Chemical Characterization of Fluids and Their Modelling With Respect to Their Damage Potential in Injection on Production Processes Using an Expert System

Abstract

Deep groundwaters, esp. oil field waters, from different sedimentary basins in Germany were characterized and evaluated with respect to their damage potential in production and injection processes. Geochemical modeling with different computer programs (PHREEQE, PHRQPITZ, SOLMINEQ etc.) was used to evaluate fluid-rock-interactions as well as their damage potential during operation processes. The geochemical program PHREEQE was integrated in an expert system (XPS FROCKI) for the evaluation of operational problems (scaling, fines mobilization, reduced permeabilities) in production or injection wells. Introduction In oil and water recovery as well as in geothermal projects fluid production or injection often fails because of interactions between the fluid and the solid phase. These interactions can be due to hydromechanical processes and/or changes in physico-chemical conditions of the fluid (Eh, pH, temperature, ionic strength) and cause a reduction of the permeability of the reservoir rocks or the technical equipment. Due to mechanical interactions finest particles, the so called fines, can be mobilized and transported until they will be deposited again within a smaller pore space. This kind of filtration can cause a sudden loss of permeability and this is the worse the closer to the borehole it happens. P. 385