海拉尔盆地贝尔凹陷铜钵庙组成岩作用及其对孔隙演化的影响

Diagenesis and Its Influence to Porosity Evolution of Tongbomiao Formation in Beier Sag,Hailaer Basin

海拉尔盆地贝尔凹陷铜钵庙组发育一套火山碎屑岩类、火山-沉积岩类和少量的陆源碎屑岩岩石组合。其中,火山碎屑岩类、火山-沉积岩类成岩作用受火山碎屑物质控制作用明显。典型的成岩作用类型包括压实作用,胶结作用和溶蚀、溶解作用等。成岩阶段属中成岩A期。通过孔隙演化研究发现,压实作用是该区原始孔隙损失的最主要因素;其次为胶结作用。早期压实作用和胶结作用共损失83%以上的原生孔隙,晚期岩屑溶蚀和长石溶蚀作用增加6.53%的孔隙度,有效地改善了储层的物性特征。此外,不同岩石类型成岩作用特征及其对孔隙的影响差异较大。

The Tongbomiao Formation consists of pyroclastic, volcanic- sedimentary and terrigenous clastic rocks in Beier sag, Hailaer Basin. Diagenesis is mainly controlled by volcanic clastic materials in pyroclastic rocks, volcanic- sedimentary rocks. The main diagenesis includes compaction, cementation, corrosion and dissolution, etc. which belongs to stage A of middle diagenesis phase. The study of porosity evolution shows the compaction is the main cause resulting in the disappearance of primary porosity, and the next one is cementation. The losing of primary porosity by the early compaction and cementation reach over 83% totally, the later dissolution of rock fragment and feldspar adds to 6.53% porosity which improved reservoir effectively. However, the different types of rock＇s diagenesis influence porosity greatly.