To determine the economic applicability of horizontal drilling technology to the Bakken, a detailed study of both vertical and horizontal Bakken completions in the heart of the Bakken horizontal play (Golden Valley, Billings and McKenzie Counties) was initiated in early 1989. This study reviewed in detail the reserves associated with Bakken completions and especially the effect of stimulation on oil reserves to be found in the Bakken. Particular attention was paid to horizontal well bore length and direction to determine their effect on IP and estimated ultimate reserves. Significant cases of interference between recent horizontal completions and existing vertical wells were investigated and some very interesting observations made.

Against this study of Bakken reserves and reserve timing was thrown a detailed investigation of horizontal drilling theory and mechanics especially currently observed practices and costs and expected costs with experience. Finally, interpretation of observed and expected well economics are presented showing what the key economic parameters are in this play and what they may be in other types of reservoirs.