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Generalized multi-scale stochastic reservoir Opportunity Index for enhanced well placement optimization under uncertainty in green and brownfieldsWell placement planning is one of the challenging issues in any field development plan. Reservoir engineers always confront the problem that which point of the field should be drilled to achieve the highest recovery factor and/or maximum sweep efficiency. In this paper, we use Reservoir Opportunity Index (ROI) as a spatial measure of productivity potential for greenfields, which hybridizes the reservoir static properties, and for brownfields, ROI is replaced by Dynamic Measure (DM), which takes into account the current dynamic properties in addition to static properties. The purpose of using these criteria is to diminish the search region of optimization algorithms and as a consequence, reduce the computational time and cost of optimization, which are the main challenges in well placement optimization problems. However, considering the significant subsurface uncertainty, a probabilistic definition of ROI (SROI) or DM (SDM) is needed, since there exists an infinite number of possible distribution maps of static and/or dynamic properties. To build SROI or SDM maps, the k-means clustering technique is used to extract a limited number of characteristic realizations that can reasonably span the uncertainties. In addition, to determine the optimum number of clustered realizations, Higher-Order Singular Value Decomposition (HOSVD) method is applied which can also compress the data for large models in a lower-dimensional space. Additionally, we introduce the multiscale spatial density of ROI or DM (D2ROI and D2DM), which can distinguish between regions of high SROI (or SDM) in arbitrary neighborhood windows from the local SROI (or SDM) maxima with low values in the vicinity. Generally, we develop and implement a new systematic approach for well placement optimization for both green and brownfields on a synthetic reservoir model. This approach relies on the utilization of multi-scale maps of SROI and SDM to improve the initial guess for optimization algorithm. Narrowing down the search region for optimization algorithm can substantially speed up the convergence and hence the computational cost would be reduced by a factor of 4.
Stimulating the drive to drive green: A longitudinal experiment on socially comparative vs. individual digital eco-driving feedbackIn the global fight against climate change, eco-driving could contribute to the reduction of CO2 emissions. Recommendations on how to drive more ecologically abound, but drivers may fail to implement them as they experience difficulties monitoring their own behaviour. Digital feedback systems can help. In a longitudinal experiment, we communicate eco-driving recommendations to a sample of drivers (N = 412). Over a seven week time frame (in addition to a 13-week pre-experimental baseline easurement), we test whether digital feedback using an eco-score index further improves eco-driving. We experimentally evaluate whether adding a competitive component to the feedback further impacts eco-driving, testing different types of socially comparative feedback. Our results show that competitive feedback may help reduce speeding (but not other aspects of eco-driving), respective of the type of social comparison provided, suggesting that possibly the competitive mind-set as such (rather than the specific information conveyed) triggers the partial eco-driving improvement.
The value of installed base information for spare part inventory controlThis paper analyzes the value of different sources of installed base information for spare part demand forecasting and inventory control. The installed base is defined as the set of products (or machines) in use where the part is installed. Information on the number of products still in use, the age of the products, the age of their parts, as well as the part reliability may indicate when a part will fail and trigger a demand for a new spare part. The current literature is unclear which of this installed base information adds most value – and should thus be collected – for inventory control purposes. For this reason, we evaluate the inventory performance of eight methods that include different sets of installed base information in their demand forecasts. Using a comparative simulation study we identify that knowing the size of the active installed base is most valuable, especially when the installed base changes over time. We also find that when a failure-based prediction model is used, it is important to work with the part age itself, rather than the machine age. When one is not able to collect information on the part age, a logistic regression on the machine age might be a valuable alternative to a failure-based prediction model. Our findings may support the prioritization of data collection for spare part demand forecasting and inventory control.