Near-well streamline simulation utilizing a co-axial cylindrical grid structure

Abstract

Accurate reservoir simulation is key in attaining an effective and efficient reservoir completion. Typical reservoir simulators employ grid sizes that are several orders of magnitude larger than the wellbore diameter and therefore, can not capture the near-well flow attributes. To improve the depiction of near-well flow phenomenon, a cylindrical grid system with a logarithmic radial-spacing is utilized; oriented such that small radial steps are taken in nearer regions allowing us to portray a more accurate flow description nearer to the wellbore. Streamline simulation techniques are the primary focus for this work as they promise computational efficiency and enhance flow visualization. -- Herein, a robust streamline-based, cylindrical flow simulation method for the near-well region is presented. This will allow for a more accurate visualization of the near-well flow characteristics and improve overall reservoir flow simulation. -- In this work, the streamline model is an adaptation of the semi-analytical method of [Pollock, 1988]; derived for a two-dimensional, cylindrical, single-phase, incompressible, homogeneous medium, for both isotropic and anisotropic permeability fields. A discretization scheme is also presented utilizing a novel logarithmically spaced grid for the numerical model, and tested for an isotropic and anisotropic case for illustration. The results show that this methodology has potential to be useful in determining the flow characteristics in the near-well region and provide stable results.