Oil & Gas Geology ›› 2014, Vol. 35 ›› Issue (4): 494-502.doi: 10.11743/ogg20140408

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Reservoir quality differences of submarine fans in deep-water oilfield A in Niger Delta Basin, West Africa

Lin Yu1,2, Wu Shenghe1, Wang Xing3, Wan Qionghua1, Zhang Jiajia1, Zhang Wenbiao4   

  1. 1. College of Geosciences, China University of Petroleum, Beijing 102249, China;
    2. Research Centre of Reservoir Geophysics, BGP Inc.of CNPC, Zhuozhou, Hebei 072050, China;
    3. CNOOC Research Institute, Beijing 100027, China;
    4. Petroleum Exploration & Production Research Institute, SINOPEC, Beijing 100083, China
  • Received:2014-02-27 Revised:2014-06-20 Online:2014-08-08 Published:2014-08-28

Abstract:

Deep-water submarine fans are characterized by large dimensions,special deposition positions and complex formation processes.Compared with terrestrial and shallow water deposits,reservoir quality of deep-water submarine fans are poorly studied,influencing the effective development of this kind of reservoirs.In this paper,taking deep-water oilfield A in the Niger Delta Basin in West Africa as an example,reservoir quality differences and controlling factors of submarine fans are researched based on core observations and descriptions,logging cross plot analyses and seismic attribute slicing.The results show that reservoir spaces of submarine fans are dominated by primary pores and the diagenesis is weak.Therefore,the reservoir quality is mainly controlled by sedimentary factors.According to lithology and sedimentary structures,these reservoirs could be divided into six types of rock facies,such as cross-laminated fine sandstones,parallel-la-minated medium to fine sandstones,massive medium to fine sandstones and so on.Microscopically,porosity and permeability of submarine fan reservoirs are controlled by sorting and matrix content respectively,but insignificantly influenced by median grain size,resulting in unique variation patterns of reservoir quality of different rock facies or sedimentary facies.Microscopically,spatial quality differences of submarine fan reservoirs are influenced by sequence,which controls spatial-temporal distributions of various sedimentary facies and rock facies combinations of the same type of sedimentary facies.

Key words: submarine fan, sequence, reservoir quality, Niger Delta Basin, West Africa

CLC Number: