Oil & Gas Geology ›› 2023, Vol. 44 ›› Issue (3): 553-564.doi: 10.11743/ogg20230303

• Petroleum Geology • Previous Articles     Next Articles

Hierarchical division and fine architectural depiction of the interior of deep-water channel deposits

Dongwei LI1,2(), Chenglin GONG1,2(), Lin HU3, Xiaohu HE3, Quanyuan LUO3   

  1. 1.State Key laboratory of Petroleum Resources and Prospecting,China University of Petroleum (Beijing),Beijing 102249,China
    2.College of Geosciences,China University of Petroleum (Beijing),Beijing 102249,China
    3.Hainan Branch of CNOOC,Haikou,Hainan 570100,China
  • Received:2023-02-04 Revised:2023-04-01 Online:2023-06-01 Published:2023-06-05
  • Contact: Chenglin GONG E-mail:dongweilip2p@hotmail.com;chenglingong@cup.edu.cn

Abstract:

Deep-water channel deposits are of an important type of deep-water hydrocarbon reservoirs. Given their complicated depositional processes and variable facies, it is urgent to establish a method for the hierarchy division and fine architectural depiction of the interior of deep-water channel deposits. The study proposes an efficient method to characterize and evaluate the interior hierarchy of deep-water channel deposits by using seismic data while considering the characteristics of diverse deep-water channel deposits. If the bottom boundary of seismically resolvable channel-complex set is recognized, the methodology of “three boundaries plus six facies belts” can be applied to hierarchical division and fine architectural depiction of the interior of deep-water channel deposits. According to three types of geological interfaces (i.e., the bottom boundary of channel sedimentation system, the bottom boundary of channel-complex set, and the interface of sedimentary facies belts), six facies belts (including basal lags, axial fills, marginal fills, slumps and debris flows, levee, turbidite mud) can be delineated in this type of deep-water channels. While, if not, the methodology of “two boundaries plus two facies belts” can be used, where two facies belts (i.e. channel fills and levee) can be delineated by two kinds of boundaries (i.e. bottom boundary of channel sedimentation system and boundary of levee) in this type of deep-water channel deposits. “Basal lags and axial fills of the six facies belts” and “channel fills of the two facies belts”, among others, could have quality reservoirs developed, the sand-rich property of which can be recognized by top convexity (that is, relatively sand-rich property indicated when the top convex seismic reflection is visible, and relatively mud-rich property when this is invisible). Applying the methodology of “three boundaries plus six facies belts” and “two boundaries plus two facies belts” in the investigation of the deep-water channel deposits in the Qiongdongnan Basin, we can conclude that it could better achieve the hierarchical division and architectural depiction of the interior of deep-water channel deposits. This also shows that the methodology can be applied to deep-water channel deposits in other regions, and is promising in industrial application.

Key words: geological interface, sedimentary facies belt, fine depiction, hierarchical division, interior of deposits, hydrocarbon reservoir, deep-water channel, Qiongdongnan Basin

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