## 5 Engineering Application
### Luling Coal Mine of Huanbei Mine Area  
LG01 well cluster was constructed in Luling coal mine, Anhui Province, China [32]. The horizontal well was adjacent to the No. 8 coal seam, which was beneficial for creating transverse fractures during fracturing. The horizontal section length of the LG01-H well was 582 m. Hydraulic fracturing was conducted in seven stages while considering the distribution characteristics of the flat well section, the cementing quality. Perforation and isolation were efficiently implemented using the combined perforation and bridge plug technology, and a total of 6627 m\({}^{3}\) of fracturing fluid and 542 m\({}^{3}\) of quartz sand were injected in seven stages. The spacing between each stage was between 70 m and 90 m. The maximum injection displacement was 10 m\({}^{3}\)/min. The maximum construction pump pressure was 27 MPa. The average sand volume was 77 m\({}^{3}\) per stage, and the average fracturing fluid injection was 947 m\({}^{3}\) per stage. The fracturing construction parameters are shown in Table 6. The microseismic monitoring technology was used during the fracturing construction to monitor the fracture shape. The total length of central fractures in the first stage was 169.1 m, averaging 84.6 m per wing. The total fracture length in the fourth stage was 163.2 m, averaging 81.6 m per wing, as shown in Figure 18. Both fractures extended slightly more towards the east flank. The height of the primary fractures in the first stage was 20.5 m. The height of the main fractures in the second stage was 17.6 m, and the shape of the prominent fractures in both stages was vertical, as shown in Figure 19. The monitoring results of the microseismic fracture length are shown in Table 7. The roof fractures can cross over into the coal and  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Section Sequence**} & \multicolumn{2}{c}{**Hydraulic**} & \multirow{2}{*}{**Sand Total/m\({}^{3}\)**} & \multirow{2}{*}{**Average Pump**} & \multirow{2}{*}{**Average Sand**} & \multirow{2}{*}{**Average**} \\  & **Fracturing** & & & & \\  & **Liquid Volume/m\({}^{3}\)** & & & & \\ \hline
1 & 979 & 63.8 & 30.9 & 9.27 & 10.0 \\
2 & 976 & 65.5 & 24.4 & 9.77 & 10.0 \\
3 & 927 & 78.8 & 22.9 & 13.19 & 10.0 \\
4 & 920 & 80.0 & 21.8 & 13.37 & 9.50 \\
5 & 1019 & 86.9 & 26.7 & 12.48 &extend for a long distance. The fracturing with specific conductivity communicates the coal seam with the horizontal wellbore and transforms the reservoir. The LG01 horizontal well group started to discharge and produce on 19 January 2015. The daily coalbed methane production was stable at more than 10,000 m\({}^{3}\) for 92 consecutive days, and the average daily co \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Section** & **Orientation/\({}^{p}\)** & **Total Fracture** & **East Wing** & **West Wing** & & & \\
**Sequence** & & **Length/m** & **Fracture** & **Fracture** & **Fracture** & **Height/m** & **Inclination Angle/\({}^{\circ}\)** \\ \hline
1 & 45.2 & 169.1 & 90.5 & 78.6 & 20.5 & 2 \\
4 & 46.1 & 163.2 & 89.8 & 73.4 & 17.6 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Statistical table of microseismic monitoring for fracture lengths in LG01-H horizontal well. Figure 19: Profile of microseismic monitoring for fractures in LG01 well. Figure 18: Fracture orientation and length of LG01 well. The cumulative coalbed methane production of the single well was 590 \(\times\) 10\({}^{4}\) m\({}^{3}\), with considerable safety and economic benefits (Figure 20). It also created the record for the highest daily coalbed methane production in China's broken and soft coal seam with weak permeability. [PERSON] predicted the effect of the LG01 horizontal well extraction over a period of five years. The average gas content within the control range of the horizontal well can be reduced to 4.2 cubic meters per ton, which was a decrease of 4.3 cubic meters per ton, 50.6% compared to the initial value of 8.5 cubic meters per ton.