Where conditions permit, the lowest cost completion with a tubing string leaves the tubing hanging from the wellhead with no packer used to isolate the casing annulus. This system allows production to flow up the tubing, the annulus, or both. The tubing string provides a means for the injection of inhibitors or the circulation of kill fluids. It typically includes a tubing retrievable safety valve with cement-through capability. In addition to the tubing, a seating nipple or a profile landing nipple can be providing for a standing valve or retrievable plug. The wireline entry guide will ensure reliable retrieval of wireline tools that might run past the tubing end.
Although this completion is economical, its use is limited by fl owing conditions and concern for protection of the tubular goods. Efficiency of fl ow can be compromised, and any leaks in the tubing or casing are difficult to detect. It also adds to the difficulty in gathering bottom hole pressure survey data.