广北地区沙四段滨浅湖微相的垂向演化及其地震相解释

Vertical evolution and seismic interpretation of the microfacies from the littoral and shallow lake subfacies in the fourth member of the Shahejie Formation, northern Guangrao region, Shandong

关键词:  东营凹陷  沙四段  滨浅湖沉积  地震相

Key words:  Dongying depression  fourth member of the Shahejie Formation  littoral and shallow lake deposits  seismic facies

摘要:

笔者通过关键井的岩性、测井相和地震相的研究,认为东营凹陷广北地区的下第三系沙四段为滨湖亚相的砂坝、砂泥混合滩、泥滩等微相以及浅湖亚相的远砂坝、席状砂、浅湖泥等微相构成的滨浅湖沉积体系;由老到新的垂向上沉积演化为浅湖亚相(ES₄⁶)-滨湖亚相(ES₄³,ES₄⁴,ES₄⁵)-浅湖亚相(ES₄¹,ES₄²),反映出水进-水退-水进的沉积旋回。通过地震剖面的对比和地震相的解释,建立了各沉积微相与地震相的对应关系。探讨不同沉积微相砂体中油气的富集规律。

Abstract:

The integration of the data on lithology, well-logs and seismic facies shows that the fourth member of the Paleogene Shahejie Formation in northern Guangrao region, Dongying depression, Shandong represents the littoral and shallow lake depositional systems including the microfacies such as sand bar, mixed sand-mud beach and mud beach in the littoral lake subfacies, and offshore bar, sheet sand and shallow-lake mud in the shallow-lake subfacies. There are vertical gradations, from the base upwards, from the shallow lake subfacies(ES₄⁶) through the littoral lake subfacies (ES₄³,ES₄⁴,and ES₄⁵) to the shallow lake subfacies (ES₄¹ and ES₄²) again, indicating a transgression-regression-transgression cycle. The correlation has been made between the sedimentary microfacies outlined above and seismic facies on the basis of the correlation of seismic profiles and interpretaion of seismic facies. The approaches are also made for the oil and gas accumulation in different microfacies.