Effective Casing Integrity Evaluation Using Multiple Technologies in a Challenging Downhole Condition, a Case Study from Abu Dhabi Onshore

Abstract Four different corrosion and leak detection evaluation technologies utilized in one of the wells located in Abu Dhabi onshore which encountered unstable downhole conditions and sustainable annulus pressure which suggests tubular integrity failure. The study discusses optimization of pipe evaluation tool(s) selection process through a comparison of these technologies across the problematic intervals for effective decision-making and better asset management. Deploying four different technologies (Acoustic Noise Detection, Ultrasonic Pulses, Mechanical Inner Wall Measuring and Magnetic Flux Leakage) in this particular tubular condition provided a full understanding of each tool measurements, outputs, and contributed to have a better guidance to choose the appropriate tool according to each specific well condition and objectives. The Spectral Noise logging offers a complete frequency distribution for identifying inter-reservoir communication including cross-flows behind casing and leak points, while Ultrasonic measurement provided qualitative indication of the possible damaged casing joints and scale build-up sections. The mechanical measurement provided a detailed inner pipe wall profiling and provided better understanding of the deposits profile. High-resolution Magnetic Flux leakage technology provided full circumferential inspection of internal and external metal loss overcoming the scale build up masking the inner pipe wall indicating high general corrosion Combining and Comparison of different technologies logs responses in same well provided comprehensive well integrity analysis. This comparison shows the limitations and advantages of each measurement principle, vertical and radial resolution differences between the four technologies especially in challenging downhole condition with scale deposition. After completing the SNL program possible multiple acoustic streaks typical for tubing and casing leaks were detected and supported by significant change on temperature gradient across several intervals, this allow the analysis for identifying the possible casing leak, however using only Noise detection was not conclusive assessment for the integrity of the casing. Ultrasonic tools suffered from acoustic signal distortion due to scales that is not uniform in nature. Mechanical multi-finger caliper measurement provided more accurate profiling of inner pipe radii and detected possible holes that were not masked by scale and it helped to confirm the SNL results. High-resolution magnetic flux leakage technology, responded to changes in metal loss which makes it to some extent immune to scale build up providing accurate quantification of severe external generalized corrosion with presence of many small isolated holes and It confirmed the highly corroded interval. The integrated analysis showed the conclusive leak detection scenario and way forward. This study describes the advantages and limitations of different pipe evaluation technologies in challenging downhole condition. In addition to drawing a guideline for optimum well integrity logging tool selection for each specific well condition and objectives to get conclusive results.