Aboulghasem Kazemi Nia - MSc student at Sharif University of Technology
Shahab Gerami - R & D associate incorporated
Cyrus Ghotbi - Sharif University of Technology
Abdonabi Hashemi - Petroleum University of Technology

Diffusion in fractured reservoirs, unlike in unfractured reservoirs, can affect significantly the efficiency of gas injection in oil reservoirs and recycling in gas condensate reservoirs also. Regarding of molecular diffusion drive simultaneously with the pressure gradient drive usually refers as multi-mechanistic flow in the reservoir. A multi-mechanistic flow environment is the result of the combined action of a Darcian flow component and a Fickian-like or diffuse flow component taking place in hydrocarbon reservoir. In this work, single block approach saturated with a two-component (80% methane, 20% n-pentane) synthetic gas condensate is applied to find out main mechanisms of recovery in naturalgas injection of gas condensate fractured reservoirs. Fully implicit with the using of Newton-Raphson technique was applied to solve highly non-linear equations at this simulation model. In order to speed up the simulation technique, Broyden updating approach is used to build jacobian matrix. At the end, it will be concluded that, diffusion phenomenon is considerable for matrix blocks with the permeability of less than 0.01 md and it can be ignored in the simulation of matrix blocks with permeability of higher than 0.1 md. Although, diffusion phenomenon is moresignificant in simulation of two phase flow than single phase.

1- Gas condensate 2-Diffusion 3-Muli-mechanistic 4-Darcian flow 5-Fickian flow