Abstract
The Amethyst B1D platform is a small normally unattended installation (NUI) in the southern sector of the U.K. North Sea. A coiled tubing (CT) intervention was required on well L04 during the winter because of gas contract demands and a combination of failures on production facilities and other wells. As this horizontal well had not produced since 1996, only limited well data was available.
This paper details the entire operation, from the choice of zonal isolation material (ZIM) and the equipment selection to the preparation for the multiple run CT intervention. The intervention design was tailored to operate within the operating environment of an installation with limited deck space, compact facilities, and only a 10-ton crane lift capacity. New equipment was manufactured and tested in the provision of this solution. Trials were performed onshore to optimize the rig up. Deck layouts, lifting, and boat loading plans were generated as a result of these trials. The rig up design was improved, and the equipment specifications were reviewed.
The basis of the actual intervention was to shut off the watered-out lower completion and isolate the unsupported annulus to prevent water from coning up from the toe of the well. This required the use of inflatable plugs and packers and the placement of a suitable ZIM. This paper details the knowledge gained during the planning, operational, and post job phases. This knowledge includes the importance that the logistical aspects provided to the intervention.
The well was put on production following the water shutoff operation and is now part of Amethyst potential.
