Abstract
The Bakken is one of the most active basins in the world in terms of number of rigs, with over 200 operating on the US side of the US-Canadian border. Production has rapidly increased from 100,000 BOPD in 2005 to 600,000 BOPD in 2012 in the state of North Dakota with the majority of production coming from the Bakken (Uptream Online, 2012). Greater horizontal drilling activity and a continuing increase in the number of hydraulic fracture stages per lateral have helped North Dakota grow its oil production six-fold in just seven years.
The Bakken is a fairly tight dolomitic siltstone requiring hydraulic fractures to produce economically. The stage count for hydraulic fracture treatments averaged nearly three stages in early 2007 and increased steadily over time to nearly 30 stages in late 2011. Some wells have even been completed with 40 or more stages. With the ever increasing stage count, the question remains: has the economic stage count limit been reached in the Bakken?
This paper analyzes the stage count versus the production impact of horizontal Bakken wells to determine if the economic stage count has been reached in the play. Wells are grouped and analyzed based on geographic considerations to help normalize for changes in geologic attributes such as natural fractures, reservoir quality, and net pay. Lateral length was also taken into account as varied lengths can impact stage spacing and interference issues.
Analyses were run with various oil and well service costs to determine how the economic stage count may change over time. If the economic limit was not reached under certain circumstances, this paper analyzes possible scenarios to determine when the economic stage count would be reached. This approach should provide insight into how other unconventional oil plays can evolve in the future.
