A Modeling Study for Foam Generation for EOR Applications in Naturally Fractured Reservoirs Using Disperse Surfactant in the Gas Stream

The preferential flow channels in oil reservoirs affect the performance of oil recovery processes, reducing the sweep efficiency and affecting the expected recovery factor. Preferential flow channels are generated by viscous fingering, gravitational segregation or porous media heterogeneity like natural fractures. In the Colombian foothills fields where the gas injection is the main method of recovery, the gravitational segregation and the presence of natural fractures strongly reduce the sweep efficiency. For these fields, foam generation is an alternative with high potential to increase sweep efficiency in gas displacement processes. Different foaming methodologies have been evaluated at laboratory core scale and field pilots with good incremental production, but with high operational expenses associated with high surfactant retention and lack of water injection facilities. Dispersed surfactant injection in a gas stream is a new proven method for foam generation. Different core flooding results and field pilots have shown that disperse injection increase cumulative oil production. However, there is a high level of uncertainty due to a few experimental and field information. For compensating the high uncertainty of the method, a mechanistic model was previously developed and validated with information from homogeneous cores. Nevertheless, it is necessary to extend the scope of the model to evaluate the effect of blocking foams in naturally fractured reservoirs, in this work we scale the previously built foam models to evaluate the disperse surfactant injection in Naturally Fractured Reservoirs through thin, high permeability, and horizontal layers to represent fractured systems and reproduce laboratory and field pilot results.