Understanding Reservoir Mechanisms Using Phase and Component Streamline Tracing and Visualization

Kumar, Subodha; Datta‐Gupta, Akhil; Jiménez, Eduardo Araque

doi:10.2118/124252-ms

Cited by 8 publications

(2 citation statements)

References 37 publications

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“…In this work, we will use phase streamlines, which are trajectories obtained from individual-phase fluxes. Thus, there will be a set of streamlines for each individual phase (Kumar et al 2009). …”

Section: Background and Methodologymentioning

confidence: 99%

Use of Phase Streamlines for Covariance Localization in Ensemble Kalman Filter for Three-Phase History Matching

Watanabe

Datta‐Gupta

2012

SPE Reservoir Evaluation &Amp; Engineering

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The ensemble Kalman filter (EnKF) has gained increased popularity for history matching and continuous reservoir-model updating. It is a sequential Monte Carlo approach that works with an ensemble of reservoir models. Specifically, the method uses cross covariance between measurements and model parameters estimated from the ensemble. For practical field applications, the ensemble size needs to be kept small for computational efficiency. However, this leads to poor approximations of the cross covariance and can cause loss of geologic realism from unrealistic model updates outside the region of the data influence and/or loss of variance leading to ensemble collapse. A common approach to remedy the situation is to limit the influence of the data through covariance localization.In this paper, we show that for three-phase-flow conditions, the region of covariance localization strongly depends on the underlying flow dynamics as well as on the particular data type that is being assimilated, for example, water cut or gas/oil ratio (GOR). This makes the traditional distance-based localizations suboptimal and, often, ineffective. Instead, we propose the use of water-and gas-phase streamlines as a means for covariance localization for water-cut-and GOR-data assimilation. The phase streamlines can be computed on the basis of individual-phase velocities which are readily available after flow simulation. Unlike the total velocity streamlines, phase streamlines can be discontinuous. We show that the discontinuities in water-phase and gas-phase streamlines naturally define the region of influence for water-cut and GOR data and provide a flow-relevant covariance localization during EnKF updating.We first demonstrate the validity of the proposed localization approach using a waterflood example in a quarter-five-spot pattern. Specifically, we compare the phase streamline trajectories with cross-covariance maps computed using an ensemble size of 2,000 for both water-cut and GOR data. The results show a close correspondence between the time evolution of phase streamlines and the cross-covariance maps of water-cut and GOR data. A benchmark uncertainty quantification (the PUNQ-S3) (Carter 2007) model application shows that our proposed localization outperforms the distance-based localization method. The updated models show improved forecasts while preserving geologic realism.

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Section: Background and Methodologymentioning

confidence: 99%

Use of Phase Streamlines for Covariance Localization in Ensemble Kalman Filter for Three-Phase History Matching

Watanabe

Datta‐Gupta

2012

SPE Reservoir Evaluation &Amp; Engineering

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“…The proved advantages of streamline simulation are fast computation speed, low numerical dispersion, and visualization. As a promising use of the method, Kumar et al 13 proposed phase and component streamlines that help understand phase distributions, drive mechanisms, and miscibility conditions in reservoirs under waterflooding and CO 2 flooding.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Oil Compressibility Effects on Pressure Maintenance in Naturally Fractured Reservoirs Using Streamline Simulation

Tanaka

Arihara

Al-Marhoun

2010

Proceedings of International Oil and Gas Conference and Exhibition in China

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As naturally fractured reservoirs present wide ranges of geological characteristics and complex flow mechanisms between matrix and fracture, reservoir simulation is highly necessary to properly evaluate production performance. Pressure maintenance by gas and/or water injection is often required in naturally fractured reservoirs to control production GOR and to extract more oil from matrix rock. We studied by simulation particularly about effects of oil compressibility below bubblepoint pressure on pressure maintenance and production performance.We first developed and validated a 3-phase 3-dimensional dual-porosity model with the streamline method considering dissolved gas, capillary pressure and gravity. The fluid compressibility is a primary parameter that directly affects the reservoir performance. We accounted for compressibility effects with the total compressibility in the 3-D pressure equations, and with the effective density in the 1-D flow equations along streamlines. A flash-calculation algorithm was incorporated to treat the gas and oil phases correctly.The oil and gas compressibility definitions presented by Perrine, that have been being used conventionally, have inherently a physical inconsistency such that oil compressibility below the bubble-point pressure increases with the increase of density, and that the mass of gas phase remains constant with changing pressures. To correct those, new derivation based on the basic compressibility definition was introduced.Simulating peripheral water-injection with and without crestal gas-injection, results of pressure and production performance were compared for the new and conventional compressibility formulation. With the new compressibility, higher degrees of effectiveness were demonstrated in pressure maintenance. Gas injection also showed effectiveness in pressure maintenance, though it caused higher production GOR and a faster rise of water cut.

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Understanding Reservoir Mechanisms Using Phase and Component Streamline Tracing and Visualization

Kumar

Datta‐Gupta

Jiménez

2009

SPE Annual Technical Conference and Exhibition

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Streamline simulation has received considerable attention because of its computational efficiency and also for being visually appealing and physically intuitive. Conventionally streamlines are traced using total fluid fluxes across the grid cell faces. The visualization of total flux streamlines shows the movement of tracer and water flood front, injector-producer relationship, swept volumes for injectors and drainage volumes for producers. However, total fluxes mask many important features of reservoir flow embedded in the individual phase fluxes. These include reservoir dynamics, such as phase distribution, appearance and disappearance of phases, local drive mechanisms and reservoir miscibility conditions for CO 2 or solvent flooding.In this paper we demonstrate the benefits of visualizing phase and component streamlines, which are traced using phase and component fluxes respectively. Both three-phase black oil and compositional simulation are used to visualize reservoir flow and to understand the drive mechanisms active in the reservoir. Although the phase and component streamlines are not suited for flow simulation because of their local discontinuities, these streamlines provide unique insight into the reservoir processes and recovery mechanisms. In this study, the phase and component streamline tracing is done using phase/component fluxes from commercial finite-difference black oil and compositional simulators.We demonstrate the power and utility of the phase and component streamlines using synthetic and field examples. The phase streamlines are shown to capture the dominant flowing phases in different parts of the reservoir and to help us optimize locations of infill injectors and producers. Based on the appearance and disappearance of phase streamlines, we can identify the regions of the field where different drive mechanisms such as waterflood and solution gas drives are active. The field applications involve waterflooding in a structurally complex reservoir in South America and also, a CO 2 injection project in a large carbonate reservoir in Canada. We use component streamlines to track the movement of injected CO 2 in the reservoir. By tracking the phase and component streamlines, we can clearly distinguish the CO 2 in the gas phase and the dissolved CO 2 . This not only helps optimize CO 2 injection but also has important implications in the effectiveness of the CO 2 sequestration.

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Understanding Reservoir Mechanisms Using Phase and Component Streamline Tracing and Visualization

Cited by 8 publications

References 37 publications

Use of Phase Streamlines for Covariance Localization in Ensemble Kalman Filter for Three-Phase History Matching

Use of Phase Streamlines for Covariance Localization in Ensemble Kalman Filter for Three-Phase History Matching

Evaluation of Oil Compressibility Effects on Pressure Maintenance in Naturally Fractured Reservoirs Using Streamline Simulation

Understanding Reservoir Mechanisms Using Phase and Component Streamline Tracing and Visualization

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