Oil & Gas Geology ›› 2011, Vol. 32 ›› Issue (6): 873-881.doi: 10.11743/ogg20110609

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Charging time sequence of mantle CO2 and hydrocarbon in southern Songliao Basin: an evidence from dawsonite-bearing sandstones

Liu Li1, Hou Qijun2, Liu Na1, Yang Huidong3, Li Fulai1, Yu Zhichao1   

  1. 1. College of Earth Sciences, Jilin University, Changchun, Jilin 130061, China;
    2. PetroChina Jilin Oilfield Company, Songyuan, Jilin 138001, China;
    3. Exploration and Development Research Institute, PetroChina Jilin Oilfield Company, Songyuan, Jilin 138001, China
  • Received:2011-01-15 Online:2011-12-28 Published:2012-02-08

Abstract:

Charging time of mantle CO2 in sedimentary basins is a basis for studying interaction of CO2-sandstone and CO2-crude oil.Generally,eruption age of volcanic rocks near CO2 reservoirs is supposed to be the charging time of mantle CO2,but this approach is obviously not suitable to hydrocarbon basins with multi-stage volcanic eruption.Two hydrocarbon charging phases and one CO2 charging phase have been identified in the dawsonite-bearing sandstone by the systematic observation and determination of diagenetic sequence and fluid inclusions in Southern Songliao Basin.The first and second hydrocarbon charging were recorded by the liquid hydrocarbon inclusion and gas-liquid hydrocarbon inclusion within fractures of authigenic minerals and detrital minerals,while the mantle CO2 charging by the dawsonite and CO2-bearing inclusion within fractures of detrital minerals.The charging time of mantle CO2 is slightly latter than or approximately the same as the second phase of hydrocarbon charging.According to the analysis of diagenetic sequence and liquid inclusions in dawsonite-bearing sandstone,and in combination with the timing of hydrocarbon accumulation and structural fractures development,the charging time of mantle CO2 leading to dawsonite formation in Songliao Basin might be from the end of Cretaceous (the end of Mingshui period) to Paleogene.

Key words: charging time sequence, mantle CO2, hydrocarbon, dawsonite-bearing sandstone, southern Songliao Basin

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