Downhole Data Analysis for Pressure-Pulse-Generating Tool Coupled with a Shock Tool

Abstract

High levels of friction, especially in horizontal and extended-reach operations, can be a major concern during sliding or rotating. Friction increases drag, which increases the required torque and weight on bit (WOB), thereby reducing efficiency. Other related issues include excessive tool wear, lower rate of penetration (ROP), and poor directional control. There are several methods used by the industry to combat the torque and drag phenomenon, one of which is the use of a drilling agitator tool (DAT). A DAT is commonly used in extended lateral formations to improve weight transfer to the bit. The operational principal of the DAT is the production of a pressure pulse that causes a repetitive axial motion. A DAT consists of a pulse generator and displacement generator, also known as a shock tool (ST). The system ultimately produces axial oscillation in the drillstring, which helps reduce the effective frictional coefficient regardless of whether the string is sliding or rotating. The DATs are sometimes used in conjunction with standalone STs, which are placed in a remote location where the DAT displacements may be out of range. Standalone STs placed at the bottomhole assembly (BHA) also help isolate downhole dynamics, improving drilling efficiency. The objective of this study is to see how a DAT and ST combination impacts drilling. Furthermore, a closer look is taken at the impact on the operational drilling efficiency of drillstrings with a DAT and standalone ST. These results are discussed in detail and supported by high-resolution data collected during drilling. The information presented in this paper can be used to evaluate the performance of DAT and ST combinations, their impact on drilling performance, and their zone of effectiveness. The data analysis presented here also provides an in-depth look into the operation of a DAT and how the BHA below the DAT is impacted by its operation. This study takes data from a novel, small, self-contained tool located directly above and the DAT, ST, and the BHA. This tool measures axial vibration, internal pressure, temperature, and axial displacement, allowing a comparative assessment to be made and delivering information about drilling performance that is otherwise not available via conventional downhole measurement tools. This new measuring tool specializes in collecting high-speed data in memory mode and is dedicated to the analysis of the operation of the DATs.