Oil & Gas Geology ›› 2005, Vol. 26 ›› Issue (3): 284-289,296.doi: 10.11743/ogg20050304

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Carbonate reservoirs transformed by deep fluid in Tazhong area

Lu Xiuxiang1,2, Yang Ning1,2, Xie Qilai3, Yang Haijun4   

  1. 1. Basin & Reservoir Research Center, China University of Petroleum, Beijing;
    2. Key Laboratory for Petroleum Accumulation, Ministry of Education, Beijing;
    3. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou;
    4. Tarim Oilfield Company, PetroChina, Korla, Xinjiang
  • Received:2005-04-28 Online:2005-06-25 Published:2012-01-16

Abstract:

Occurrence of deep fluids in Tazhong area has been confirmed through analyzing rare-earth elements in rock and oil samples,carbon isotope of carbon dioxide and fluid inclusion thermometry in reservoir rocks.The deep fluids below the basement entered the basin along the discordogenic faults and through volcanic activity,and the carbonate reservoirs were modified by dissolution and metasomatosis through material and energy exchanges.The porosity and permeability of the carbonate reservoirs were thus improved,leading to the formation of deeply buried and modified type good carbonate reservoirs.The fluorspar ore belts,discovered along the large fault and in volcanic activity area in the western part of Tazhong,are the result of activities of deep fluids,and they are the main reservoir types in Tazhong 45 oilfield.The origin and sphere of activity of deep fluids are closely related to discordogenic faults and volcanic activities.Areas with well-developed discordogenic faults and volcanic rocks can be considered as indicators for seeking deep fluid modified reservoirs.

Key words: deep fluid, carbonates, moeified reservoir, Tazhong area

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