12.6 Blocked Wells

Reservoir simulation often requires discretization of a well based on one or several reservoir grids. The blocked wellbore representation (Figure 12.6-1) is the intersection of the grids and a trajectory. It is a well marker frame where each node typically represents a limit between grid cells. It has these characteristics:

• Contains the list of grids on which it has been discretized and the number of grid cells that are intersected.
• For each frame interval corresponding to a grid cell, the corresponding grid index in the list is stored.
• For the intervals between nodes that may not correspond to actual grid cells—for example if the well is outside of any grid or grid geometries have not yet been defined—a value of -1 is used.
• For each actual grid cell, the blocked well contains the cell index and the cell face indices where the trajectory enters and exits. So each cell has a pair of local face indices, and when the trajectory begins or ends within the cell, the entry or exit value is -1.

Figure 12.6-1 The blocked wellbore representation is the intersection of the grids and a trajectory.It is a well marker frame where each node typically represents a limit between grid cells.