Abstract
This paper describes a system developed for live well perforating and presents several case histories of its usage. The system has currently been used on 13 jobs on the Statfjord field. A total of 2106 m has been perforated, and the longest interval in one run has been 277 m in this particular field. The system has been used both for initial perforation on new wells and reperforation in live wells or in combination with zone isolation. Both injectors and producers have been perforated using this system.
An optimum perforating strategy can have significant impact on the economy of a well. During the past few years, techniques to perforate wells without having to use kill fluid have been developed. This reduced the cost and the problems that can occur as a result of kill the well. Kill fluid can not only affect the productivity of the wells, but may also create problems when produced back to the hydrocarbon process equipment. In addition, it has been noted that a higher and more stable sand free production rate will be obtained if the entire interval is perforated simultaneously.1
Perforating underbalanced allows the debris in the perforating tunnel to be cleaned more easily.2 If the well does not have to be killed, considerably less formation damage will occur, and the costs of kill fluid, lifting the well, and handling of the returned kill fluid are also eliminated.
This paper describes a new live well perforating method deployed with a hydraulic workover unit, that allows long intervals to be perforated in wells with complicated well trajectories
