A Different Approach to Coupling a Reservoir Simulator with a Surface Facilities Model

The formulation of a black-oil or compositional fully coupled surface and subsurface simulator is described. It is based on replacing the well model in a conventional reservoir simulator with a generalized network model of the wells and facilities. This allows for representation of complex wellbore geometry and downhole equipment. The method avoids the inefficiencies and/or inaccuracies of other coupled models, in which wells and facilities are treated as separate domains or in which the global system is not solved simultaneously. Example cases demonstrate the performance of the model for cases with simple and segmented wellbores (with and without facilities).

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“…Hepguler et al 17 and Tingas et al 18 presented timestep-level implicit couplings of (black-oil) reservoir and network simulators. Trick 19 …”

Section: Conventional Well Model a Basic Example Of Domain Decomposimentioning

confidence: 99%

A Generalized Wellbore and Surface Facility Model, Fully Coupled to a Reservoir Simulator

Coats

Fleming

Watts

et al. 2004

SPE Reservoir Evaluation &Amp; Engineering

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“…8,9 It has since been extended and ported to the ECLIPSE compositional reservoir simulator. We shall summarize its current features here before describing in detail the coupling scheme that we employ.…”

Section: The Open Interfacementioning

confidence: 99%

A General Purpose Controller for Coupling Multiple Reservoir Simulations and Surface Facility Networks

et al. 2003

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIntegrated surface-subsurface modeling has been shown to have a critical impact on field development and optimization. Integrated models are often necessary to analyze properly the pressure interaction between a reservoir and a constrained surface facility network, or to predict the behavior of several fields, which may have different fluid compositions, sharing a common surface facility. The latter is gaining a tremendous significance in recent deepwater field development.These applications require an integrated solution with the following capabilities:• To balance a surface network model with a reservoir simulation model in a robust and efficient manner. • To couple multiple reservoir models, production and injection networks, synchronising their advancement through time. • To allow the reservoir and surface network models to use their own independent fluid descriptions (black oil or compositional descriptions with differing sets of pseudocomponents). • To apply global production and injection constraints to the coupled system (including the transfer of re-injection fluids between reservoirs). In this paper we describe a general-purpose multi-platform reservoir and network coupling controller having all the above features. The controller communicates with a selection of reservoir simulators and surface network simulators via an open message-passing interface. It manages the balancing of the reservoirs and surface networks, and synchronizes their advancement through time. The controller also applies the global production and injection constraints, and converts the hydrocarbon fluid streams between the different sets of pseudo-components used in the simulation models. The controller's coupling and synchronization algorithms are described, and example applications are provided. The flexibility of the controller's open interface makes it possible to plug in further modules (to perform optimization, for example) and additional simulators.

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“…Barroux et al (2000) suggested remedying the oscillations by replacing the well productivity with the derivative of rate against bottomhole pressure when producing IPR for coupling independent simulators at the Newton iteration level. Zapata et al (2001) investigated the use of an iteratively (reservoir-network) updated implicit bottomhole pressure to reduce the oscillations. The instability of a coupled system is also a cause of excessive computational time if separate models are solved iteratively (Coats et al 2004).…”

Section: Introductionmentioning

confidence: 99%

A Semi-Implicit Approach for Integrated Reservoir and Surface-Network Simulation

Liang¹,

Rubin²

2014

SPE Reservoir Evaluation &Amp; Engineering

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Conventionally, methods of coupling reservoirs and surface networks are categorized into implicit and explicit approaches. The term "implicit coupling" indicates that the two simulators solve unknowns together, simultaneously, or iteratively, whereas "explicit coupling" indicates that the two simulators solve unknowns sequentially and exchange their boundary conditions at the last coupled time t n .The explicit approach is straightforward to implement in existing reservoir and surface-network models and is widely used. Explicit coupling does have drawbacks, however, because well rate and pressure oscillations are often observed.In this paper, a new semi-implicit method for coupled simulation is presented. This technique stabilizes and improves the accuracy of the coupled model. The "semi-implicit coupling" overcomes the problems found in explicit-coupling methods without requiring the complexity of a fully implicit coupled model.The new approach predicts inflow-performance-relationship (IPR) curves at the next coupled time t nþ1 by simultaneously conducting well tests for all wells in the reservoir before actually taking the required timestep. All wells first flow simultaneously to the next coupled time t nþ1 with the well rates unchanged from the last coupled timestep. The timestep is rewound, and all well rates are reduced by a uniform fraction and then simultaneously flow again to t nþ1 . By extrapolating the resulting well pressures, the well's shut-in pressures at time t nþ1 are determined, and thus, straight-line IPRs are produced. The new IPR curves approximate better each well's drainage region at t nþ1 and each well's shut-in pressure at t nþ1 which helps to stabilize the explicitly coupled model.The new coupling technique normally does not require iteration between the reservoir and surface network and normally has the stability and accuracy characteristics of an implicitly coupled approach. Because the well tests already account for individual well-drainage regions, an explicit knowledge of the well-drainage region is not required. Because of the stabilized IPR, the approach also was found to reduce the overall computational time compared with explicit coupling.Applications of the new approach are presented that show significant improvements surpassing explicit coupling in both stability and accuracy. IntroductionIt has been widely recognized that when reservoir-deliverability forecasting and surface-network planning are required, integrated reservoir and surface-network simulation can provide more-realistic results than separate models of the reservoir and surface network. During the last 40 years, different methods to couple reservoir and network models were developed and studied by a number of investigators. Dempsey et al. (1971) first presented a technique that iteratively solved reservoir, tubing-string, and gathering system models to accurately evaluate gasfield deliverability. The concept was extended to the black-oil system by Startzman et al. (1977), and the scheme was modified by Emanuel and ...

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A Different Approach to Coupling a Reservoir Simulator with a Surface Facilities Model

Cited by 31 publications

References 7 publications

A Generalized Wellbore and Surface Facility Model, Fully Coupled to a Reservoir Simulator

A Generalized Wellbore and Surface Facility Model, Fully Coupled to a Reservoir Simulator

A General Purpose Controller for Coupling Multiple Reservoir Simulations and Surface Facility Networks

A Semi-Implicit Approach for Integrated Reservoir and Surface-Network Simulation

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