松辽盆地南部永平地区泉四段沉积微相及沉积演化研究

通过岩心观察、沉积构造、矿物学特征、测井数据对松辽盆地南部永平地区泉四段进行沉积微相的判别,划分为湖泊相和曲流河三角洲相,包含2种亚相和3种微相。借助JF229井区密井网条件进行精细小层对比和砂体拆分,将永平地区泉四段划分为12个小层,按时间关系划分为9期河道,以此为依据研究该区沉积演化过程并总结沉积模式。泉四段早期,全区主要发育较稳定的三角洲前缘沉积。10小层时期伴随有一次短暂的湖侵-湖退,而后迅速恢复三角洲前缘沉积;泉四段末期从4小层开始发生广泛湖侵。结合连井剖面,进一步研究河道性质及演化特征,为追索有利砂体提供依据。

Sedimentary microfacies and evolution of the 4th member of the Quantou Formation in the Yongping region, southern Songliao Basin

The 4th member of the Quantou Formation in the Yongping region, southern Songliao Basin is divided, in terms of core examination, sedimentary structure, mineralogy and well logs, into lake and meandering delta facies, including two sedimentary subfacies such as shallow lake and delta front subfacies, and three sedimentary microfacies such as shallow lake mud, subaqueous distributary channel and interdistributary bay microfacies. With the aid of the division and correlation of the layers and sand sets based on the closely-spaced well patterns of JF-229 well field, the 4th member of the Quantou Formation may be subdivide into 12 layers or 9 phases of channels. The delta front deposits once persisted in the study area during the early stage of the deposition of the 4th member of the Quantou Formation. There occurred a short period of transgressive-regressive lake cycles during the deposition of the 10th layer, followed by the delta front deposits again. At the end of the deposition of the 4th member of the Quantou Formation, the wide-spread transgressions were initiated during the deposition of the 4th layer. Finally a sedimentary model is presented for the 4th member of the Quantou Formation, and thus may provide evidence for the delineation of the favourable reservoir sandstones in the Yongping region.