Post-Frac CT Intervention: An Overview of the Evolution of Practices in Extended Laterals in Unconventional Resources

Abstract This paper investigates post-frac Coiled Tubing (CT) intervention in extended lateral wells to evaluate the job design and the procedures implemented and how they dictate the evolution of practices, with more experience gained through the execution of many intervention operations. This paper will be conducting a systemic assessment on the latest improvements in CT intervention practices. In addition, a hindsight review of the evolution of practices will be presented. Following that, the steps undertook to tackle extended laterals for postfrac are revisited and assessed, further exploring the key enablers that allowed that milestone to be achieved repeatedly. In addition, the paper covers an overview on the evolution of practices in extended laterals as experience in intervening these wells increase. This will include best practices, an overview of the current level of efficiency, enabling technologies, and the new challenges to overcome paving the way forward. Upon looking at post-frac CT intervention, namely frac plug mill out, an improvement in practices is clearly noted with time. This improvement was enabled using tapered coil tubing string design which improved overall lateral reach, in addition to the use of specialized bottom hole assembly components such as hydraulic extended reach tools to aid in maximizing reach limits overcoming commonly faced issues like lockups and buckling. However, the changes identified new challenges and bottlenecks that require further studying and trialing to finetune the progress of CT operations moving forward. Preliminary results from the analysis done indicated that in CT milling operations, BHA components like motors and hydraulic extended reach tools are likely to be the new bottlenecks that dictate the progress and the smoothness of operations. A key enabler to overcome the bottlenecks presented and to fully unlock the potential & reach of CT intervention in extended laterals is to effectively work and collaborate with vendors and service providers to ensure tools are designed with a fit-for-purpose objective in mind. Such overview of the evolution of CT intervention in extended lateral wells will allow operators and service providers to maximize the lateral length of horizontal wells confidently, therefore, increasing the overall reservoir contact. This can all be done with mobile CT units, which will save valuable rig time in addition to being safer and more efficient.