Print this pageBakken Sweet Spot in the Sanish/Parshall Field Area of Mountrail County, North Dakota
Production from over 500 horizontal wells drilled in the Bakken Formation in western North Dakota since 2000 exhibit a distinct bimodal distribution with average best month producing rates in the area of south-central Mountrail County exceeding 1000 BOEPD. Key geologic factors contributing to the exceptional performance of this area include excellent stratigraphic trapping conditions in the Middle Bakken dolomitic sandstone along the eastern edge of the basin, active generation and expulsion of oil from Bakken organic mudstones (upper and lower Bakken Shale) into vertically adjacent Middle Bakken and Three Forks reservoir intervals, and large areas of enhanced permeability associated with predominately northeast oriented, basin-scale natural fracture trends. Initial producing rates and estimates of ultimate production are also heavily influenced by the application of modern horizontal drilling techniques with long-reach lateral wellbores oriented at a high angle to the direction of maximum horizontal stress, facilitating exposure to existing open fractures and optimizing potential to initiate new transverse fractures with fracture stimulation treatments. Modern well completions employ swelling packers and sliding sleeves to facilitate the subdivision of the horizontal wellbore into multiple isolated segments which can each be separately treated during fracture stimulation. High effort, surface microseismic monitoring of these stimulations reveals the orientation, spacing and distribution of natural and induced fractures as well as the fracture half-length, thus providing constraints on the stimulation efficiency and drainage area surrounding Bakken horizontal wellbores. Potential improvements in recovery efficiency for future wells may include modifying borehole configurations to more efficiently connect with Bakken and Three Forks reservoir intervals and increasing the number of fracture stimulation stages to contact more rock volume.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009