天然气工业2025，Vol.45Issue(12)：53-65,13.DOI:10.3787/j.issn.1000-0976.2025.12.005
常规-致密过渡型砂岩气地质特征与成藏机制
Geological characteristics and hydrocarbon accumulation mechanisms of conventional-tight transitional sandstone gas reservoirs:A case study of the Xujiahe Formation and Shaximiao Formation in the Sichuan Basin
摘要
Abstract
In recent years,the exploration and development of continental tight sandstone gas in the Sichuan Basin has progressed significantly,becoming a new growth pole for the efficient exploitation of natural gas in the basin.Nonetheless,the operations in the Upper Triassic Xujiahe Formation and Middle Jurassic Shaximiao Formation are challenged by some key scientific issues,such as unclear gas accumulation mechanism and complex gas-water distribution.Based on the results of core porosity/permeability tests and logging interpretation,the characteristics of conventional-tight transitional sandstone gas reservoirs in the Xujiahe Formation and Shaximiao Formation were analyzed,and a new concept of"conventional-tight transitional sandstone gas"was proposed.Furthermore,the gas accumulation mechanism and process were discussed to clarify the gas-water distribution.The following results are obtained.First,the physical property parameters of some sandstone reservoirs in the Xujiahe Formation and Shaximiao Formation override the tight sandstone definition criterion,i.e.air permeability=1.0×10-3μm2,resulting in the loss of self-sealing capacity of the reservoirs,which can be defined as conventional-tight transitional sandstone.Second,during the gas accumulation in conventional-tight transitional sandstone,there is a conversion process of dynamic mechanism from hydrocarbon generation-induced expansion force driving to buoyancy driving.The complex gas accumulation mechanism is the key reason for the complex pattern of gas-water distribution in the reservoirs in the Xujiahe Formation to Shaximiao Formation.Third,the process of tight sandstone gas accumulation exists with charging threshold and release threshold,with the former deciding how difficult the gas enters into tight reservoirs and the latter giving the upper limit of self-sealing of tight reservoirs.Fourth,the reservoirs from the Xujiahe Formation to Shaximiao Formation have the physical properties overriding the lower limit of buoyancy-driven accumulation.The Xujiahe Formation is located in the lower part(though closer to the source rock),and the Shaximiao Formation is located in the upper part.During the long-term reservoir-forming adjustment process,there is a differentiation trend of"gas surging upward and water seeping downward".It is concluded that the proposed concept of transitional sandstone gas enriches and supplements the theory of whole petroleum system.The cross-boundary physical property characteristics of conventional-tight transitional reservoirs are advantageous for being conducive to high production in the Shaximiao Formation,but disadvantageous due to complex gas-water distribution in the Xujiahe Formation.关键词
四川盆地/上三叠统须家河组/中侏罗统沙溪庙组/常规-致密过渡型砂岩气/储层特征/天然气成藏机制/气水关系Key words
Sichuan Basin/Upper Triassic Xujiahe Formation/Middle Jurassic Shaximiao Formation/Conventional-tight transitional sandstone gas/Reservoir characteristic/Gas accumulation mechanism/Gas-water distribution分类
能源科技引用本文复制引用
贾承造,赵文,宋岩,姜林,付晓飞,程丽娟..常规-致密过渡型砂岩气地质特征与成藏机制[J].天然气工业,2025,45(12):53-65,13.基金项目
国家自然科学基金项目"致密油成藏微观动力学机制与含油性定量预测"(编号:42402161)、黑龙江省头雁创新团队计划项目"陆相页岩油地质工程一体化评价及目标优选创新研究团队"(编号:TY24001)、中国石油天然气股份有限公司科学研究与技术开发项目"油气地质基础新理论新技术研究"(编号:2021DJ0101). （编号:42402161）
