# Dynamic Prediction of Shale Gas Drilling Costs Based on Machine Learning
## 4 Experiments and Results
### Economic Analysis of Investment in Selected Drilling Wells in the Changing Block  
The Changing Block is located at the southern edge of Sichuan Province, with an east-west length of about 90 km and a north-south width of about 49 km, in the hinterland of Yibin City, as shown in Figure 8. Tectonically, the Changing block belongs to the Sichuan-Guizhou combination at the western edge of the Yangzi plate and is under the joint control of the tectonic development of the southwest Loushan fold belt outside the basin and the southern Sichuan low fold belt inside the basin. The Changning area has undergone many periods of tectonic movements of varying intensities, among which the orogenic movements since the Yanshan period have resulted in the development of  
Figure 7: Three models fitting effects. (**a**) SVM Model, (**b**) LSTM Model, (**c**) LSTM_SVM_Stacking Model.  
a series of fold deformations and fractures in the area. The Changing backslope is a large-scale fold deformation structure under the complex tectonic background and. due to the different tectonic stresses, different parts of the backslope also show obvious differences. The two wings of the backslope show obvious asymmetric features, with the south and west wings being gentler and the north and east wings being steeper. Under extrusion stress, the Changing backslope develops a series of backslope-related fractures, which are mainly small-scale reverse faults. Compared with the stable area in the basin, the Wufeng-Longmaxi formation in this area is relatively shallow in depth, with a high degree of fracture and fold development, and the local favourable tectonic development sites in the context of tectonic activities are the main targets for shale gas exploration.  
The rapid urbanisation in recent years has led to an increasing demand for natural gas supply. In order to meet the natural gas production targets and capacity building requirements in Sichuan Province, the expeditious construction and implementation of the Changing H3 Test Mine Gas Collection and Transmission Project has become imperative. This project has significant implications for enhancing clean energy supply, optimising economic benefits for enterprises and facilitating socio-economic development. It also contributes to the transformation of the regional energy structure and atmospheric environmental quality through the increased utilisation of clean energy resources.  
Based on comprehensive geological assessments, including reservoir conditions, tectonic fracture characteristics, drilling result analysis and surface topographic evaluation of the Longmaxi Formation shale in the Ning 201 and Ning 209 well areas, 20 shale gas wells (e.g., Ning 209H70-3) have been successfully completed in the Changing Block. These wells serve as analysis and verification objects for shale gas exploration and development.  
The analysis results shown in Figure 9 indicate that the prediction model has satisfactory overall performance, achieving a Mean Absolute Percentage Error (MAPE) of 6.41%. The model shows optimal accuracy in predicting medium investment ranges (60-70 million yuan), with a correlation coefficient of 0.73, indicating robust tracking of actual value trends. However, several limitations were identified: (1) reduced ability to predict extreme values, especially in the lower range; (2) reduced amplitude of predicted value fluctuations compared to actual values; (3) delayed response to abrupt changes; and (4) reduced prediction accuracy in extreme scenarios, suggesting a tendency to underestimate risk. Nevertheless, the model retains reliable utility within median ranges, where predictive risk remains minimal.  
Figure 8: Location of the Changing Block.