Permanent-Type Well Completion

Very encouraging progress has been made in the development of the permanent-type well completion which decreases considerably the cost of completions and workovers and aids in the acquisition of reliable reservoir information at low cost. Completion and remedial operations are performed with tools which pass through the well tubing. Perforating and plug-back operations can be done with the tubing in place and do not require pipe-handling equipment. Because of the many advantages afforded by this method, development work is going forward in anticipation of ultimately being able to use it to perform all usual well completion and work over operations. Effort is also being directed to the development of a more permanent type of lift equipment suitable for use with the permanent-type well completion. Introduction The permanent-type well completion is one in which the tubing and well-head are set in place only once in the life of the well and the completion or remedial work is performed through the tubing with a tubing-type perforator, a retrievable tubing extension, and other wire-line tools. This new type completion has made possible the saving of one to two days' rig time in the completion of each of several hundred wells during the past two years, and use of equipment developed for this type of completion has resulted in a 75 per cent reduction in costs of certain types of workovers. In addition, the more reliable indication of the commercial value of a reservoir and the more accurate general reservoir information made possible promise to be of even greater value in oil recovery than the reduction of costs for completions and workovers. Recently, several wells were worked over by using the retrievable tubing extension suspended on a swab line to plug back with cement and then perforating a higher producing interval with the tubing-type perforator, thus opening the way for complete through-the-tubing workovers which may be performed without pipe-handling equipment or mud. Those items attendant to the use of pipe-handling equipment and mud, such as board matting, rig substructure, and pits, were also eliminated. There are indications that the elimination of drilling mud during completion and workover operations will frequently give increased well productivity, as plugging of the perforations will not occur.