Representation of a Horizontal Well in Numerical Reservoir Simulation

Abstract

SUMMARY The derivation of Peaceman's equation for the equivalent wellblock radius of a well in an anisotropic medium assumes that the grid is uniform and that the well is isolated, i.e., far from the grid boundaries. For a horizontal well, the assumption of being isolated may not be valid. The range of validity of Peaceman's equation is explored, using recent work of Babu and Odeh. If the reservoir is stratified or if the grid is not uniform, the assumptions underlying the equations of either Peaceman or Babu and Odeh are not valid, and a special program must be used to calculate the equivalent radius.