## 1 Introduction  
As a noble gas, helium is the lowest-melting-point and -boiling-point element known in nature. Due to its unique physical and chemical properties, helium is widely used in high-tech fields and applications such as nuclear industry, superconducting materials, medical treatments, aerospace, and so on. Especially in the ultra-low-temperature field (<1 k), helium has an irreplaceable position [1, 2]. Although helium is the second most abundant element in the universe, after hydrogen, accounting for approximately 24% of the total elemental mass of the universe, helium concentration on earth is very low, and this gas is in short supply. Statistics show that the global helium supply in 2021 was about 167 million m\({}^{3}\), while the demand was about 193 million m\({}^{3}\) in the same period, with a supply gap of about 26 million m\({}^{3}\)[3]. Furthermore, the United States, Canada, Russia,and other countries passed legislation to restrict helium exports, but the global helium demand is still growing at a rate of 4-6% per year, which further aggravates the global helium supply situation [1]. Up to now, no independently formed helium reservoir has been found. Helium is mainly coupled with hydrocarbon gas and sometimes with nitrogen and carbon dioxide [4; 5; 6; 7; 8; 9], and most of the world's commercial helium is extractfrom helium-rich natural gas reservoirs. Helium in helium-rich natural gas reservoirs is mainly generated by the radioactive decay of basement rocks, usually granite. Helium generated in a mineral lattice will enter the pore water. When gas passes through helium-containing pore water, helium dissolved in the water will enter the gas phase due to Henry's law and further migrate and accumulate with the gas. This theory emphasizes the importance of external gas extraction and migration of helium, which is usually used to explain the coexistence of hydrocarbon gas and helium [7; 10; 11; 12; 13]. However, under normal circumstances, the process of natural gas generation and accumulation often occurs in the overlying strata of a basement. Hydrocarbon gases cannot directly extract helium from basement granite. If there are no other free gases, helium in basement granite is difficult to extract and accumulate. Previous studies suggested that nitrogen and carbon dioxide play a key role in the extraction of helium from the pore water of basement rocks, but there are many helium-rich gas reservoirs with low nitrogen and carbon dioxide concentrations. The gas that promotes the migration of helium from pore water in these gas reservoirs is still unclear and needs to be studied. In the traditional exploration process, the detection of helium concentration in natural gas reservoirs requires collecting wellhead gas and sending it to the laboratory for analysis [14; 15]. Usually, only a specific layer is analyzed (usually, the hydrocarbon enrichment layer), and the continuous vertical helium concentration cannot be obtained. This will not only cause the waste of helium resources, but also restrict the study of helium migration and accumulation mechanisms. Moreover, the sampling container is usually a steel cylinder. Due to the leakage of the steel cylinder itself, if the sample cannot be tested in time after sampling, errors in the results will be inevitable. Therefore, in order to accurately measure the continuous vertical helium concentration, real-time detection is required during drilling. Since the mid-1990s, researchers have employed gas chromatography and mass spectrometry to detect gas compositions during geothermal well drilling processes [16; 17; 18; 19; 20]. Gas chromatography is utilized for detecting gases such as CO\({}_{2}\), CH\({}_{4}\), and H\({}_{2}\), while mass spectrometry is employed for detecting noble gases. In these studies, gas detection during drilling processes was primarily aimed at assessing potential gas hazards (typically, ATEX explosive atmospheres) and could also be utilized for monitoring fault fluid activities and underground fracture systems.