Numerical modeling of tracer tests

Abstract

Tracer tests are widely used in the oil and gas industry. The response curves from tracer tests can provide reservoir engineers with important reservoir information, such as flow direction, presence of faults, reservoir heterogeneities and fluid saturation. As tracer tests provide reservoir engineers representative results from the reservoir, they are very useful for enhanced oil recovery. This research begins by numerical modeling of one-dimensional single-phase tracer flow and develops to a complete two-phase partitioning tracer flow that includes convection, Langmuir adsorption, partitioning between phases, hydrodynamic dispersion and radioactive decay. This model implemented in Matlab (2014b) is an improvement of previously-used models as it includes radioactive decay and uses Langmuir adsorption instead of linear adsorption. It is also fast and easy to use. The different tracer models are discussed and compared. A case study reveals that the adsorption model chosen, the partitioning coefficients and the reservoir wetting conditions all have effects on the tracer profiles and breakthrough times. This can be applied to tracer test design and analysis.