By some industry estimates over 80% of hydraulically fractured land wells in North America employ the plug-and-perf method for zonal isolation. The dominant method for composite frack plug removal is through the deployment of a tubing conveyed hydraulically powered motor, or workover motor (WOM), to mechanically drill through plugs and remove the debris from the wellbore. Over 90% of Thru-Tubing Intervention (TTI) service companies provide to its customers is the application of WOMs to remove composite frack plugs. The effects of a mechanical failure in one of these motors during drillout operations is costly to both the customer and the respective service company. In many cases, a mechanical failure can cost several days of non-productive time (NPT) and more than double the financial burden of a drillout operation for both parties. A need was identified to validate traditional industry assumptions and refine drillout procedures by measuring and analyzing loads experienced by WOMs during live operations.
The purpose of this project is to measure and analyze the actual forces experienced by a WOM downhole during a live coil tubing conveyed drillout operation in order to experimentally prove or disprove industry tribal knowledge regarding the effects of traditional drilling parameters and procedures on downhole equipment and operational efficiency. The project involves the use of a data logging sub capable of measuring these forces in the bottom-hole-assembly (BHA). By examining the collected data; patterns and trends will be identified which give insight the most efficient procedures and drilling parameters as well as validate whether equipment is being utilized within operational limits under traditional assumptions. Additionally, the collected data could be used to identify additional opportunities to further improve the design, manufacturing, maintenance and operation of WOMs to meet the evolving challenges of drillout operations involving increased lateral lengths and stage counts.
These improvements to plug drilling procedures will reduce risk, operational time, and cost at the well site as well as internal cost associated with repairing and investigating potential mechanical failures that arise from operating WOMs beyond their limits. Future operations that include the measurement of downhole forces will enable even greater advancements in product reliability across the TTI product portfolio to further reduce the risk of additional time and financial costs to service companies and their customers.