engleski

Risk assessment from the oil waste disposal in the deep wells

In this paper we present risk assessment analysis of the oil waste disposal in the deep wells. Oil waste disposal is analyzed in the oil field Žutica (Croatia) at injection depth around 2000 m. Risk assessment analysis is based on flow and transport of injected oil waste using the stochastic Monte-Carlo numerical simulations through heterogeneous injection zone which consists of low permeable marl and high permeable sandstone zones. Injection zone is bounded by low permeable marl zones which decrease vertical spreading of the injected oil waste and considerably reduces risk. Risk assessment is defined by exceeding risk which is the probability that injected oil waste passes through selected cross section or important surface aquifers. Results show that exceeding risk is a very low or practically negligible, p_r=10^-3 for period t=100 year at depth of Z=1850 m and p_r=10^-47 for period t=10000 year at depth of Z=500 m (surface aquifers), which confirms safety and reliability of the presented oil waste disposal methodology.

risk assessment ; oil waste disposal ; flow and transport analysis ; subsurface hydrology ; Monte-Carlo simulations ; exceeding risk ; heterogeneity

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