Consequences of Rare Event During Oil&Gas Operations

The challenge

Operators put most of their effort into avoiding well incidents. Should a blowout occur, reducing how long it lasts and how much is spilled is the other critical part of managing well risk.

Our approach

kwantis developed a specialized model to assess the probability of a blowout and its consequences in terms of spilled volume and duration. The model rests on three pillars:

• Event tree analysis: the model identifies the probable blowout scenarios, their likelihood and the flow paths of hydrocarbons within the well, then builds an event tree that assigns a probability to each flow path.
• Flow rates: each scenario is given a distribution of flow rates, used to estimate the spilled volume and assess wellbore stability. This makes the evaluation of consequences probabilistic.
• Interventions: the model considers well bridging and human interventions such as capping stacks or relief wells. Each one is assessed for applicability, probability of success and time to occur, using industry data and statistical functions.

The model runs Monte Carlo simulations and takes the uncertainties into account.

The outcome

The methodology gives well-specific estimates of release duration and spilled volume. Operators can use them to evaluate the environmental impact and to size mitigation actions.

Because the uncertainties are part of the model, operators get a more detailed understanding of blowout risk and can make better-informed decisions.