Patents

The invention relates to a process utilizing natural carbon-13 isotope for identification of early breakthrough of injection water in oil wells. All natural water sources are labeled by unique ratios of carbon isotopes (13C/12C). The carbon isotope ratio for oil-bearing formation water and local aquifer water to be injected into the oil reservoir rock is determined. The carbon isotope ratio of the produced water from the selected oil wells is then monitored periodically. When the carbon isotope ratio of the produced (oil well) water shows deviation from the formation water value and tends towards injection water value, the early breakthrough phenomenon of injection water is identified. Thus the contrast in natural carbon isotope ratios of injection water, formation water, and produced water from selected oil wells serves as tracers in the identification of "Early Breakthrough" phenomenon of injection water and its movement.