(114e) Effects of Stress-Dependent Permeabilities and Non-Darcy Flow Parameters on the Productivity Index of the Hydraulically Fractured Completions in Gas Reservoirs

Non-Darcy flows are expected to be ubiquitous in near wellbore regions, completions, and in hydraulic fractures of high productivity gas wells. Further, the prevailing dynamic effective stress in the near wellbore region is expected to be an influencing factor for the completion conductivity and non-Darcy flow behavior in it. In other words, the properties (fracture permeability and beta-factor) can vary with the time and location in the reservoir (especially in regions close to the wellbore). Using constant values based on empirical correlations for reservoirs/completions properties can lead to erroneous cumulative productivity predictions. With the recent advances in the imaging technology, it is now possible to reconstruct pore geometries of the proppant packs under different stress conditions. With further advances in powerful computing platforms, it is possible to handle large amount of computations such as lattice Boltzmann (LB) simulations faster and more efficiently. The objective of this paper is to broaden the knowledge of completion performance with the hydraulic fractures by investigating the variations of the permeabilities and beta-factor due to near wellbore stresses using the image-based simulations in proppant packs.

The two technology drivers viz. imaging of pore spaces and high performance simulations, can help in simulating fluid flows in the realistic microscopic pore spaces in order to obtain inertial flow parameters for the porous media. Further, this approach is less time-consuming, repeatable, and cheaper compared to the other alternatives. In this study, absolute permeability and Forchheimer coefficient (beta-factor) of the imaged proppant packs under varying confining stresses are calculated based on the LB simulations at varying Reynolds number.

Calculated properties show reasonable agreement with the reported values for both permeability and beta-factor. These predicted stress-dependent permeability and beta-factors corresponding to the effective stress fields around the hydraulic fractured completions is included in a 2D gas reservoir simulator to calculate the productivity index. Presented results have beneficial applications in the high production rate gas reservoirs with hydraulically fractured completions.