Publications

Loss of annular integrity in a well can create loss of zonal isolation, which can significantly impair the productive capability and efficiency of the well. Effective remedial action must be based on a clear understanding of the underlying causes. It has previously been difficult or near-impossible to locate and explain the undesired fluid movements symptomatic of loss of annular integrity. Without this information, repair or control is at best a matter of informed guesswork or trial-and-error. An oil well in offshore Java was logged with the conventional production logging suite (PLT) in order to identify the water source affecting 100% of water cut production from a reservoir believed to contain oil. Nearby well on same structure proven to produce 1800 bopd, which cutting log, petrophysical data, pressure test data during drilling also suggest high confidence of oil in the reservoir. However the PLT survey failed to give an answer. The PLT data suggest that 100% water is coming from perforated interval, which is contradictive to the believed that the reservoir should produce oil. Acoustic Spectral Noise Analyzer Tool combined with fast response temperature were run in order to provide the answer to the dilemma of where water is coming from. In conclusion, the results were satisfactory for the operator as it shows water is coming from unperforated interval flowing to wellbore thru channelling behind casing to perforated zone, preventing less mobility oil to flow out from reservoir to wellbore. The development of an ultra-sensitive Acoustic Spectral Noise Analyzer Tool combined with temperature analysis techniques can significantly improve zonal isolation surveillance. Keywords: annular integrity, spectral noise, temperature.