RPS evaluated the potential effect of hypothetical land-based crude blowouts from different reservoir fields located in East Africa in support of on-going oil field development contingency planning in the region. The client was interested in understanding how quickly and how far oil would travel on land for a variety of oil release scenarios, paying special attention to oil potentially reaching water bodies. To predict the path of spilled oil, RPS utilized their OILMAPLand model, which estimates the route with the highest slope, determines where oil may pool and volume of the pool, and if oil reaches a lake or river. In addition, to more accurately simulate the complex overland flow of a highly viscous product, RPS implemented a new model based on the behaviour of lava flows. RPS used a combination of both models to predict the trajectory, timing, and mass that would potentially reach bodies of water.
High-viscous land-based blowout modelling
RPS regularly performs many land-based oil spill modelling analyses using its modeling system, OILMAPLand, which has the capability to track the trajectory of liquid hydrocarbon mixtures once spilled over-land. However, one of the main challenges of this study was the particularly high-viscosity nature and high content of waxes and paraffin of the crude oils of interest, which effectively reduced the down-slope transport. This means that a potential blowout on-land would generate a continuous flow of warm/hot crude oil that would slowly cool down and eventually solidify downstream. This particular rheological behaviour required RPS to develop a solution within the existing modelling framework.
To reproduce the trajectory of a potential release of these uniquely viscous and solidifying crude oils over land, RPS implemented a new model based on volcano-derived lava flows. The “lava” model was developed to simulate the path of a highly viscous fluid, such as lava, down a plane of slope determined by the OILMAPland simulations. With this new model, RPS was able to simulate the behaviour of the oil in order to answer client driven questions such as the distance the oil traveled overland and how long it took to solidify or reach a water body.