地质科学2012，Vol.47Issue(1)：187-201,15.
富CO2深部流体对碳酸盐岩的溶蚀—充填作用的热力学分析
Thermodynamic analysis for carbonate dissolution-filling under influence of CO2-rich deep fluid
摘要
Abstract
There are extensive activities of CO2-rich deep fluids in Songliao, Bohai Bay and Yingge Sea basins in the eastern China and Tarim Basin in the western China because of extensive and intensive magmatic activities. The interaction between CO,-rich fluid and carbonate can be simulated and calculated by a thermodynamic model for CO2-H2O-CaCO3-NaCl system which is created by Duan and Li (2008). The simulating result indicates that the solubility of CaCO3 in the CO2-rich fluid rises gradually when the fluid migrates from deep to shallow stratum and then reaches to a peak value at some certain depth. However,the solubility decreases gradually when the fluid migrates upwards further. The solubility feature reveals a rule that the CO2-rich deep fluid can dissolve carbonate in deep stratum and then fill pores by precipitating carbonate minerals in shallow stratum. Decrease of CO2 content or decrease of salinity in the fluid due to mixing with fluid in shallow strata can cause precipitation of CaCO3. CaCO3 can also precipitate from the fluid when it migrates into open fault/fracture system because of decrease of pressure. The changes of CO2 content, salinity and pressure affect actual characteristics of CaCO3 dissolution-filling. A typical example for such rule can be gotten from the central area of the Tarim Basin. Drillings in the center of Tarim Basin indicate that there are numerous dissolution pores in the lower Ordovician carbonates, however there are large amount of calcite fillings in the relatively shallow Ordovician carbonates or Silurian sandstones. Both the rule and example indicate that the existence of well carbonate reservoir bed is possible in the deep lower Paleozoic strata in the Tarim Basin and the similar others where magma or volcano activities were extensive and intensive.关键词
塔里木盆地/CO2/深部流体/碳酸盐岩/溶蚀/充填Key words
Tarim Basin/ CO2/ Deep fluid/ Carbonate/ Dissolution/ Filling分类
天文与地球科学引用本文复制引用
朱东亚,孟庆强,金之钧,胡文瑄..富CO2深部流体对碳酸盐岩的溶蚀—充填作用的热力学分析[J].地质科学,2012,47(1):187-201,15.基金项目
国家自然科学基金项目(编号:41002037)、国家重点基础研究发展计划“973”项目(编号:2012CB214802)和国家重大专项(编号:2011ZX05005-002)资助. （编号:41002037）
