煤相分析在煤储层评价中的应用

Application of the Technique of Coal Facies Analysis to Evaluation of Coal Reservoir

煤储层研究的重要内容是孔裂隙系统发育特征、渗透性及其空间不均一性特征。煤储层的孔裂隙特征决定煤储层的渗透性,而煤储层的孔裂隙特征主要取决于煤岩成分和煤级。对一个特定的煤层气田而言,煤级变化不大或者规律明显。煤岩成分往往成为控制煤储层渗透率分布不均性的主导因素。煤岩成分,包括有机显微组分和矿物质均受控于煤相。可以通过系统的煤相分析认识煤储层中煤岩成分、结构、层序等的空间展布特征,为科学预测煤储层的渗透率奠定基础。煤相分析在注重横向变化的同时,更强调垂向层序分析。

The pore-fracture system, permeability of the coal reservoir and the heterogeneity of the pore-fracture system and permeability are very important aspects of the coal reservoir evaluation . The permeability of the coal reservoir depends on the pore-fracture system of the coal reservoir, and the pore-fracture system of the coal reservoir depends on coal rank, coal lithotypes and maceral. In a small districts, the coal rank is usually stable or changes regularly, the permeability of the coal reservoir is mainly related to the coal lithotypes and maceral. The coal lithotypes, organic maceral, minerals depend on environment during the peat formation. The evaluation and forecasting of the pore-fracture system and permeability of the coal reservoir may be carried out by coal facies analysis, in which the important contents are coal maceral, structure of maceral, sequence of coal lithotypes and parting.