Today's competitive environment within the natural gas industry requires gas storage operators to apply various risk management practices to effectively maintain and manage gas storage facilities. One operator's business management strategy includes tracking two key monitoring and maintenance parameters – reservoir integrity and storage well mechanical integrity. Reservoir integrity management consists of applying recognized standard reservoir engineering methods to monitor pressure and volume relationships. A storage well Condition Assessment Program is proposed to provide a consistent means to monitor and assess storage well mechanical condition in order to optimize limited capital resources applied to asset integrity management. A relative risk assessment methodology is proposed to identify candidates for storage well reconditioning programs. A standard relative risk equation is applied to generate a relative risk profile based on certain probability of failure and consequence of failure parameters. By normalizing the information used in evaluating mechanical condition, wells within a controlled population are examined as possible reconditioning candidates. Introduction The post-Order 636 environment has resulted in an increased focus on and awareness of underground gas storage. Storage operators are seeing an increased customer emphasis on storage reliability and flexibility as new markets arise. Storage assets must be effectively maintained and managed to assure the integrity and performance of the facilities in order to meet present and future storage obligations. Columbia's storage business management strategy includes monitoring and maintaining two key parameters – reservoir and mechanical integrity. Monitoring reservoir integrity involves the application of standardized engineering methods, such as monitoring foreign well activity and annual gas volume verification. What has been missing is a standardized method for evaluating mechanical integrity. Columbia's Condition Assessment Program (CAP) is intended to provide a consistent means of monitoring and assessing mechanical condition, thus optimizing asset integrity management. To assure the physical integrity and mechanical soundness of storage facilities, several general strategies were implemented. These included:Properly maintaining storage wellsImproving data collection and processing techniquesCreating records management systemsAddressing environmental issuesUsing advanced technologiesDeveloping a continuous improvement program CAP helps to accomplish these tasks by assessing the relative risk of Columbia's well assets. This is achieved by using existing information compiled in databases and applying it to a standard risk analysis procedure. CAP will refine work requirements and improve the reconditioning program prioritization process, and aid in optimizing asset integrity capital expenditures. History. Columbia Gas Transmission owns and operates approximately 3700 gas storage wells in 5 states. These facilities provide a working gas capacity of 243 Bcf and deliverability of 4.4 Bcfd. Columbia's storage well risk assessment initiative began in earnest in 1994, when a corporate re-engineering process led to a program recommendation of working over 150 wells (1,500 total over 10 years) and plugging 40 wells per year. Management challenged these recommendations with the following questions: which 1,500 wells are they and which one will be worked on first?

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