横山气田的勘探突破，证实鄂尔多斯盆地中东部二叠系太原组灰岩具备规模成藏潜力。系统分析太原组灰岩天然气成藏地质条件，揭示其“三明治”式成藏模式：山西组5^#煤岩与本溪组8^#煤岩为气源岩，与灰岩储层紧密接触，形成“源-储-源”夹置结构，高源储压差（8~12 MPa）驱动天然气高效充注。生屑滩（孔隙度2.6%，厚度4~10 m）与生物丘（溶蚀孔发育，厚度2~6 m）为两类优质储层，裂缝与准同生岩溶作用共同改善储集性能。优选容积法、小面元容积法、资源丰度类比法和盆地模拟法4种方法估算资源量，并采用特尔菲法综合评价太原组灰岩天然气原地资源量为1.553 5×10¹² m³，剩余待探明资源量达1.544 7×10¹² m³，其中生屑滩相带富集程度最高（占比53.1%），是优先勘探方向。研究可为鄂尔多斯盆地天然气增储上产及同类碳酸盐岩致密气藏评价提供重要依据。

The exploration breakthrough of the Hengshan Gasfield in the Permian Taiyuan Formation limestone, regarded as a non-effective reservoir in a long term, has demonstrated its significant accumulation potential in the central-eastern Ordos Basin. This study systematically analyzes the geological conditions controlling natural gas accumulation and reveals a "sandwich-type" accumulation model, in which the coal seams of No. 5 in the Shanxi Formation and No. 8 in the Benxi Formation respectively served as source rocks, directly contact the limestone reservoir, and a high source-reservoir pressure difference about 8-12 MPa drives efficient gas charging. Bioclastic shoals (porosity of 2.6%, and thickness of 4-10 m) and bioherms (thickness of 2-6 m, dissolution pores developed) are identified as high-quality reservoirs, with fractures and penecontemporaneous karstification jointly improving reservoir performance. By integrating the volumetric method, small-element volumetric method, resource abundance analogy, and basin modeling, the total in-place natural gas resources of the Taiyuan Formation limestone are estimated at 1.553 5×10¹² m³, with the remaining unproven resources amounting to 1.544 7×10¹² m³. The bioclastic shoal facies has the highest enrichment (about 53.1% of the remaining unproven resources), being the priority exploration target. This study provides a critical basis for increasing natural gas reserves and production in the Ordos Basin and for evaluating similar tight carbonate gas reservoirs.