This paper presents a decision-making approach based on the analytical hierarchy process (AHP). The general AHP approach is outlined and discussed, and applied to important decisions during the engineering phase of oil and gas wells. A case study involving selection among five different system options for managed pressure drilling (MPD) is described and discussed. The most favorable system option is chosen based on decision criteria like: operational profit, project reliability, working environment, personnel safety, risk to environment, and project cost. The decision process is shown in detail and is illustrated by results obtained by using the computer program DecisionPlus.

New drilling technology imposes risk and uncertainty, both regarding the technology itself, and the application of the technology. During the design phase, the project team has to make a high number of decisions and to evaluate the risk and uncertainty related to the various options. In the petroleum industry, these issues are mostly discussed and decided in project meetings with representatives from the technical and geological disciplines. It is, however, a tendency that each topic is handled separately, and only related to the project delivery plan. It is believed that these discussions and decisions could benefit from a more holistic approach.

Decisions should always be based on the most updated information available at that point of time. However, information is often scarce or lacking, and too little time is available to make the decisions. Handling of dynamic decision situations may also be required, that makes it even more challenging. An example is changing conditions during the time span of a well engineering project. Important means in that respect will be to maintain good communication and cooperation in the multidisciplinary project teams throughout the decision process.

The AHP approach is found to improve the structuring of information and the communication between responsible persons in a project team. It leads to a significantly improved decision quality because the decision makers are able to organize and evaluate the relative importance of the decision criteria and the decision options more effectively. The consistency of the judgments is easily measured, and it is straightforward to reevaluate the judgments that are found to be inconsistent. It is, however, important to maintain a strong leadership throughout the decision process. A continuous focus and loyalty to the approach throughout the decision process are required in order to succeed.