DENVER ̶ With the Bakken rig count staying relatively flat since 2011 to 2012, production growth in the basin is driven by maximizing recovery efficiency. This includes methods of enhancing frack distribution and improving completion designs, Whiting Petroleum Corp.’s senior vice president, exploration and development, Mark Williams, told the Energy Finance Discussion Group here recently.
Williams noted that oil production by industry in the Bakken has grown at an annual rate of about 25% since 2010 and shows few signs of rolling over. Production per rig is increasing “pretty significantly,” which he attributes to switching to—and further upgrading—cemented liner techniques and using coiled tubing-conveyed plug-and-perf (PNP) completions. Whiting also uses slick water in its fracks.
Williams recalled that in March 2013 Whiting (NYSE: WLL) moved away from sliding-sleeve completions and took up a new style of cemented liner completions. Previously, the sliding-sleeve completion would typically have 30 frack stages set 300 feet apart. As pressure built up and found the weak spot in the rock, “that would almost assure you that you’re going to get one—and only one—break” in the 300-foot interval between the two packers, he said.
In contrast to a sliding-sleeve completion, a cemented liner completion has 40 stages set 250 feet apart, each with three perforation clusters. This potentially provides as many as 120 discrete entry points, said Williams. “We’ve had great success with that technique.”
Following the adoption of cemented liners, Williams cited increases in IP rates ranging from 41% at Whiting’s Hidden Bench area to 106% at its Missouri Breaks area, where work on the new completion technique began. The new completion is now being used “across the basin,” he noted.
Subsequently, a more advanced version of the cemented liner technique has been developed with 40 stages and as many as five perforation clusters per stage, providing up to 200 entry points, according to Williams.
Another innovation typically used during periods of high activity, particularly of truck traffic, is coiled tubing-conveyed PNP techniques. These offer an advantage because they can be done in as few as two or three days, said Williams. Results from Missouri Breaks show a 73% improvement in IP rates vs. a sliding-sleeve completion for just an 11% increase in costs.
Another set of tests involves slickwater fracks, an area in which other Bakken operators have had good results, said Williams. Although results have yet to be disclosed, “We’re finding slickwater fracks work very well in specific parts of the basin.”
Noting Whiting’s slogan of “break more rock,” Williams said the goal is to “try to make sure we take maximum advantage of this tremendous resource that we have in the Bakken and maximize the recovery efficiency by increasing technology” applied to it.