This paper summarizes production forecasting methods for horizontal wells. The forecasting methods are based on analytical solutions and correlations of numerical model results. Methods are suggested for single phase flow, solution gas drive, naturally fractured, and bottom water drive reservoirs. These forecasting methods could be used for an initial evaluation of horizontal well drilling prospects.
A horizontal well can be looked upon as a controlled infinite-conductivity vertical fracture of limited height. Therefore, this paper compares horizontal well productivity with finite and infinite-conductivity, and uniform-flux fractures. A choice between horizontal wells and stimulated vertical wells should be determined by considering local fracturing experience and local costs for stimulation treatments and horizontal drilling.