浅淡地层基准面对沉积相迁移及砂体展布的控制作用——以松辽盆地北部杏13区葡萄花油层为例

Control function of base level for facies and sand body distribution, Putaohua oil layer of X13 area,Songliao basin

综合岩心、测井、录井及区域地质背景等各方面资料,对松辽盆地北部杏13区葡萄花油层进行高分辨率层序地层学研究,在此基础上讨论基准面变化与沉积相及砂体展布之间的关系.研究区葡萄花油层可划分为2个对称的长期基准面半旋回、6个中期基准面旋回和19个短期基准面旋回.长期基准面升降对沉积相的迁移和砂体展布起到了重要的控制作用.当长期基准面下降时期,沉积相向湖迁移;而当长期基准面上升时期,沉积相向陆迁移,砂体展布特征也随之发生变化.

Determination of the sand body distribution is a crucial point in oil reservoir. The base level can affect the facies migration and the sand body distribution. Based on the analysis of data of core, well logging and regional geological background, the research on the high resolution sequence stratigraphy of X13 area was carried out in the north of Songliao basin and the results show the relationship between base level cycles and facies and the sand body distribution. High resolution sequence stratigraphy data and concepts have been used to subdivide the strata of the Putaohua oil layer of Songliao basin into two symmetric long-basal level-hemicycle, six medium-basal level-cycles, and nineteen short-basal level-cycles. Applied to observation of cores in detail, combined with the characteristics of the electrical wireline logging, and the data of borehole log and paleontologic evidence, X13 area was been considered the ＂type＂ river-dominated shallow delta that prograded into four kinds of subfacies and twelve kinds of microfacies. The vertical facies evolution suggested the control of basal-level to microfacies： the basal-level descent in the earlier stage of Putaohua formation, and sediments migrated towards lake while in the later period, the basal- level ascent, and microfacies migrated towards land, and the characters of sand body distribution was changed with the microfacies.