Paper: Key Parameters For Economic Success Of Horizontal Wells

The objective of this paper is to review applications of horizontal wells, discuss their successes and failures, and summarize the key parameters for economic success. Horizontal wells have been used in 1) thin payzones, 2) naturally fractured reservoirs, 3) formations with gas and/or water coning problems, 4) gas reservoirs and 5) EOR applications. Based upon field results, the paper summarizes the following key parameters for economic success: 1) fracture intensity and direction, 2) hydrocarbon payzone thickness, 3) well spacing, 4) areal anisotropy, 5) vertical permeability, 6) formation damage and post drilling clean-up, 7) necessity of multiwell prospect and, 8) geological control. This paper includes discussions on these parameters. Also, whenever possible, pertinent field histories are presented. Available field results indicate that the success rate of horizontal wells in reducing water coning is much higher than in reducing gas coning, especially in low permeability reservoirs.