The division’s activity hinges around 2 departments that support each other to improve the modeling and simulation of flows in porous media. The objective is to develop fields and preserve the environment.
 

Petrophysics

The department possesses conventional experimental resources adapted to the study of the petrophysical properties of porous media. In particular, it has various pieces of specific and innovative equipment. This equipment relates, for example, to rock characterization as well as the measurement of reservoir conditions in a very broad range of pressures and temperatures:

• triaxial cells,
• CT-scanner,
• NMR,
• PT transparent micromodel,
• X-ray microscanner.

Results are interpreted using digital simulations in order to conceptualize the physical mechanisms identified by the experiment. Generally speaking, these simulations are developed in close collaboration with teams from the division’s other department.

The majority of the department’s activities fall into five broad categories:

• rock characterization over various scales,
• multiphase flows in porous media,
• reactive flows,
• complex fluid flows in porous media,
• "pore network-type" modeling.

These research activities provide information on professional problems, such as:

• reservoir characterization,
• optimization of enhanced oil recovery (EOR) procedures, particularly for heavy oils,
• wellbore damage during injection or production,
• the characterization and modeling of very deeply buried reservoirs and the geological storage of CO₂.

• Rock characterization over various scales

Research in this field concerns the development of methods to characterize the porous structure over various scales and the quantification of heterogeneities. These methods are applied to:

• carbonate reservoirs that present heterogeneities over various scales,
• gas reservoirs with very little permeability (“tight”),
• little-consolidated reservoirs with properties that are highly dependent on the constraint level.

The rock characterization methods implemented include:

• nuclear magnetic resonance (NMR) measurements,
• electrical measurements,
• drill cutting measurements,
• tracer propagation coupled with inertial effects,
• permeability measurement under anisotropic constraint,
• determination of displacement pressure.

An X-ray microscanner is used to visualize the porous space and determine the distributions of pore sizes and connectivity with a resolution of the order of 1 micron.

• Modeling of multiphase flows in porous media

The objective of these activities is to provide determination and physical modeling methodologies for the petrophysical properties in relation with multiphase flows in rocks. The principal objective here is to measure and model the relative capillary pressures and permeabilities of the various phases.

The Petrophysics Department has a solid platform of expertise and experimental resources for the study of multiphase transport in ambient or reservoir conditions. Recent activities include:

• the determination of Pc and Kr by the semi-dynamic method (SDM),
• flow modeling with phase change or compositional effects,
• spontaneous or forced imbibition and recovery in low-permeability media.

Innovative measurement methods and interpretations within the context of these activities are based on the ability to measure local fluid saturations and their evolution mover time. This is possible in ambient and reservoir conditions (P=300 bars, T=120°C) thanks to the acquisition and development of dedicated equipment (X-ray scanner, 3 horizontal X-ray benches, 1 vertical X-ray bench).

The following are examples of applications for the methodologies developed:

• the semi-dynamic method has made a significant contribution to the determination of Pc and Kr in porous media containing heterogeneities at core level (carbonates in the Middle East),
• depressurization modeling has found an application in the cold production of viscous oils,
• Relative permeability hysteresis is a fundamental phenomenon in the understanding of tight gas reservoir damage.
   

• Reactive flow modeling

In the case of a reactive flow, dissolutions and re-precipitations can occur which have a varying impact on rock porosity and permeability. This type of flow is encountered either during the acid treatment of wells with a view to stimulation or, more recently, when CO₂ is injected into aquifers or depleted reservoirs with a view to storage. Previously acquired expertise in the area of acidification is currently being developed further in research and development relating to CO₂ injectivity.

A pore network-type approach has been used to model permeability evolutions related to modifications in the porous structure following geochemical-type interaction mechanisms that occur during CO₂ storage operations.

• Complex fluid flow modeling

This activity includes research in the following areas:

• enhanced oil recovery,
• inhibitor injections to limit formation deposit damage (scales, asphaltenes),
• well treatment to limit water encroachment and re-injection of production water.

The department’s research work relates in particular to:

• the use of microgels to modify transport properties,
• mineral deposits in porous media,
• asphaltenic deposits,
• the injection of a fluid containing solid particles. This theme, linked to injectivity decline caused by the re-injection of production water, is the subject of the PROWIDE JIP.

In the context of the prevention of water encroachment, the STARGEL process uses a modified polyacrylamide-type polymer and reticulating agents which have the benefit of being non-toxic for the environment. It also enhances the chance of success of well treatments.

• “Pore network”-type modeling

“Pore network”-type modeling is an efficient tool employed to:

• interpret experiments,
• facilitate "rock-typing" and scaling,
• calculate petrophysical parameters.

The network model developed at IFP deals with drainage and imbibition, the presence of 3 phases presence, heterogeneous-type wettability and flows by wetting films and spreading films. It is thus able to deal with 2 or 3-phase immiscible flows. Recent research in this field hinges around two axes:

• anchoring of the network model to data obtained experimentally,
• modeling complex multiphase flow mechanisms with consideration of interfacial phenomena and the simulation of various types of experiment for the calculation of corresponding petrophysical properties.
   

Modeling of flows and transfers in porous media

The majority of the department’s research activities lie within four scientific fields:

• modeling of flows and transfers in porous media,
• scaling,
• constraint modeling,
• uncertainty management and quantification and risk analysis.

These research activities provide information on professional problems, such as:

• fissured reservoirs,
• well injectivity and productivity,
• enhanced gas and oil recovery (EOR procedures),
• CO₂ storage,
• heat storage.

• Modeling of flows and transfers in porous media

Research in this field relates in particular to:

• modeling of flows in fissured media (DFN and double-medium) with hydraulic characterization of fractured/fault networks modeled by FRACA^Flow,
• double-medium modeling of matrix-fissure polyphase transfers and permeable faults in PUMA^Flow software,

• modeling of subtle phenomena near horizontal wells (such as formation damage by drilling fluids),
• digital modeling of assisted thermal recovery processes with dynamic sub-meshing techniques,
• professional specifications and validation of the COORES geological storage of CO₂ software.
   

	Oil & Gas Science and Technology - Revue de l'IFP THEMATIC DOSSIER: "CO2 Capture and Geological Storage: State-of-the-Art" Download the articles free of charge

• Scaling

The problems examined relate to the scaling of:

• flows in fissured media, from the discrete model (DFN) to the simple or double-medium reservoir model,
• flows in the well neighborhood in the context of acid injection for the stimulation of damaged wells, an unstable procedure that leads to the formation of dissolution figures known as wormholes,
• petrophysical properties on flexible meshing,
• compositional flows in gas injection.
   

	Oil & Gas Science and Technology - Revue de l'IFP THEMATIC DOSSIER: "Upscaling of Fluid Flow in Oil Reservoirs" Download the articles free of charge

• Constraint reservoir modeling

The objective of the research conducted on this theme by the department over the last ten years or so is to develop constraint modeling methods that can be used to work on the basis of dynamic data, not only with the reservoir model, but also with the underlying geological model. The flow model can then be used to carry out simulations that more accurately predict reservoir behavior during development

Moreover, the surge in reservoir monitoring technologies, and 4D seismics in particular, requires appropriate modeling techniques in order to update reservoir models effectively as a function of new data acquired during production. The methodologies and algorithms studied in the context of this theme relate to simple, but also double-medium fissured reservoirs and are also likely to be applied to the monitoring of CO₂ storage.

Current research avenues concern:

• the parametrization of the model to reduce the number of calibration parameters (with the gradual deformation technique), for pixel-type models but also object models (particularly for faulted/fissured reservoirs),
• the use of the adjunct state for calculation of the gradient of the objective function,
• the optimal choice of objective function,
• the use of effective objective function minimization algorithms and high-performance calculation techniques to reduce calculation time,
• the integration of 4D seismics into reservoir constraint modeling,
• the application on a core scale of techniques developed on a reservoir scale.

These methodologies and algorithms are developed and validated in the context of fundamental or themed research projects and joint industry funded project (CONDOR I, CONDOR II, MC2) and then integrated into the CONDOR^Flow industrial software.

• Uncertainty management and quantification and risk analysis

Uncertainty management and quantification are involved at each stage of a field’s exploitation, from exploration to development and production. A rigorous probability analysis is thus useful for decision-making purposes within risky environments. Statistical theories, and more particularly an experimental design approach, are well suited to:

• determining the principal uncertain parameters,
• evaluating the impact of uncertainties in production forecasting,
• facilitating decision-making during the development of an oil field.

Current research, for example, relates to:

• improving the quality of response surfaces,
• combining decision trees with experimental design,
• uncertainty management for a large number of parameters,
• uncertainty quantification in mature fields.

These methodologies and algorithms are developed and validated in the context of fundamental and themed research projects and joint industry funded projects (COUGAR I, COUGAR II, COUGAR III) and then integrated into the COUGAR^TM industrial software marketed by Schlumberger.