西南石油大学学报(自然科学版) ›› 2018, Vol. 40 ›› Issue (5): 37-46.DOI: 10.11885/j.issn.1674-5086.2017.05.05.02

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Mixed Sedimentation Characteristics and Evolution of Lower Member 3 of the Shahejie Formation in the KL Oilfield

HAN Jianbin, TIAN Xiaoping, KANG Kai, SHEN Chunsheng, WANG Libing   

  1. CNOOC China Limited, Tianjin Branch, Tanggu, Tianjin 300459, China
  • Received:2017-05-05 Online:2018-10-01 Published:2018-10-01

Abstract: There is still limited understanding of the formation conditions, sedimentation characteristics, and modes of the terrestrial debris-carbonate rock mixed sedimentation in the lower sub-member of Member 3 of the Shahejie Formation in the KL Oilfield in the southern slope of the Laizhou Bay Depression. In this study, data from side-wall cores from the area, thin sections, and scanning electron microscopy were obtained and integrated with contextual information, including tectonic evolution, paleoclimate, and paleogeomorphology. The sedimentary and sedimentary characteristics were analyzed within a sequence stratigraphic framework. The results reveal that mixed sedimentation developed in the study area due to wide and gentle slopes, humid subtropical climate, and periodically varying lake surfaces, water sources, and hydraulic conditions. This mixed sedimentation includes two sedimentation modes, gradual mixing along the facies edges and in situ mixing; two mixing modes, rhythmic bedding and compositional mixing; and four mixing patterns. The two mixed sedimentation modes differ in their mechanisms, while the mixing modes and mixing patterns show relatively significant variations, which has resulted in different microscopic characteristics in the reservoir.

Key words: KL Oilfield, mixed sedimentation characteristics, genetic types, evolution modes, southern slope of the Laizhou Bay Depression

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