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Abstract:
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The performance of Enhanced Oil Recovery (EOR ) processes is adversely affected by the heterogeneous distribution of flow properties of the rock . The effects of heterogeneity are further highlighted when the mobility ratio between the displacing and the displaced fluids is unfavorable . Polymer flooding aims to mitigate this by controlling the mobility ratio resulting in an increase in the volumetric swept efficiency . However , the design of the polymer injection process has to take into account the uncertainty due to a limited knowledge of the heterogeneous properties of the reservoir . Numerical reservoir models equipped with the most updated , yet uncertain information about the reservoir should be employed to optimize the operational settings . Consequently , the optimal settings are uncertain and should be revised as the model is updated . In this report , a feedback -control scheme is proposed with a model updating step that conditions prior reservoir models to newly obtained dynamic data , and this followed by an optimization step that adjusts well control settings to maximize (or minimize ) an objective function .
An illustration of the implementation of the proposed closed -loop scheme is presented through an example where the rate settings of a well affected by water coning are adjusted as the reservoir models are updated . The revised control settings yield an increase in the final value of the objective function . Finally , a fast analog of a polymer flooding displacement that traces the movement of random particles from injectors to producers following probability rules that reflect the physics of the actual displacement is presented . The algorithm was calibrated against the full -physics simulation results from UTCHEM , the compositional chemical flow simulator developed at The University of Texas at Austin . This algorithm can be used for a rapid estimation of basic responses such as breakthrough time or recovery factor and to provide a simplified characterization the reservoir heterogeneity .
This report is presented to fulfill the requirements to obtain the degree of Master of Science in Engineering under fast track option . It summarizes the research proposal presented for my doctorate studies that are currently ongoing . |