加拿大西加盆地泥盆系页岩气储层特征

Reservoir characteristics of Devonian shale gas in the West Canadian Sediment Basin,Canada

西加盆地作为加拿大最重要页岩气产地,其中尤以泥盆纪页岩最为著名,针对该页岩气储层特征的研究对于页岩气富集规律研究、开发方案设计以及有利区优选意义重大。在岩心分析、测井识别、岩心观察以及实验室分析基础上,采用薄片鉴定、XRD全岩分析、储层物性分析、有机地球化学分析、含气量测定以及页岩三轴应力分析等手段,开展岩石学、矿物学、储层物性、有机地球化学、含气性以及岩石力学等页岩气储层特征相关研究。研究结果表明目的页岩气储层为灰色、黑灰色硅质、钙质泥岩;骨架矿物为石英、方解石;孔隙类型则以裂缝、有机孔为主,岩心分析孔隙度为1.32-6.88%;总有机碳含量百分数为0.23%～8.37%;含气量为0.76～2.95 m^3/t;页岩的静态杨氏模量与泊松比分别为32.4～41.2 GPa,0.24～0.28.表明西加盆地泥盆纪页岩储层具有脆性矿物含量高、物性良好、有机质成熟度高、含气量高且易于压裂的特点。综合认为加拿大西加盆地泥盆系页岩气储层具有很好的勘探开发潜力。

West Canadian Sediment Basin is the most important production place of shale gas,especially in the Devonian shale,so the study of the reservoir characteristics is of great significance to shale gas enrichment,design of the shale gas development scheme and the prediction of the favorable areas.Thin slice identification analysis,XRD analysis,reservoir physical property analysis,organic geochemical analysis,gas content measurement and triaxial stress analysis are used to study petrologic,mineralogy,reservoir properties,geochemistry,gas-bearing properties and rock mechanics of the Devonian shale reservoir characteristics in the West Canadian Sediment Basin.The results show that the Devonian shale gas reservoir in the West Canadian Sediment Basin is dominated by gray,black and gray siliceous and calcareous mudstones.Skeletal minerals are quartz and calcite.The pore type is mainly composed of cracks and organic pores,and the tested effective porosity is 1.32%~6.88%.TOC is 0.23%~8.37%,gas content is 0.76~2.95 m^3/t,which belongs to high gas content.Static Young’s modulus and Poisson ratio are 32.4~41.2 GPa and 0.24~0.28.The results show that the Devonian shale gas reservoir in the West Canadian Sediment Basin has the characteristics of high brittle mineral content,good reservoir physical condition,high maturity,high gas content and easy fracturing.It is concluded that the Devonian shale gas reservoirs in the West Canadian Sediment Basin has a good prospect of exploration and development.