Abstract
While history matching of a reservoir simulation model principally aims at reproducing past shut-in pressure and fractional flow observations, transition from history to forecast further requires honoring the productivities (or injectivities) of wells, and implementing the current field operational strategy to avoid unwanted reallocation of rates.
Well-level matching is particularly lengthy for giant oilfields with several hundreds to thousands of completions, hence sometimes not refined enough to warrant using observed flowing pressures as forecast constraints. Furthermore, breakthrough times are not necessarily replicated in all wells; this strongly increases discrepancies between measured and simulated flowing pressures, and can cause spurious shutting of wells infringing on reservoir management guidelines.
Short-term forecast confidence can be improved by compensating well-level mismatches observed at the end of history for production and injection control purposes only, without solving the inherent model problems. The purpose of this paper is to describe a workflow followable with most commercial reservoir simulators to achieve such objective, forcing production and injection continuity at the onset of forecast while keeping the choked margin of wells producing below capacity.
A successful application of the workflow is illustrated using the model of a giant Middle Eastern carbonate oilfield with more than 150 active production strings, using an eight-year (2015–2023) drilling schedule followed by no further activity. In this example, confidence in long-term field-level forecasts does not deteriorate after applying the proposed well-level compensations.
