A Comprehensive Expert System for Diagnosing and Assessing Formation Damage

摘要

An expert system capable of diagnosing the potential ofrnformation damage caused by clay swelling, fines migration,rninorganic scale deposition, and organic scale precipitation wasrndeveloped and implemented. In this manuscript, we presentrnresults for the expert modules pertaining to asphaltenernprecipitation and asphaltic sludging. These modules estimaternheuristically the potential for asphaltene precipitation, and forrnasphaltene sludge due to acidizing.rnRules of thumb pertaining to asphaltene precipitationrncaused by solubility incompatibility between crude andrnsolvent were collected. Membership functions to fuzzify thesernrules were constructed. The asphaltene module is capable ofrnestimating the potential of asphaltene precipitation for a widernrange of phase-behavior reservoir conditions, and for a muchrnwider range of live and stock-tank crude compositions thanrnwhat can normally be handled by a human expert. The acidrnsludge module makes its judgment based on factors such asrnacid strength, acid type, solvent preflush, iron controlrnadditives, Ferrous and Ferric ion concentrations, mutualrnsolvent concentration, corrosion inhibitor type, and surfactantrntypes used. A model has been formulated to predict thernamount of asphaltene sludge that is likely to form as arnconsequence of crude-acid contact.rnA graphical user interface using various templates for datarninput and modules output has been built to make the expertrnsystem user friendly. The expert modules have been validatedrnusing a range of field data. This expert system gives thernadvantage of automating the diagnosis process pertaining tornformation damage.