Oil & Gas Geology ›› 2020, Vol. 41 ›› Issue (3): 513-524.doi: 10.11743/ogg20200308

• Petroleum Geology • Previous Articles     Next Articles

Architecture of channel reservoirs of shallow-water delta in the 4th member of Cretaceous Quantou Formation in southern Sanzhao Sag,Songliao Basin

Deng Qingjie1, Kang Dejiang2, Hu Mingyi1, Shen Jiao3, Lei Ming4   

  1. 1. School of Geosciences, Yangtze University, Wuhan, Hubei 430100, China;
    2. Exploration and Development Institute of Daqing Oilfield Limited Liability Company, PetroChina, Daqing, Heilongjiang 163712, China;
    3. CNOOC Research Institute Company Ltd., Beijing 100027, China;
    4. School of Urban Construction, Yangtze University, Jingzhou, Hubei 434000, China
  • Received:2018-02-26 Revised:2020-01-06 Published:2020-06-16

Abstract: The channel reservoirs in the 4th member of Cretaceous Quantou Formation (Quan 4 member) were mostly deposited in a lake-shallow-water delta system on a gentle slope,and are targets for hydrocarbon exploration and development in southern Sanzhao Sag of Songliao Basin.We study the reservoir architecture via core,logging and seismic data based on Miall's architecture theory,and identify two types of fourth-order architecture interface,namely the interfaces of fine-grained conglomerate or mud pebble-bearing fine sandstone,and of mudstone or silty mudstone.In turn,6 categories of architecture units in accordance are identified according to 17 types of lithofacies assemblages,and 4 vertical combinations of architecture units are defined as Type CH1,Type CH2,Type CH3,and Type CH4 by their contact relations.The 4 lateral combinations of composite channel architecture units are described via flattening on top of the composite channel deposits and well-to-well correlation in four development blocks.Following well-to-seismic tie and 90° phase transformation,we count the key locations of the composite channel growth,and study the architecture evolution of the Quan 4 member reservoirs in southern Sanzhao Sag by extracting volume attribute of time-frequency in three primary color display.The results show that Type CH1 is composed of 3-7 GB-DA in vertical accretion;Type CH2 is composed of 2-5 GB-SL-OF or SB-SL-OF in lateral accretion; Type CH3 is composed of 2-4 SB-SL-OF in lateral accretion; and Type CH4 is composed of 1-3 SB-DA-LS in vertical accretion.The fourth-order architecture interfaces of Types CH1 or CH4 horizontally extend forward,whereas those of Types CH2 or CH3 extend a short distance with low-angle inclination.In addition,from Q4-sq1 to Q4-sq4 periods,the architecture unit assemblages in the channel reservoirs evolve in a pattern of Type CH1 -Type CH2 -Type CH3 -Type CH4 as the lake level keeps rising.

Key words: river channel, architecture unit, assemblage pattern, shallow-water delta, Quantou Formation, southern Sanzhao Sag, Songliao Basin

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