条纹长石在松辽盆地深层碎屑岩储层形成中的作用分析

Effect of perthite on the formation of the deep clastic reservoir in Songliao Basin

通过大量岩石薄片的观察发现,松辽盆地深层碎屑岩中含有大量的条纹长石,主要为正条纹长石.条纹长石在深层碎屑岩储层形成过程中起到了重要的作用,表现为条纹长石在溶蚀过程中被选择性地溶蚀了主晶钾长石,从而保留了长石骨架,因此,在3600m埋深下,富含条纹长石的碎屑岩还能保留较高的孔隙度.结合沉积相和条纹长石物源的研究,初步总结了登娄库组砂岩有利储层形成模式,预测出深层登娄库组砂岩有利储层发育的主要区域为近条纹长石物源的河道砂岩区.

The understanding of the geologic features of this kind of reservoirs is of importance to the exploration of deep target reservoirs.According to the observation of a lot of rock thin-sections,it is found that there are a lot perthite in the deep clastic reservoir in Songliao Basin,and it plays an important role in the formation of the deep clastic reservoir.When the perthite is dissolved,principal crystallineI potassium feldspar is selectively dissolved while feldspar skeleton is preserved,and therefore the clastic reservoir below 3 600 m has high porosity,which greatly increases the confidence to the exploration of the clastic reservoir.The perthite is mainly from granite and intermediate acidic volcanic rock.Based on the study on the sedimentary facies and the provenance of the perthite,the formation model of the clastic reservoir of K1d is proposed,and it is held that the favorable reservoir of Dengluku Formation is in the channel sand region near the provenance of the perthite.