## 5 Discussion  
### Inhomogeneity of Helium Distribution  
Among the above three wells, helium was detected only in the HJQ-H501 well; so, we will mainly analyze this well. Since the mud gas is contaminated by atmospheric components during the degassing process, it is necessary to correct the measurement results considering the air pollution to determine the true helium concentration in the examined formation. It is generally believed that the reliability of the data is low when the total hydrocarbon concentration in the mud gas is less than 0.2%. Therefore, the corresponding value needs to be removed when correcting the helium concentration. The corrected helium concentration is indicated as He\({}_{\rm r}\) (%). After data processing, the helium detection results for the HJQ-H501 well are shown in Figure 9.  
It can be seen in Figure 9 that there was very good consistency between the helium concentration and the total hydrocarbon concentration. This was due to the fact that because of their small size and of the poor sealing of the capr  
Figure 9: Detection results for helium, C\({}_{1}\)–C\({}_{4}\), and total hydrocarbon components in the HJQ-H501 well. not remain isolated. Helium is usually coupled with hydrocarbon gases in reservoirs and further enriched in natural gas reservoirs. The helium concentration in the natural gas field in this area was tested by previous researchers, and the results showed that the average helium concentration in the Dongsheng gas field is higher than 0.1%, which, basically, is industrially valuable. Moreover, the Duguiijahan area has a higher helium concentration and, therefore, a greater potential for helium exploration and development [15; 21]. We used the helium detector to measure the helium concentration in the P1x section of the HJQ-H501 well in the Duguiijahan area, which was found to be about 0.27% \(\pm\) 0.0081%. This area has industrial value and can be classified as a helium-rich natural gas field (helium concentration between 0.15% and 0.5%, [PERSON] et al., 2017). The detection results are comparable to previous test results by other researchers in the same section of this area, which further verifies the stability of the helium detector in field drilling sites and the reliability of the data. Through further analysis, it can be seen in Figure S1 (the a-f layers in Figure S1 correspond to the a-f layers in Figure 9) that some non-natural gas layers showed a higher helium concentration, with an average of 1%, which is generally higher than the concentration in the P1x section (average 0.3%), far exceeding the helium industrial concentration standard. These layers mainly appeared in the Shiqianfeng Formation, Upper Shihezi Formation, and Lower Shihezi Formation. By analyzing the logging curves, it can be seen that the sandstone section had low natural gamma-ray values, negative spontaneous potential anomalies, and low neutron and interval transit time values. In contrast, the mudstone section showed properties opposite to those of the sandstone section, and resistivity was lower than in the adjacent sandstone section, making it easy to distinguish between sandstone and mudstone. Combining the analyses of lithology and helium concentration, it was found that there was an obvious positive correlation between them. Almost all high helium concentrations appeared in the sandstone section. This is because sandstone has higher porosity and better reservoir properties than mudstone, which usually forms reservoirs. It is worth noting that these sandstone sections appeared often overlain and underlain by mudstone, which is particularly obvious in Figure S1a,c,e,f, and the helium concentration showed an increasing trend in the sandstone sections sandwiched by mudstone. By observing the logging curves, it can be seen that the mudstone had a high natural gamma-ray value, indicating that the concentrations of uranium, thorium, and potassium were high. Helium in gas fields is mainly supplied by the mantle and the crust.