Abstract
The drilling of wells for which there is a small pressure margin is often challenging with respect to well control issues. A kick, which occurs if the wellbore pressure drops below the pore pressure, is one of the major risks being dealt with in the planning phase of the well. A kick can occur due to several factors, such as human errors, equipment failures or a wrong pore pressure prognosis. Since the ultimate consequence of a kick may be a blowout, it is essential to be able to assess and reduce the probability of a kick occurring.
In order to be able to quantitatively assess well control risks, a tool and methodology called KickRisk has been developed for supporting technical and operational decisions in the well planning phase. The methodology is based on a probabilistic framework which takes into account a variety of factors that may cause a kick, and the calculations are executed by means of Monte Carlo simulation. The methodology allows the analyst to:
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Quantify the probability of kick and fracturing
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Systematize all information relevant to the occurrence of a kick
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Pinpoint critical factors
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Evaluate alternative solutions on e.g. well design and operational procedures
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Quantify the effect of risk reducing measures
This paper will present the overall probabilistic approach and the composition of the KickRisk model. Further, it will be shown how the KickRisk methodology can be incorporated into a risk management workflow. The practical application of the methodology will be explained through a case study.
