Oil & Gas Geology ›› 2010, Vol. 31 ›› Issue (1): 119-125.doi: 10.11743/ogg20100119

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Hierarchical subdivision and origin of single sandbody in the reservoirs of meandering river facies in the Yangdachengzi Formation of Fuyu oilfield

Li Jun1, Song Xinmin1, Xue Peihua1, Zhang Hailong2, Sun Jingmin1   

  1. 1. Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China;
    2. Fuyu Oil Production Plant, PetroChina Jilin Oilfield Company, Songyuan, Jilin 138000, China
  • Received:2009-11-25 Online:2010-02-25 Published:2012-01-16

Abstract:

It is acknowledged that distribution of sandbodies in reservoirs of meandering river facies is very complex,which makes it hard to rebuild the subsurface system.Based on the analyses of formations in terrestrial basins and the development of meandering river reservoirs,we divide the meandering river reservoirs of the Yangdachengzi Formation in the Fuyu oilfield into 4 different sand groups and 21 subzones by using the hierarchical subdivision method.Based on the subdivision of subzones,we focus on the configuration of internal architecture of single sand body in meandering river reservoirs.With data of cores,dense well log and production perfor-mance,we systematically study the hierarchical interfaces,lithofacies combinations and spatial distribution and assemblage of single point bar sandbodies in the study area.The genesis and distribution of remaining oil are also discussed in this paper.The results show that,the single point bar sandbody of meandering river reservoirs in the Yangdachengzi Formation deposited in an environment with weak hydrodynamic force is controlled by two hierarchical sedimentary interfaces.The number of lateral accretion bodies is mainly 3 or 4;the included angle of la-teral accretion face ranges from 4? to 7?;the horizontal scale varies greatly.The main types of spatial combination of single sandbody are isolated type,lapping type,overlaying type and cutting-piling type.Influenced by la-teral-accreted mudstones of point bars and injection-production strategies,the remaining oil is mainly distributed in point bars,isolated and cutting-pilling sandbodies,which lays the foundation for secondary recovery.

Key words: hierarchical subdivision, architecture of single sandbody, spatial assemblage, remaining oil, meandering river reservoir, Fuyu oilfield

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