During an underbalanced milling campaign in an area of the Montney formation in the Western Canadian Sedimentary Basin (WCSB) in 2017 to early 2018, a well servicing company experienced a series of three coiled tubing complete immobilization incidents. An initiative was created between the well servicing company and the well operator to address the growing challenges associated with underbalanced milling.
The approach was a yearlong process of introducing real time downhole telemetry and fluid loss agents to milling operations. Downhole telemetry was utilized to better understand motor performance, decrease motor damage and identify the key factors in lost circulation events. Far field diverting agents were then pumped through the cleanout or milling bottomhole assembly (BHA) to optimize fluid returns and reduce the required nitrogen volumes.
After tracking results, best practices were put in place to ensure a repeatable operation. Not only were immobilization events eliminated, but achievable depth, well complexity and operational efficiencies were all pushed further than predicted. By utilizing data from the downhole telemetry tools, fluid inflow in specific zones was identified as the reason for lost circulation. Best practices were then put in place to identify and rectify fluid inflow in less time than previous practices. Overall time savings were realized by the operator along with repeatable results that reduced financial risk.
This paper outlines the technical details that contributed to a new and unique approach to underbalanced coiled tubing interventions that has exceeded the limits previously considered possible in challenging well conditions.
Number of Pages
Pope, C.Charlton, A.Inscore, J.. 2017. Stop, Drop and Circulate; An Engineered Approach to Coiled Tubing Drillouts. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 9-11 October. SPE-187337-MS. http://doi.org/10.2118/187337-MS
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