Abstract

Cook Inlet Energy (CIE) had several wells producing gas from the Tyonek formation, which overlays the oil-bearing Hemlock formation. CIE needed to obtain a fluid sample and/or well test from the Hemlock without interrupting flow from the Tyonek. This paper discusses methods for independently testing a particular zone in a comingled completion, without requiring a rig or a production interruption.

The procedure began with setting a cement retainer across the Hemlock with tubing-conveyed perforating guns made up to the bottom. Next, a stinger was run on the end of a coiled tubing (CT) string, which landed in the retainer. This isolated the inside of the CT from the Tyonek formation and put it in communication with the perforating guns. The CT was then cut at surface and pressured up with nitrogen to fire the perforating guns. This allowed the Hemlock formation to be tested through a temporary CT velocity string without ever shutting in the Tyonek formation. Also addressed in the design and execution phases were the maintenance and confirmation of well barriers, restricted centralization, inability to confirm spaceout, and unusually sized components that had to be custom designed.

This operation was executed in June and July of 2014. It was a challenging and unconventional job, which required major collaboration. Ultimately, the decision was made to kill the Tyonek formation during the CT cutting stage, as the health, safety, and environment (HSE) exposure was intensified by the novelty of the method. Recommendations are made in this paper to remove this necessity in similar jobs in the future. The well was brought online successfully and is still producing gas in 2016. The job was executed effectively, efficiently, and without major cost or time overruns.

In a depressed price environment, operators must seek creative solutions to execute well work at a fraction of the previous cost. This paper shows how jobs that would traditionally necessitate a workover rig or snubbing unit can be reimagined with less costly intervention equipment while maximizing the flow time of producing wells.

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