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Title: A kinetic model of CO sub 2 generation and mineral and isotopic alteration during steamflooding

Journal Article · · SPE (Society of Petroleum Engineers) Reservoir Engineering; (USA)
DOI:https://doi.org/10.2118/16267-PA· OSTI ID:6088615
 [1]; ;  [2]
  1. Cornell Univ., Ithica, NY (US)
  2. Chevron Oil Field Research (US)

CO{sub 2} is commonly produced during steamflooding. In higher-temperature steamfloods the amount of CO{sub 2} produced is such that the only viable source is carbonate minerals. The authors show by reference to CO{sub 2} concentrations in natural geothermal systems that in most common rocks and sediments, CO{sub 2} is generated naturally under hydrothermal ({approximately}572{degrees}F) conditions by the dissolution of carbonate minerals. CO{sub 2} solubility is a strong positive function of temperature and, at 572{degrees}F, is more than sufficient to account for high CO{sub 2} concentrations like those encountered in a steamflood pilot test. A linear kinetic model is developed to describe chemical equilibration and CO{sub 2} generation in the hot parts of the reservoir. The model also describes CO{sub 2} removal through carbonate precipitation in the cooler parts of the rock formation where the fluid moves ahead of the thermal front. Changes in carbon isotope concentration are included in the model. The small difference between the {sup 13}C in the produced gas and the source carbonates suggests that little CO{sub 2} is precipitated as carbonate within that reservoir, a prediction that can be tested by poststeamflood coring.

OSTI ID:
6088615
Journal Information:
SPE (Society of Petroleum Engineers) Reservoir Engineering; (USA), Vol. 5:4; ISSN 0885-9248
Country of Publication:
United States
Language:
English