Drilling across two sections (10,000-ft laterals) in a horizontal well in the Middle Bakken formation of North Dakota offers challenges and opportunities for improved well-construction performance. The wells in this area were drilled with three different hole sections after setting the 16-in. conductor at 60 ft.

The first hole section was drilled 13 ½-in. vertical hole with fresh mud to the 9 #x215D;-in. casing set at +/− 2,000 ft and cemented to the surface. The second hole section was drilled 8 ¾-in. vertical hole with oil-based mud and built the curve to the 7-in. casing set at +/− 11,000 ft and cemented to a point above the Dakota formation. The curve was built at a 12 to 14° BUR to a landing point in the Middle Bakken target zone at approximately 90°. The last interval drilled was a 6-in. lateral-hole section, geosteering with mud motors, using two different bend settings of 1.15° ABH and 1.5° ABH. Wellbore stability in the Middle Bakken is not an issue when using a cut brine-produced fluid. Most of the wells were completed by installing 4 ½-in. liner with swell packers and ball-actuated stimulation ports without cementation.

The lesson learned on three offset wells in this area found that a bend setting of 1.15° has contributed to reduce tortuous well paths, controlled dogleg severity, and stayed in a very tight target interval while drilling the lateral section of 10,000 ft along the hole. The reduced spiraling saved countless hours of reaming requirements and allowed the Swellpacker→ liners to be run to TD without significant working. Drillstrings, bottomhole assembly (BHA), bits, the length of the lateral section of horizontal and drilling fluid were all considered.

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