Accurate modeling of fluid transport in fractured reservoirs is challenging because of their heterogeneous nature. One of the sources of heterogeneity is the fracture spacing. In this study, an analytical model which describes the effect of fracture intensity on mass transfer during an advective-dispersive process in dual porosity systems is introduced.
The mass transfer process is modeled using different distributions of the fracture network that results in a various range of matrix-fracture connectivity inside the reservoir and resembles the variable flow path for the mass transport. In this work probable fracture network distributions in the field are tested and the effect of the matrix block size distributions and longitudinal dispersivity inside the fracture network on the transport of the injected tracer in the reservoir is obtained. The model consists of an infinite acting reservoir with planar matrix blocks and a radially divergent continuous injection system. Results show that using the breakthrough time of the injected tracer, the stored mass inside the reservoir as a function of fracture intensity and the dispersivity coefficient can be estimated. Analytical solutions are provided and can be used to study the tracer transport in fractured reservoirs with variable fracture intensity.