High levels of drag, especially in horizontal and extended-reach operations, can be a major concern during sliding or rotating. Drag reduces drilling efficiency by requiring increased energy input, primarily through increasing torque and weight on bit, to achieve the desired rate of penetration (ROP). Reduced drilling efficiency results in excessive tool wear, lower ROP, and poor directional control. Of the several methods the industry uses to combat drag, the scope of this study was focused on the use of a pulse generator paired with a displacement generator, which makes up a drilling agitator tool (DAT). A DAT is commonly used in extended lateral formations to improve weight transfer to the bit in vertical and nonvertical drilling applications. The operational principal of the DAT is the production of a pressure pulse that causes a repetitive axial motion in a shock tool. This paper compares offset run data between two DAT cases—one run with a traditional DAT and the other on a new, efficient, "high-energy" DAT (HE DAT). The run performance in similar portions of vertical and horizontal sections was compared between the two systems.
This study was based on data collected from a pressure pulse and axial displacement data recorder from horizontal wells in the STACK play drilled by Devon Energy. The objective of this study was to observe the performance of the HE DAT and determine if there was a noticeable gain in performance in terms of drilling efficiency and ROP as compared to a standard DAT. These results are discussed in detail and supported by high-resolution data collected during drilling.
The data analysis presented here provides an in-depth look into the operation of the HE DAT's performance as compared to the standard DAT in a very similar offset well. Overall, a 20 to 25% increase in ROP with the HE DAT was expected, effectively validating the enhancements made to the tool. This study collected data using data recorders—novel, small, self-contained devices measuring axial vibration, internal pressure, temperature, and axial displacement—located directly above and below the DATs to make a comparative assessment and deliver information about drilling data that was otherwise not available via conventional downhole measurement tools.