BAKKEN DRILLING TO EXPAND

John McCaslin
Exploration Editor

Horizontal well economics make the Mississippian Bakken formation, once a bailout zone for wells aimed for Devonian and Ordovician zones, a primary exploration goal in the Williston basin.

A horizontal well's cost of nearly double that of a vertical well is more than offset by a doubling of reserves and a fivefold increase in initial Potential test, based on data for Bicentennial field. Last November the scoreboard for horizontal wells drilled to the Bakken shale stood at 25 oilers and no dusters. This excellent rating continues to impress the industry.

BAKKEN PLAY MOVES OUT

Most of the Bakken drilling to date has been along the "feather edge", OGJ Nov. 6, 1989, p. 22.

Projected ultimate reserves of several hundred million bbl of oil from the Bakken are realistic, say investment people. Reserves could be larger if the play is extended outside the main fairway to the north.

It appears this move is now under way. American Hunter Exploration and BWAB Inc. plan to drill a pair of Bakken tests in an undeveloped area in the central part of the Williston basin in northwestern North Dakota. Montana Oil Journal notes that both these horizontal tests are in Williams County. The surface location for the 41-9H will be in SW NE NE 9-157n-99w, 22 miles northeast of Williston and 21 miles west of Nesson anticline production. Nearest Bakken oil is 24 miles northeast in Temple field. The nearest Bakken penetration is a Madison well in Dublin field, 3 miles west-northwest. The 41-9H will be drilled southward, the 3,100 ft horizontal leg will end in NW SE SE 9-157n-99w. The measured TD will be at about 13,500 ft.

Eight miles southwest of Temple field, the 11-11H will locate in NW NW 11-158n-97w, 6 miles south of Wildrose town. This well will terminate in NE SW SW 11. The measured total depth is to be at about 13,700 ft.

AND MORE OIL IS FOUND

Continued success in horizontal Bakken holes is reported in North Dakota.

Chevron USA completed a horizontally-drilled Bakken pool discovery in Little Knife field. This well is capable of producing 200 b/d of oil. It is the 5-3 Zablotny in SE SW 3-144n-98w, northeastern Billings County. The well was drilled by Noble Drilling Co. in an area of shallower Mississippian Mission Canyon oil production at Little Knife. There are several wells in the area with Duperow Devonian oil production.

Petroleum Information of Denver reports that the new pool discovery, 8 miles north of vertically-drilled Bakken oil wells in South Little Knife, marks the easternmost horizontally drilled producer in North Dakota to date. Nearest horizontal Bakken production is about 16 miles west-southwest at a Meridian Oil Co. 1989 discovery in Four Eyes field on the Billings Nose.

That well made 49 b/d of oil from a horizontally drilled Bakken section between 11,982 and 14,227 ft, measured depths.