The operator of an offshore jackup rig in the North Sea required safe and efficient deployment of the completion string without killing the well during tripping. A solution other than a snubbing unit was needed because of the length of the completion string, which included 12 swellable packers for 13 zones. To provide for a safer, less-expensive, and efficient method of tripping pipe, the operator chose a downhole-isolation-valve (DIV) solution that allowed for the process to be performed in a conventional manner under conditions of complete well control.
Introduction
During the past decade or so, the industry has developed drilling methods to address more-complex and -challenging prospects such as ultradeep prospects, deepwater applications, and high-pressure/high-temperature wells in order to continue meeting the worlds’ demand for energy. This seemingly insatiable demand has led to the development and widespread use of unconventional techniques such as underbalanced drilling (UBD) or near-balanced drilling and various forms of managed-pressure drilling, including pressurized-mud-cap drilling (PMCD) and constant-bottomhole-pressure drilling with their attendant well-control and safety challenges.
