The regulatory and technical documents of the Russian Federation currently regulate only the content of light organochlorine compounds (COCs) in oils (the boiling point of which does not exceed 204 ° C), with a complete prohibition of COCs including heavy COCs (the boiling point of which goes above 204 ° C) in chemical reagents. In this regard, the control of the content of COCs in chemical reagents used to intensify oil production remains an urgent issue. This article describes the results of studies aimed at studying the possibilities of the formation of COCs because of the interaction of core and reservoir waters with the main chlorine-containing reagents used in geological and technical operations (GTOs), in particular, hydrochloric acid. An assessment of the effect of HCl concentration on the formation of COCs is presented, considering the partial neutralization of hydrochloric acid by carbonates included in the core. An increased formation of COCs in oils was revealed when interacting with mixtures of hydrochloric acid and calcium nitrate, and a theoretical justification for this observation was given. To determine possible sites of formation and concentrations of COCs in reservoir conditions close to real ones, hydrodynamic modeling of the technological process of hydrochloric acid treatment of a horizontal well was performed. The numerical CFD model showed a satisfactory convergence with analytical and laboratory values. With appropriate adjustment and addition of the model to the geological and physical characteristics of the reservoir and fluids, as well as the kinetics of possible reactions of COCs formation, the model can be used in planning the hydrochloric acid treatment and assessing the risks of COCs formation.
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DOI: http://doi.org/10.1016/S0039-9140(01)00323-X
