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Abstract
It is important to be able to have an overview of the well integrity at all times. Statoil, Norsk Hydro and Total E&P UK Ltd. therefore joined forces in a JIP with ExproSoft to develop a software application for data collection, handling and reporting of well integrity. The resulting software is called WIMS, short for Well Integrity Management System. A pilot version was installed and tested by the operators’ spring 2007, prior to the release of the final version.

WIMS enables a uniform and structured approach for describing the status and handling of well integrity issues throughout the production phase of a well. This paper discusses the philosophy behind how WIMS handles well integrity information from when the well completion is installed until the well is permanent abandoned. The well integrity data follows the well from it is new, and is continuously updated when a well leak or other well integrity derogations occur. To assist in leak diagnosis, risk assessment and defining corrective measures; test results, continuous pressure and temperature data, annuli top-up and bleed-off data is presented in WIMS. The paper also describes how information is aggregated from well level and summarized to give an overview of the well integrity status for any defined cluster of wells.

WIMS is developed with the input and needs from three different operators, and the paper also includes a discussion of how WIMS will be used by the three operators.

Apart from the need of systemized and easily communicated well integrity data, the success of WIMS is dependant on the implementation process. Very often the implementation process is neglected, and there are numerous examples of failed attempts at introducing new software in the oil and gas industry. The paper shares the experience from the evaluation and implementation of WIMS.

Introduction
The NORSOK D-010 standard [1] describes well integrity requirements, where well integrity is “the application of technical, operational, and organizational solutions to reduce risk of uncontrolled release of formation fluids throughout the life cycle of the well.” Well integrity has always been focused on in the design of new wells, but well integrity in the operational phase is now of increasing concern. Because of high oil prices, new technology for increased recovery, and government incentives, it is now possible and profitable to extend production beyond the assumed design life. However, life extension may result in more frequent critical failures involving leakages to the environment. The outcome of such leaks can be catastrophic. 10% of the wells on the United Kingdom Continental Shelf (UKCS) were shut-in due to well integrity problems during the last five years (from 2005) [2]. The article refers to a study based on interviews with 17 UKCS operators. Approximately 83% of these operators experienced well integrity problems. Other topics highlighted in the study are [2]:

• Little is known about the implications of operating wells beyond their design lives, and UK operators found growing concern about the safety, environmental, and economic standards associated with well structural integrity.
  
• More subsea wells will have implications on the identification and remediation of integrity problems.
  
• 32% of UKCS completed or suspended wells are more than 20 years old, with some over 38 years old.
  
• Well lives are being extended, older assets are being sold to smaller operators, and the number of subsea wells is increasing.
  
• Erosion, corrosion, and fatigue problems associated with prolonged field life are thought to have led to more frequent well integrity problems.
  
• Some operators believe that well functionality can be maintained, regardless of age, through inspection, monitoring, and maintenance. Nevertheless, 87% of the operators questioned believe that the incidence of structural integrity problems is increasing and will continue to do so.