Blowout & Kill Simulations

Oliasoft’s blowout and dynamic kill simulator is built on the BlowFlowengine, developed by NORCE together with Equinor and a consortium of oil companies.  It represents the only solution capable of performing stochastic blowout calculations according to the new guideline from Norsk Olje & Gass, and can also be used to check that oil companies drilling in the US is compliant with API standard 53; regulated by Bureau of Safety and Environmental Enforcement (BSEE). (⇩ Report)

When simulating both blowout potential and dynamic kill requirements, most reservoir and fluid properties are largely uncertain, especially for exploration wells. Oliasoft’s blowout engine enable users to express input parameters by probability distributions. This way the uncertainty is maintained, enabling probabilistic simulations, rather than deterministic – which is the approach taken by the blowout & kill simulation tools used in the industry today. Thus, the results from a blowout simulation should be expressed by a probability distribution rather than a single value. Hence, by performing a probabilistic simulation with input values expressed by probability distributions the simulation results will also be expressed by a distribution, covering the probability spectrum.

Determining the blowout potential of a well design is extremely important. For the Montara and Deepwater Horizon incidents, the actual blowout rate was more than 5 times higher than the simulated potential. It is essential to include the effect of uncertainties in order to implement meaningful risk reducing measures

By expressing the blowout results using a probability distribution the software generates a probability range expressing different scenarios such as P10, P50 and P90 in addition to a cumulative distribution function (CDF-curve). This approach enables the user to choose different scenarios to analyze further, and will increase the use of the blowout results. The user can for example choose the worst case scenario as input values in oil drift modelling and environmental risk analysis or choose the most likely scenario as input in a kill simulation.

Oliasoft’s WellKill engine simulates dynamic kill rates for both off-bottom-injection and relief-well kill-scenarios, combining the static head of a kill fluid with frictional pressure losses. The dynamic kill is modelled with the use of two-phase flow simulations based on conservation equations and closure laws for the different flowing phases. This results in a better understanding of blowout scenarios and parameters such as bottom hole pressure, flow rate, pump rate, mud volume and kill fluid density. Oliasoft’s kill engine calculates both upper and lower kill limits using zero-derivative and advanced finite volume methods, presented in industry standard formats to determine if the kill operation is possible with one or more injection points. The numerically predicted results produced by a kill simulation will be a ¨kill program¨ providing the pump pressure and pump power required to kill the chosen scenario using predefined kill mud weight and kill rate in addition to dynamic plots visualizing the downhole pressure and flow rate, pump pressure and power, kill rate and mud consumption, and wellbore volumes.

Oliasoft’s technology infrastructure enable  simulations to be performed either client side or server side, where the latter is necessary for computationally heavy scenarios. Integration of other modules enables automatic recalculation of blowout & kill when changes are performed at any point in the calculation chain. Additionally, by integrating the blowout & kill simulations into the well planning software, the drilling engineer will always have control over every choice being made regarding inputs and settings related to the simulations. The time it takes to complete the blowout & kill simulations will also be reduced, making it possible to optimize the well design based on the simulation results, which again will reduce the number of overdesigned wells.