Improving Field Economics Through the Use of Modern Casing-Corrosion Logging Tools and Techniques

Abstract

Abstract Because casing integrity is vital to the success of sidetrack, workover, recompletion, and enhanced-recovery operations, it is important to use reliable means of examining casing downhole. Modern casing inspection tools provide valuable diagnostic information for planning future work in a single well or an entire field. An operator wished to improve economics in a field where casing corrosion and water production was becoming a significant problem. The goal was to increase overall production and reduce production costs by (1) performing remedial work on wells that still had production potential and could be repaired, and (2) discontinuing production from the remaining wells. A critical component in the operator's plan was the selection of wells in which corrosion problems were not severe enough to preclude remedial operations. Complete histories were not available for every well, so the operator chose to use the latest technology and techniques in electromagnetic, acoustic, and video logging for corrosion detection and evaluation. Electromagnetic logs were used to grade casing, create pipe tallies, and identify pipe anomalies on the inner and outer casing surfaces. Acoustic logs were used to image the interior of the pipe, analyze internal corrosion, and study cement bonding to the casing. Video logs provided real-time views of the downhole casing environment for assessing casing problems, locating fluid entry points, and identifying fluid phases. This paper discusses the corrosion-logging program that was developed for this field. Examples are presented of different problems encountered, the solutions recommended, the results obtained from those solutions, the current status of the wells, and the economic impact of the casing evaluation program. The paper discusses the logs used in this program, and includes comparisons of different log types. Furthermore, photographs of casing pulled from one well are compared with an electromagnetic log run in that well. P. 761