中文摘要：

页岩气是以游离、吸附和溶解状态赋存于暗色泥页岩中的天然气,其赋存形式具有多样性,但以游离态和吸附态为主,溶解态仅少量存在。综述了页岩气的赋存形式及其影响因素,包括页岩气成因、页岩的物质组成（有机碳含量、矿物成分、岩石含水量）、岩石结构（孔隙度、渗透率）和温度、压力等。认识影响不同形式页岩气赋存量的地质因素,有助于利用容积法评估页岩气地质储量的水平,因为游离态页岩气的含量取决于页岩的有效孔隙度和含气饱和度,而吸附态页岩气的含量则受页岩的气体吸附能力影响。认为发展页岩孔隙结构表征技术,研究页岩气在粘土矿物表面和纳米孔隙中的吸附行为,可以进一步了解不同地质条件下页岩气的赋存形式,并为页岩气的资源评价提供更为准确的参数,因此它们将是页岩气下一步研究的重点之一。

英文摘要：

As unconventional gas resources,shale gas is mainly consistent of the free,adsorbed and dissolved gas accumulated in dark shale beds.Among these occurrences,adsorbed and free gases are the dominated phases.The occurrence of shale gas and various influence factors,such as gas component,material composition（sedimental organic carbon,mineral components,and water saturation）,rock texture（porosity,pore structure,and permeability）,temperature and pressure,are summarized and evaluated based on previous geological and experimental studies.Because effective porosity and gas saturation are the key factors determining the reserves of free gas,and gas adsorption capacity of shale is the maxium limit of the content of adsorbed gas,it is important to disclose the occurences of shale gas and evaluate potential influencing factors,which will improve the reliability of resource assessment based on volumetric method.Development of new characterization techniques of nano-pores structure of shale,and study on the adsorption behaviors of metane on clay surface and in nano-pores under various geological conditions should be carried out urgently to promote the understandings of the occurrences of shale gas,and to acquire reliable parameters used in resource assessment.