Coupling Mechanisms of Qualitative-Quantitative and Macro-Micro Analyses for Helium Reservoir Characteristics in Northern Huazhou Area, Weihe Basin

The North Huazhou area in Weihe Basin, a transition zone between the Ordos Block and Qinling Orogenic Belt, hosts multiple Cenozoic reservoirs critical for helium, geothermal, and tight oil/gas exploration. Based on Well H1 core, logging, and laboratory data, multi-scale analyses of the Sanmen, Zhangjiapo, Lantian-Bahe Formations, and Gaoling Group reveal significant lithological differentiations: the Zhangjiapo Formation is a medium-porosity, medium-permeability reservoir, whereas the Lantian-Bahe Formation exhibits low porosity and permeability. X-ray diffraction confirms dominant siliceous minerals with clay fluctuations reflecting strong hydrodynamic environments. Moderately strong velocity ($D_{\mathrm{v}} = 55.53%$) and acid sensitivity ($D_{\mathrm{ac}} = 57.68%$) necessitate reservoir-protective development strategies. The Lantian-Bahe gas-water zone (76.5\,m, 20.6%) displays dominant positive rhythms macroscopically, while residual intergranular and dissolution pores with sheet-like and necked throats restrict fluid flow microscopically. Noble gas isotopes ($^{4}\mathrm{He}/^{20}\mathrm{Ne} = 37{,}164$) confirm anomalous $^{4}\mathrm{He}$ from uranium-rich Qinling granites. A ``multi-source supply--fault transport--exsolution enrichment'' model is proposed, whereby coal-type gas drives helium exsolution from pore-fracture waters into the free gas phase. The Gaoling Group and Lantian-Bahe Formation are identified as primary targets, providing a geological basis for helium evaluation and multi-energy development in Weihe Basin.