Application of Targeted Bit Speed (TBS) Technology to Optimize Bakken Shale Drilling

Abstract

Abstract Since 2010, shale drilling in the North Dakota sector of the Bakken has seen an industry changeover to long laterals (> 7,500 ft) with the majority being closer to 10,000 ft. These longer laterals require a tremendous engineering effort and create several issues with hole cleaning, ledging and reduced rate of penetration. In order to improve performance in these laterals, operators have long been looking for an economic alternative to rotary steerable systems, while maintaining their inherent benefits. A new system to achieve 3D directional control has been developed to improve drilling efficiency using Targeted Bit Speed (TBS) technology. The system uses a conventional positive displacement motor with a bent housing and a measurement-whiledrilling (MWD) tool that mimics many of the features offered by a rotary steerable system. The steering technique is achieved by accurately modulating the flow of the drilling fluid through the drillstring. This allows rapid variations in the drilling parameters to accurately control the bit speed along the desired toolface setting. If the wellbore objectives cannot be achieved in rotary mode using TBS technology, then the mud motor can be oriented in a conventional manner to follow the well plan. This paper examines the results of two horizontal wells drilled in North Dakota. The first well was drilled to the planned total depth (TD) using TBS technology; the second well (not using TBS technology) had to be terminated prematurely, due to high torque and drag. This paper focuses on showing the improvement in the drilling process that this new technology offers by way of key metrics, such as reduced drilling time and improved wellbore geometry, with consequent cost savings.