Background Helium is identified as a scarce strategic resource, having found widespread applications in high-tech fields such as high-end manufacturing, aerospace, and national defense due to its stable chemical properties and low boiling point. The Kuqa Depression in the Tarim Basin is a significant natural gas production base in China. Determining the distribution characteristics and controlling factors of helium in coal-measure natural gas in the Kuqa Depression holds great significance.

Methods Using two helium resource assessment methods and geological data, this study explored the dominant factors causing helium deficiency in the coal-measure natural gas in the Kuqa Depression.

Results and Conclusions The natural gas in the Kuqa Depression exhibits helium content (Volume fraction) ranging from 22×10⁻⁶ to 93×10⁻⁶ (average: 57.6×10⁻⁶), suggesting helium-deficient natural gas. Its ³He/⁴He ratios range from 3.33×10⁻⁸ to 11.24×10⁻⁸, indicating crust-derived helium. Helium in the natural gas originates primarily from the Jurassic coal-measure source rocks, with minimal contribution from the basement. The helium deficiency is predominantly governed by the regional structural evolution and the coupling effect of the helium- and hydrocarbon-generating intensities of coal-measure source rocks. In terms of structural evolution, differing from the discovered helium-rich gas fields, the Kuqa Depression has experienced continuous stratigraphic burial since the Himalayan, hindering the desorption and migration of helium. Regarding helium accumulation, the high hydrocarbon-generating intensity of coal-measure source rocks exerted a strong dilution effect on helium. Consequently, gas fields located in the hydrocarbon kitchen have a significantly lower helium content than those in the slope zone. The exploration of helium resources in coal-measure natural gas should focus on helium source rocks connecting the ancient basement, areas with strong regional tectonics and significant uplift of strata, and areas with weak natural gas charging and dilution. Exploration targets should be rationally selected according to helium accumulation conditions.