Methods of detecting and locating tubing and packer leaks in the western operating area of the Prudhoe Bay field

Production in the Prudhoe Bay Unit Western Operating Area (WOA) began in June 1977. In the early years of field life few workovers were required. Most of these were to replace defective packers and thermocase tubing. An increasing number of mechanical failures of tubular components as well as worsening corrosivity of produced fluids has significantly increased the occurrences of tubing-annulus communication and corresponding workover requirements. In 1988--1989, 50 cases of tubing-annulus communication were found in the WOA. Of these, 5 were permanently repaired with wireline techniques and 3 were temporarily repaired until a workover could be implemented. The remaining 42 wells were shut in and worked over without attempting remedial measures. This paper discusses methods used at Prudhoe Bay for identifying problem wells and determining the exact location of the leak in naturally flowing, gas lifted, and injection wells.