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Well Placement Optimization Under Uncertainty Using Opportunity Indexes Analysis And Probability Maps
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, ECMOR XVI - 16th European Conference on the Mathematics of Oil Recovery, Sep 2018, Volume 2018, p.1 - 16
Abstract
Improving hydrocarbon recovery from green and mature fields through targeting potential drilling requires a computationally complex process of well placement optimization. Because these operational activities are expensive and particularly critical in the periods of low oil prices, a risk quantification analysis is often required for uncertainty considerations.
A new automated probabilistic workflow optimizes well placement using probability maps based on reservoir and simulation opportunity indexes. Well types include vertical wells and horizontal wells. The probability map concept aims at unifying the existing model realizations into a single probability map by establishing thresholds for key physical parameters and reservoir characteristics. The opportunity indexes method is a fast way to identify zones with high potential for production from both oil and gas reservoirs.
The workflow is generic and can be applied to oil and gas in both mature and green fields as a fast method of well placement optimization under uncertainty. Starting from a set of reservoir modelling scenarios, a pattern recognition algorithm is first applied to classify and rank the realizations. A representative subset of these realizations is then used in an ensemble-based method and, when needed, calibrated to existing observed data. Reservoir and simulation opportunity indexes are applied to all calibrated realizations. Finally, a single probability map is created to unify the opportunity index maps. Based on the pattern observed in the probability map, areas of interest (AOI) are outlined, and several realizations of well configurations are generated. The designed wells are screened based on engineering criteria and ultimately assessed using numerical simulations on each realization.
The workflow terminates by results analysis and well design selection. This considers not only the improvement in oil recovery, but also a measure of risk coming from the uncertainty assessment. In testing on several simulation models, the unswept reservoir regions were successfully identified and ranked for drilling targets. Compared to existing methods, the workflow showed superior results.