Field Premiere of Along-String Dynamic Measurements for Automated Drilling Optimization Using Downhole Information

Abstract

The question of what is happening downhole is routinely answered through human interpretation of surface data. While widely available, subsurface data is typically pulsed from near the bit and acquired at low frequencies, resulting in considerable latency issues. Consequently, the majority of acquired subsurface data is memory-stored in drilling tools for post-well analysis, which, while useful for drilling subsequent wells in similar environments, does not allow for early detection and mitigation of unexpected downhole events. This paper details field deployments of a system that offers real-time downhole measurements from the bottomhole assembly (BHA) and from two additional positions along the string. The system aids wellsite personnel and yields consistent performance through the use of automated closed-loop surface machinery control based on these real-time downhole measurements through an 80Hz downhole data-stream. The high-frequency data acquisition system provides sufficient sampling resolution to diagnose many drilling dysfunctions in real time, including damaging events such as severe torsional oscillations leading to stick/slip, bit-bounce and whirl-induced vibrations. This allows mitigation strategies to be quickly evaluated and implemented based on adequacy and performance, preventing damage and improving performance. In addition, high-frequency toolface and survey data promoted directional drilling and sliding-drilling efficiency in the build and horizontal lateral. This field test marks the premiere of along-string dynamic measurements above and beyond the pressure and temperature measurements that were already available to identify, analyze and control events along the wellbore. These include detecting tri-axial vibrations and rotation in real time, allowing drilling phenomena to be identified and quantified while also highlighting the dynamic variability of drillstring rotation and motion. In addition, the system improves the efficiency of hole cleaning and, through equivalent circulating density (ECD), evaluation along the string. The system provides clarity regarding what is happening subsurface and offers automated rig control based on high-resolution downhole information from along the drillstring. Recommendations are offered, providing useful techniques for automation and drilling optimization projects.