Numerical Modeling of Inertial Flows in Proppant-Reservoir Rock Interfaces.

摘要

Predicting accurate pressure drops in the reservoirs is essential for estimating the ultimate hydrocarbons recoveries and production rates. In hydraulically fractured wells, inertial flows can cause excessive pressure drops, beyond the predicted values form the Darcy equation. Therefore, predicting these excessive pressure drops through defining non-Darcy factors is of particular significance.;Excessive pressure drops in inertial flows are caused by acceleration/deceleration of fluids, which usually occur when fluids are moving from constricted areas to larger pores and vice versa. In the interface between the propped fracture and the reservoir rock, the pores in the latter are in connection with the former that can generate eddies and thus fluid acceleration/deceleration.;In this work, two-dimensional geometries are generated by combining coarse and tight porous media and their hydraulic properties, i.e., absolute permeability and non-Darcy factors, are calculated using lattice Boltzmann simulations. Based on the simulation results, calculated absolute permeability of generated porous media follows the harmonic averaging theory for flow through series of constituting porous media. However, the non-Darcy factor for the generated geometries are higher than the constituting geometries, which does not conform to any averaging approach. This affirms the common knowledge that non-Darcy factor is a property that cannot be upscaled. The results in this study broadens our knowledge of fluid flow in hydraulic fractures.