Abstract: In 2022, Hengshan gas field, the first large-scale limestone gas field in Taiyuan Formation, was discovered in Ordos Basin, with the cumulative proved and predicted natural gas reserves of over 2000×10⁸m³, thus achieving a breakthrough in natural gas exploration in tight limestone reservoirs in Taiyuan Formation of North China Platform. Based on the actual exploration and development of Hengshan gas field, the paper comprehensively analyzes the source rock conditions, favorable reservoir facies belts, transport systems and accumulating models for limestone gas reservoirs in Taiyuan Formation, and systematically summarizes key exploration and development technologies. The widespread hydrocarbon supply from the Carboniferous-Permian marine-continental coal rocks in Ordos Basin lays a solid material foundation for the limestone gas reservoirs in Taiyuan Formation. The widely distributed reservoir facies belts of bioclastic beach and bioherm and the three-dimensional network reservoir space composed of corrosion pores, nano-submicron intercrystalline micropores and fractures are the key geological conditions for hydrocarbon accumulation in the dense limestone gas field in Taiyuan Formation. The Permian Taiyuan Formation limestone in Hengshan gas field developed an in-source accumulating model of "reservoir control by bioclastic beach and bioherm, transport by fracture system, and hydrocarbon supply by coal rock", showing a sandwich structure. In order to achieve efficient exploration and development of limestone gas reservoirs in Taiyuan Formation, a series of key supporting technologies have been established, such as high-resolution seismic data processing and interpretation technology, tight limestone gas reservoir logging identification technology and horizontal well fracture network volume fracturing technology. The research has enriched the geological understandings and exploration thoughts of limestone gas reservoirs in Ordos Basin, and is of important reference significance for natural gas exploration in areas with similar geological conditions.

Key words: Hengshan gas field, Ordos Basin, Taiyuan Formation limestone, geological conditions for hydrocarbon accumulation, key exploration technologies

摘要： 2022年在鄂尔多斯盆地发现了第一个太原组灰岩大型气田——横山气田，累计提交天然气探明储量和预测储量超过2 000×10⁸m³，实现了华北地台太原组致密灰岩天然气勘探突破。基于横山气田的勘探开发实践，综合分析了太原组灰岩气藏的烃源岩条件、有利储集相带、输导体系及成藏模式，并系统总结了勘探开发关键技术。鄂尔多斯盆地石炭系—二叠系海陆交互相煤系烃源岩广覆式供烃为太原组灰岩气藏奠定了坚实的物质基础；生屑滩和生物丘有利储集相带大面积分布，溶蚀孔、纳米—亚微米级晶间微孔和裂缝构成立体网络储集空间，是形成太原组致密灰岩大气田的关键成藏地质条件。横山气田二叠系太原组灰岩发育"丘滩控储、断裂体系输导、煤岩供烃"的源内成藏模式，具"三明治"结构。为实现太原组灰岩气藏的高效勘探开发，探索形成了高分辨率地震资料处理解释技术、致密灰岩气层测井判识技术和水平井缝网体积压裂技术等关键配套技术。研究认识丰富了鄂尔多斯盆地灰岩气藏的地质认识和勘探思路，对地质条件相似的地区开展天然气勘探具有重要借鉴意义。

关键词: 横山气田, 鄂尔多斯盆地, 太原组灰岩, 成藏地质条件, 勘探关键技术