In coiled tubing conveyed through-tubing fishing operations, conventional jarring technology often creates limitations due to the requirement to repeatedly cycle the coiled tubing over the gooseneck in order to actuate and re-cock the jar. It is well known and documented in our industry that this repeated cycling leads to pipe fatigue and coiled tubing life reduction. Additionally, the low frequency, high-impact of the jarring assembly, may in some cases cause the fish to become wedged tighter.

Vibratory and high frequency impact tools have been found to provide operational and economic benefits over hydraulic, time delayed jarring tools in a variety of through tubing fishing and workover applications, particularly in horizontal and extended-reach wells.

As opposed to jars, vibratory type impact systems are capable of delivering significant impact forces at the fish with only limited set-down weight or over pull available making them particularly well suited to the constraints of coiled tubing operations. These hydraulically powered systems are configured to deliver downward impacts in compression and upward impacts in tension. Both downward and upward impacts are achieved without the necessity to cycle the coiled tubing between impacts, therefore significantly reducing low-cycle pipe fatigue. Additionally, when a fish is stuck in sand or debris, temporarily suspending or liquefying sand particles by lighter high frequency blows as delivered by an impact tool while over pull is applied offers a higher degree of success in freeing the fish.

This paper will outline the uses and advantages of down-hole high-frequency vibration technology from a coiled tubing perspective and also describe the development and laboratory testing results of a new, modular vibratory impact tool offering a significantly reduced operating length yet delivering greater impact thus increasing the operating envelope for such tools adding demonstrable value to a variety of coiled tubing fishing and workover operations.

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