Project Description

SPE 159400: Dynamic Delumping of Reservoir Simulation

Arif Kuntadi, SPE, NTNU, Petrostreamz AS | Curtis H. Whitson, SPE, NTNU, PERA AS | Mohammad Faizul Hoda, SPE, Petrostreamz AS

SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, 8-10 October 2012

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Integrated modeling is becoming a necessary tool in the petroleum industry to manage the value chain of different models. Reservoir models commonly utilize a simple fluid model to reduce computational time. However, the downstream models often require a more detailed EOS fluid model to perform surface-process facility modeling. This paper presents a dynamic delumping method to generate detailed compositional streams from either black-oil or compositional (lumped-EOS) reservoir simulations, performed as a simple post-processing step.

A set of phase-specific, pressure-dependent split factors are used to perform dynamic delumping. The split factors are generated from simulated depletion PVT experiments using a detailed-EOS model. Delumping is performed phase-wise at the well-connection level, for each time step of the reservoir simulator. For gas injection processes, the amount of injection gas is estimated from stream information and, accordingly, removed from the stream before applying the phase-specific pressure-dependent split factors. Different split factor sets are used when the reservoir model has multiple PVT regions.

We have run many reservoir simulation cases using different production mechanisms and reservoir fluids. Compared with detailed-EOS simulations, the proposed method gives near-exact results for depletion, and excellent agreement in gas injection cases. Dynamic delumping also works with complex fluid systems exhibiting large in-situ compositional (GOR) variations. For injection gas cases, improved accuracy is obtained using a tracer option in the reservoir simulator, to better estimate injection-gas quantity. This approach requires negligible cpu compared with detailed-EOS reservoir simulation.

Dynamic delumping is applied as an automated post-processing for any reservoir simulator. The results of our work provide a key technology for integrating subsurface and surface petroleum models, ensuring greater consistency in the complete value chain and enabling engineers to optimize assets, both locally and globally.

Copyright 2012, Society of Petroleum Engineers