Abstract
Site-specific challenges related to water depth, geological and environmental conditions, rapid technological development and increased demands with respect to cost effectiveness and environmental consciousness are all factors that impact the uncertainty picture related to drilling and well operations. Thus risks related to undesirable outcomes such as kick and blowout are also influenced. It is however questionable whether the ruling practices for use of quantitative risk analyses in planning of the operations keep up with this development. As the nature of the operations change drastically, use of overall statistics from earlier incidents hardly provides a satisfactory basis for decision making. Such statistics does not reflect the exposure of the specific well to the various kick and blowout mechanisms or the effect of measures introduced to reduce the probability of these mechanisms to occur. KickRisk, a new risk analysis tool with focus on kick and blowout is developed in order to improve the basis for risk-based well control planning. The idea behind this tool is a more detailed system modeling, which enables the planning to include more well- and operation-specific information in the analyses and to obtain a more differentiated risk description. Uncertainty is expressed through probabilities related to factors at a detailed system level and is propagated in kick and blowout probabilities through the logic of the model structure. The intention of this paper is to discuss the requirements for risk analysis methods with respect to kick and blowout in well planning and how these can be met in practice. The principles of the new tool KickRisk are described and the experiences from case studies on real wells are presented.
