Well Abandonment—A ‘Best Practices’ Approach Can Reduce Environmental Risk

摘要

Wells are drilled and completed for a typical production life ofrn15 to 20 years. After a well is depleted, it must be abandoned sornthat the permeable intervals penetrated by the wellbore arernisolated. For an abandonment to be successful, it must stabilizernthe wellbore and its associated annuli until geologic forces canrnre-establish the natural barriers that existed before the well wasrndrilled. The isolation of the hydrocarbon-bearing intervals,rnoverpressured intervals, uncemented annuli, and any freshwaterrnintervals penetrated by the wellbore is critical to successfulrnabandonment. The abandonment plan must be based on the typesrnof fluids contained in reservoirs and the well?s mechanicalrncondition at the time of abandonment. Government regulationsrnfor well abandonment are minimal guidelines for abandonment,rnand should not be considered finite answers to environmentalrnsafety issues.rnThis paper describes ?best practices,? concepts and techniquesrnthat operators should consider during abandonment planning,rnthat will help ensure effective isolation within the wellbore.