Improving Peaceman well flow modelling with 1D radial simulation

Abstract

In reservoir simulation, Peaceman’s method is the most popular solution for simulating the flow from the reservoir to the well. It is easy to implement and works well if there are no phase changes in the well block. However, it will give inaccurate results when there is rapid pressure change near the wellbore. There are various methods for obtaining a detailed pressure profile around wells. But these methods either require dedicated gridding technique or perform poorly. In the present work, Peaceman’s method has been improved by conducting an extra 1D radial simulation from the equivalent well block radius to the wellbore radius. A series of virtual coaxial cylindrical nodes are introduced which can be mapped from the existing blocks that come from either the local grid refinement or inactive blocks. Features such as relative permeability and pressure–volume–temperature can be retained in the 1D radial simulation. The new method can be easily adapted by most reservoir simulators that have implemented Peaceman’s method. The new method can accurately mimic the local physics around a well and provides insight into the flow behaviour around the well with little extra computational effort.