A fluid dynamic model for Single Well Chemical Tracer tests with variable petrophysical and pre-flushing parameters

Porosity and permeability are two fundamental reservoir parameters. We study how important large variations in their values for residual oil saturation estimates from Single Well Chemical Tracer tests. Although porosity do not enter the classical chromatography formulae, or thereof, that does necessarily imply they irrelevant all real scenarios. This is because govern fluids distributed within oil-bearing formation, thus influence dispersion, temperature, rate of hydrolysis primary tracer, pH, partitioning etc., which may affect estimates. focus on coarsening fining upwards sedimentary sequences, but we also consider constant In addition, examine spatial single value ‘average’ obtained by tracer test. The impact pre-flushing estimated estimate investigated as well. An axially symmetric finite element model was developed calculates fluid flow wellbore well target formation; cooling caused injection cold brine; transport solutes pH driven changes ethyl acetate. A Reynolds Averaged Navier-Stokes equation with an algebraic turbulence applied to calculate there, whereas Brinkman used porous formation. temperature brine pumped into a function time calculated analytically down casing model. induced acetic acid produced acetate buffered injected calcite formation were accounted for. calculations account advection, diffusion, dispersion dependent between brine. use test data based published composition realistic sandstone reservoir. synthetic production curves generated vary only modestly various porosity, permeability, models. simple widely formula curves. yields 18–19% porosity-permeability scenarios when true 22%. studied six cases variable S . these cases, chromatographic underestimates average 1–3% except models where increases increasing porosity; then, 8% too low. More work needed understand why. summary, find significantly increase estimation error relative models, varies spatially – be much larger. Finally, four yield 18% 22%, i.e., like tests without pre-flushing. • have SWCT permeability. Flow turbulent governed underestimated 3–4% With underestimate reach 8%. Pre-flushing had no significant saturation.