The wells become independent of the finite difference equations. Therefore they need not be oriented with the grid. They can be vertical, horizontal, inclined, undulating, or any other shape that can be described as a series of straight-line segments. Wells need not be in the center of grid cells. They can be placed close together without regard for the number in intervening cells.
Several well can even be in the same cell.
Ease of Implementation. The finite difference mathematics is much the same as in traditional simulators. Hence the method can be easily implemented in existing reservoir simulators. These advantages of the new hybrid approach to the pressure solution are still believed to exist. However, recent multiphase results show that the principle errors in reservoir simulation result from numerical dispersion.