Compositional flow simulation applied to gas tracers' study in a reservoir recovered by WAG-CO2 injection

Raphael Leopoldo Cotta Macedo¹; Anderson do Nascimento Pereira¹

¹ Universidade Santa Cecilia

doi:10.20906/CPS/CILAMCE2017-1053

Resumo

In the oil industry, the reduction of uncertainties is very important due to high risks and values associated with E&P activities. Tracers have been used for better understanding the flow performance of the reservoir and for history matching the simulation model so that it represents, in a more reliable manner, the real reservoir. This work's objective was developing simulation studies of tracers associated to enhanced recovery methods such as CO2 and WAG-CO2 injection. The simulation study was carried out using the Computer Modelling Group simulation package. This work involves the creation and insertion of gas tracer components to the main fluid of both gas and oil reservoir models drained by two inverted five-spot patterns. As a means of testing and of eliminating tracer partition into oil phase different scenarios were generated on the gas reservoir model in order to investigate the gas tracer's production. These were permeability barrier, discontinuity and layering permeability contrast. Simulation results indicated no tracer production by wells located in an hydraulic isolated zone; increment of tracer production on wells nearing the high permeability zone and shrinkage of tracer production on a well nearing a low permeability zone. Then, sensibility analysis was conducted varying tracer concentration within the gas stream injection. The reservoir model was then converted into oil reservoir, so that CO2 and WAG-CO2 injection could be studied. The first sensibility study on the oil reservoir model recovered by CO2 injection was the variation of tracer injection form (continuous or in pulse) and concentration. The results showed that tracer production curves were proportional to its concentration, as it was for the gas reservoir model, and that the same recovery factor was obtained for all cases. WAG-CO2 injection was also studied. Within it, tracer retention due to partitioning was analyzed; greater retention was observed in remaining oil phase for higher reservoir pressure. The results of tracers' flow thro

Palavras-chave: Enhanced Recovery; Tracers' Simulation; Compositional Simulation; WAG-CO2