E&P independent and new play hunter Whiting Petroleum believes the Williston Basin’s Red River formation, generally viewed as a conventional reservoir system developed primarily with vertical wells, contains a zone that also may be suited for horizontal drilling.
Later this year Whiting plans to drill what it believes will be the first horizontal well to enter the Lower Red River “D” zone. If successful, the addition of horizontal wells, which significantly increase well-bore exposure to oil, could dramatically change the production dynamics of the play, the company indicated.
Whiting characterizes Red River as one of the oldest known but least understood geological trends in the Williston Basin. The company holds large acreage positions in several counties through which the trend crosses in eastern Montana and western North Dakota.
Vertical wells successful
The use of vertical wells to extract hydrocarbons has been a successful undertaking for Whiting. It recently announced that it had identified more than 50 drilling locations in the Upper Red River “D” zone on its Big Island prospect in Golden Valley County, N.D.
“We’re nine for 10 on drilling Red River bumps — traditional bumps found with 3-D seismic,” James Volker, Whiting’s chief executive officer, told analysts at an April 15 conference in New York hosted by the Independent Petroleum Association of America, IPAA.
These vertical Big Island wells have “excellent economics,” with ultimate recovery rates of about 300,000 barrels of oil equivalent per well and drilling costs in the range of just $5-$5.5 million per well, Volker noted.
“So there’s the great economics, quick payouts here in around 12 months — and then three-to-one, four-to-one, on your money,” he added.
Bakken-like ‘porosity highlights’
However, interesting anomalies have appeared in Whiting’s extensive 3-D seismic studies — Bakken-like horizontal “porosity highlights” located in the Lower Red River “D” zone at Big Island.
“It’s very similar to drilling in a lower porosity zone like the Bakken,” Volker explained. “It really would allow us to go horizontal in areas that essentially show up on our 3-D, sort of between the porosity indications that are seen on the 3-D.”
He added: “With these large acreage positions that we hold here, they may turn into a horizontal play as well as a vertical play. If that happens, it’s a major game-changer for Whiting and some of the other producers in the area.”
However, the massive Bakken shale formation itself, a world-class unconventional play being developed with horizontal wells, does not exist in the Big Island prospect, said Mark Williams, Whiting’s senior vice president of exploration and development. And though the underlying Three Forks formation is present, he added, it’s not a prospective reservoir without the Bakken “to charge it.”
Little shale at Red River
Three-dimensional seismic is used by Whiting on its Red River play to identify areas of high porosity that have “very good economics” for inexpensive vertical wells, Williams said.
“There is little to no shale in the Red River,” he said.
Nevertheless, he added, reservoir distribution “is fairly continuous and structure is not a dominant control on oil saturation, which is the distinction of an unconventional reservoir or resource play. We are developing the Red River ‘D’ zone at Big Island with vertical wells and testing this zone with horizontal wells later this year.”
Whiting is currently extending its huge Big Island prospect to the west into Wilbaux County, Mont. Big Island alone encompasses 172,464 gross (122,389 net) acres.
Whiting’s other prospects
In addition to Big Island, Whiting’s Starbuck and Missouri Breaks prospects are located in the Red River play corridor. Starbuck, where 3-D seismic was recently acquired, encompasses 104,508 gross (92,227 net) acres. Missouri Breaks, where 3-D is planned for 2014, consists of 95,928 gross (66,095 net) acres.
Other operators, resulting in a successful oil play, have drilled into the Red River “B” zone in southern Williston Basin.
Starbuck, Missouri Breaks and another Whiting prospect, Lewis & Clark, are prospective in the “B” and “C” zones with both vertical and horizontal wells, Williams said, adding: “We will be testing these later this year.”
Whiting a noted explorer
Whiting, a noted explorer and a major Williston Basin producer, is generally credited with discovery of the highly productive Pronghorn Sand zone in southern North Dakota, at the company’s Pronghorn prospect in Stark County.
More recently, Whiting Petroleum disclosed plans to test an untapped and highly prospective oil formation within the Bakken petroleum system known as the Lower Bakken Silt. Sandwiched between the producing Middle Bakken and Three Forks, the “Silt” is situated in the central portion of the Williston Basin, and is primarily present at the company’s Hidden Bench prospect in North Dakota’s McKenzie County.
