New Mathematical Analysis to Identify Channelling and Coning in Oil Wells Removes Diagnostic Uncertainty of Conventional Approaches Provides Timely Mitigation to Arrest Decline

Abstract Reservoir heterogeneity coupled with unoptimized production practices often leads to premature water breakthroughs in oilwells due to channelling or coning. Thus, resulting in unwarranted production decline and the inability to realize committed reserves. Accurate and timely Identification of channeling or coning helps to put the right mitigation plan to revive production and monetize stranded reserves. Such prudent well management helps to extend economic life. Current industry approaches including Chan plot often have significant uncertainty in diagnosing channeling or coning. This warranted the need for a new approach to identify channelling or coning more prudently. A novel mathematical approach is formulated using the technique of Derivative of Cumulative to easily identify channelling or coning in producers. This technique provides a clear signature of the premature water breakthrough forms of channeling or coning. More beneficially, it helps to eliminate the uncertainty in results from currently used Chan plot as often the production data has variation due to frequent choke management. The production data of many oil wells having faster rise of water cut have been analyzed both by this new technique and Chan plot to investigate channelling or coning. The Chan derivative plot shows high scatter in many wells and thus provides significant challenge in fitting a trend line to get a meaningful interpretation. The Chan plot thus often needs the support of PLT/RST logs before concluding on the nature of breakthrough and fit the right trend line. While the new technique results in significantly low scatter, showing distinct trends to identify channelling or coning. Thus, often can save the cost of diagnostic logs for identification. This paper provides a methodical screening of the new technique and a detailed analysis with the same of actual field data of wells having channeling or coning as confirmed by PLT/RST logs. All actual cases have been compared with the Chan plot to show how the new technique improves diagnosis. Included also field examples where Chan plot could not provide meaningful interpretation, which then analyzed by this new technique showed distinct results. Results by using this new technique, have then been successively confirmed by PLT/RST logs and thus acted as successful blind testing for this new technique. It has become a helpful tool for well production management.