Through Barrier Flow and Integrity Diagnosis of Complex Completion Enables Targeted Remediation to Reduce Water Cut and Restore Productivity

Abstract

Abstract Well completions featuring an ICD, swell packers and sliding sleeve doors (SSD) are a popular option in highly heterogeneous reservoirs and homogeneous with barriers. However, this arrangement presents challenges for evaluating the integrity isolation in terms of the swell packer's isolation of layers. The subject well, an oil producer in Raudhatain field, Kuwait, was completed with an ICD with seven packers and five SSDs. The well showed a 100% water cut from the start of production. This paper describes a technique that combines high-precision temperature surveys and a spectral acoustic method to enable accurate flow profiling and integrity evaluation in such wells. A diagnostic survey was planned for the subject well. This was designed to determine if there was flow from below the survey interval, establish whether the SSDs were active and check the integrity of the swell packers. This comprehensive study combined results from high-precision temperature surveys and spectral acoustic surveys. The analysis identified the contributing intervals of the formation behind the ICD blank zone. Each of the swell packers was assessed for possible leaks and the performance of each SSD was evaluated. The survey indicated that two of the SSDs were not contributing to production and that one of the swell packers was being bypassed. The temperature divergence between shut-in and flowing and temperature gradients suggested a significant inflow of fluid from a source, below the survey interval. The survey provided an accurate evaluation of swell packer and SSD performance and enabled the operator to formulate an effective and efficient remediation strategy. This operator performed a straightforward workover program that involved setting a coilflate (plug) in the ICD shoe where damage was found. Confirmation from the diagnostic survey that the swell packers were holding above the planned depth for the plug suggested that this kind of workover would be effective. After confirming that the plug was holding (by pressure test), a surface-produced gas oil ratio (PGOR) test showed that the water cut in the well had been reduced to 74% and there was now a significant inflow of oil. The result of the diagnostic survey and subsequent workover operation enabled the operator to kick-start production from what had been a nonproductive well. The combination of a high-precision temperature survey and a spectral acoustic method enabled accurate flow profiling and integrity evaluation in a well with ICD, swell packers and SSDs. These accurate assessments of reservoir flow and well condition would not have been possible with conventional production logging [PLT] techniques.