Correct Way to Represent a Pumping Well in FLAC3D?

FLAC3D
1

Hello,

I am simulating a pumping scenario, and my procedure is as follows:

1. I use a command to search for the grid points around the well (using range cylinder). Suppose the total number of selected grid points is N.

2. I distribute the total pumping rate of a single well (L, in m³/s) evenly to these grid points by applying
gp.fluid.load(gp) = L / N.

My question is: Is this approach reasonable for representing a pumping well?

2

Hi Wenjie,

Are you using the zone apply well command?

This command applies a prescribed volume rate of fluid flow (a source or a sink) to a specified range of zones or gridpoints. For a pumping well (fluid outflow), you apply a negative flow rate.

For example, assuming using consistent metric units:

zone apply well rate -0.001 range cylinder 0 0 10 0 0 -10 radius 0.5

This command applies an outflow rate of -0.001 m^3/s to the zones within a cylinder centered at (0,0,0) with a radius of 0.5 m along the z-axis from z = 10 m to z = -10 m.

Note:

  • Since you typically know the total well flow rate, you need to distribute this total flow rate (Qtotal) evenly across all the zones or gridpoints (N) that constitute the well.
  • Ensure your model is set up for fluid flow by using the model configure fluid command before running the simulation.
  • Since the highest hydraulic gradient occurs near the wellbore, you should use much finer meshing in the area immediately surrounding the well to capture the pore pressure (and resulting effective stress) changes accurately.
3

Hi David,

Thank you for the explnation, this indeed helps.