涪陵地区页岩含气量计算模型及应用

目前页岩含气量的预测获取方法主要包括现场解吸法、测井解释法、等温吸附法、线性拟合法以及地震反演法等，但每种方法都存在不足，因此研制了涪陵地区页岩含气量计算模型，为页岩资源量评价奠定基础.以岩心实验为基础，筛选并分析了研究区页岩游离气含量和吸附气含量的主控参数，分别建立了游离气含量和吸附气含量的计算模型，最终利用该模型得到了研究区页岩含气量与孔隙度、OC和深度的演化图版以及单井页岩含气量分布特征.当孔隙度和OC一定时，页岩含气量随深度的增加而增加，但是增加幅度逐渐降低；当深度一定时，页岩含气量随孔隙度和OC的增大而增加.A井五峰组-龙马溪组页岩气储层含气量呈现上低下高且随深度的增加而明显增加的特征；其中下部Ⅰ段储层段，总含气量高达7.76m3/t，游离气含量占60.7%，为优质层段. 

Calculation Model of Shale Gas Content and Its Application in Fuling Area

The existing prediction methods of shale gas content include in situ desorption, logging interpretation, isothermal adsorption, linear fitting, seismic inversion and so on, but each method is deficient in some aspects. A new calculation model of shale gas content in Fuling area is established in this study, laying the foundation for the evaluation of shale resources. Based on the core experiment, the main controlling factors were selected through analyzing the influencing factors of shale free gas content and adsorbed gas content in Fuling area. Then, calculation models of free gas content and adsorbed gas content were established respectively with the integration of the theoretical calculation model and experimental formula to analyze the main controlling factors. Finally, the evolution charts of shale gas content versus porosity, TOC and depth and distribution characteristics of shale gas content in single well in studied area were obtained utilizing the calculation models proposed above. The shale gas content increases with depth when porosity and TOC are constant, but the increment decreases progressively; when the depth is certain, the shale gas content increases with porosity and TOC. The shale gas content of Wufeng Formation and Longmaxi Formation of well A increases with layer depth; the total gas content is up to 7.76m3/t under lower shale reservoir of Member 1, the content of free gas accounted for 60.57%, which indicates high-quality member for shale gas reservoir.