O + 15% NaCl + 0.5% NaOH + 0.8% KL + 0.6% GC  
Sample 5: 1 L H\({}_{2}\)O + 15% NaCl + 0.5% NaOH + 0.4% PAM + 0.6% GC  
Sample 6: 1 L H\({}_{2}\)O + 15% NaCl + 0.5% NaOH + 0.8% XC + 0.6% GC  
The drilling fluid samples were analyzed for rheological properties with respect to their temperature response after the addition of a GC treatment agent and was determined, as shown in Figure 4.  
Using the same method, by comparing the distribution of the residual in different functions, the curves in Figure 4 were used to select and fit functions that were close to a normal distribution (Table 6). Figure 4 shows the following:  
(1) The addition of GC had a pronounced effect on the apparent viscosity of the three kinds of polymer drilling fluid. The performance of the samples could be ranked as: Sample 4 > Sample 6 > Sample 5. As temperature decreased, the apparent viscosity of drilling fluid increased. Although overall viscosity was high, with respect to Figure 3a, after addition of the GC treatment agent, as the temperature decreases, the increasing trend of the drilling fluid viscosity is smaller, especially in the XC drilling fluid, where the temperature change has very little impact on the viscosity of the drilling fluid. Perhaps some kind of cross-linking between the polymers caused the temperature resistance \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
**Parameter** & **AV\({}^{1}\)** & \(R^{2.1}\) & **SSE\({}^{3}\)** & **by \({}^{4}\)** & \(R^{2}\)** & **SSE** & **n\({}^{5}\)** & **R\({}^{2}\)** & **SSE** & **K\({}^{*}\)** & **R\({}^{2}\)** & **SSE** \\ \hline Sample 4 & y \(-\)85.07 \(-\)1.39x & 0.97 & 1.21 & \(y\)\(-\)4.49 \(-\)0.11x & 0.929 & 0.47 & \(y\)\(-\)0.57 \(-\)0.10x\({}^{-}\) & 0.938 & 0.03 & y \(-\)14\({}^{\prime}\) + 0.04x & 0.985 & 0.09 \\  & & & & & & & & & & & & \\ \hline Sample 5 & y \(-\)11.71 \(-\)0.25x & 0.978 & 0.61 & \(y\)\(-\)0.16 \(-\)0.01x & 0.972 & 0.02 & \(y\)\(-\)0.02 & \(y\)\(-\)0.02 & \(y\)\(-\)0.018 & \(y\)\(-\)0.018 & 0.02 \\  & & & & & & & & & & & & \\ \hline Sample 6 & y \(-\)51.65 \(-\)0.54x & 0.984 & 1.15 & \(y\)\(-\)9.57 \(-\)0.04x & 0.995 & 0.31 & \(y\)\(-\)0.52 \(+\)0.01x\({}^{-}\) & 0.963 & 0.03 & \(y\)\(-\)0.039 \(-\)0.06x & 0.02 & 0.02 \\  & & & & & & & & & & & & \\ \hline \hline \end{tabular} \({}^{1}\) apparent viscosity; \({}^{2}\) goodness-of-fit; \({}^{3}\) the sum of square errors; \({}^{4}\) yield stress; \({}^{5}\) flow behavior index; \({}^{6}\) consistency coefficient.  
\end{table} 
Table 6: Rheological properties with temperature characteristic equations of the SFPDF containing GC. ability to enhance after the addition of the GC treatment agent. Because the GC treatment agent was added in drilling fluid, the concentration of the polymer in the drilling fluids increased and the viscosity increased. (2) The drilling fluid could be ranked by yield stress as: Sample 6 > Sample 4 > Sample 5. However, after addition of GC, these three systems of polymer drilling fluids showed only small increases in yield stress as the temperature decreased. After the GC treatment agent added in drilling fluid, as the temperature decreases, the grid structure between the polymers in the drilling fluid became more stable, the result is that the yield stress is also more stable.