# Eccentric Wear Mechanism and Centralizer Layout Design in 3D Curved Wellbores
## 4 Comparative Analysis of Application Cases
### Experiment Case 2. A2# Oil Well Engineering Design  
Application example 2 is A2# well of an oil production plant in Daqing Oilfield. The parameters are shown in Tables 1-3. The matching pump depth is 992.33 m, and the pump type is \(\varphi\) 57 mm; the inner diameter of the oil pipe is 0.076 m. The length of the sucker rod is 971.41 m, the stroke of the sucker pumping unit is 4.2 m, and the frequency of strokes is 4 times/min (as shown in Table 4). The production performance of oil well A2# under the traditional centraliser design method is as follows (as shown in Table 5): This well employs a pumping system with a stroke length of 4.20 m, a pump diameter of 70 mm, and a stroke frequency of 4.00 Hz, with a pump setting depth of 992.3 m. Under these design conditions, the pump efficiency is 39.8%, the system efficiency is 33.4%, and the daily liquid production is 36.39 m\({}^{3}\). The dynamic liquid level depth is 961.88 m, with a submergence depth of only 30.45 m. Overall, \begin{table}
\begin{tabular}{c c c} \hline \hline
**Specific Elements** & **Unit** & **Data** \\ \hline Medium-deep oil layer & m & 1057 \\ Relative density of crude oil & \% & 85 \\ Production gas oil ratio & m\({}^{3}\)/m\({}^{3}\) & 10.0 \\ Casing inner diameter & mm & 124.0 \\ Formation pressure & MPa & 10 \\ Relative density of formation water & \% & 100 \\ Water cut & \% & 89 \\ Inner diameter of oil pipe & mm & 76.0 \\ Reservoir temperature & \({}^{\circ}\)C & 53.35 \\ Relative density of natural gas & \% & 70 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Basic design parameters of oil wells (oil well A2#). Figure 8: Design results of SRS along well depth (A1# well). (**a**) Maximum load distribution along well depth; (**b**) minimum load distribution along well depth; (**c**) lateral force distribution of SRS; (**d**) number of centralisers distributed along well depth. the production performance under the traditional centraliser design method demonstrates relatively low pump efficiency and system efficiency, along with insufficient submergence depth, which may affect the stable operation of the pump and production efficiency. There is potential for further optimisation. The production status of oil well A2# under the centraliser design measures proposed in this paper is as follows (as shown in Table 6): This well utilises an oil extraction system with a stroke length of 4.20 m, a pump diameter of 57 mm, and a stroke frequency of 4.00 Hz, with the pump set at a depth of 992.3 m. Under these design conditions, the pump efficiency has significantly improved to 58.9%, and system efficiency has increased to 35%, while the daily liquid production remains at 36.39 m\({}^{3}\). The dynamic liquid level has risen to 700 m, and the submergence depth has increased to 292.33 m. The maximum load is 51.23 kN, and the minimum load is 14.25 kN. Overall, the design measures presented in this paper have optimised the arrangement of the centralisers, significantly enhancing pump efficiency and system efficiency, improving the submergence depth, reducing the operational risks of the pump, and increasing production stability and efficiency. Comparing the production performance of oil well A2# under the traditional design method and the design method proposed in this study, the changes in various parameters are as follows: Pump efficiency increased by 19.1 percentage points; system efficiency improved by 1.6 percentage points, with a relatively small increase; the dynamic liquid level depth significantly rose from 961.88 m to 700 m, with the submergence depth increasing nearly 9.6 times; the maximum load decreased by 9.24%, indicating a more reasonable force distribution in the rod string. The design method proposed in this study has significantly