Management: Well-Integrity Management and Profitability
- Gunnar Andersen (TecWel A/S)
- Document ID
- Society of Petroleum Engineers
- Journal of Petroleum Technology
- Publication Date
- July 2006
- Document Type
- Journal Paper
- 40 - 42
- 2006. Copyright is retained by the author. This document is distributed by SPE with the permission of the author. Contact the author for permission to use material from this document.
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Well-integrity management (WIM) is an important part of health, safety, and environment and quality-assurance programs in the petroleum industry. Still, there is room for improvement; it is a matter of protecting an investment. Hardly any other industry is building such “expensive factories” as the petroleum industry when it drills and completes a well. Then again, hardly any other industry is putting so few resources into maintaining and running these “factories,” or, in other words, not making the maximum profit. This is not because of a lack of brains, capacity, or financial muscle.
Ranking a project and justifying its value should be done by calculating its net present value (NPV). Every company should perform NPV calculations before approving or disapproving a well-intervention project. The NPV model accounts for the long-term prospect of a project and is used to model the economy of the well’s remaining life. The model does not necessarily come up with exact values of the project but will rank the project among other projects and make its value visible.
WIM has been described as an “unimpaired condition based on a standard,” indicating that it is something forced on operators. But a more easily understood definition is “prevention of uncontrolled flow of fluids.” When things go wrong, it can have catastrophic consequences, such as loss of lives and equipment or contamination of groundwater reservoirs. It is fair to say that WIM is focused on the drilling and completion phase of a well, and a well’s life cycle has room for improvement all the way from the design through the operational phase to the final abandonment. The lack of WIM in all of these phases is based on a restricted understanding of its benefits. Some wells may have a lifetime of a hundred years, including possible sidetracking out of old casings and a final abandonment that lasts “forever.” It is a huge task the well owner has undertaken. But that task can be managed under a profitable WIM system consisting of three factors: preventing leaks, identifying leaks, and stopping leaks.
Operating a Well
During the design phase of a well, it is prudent to look at its planned life cycle, keeping in mind that some day the well will be abandoned. A well can be produced from a high-pressure reservoir; then, later in life, it may require gas lift, while at a later stage, it may serve as an injector before it is abandoned. In addition, there might be plans for sidetracks. Such a life cycle requires the selection of proper material, especially in the casing. The tubing is more cheaply replaced and is the part of the well exposed to the most hostile environment. Tubing cannot be expected to last forever. It is often more prudent to sacrifice some quality initially in a well to reduce investment and then compensate by a more active maintenance program during operation. It also may be economically profitable to postpone the investment. But it is not possible to design, drill, and complete a well that will escape the need for intervention throughout its lifetime (unless its lifetime is just a few years).
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