Eagle Ford Study Pinpoints Keys To Success In Drilling 'One-Run' Wells By Luke S. Walker and Kathryn J. Patton HOUSTON-In early 2014, BHP Billiton began experimenting with well design variations to optimize and uniformly align its multiple-rig Eagle Ford drilling program in Karnes and DeWitt counties in South Texas. One variation eliminated the need for two bottom-hole assembly configurations to drill from surface casing to total depth. Horizontal wells in the area traditionally have required at least two BHAs: one to drill an 8¾-inch hole vertically from the 95⁄8-inch surface casing to the kickoff point of the curve, and a second 8¾-inch BHA designed specifically to drill the curve and lateral sections. Significant reductions in rig time and the amount of equipment used in "one-run" applications result in increased economic efficiency-specifically time and cost savings associated with eliminating a trip to pick up a second BHA-and create a simpler operation that provides a safer work environment for rig personnel. After drilling successfully from surface casing to TD using a single BHA on a few initial wells, several problems were encountered, resulting in multiple unsuccessful one-run attempts. What began as a study to determine the best bit and BHA combination evolved into a multivariable study to identify the key factors for achieving successful one-run wells. The ultimate goals included increasing the likelihood of successful runs, and predicting when and where single-BHA runs should be attempted. APRIL 2016 61