松辽盆地长岭断陷营城组火山熔岩流单元储层特征及量化表征

依据松辽盆地盆缘及邻区中生代火山岩露头剖面和剖面浅钻,长岭断陷28口钻井岩心、测井、铸体薄片和扫描电镜资料,并结合地震解解释剖面,对该区中生代熔岩流单元形态、内部结构和储层特征进行研究。结果表明:熔岩流单元根据外部形态可分为熔岩穹丘、板状熔岩流和辫状熔岩流3类;垂向序列可分为顶部气孔带、韵律性气孔带、稀疏气孔带、致密带和底部气孔带5种孔隙带;从熔岩流单元顶部气孔带到底部气孔带,原生孔隙面孔率先减小后增加,次生孔隙面孔率始终减小,面缝率始终增加;辫状熔岩流储层物性最优,其次为板状熔岩流,再次为熔岩穹丘;该研究有利于更加深入地认识松辽盆地深层火山岩储层空间发育规律,并有助于对火山岩储层进行精细刻画。
The outcrops and the shallow wells of the Mesozoic volcanic rocks in the margin of Songliao Basin and the adjacent regions were studied to infer the shape, inner structures and reservoir characteristics of the associated lava flow units. A series of data were used in the study, including the core data, well logging, casting thin sections, SEM date of 28 wells, as well as the seismic sections in the Changling Depression. The results are as follows:the lava flows can be divided into three types, including lava dome, tabular flow and braided flow based on the envelope shapes; the vertical successions of lava flow units can be classified into five zones, the top vesicle zone, the rhythmic vesicle zone, the sparse vesicle zone, the dense zone and the basal vesicle zone; from the top vesicle zone to the basal vesicle zone, the surface porosity of the primary pores decreases in the beginning and increases afterwards, and the surface porosity of the secondary pores generally decreases, and the surface porosity of fissures generally increases. Logging porosity analyses show that there are more reservoirs in basic braided lava flow units than tabular lava flow units and the lava domes. This study provides insights to the distribution of volcanic reservoirs in Songliao Basin, and is useful for the refined volcanic reservoir description