Guillaume Caumon

University of Lorraine | UdL · ENSG-Georessources

We propose a method to remesh the surfaces of 3D sealed geological structural models for subsequent volumetric meshing. The input of the method is a set of triangulated surfaces that are in contact along given lines and at given points. The output is a set of surfaces meshed with triangles as equilateral as possible. The method relies on a global C...

This paper focuses on fault-related uncertainties in the subsurface, which can significantly affect the numerical simulation of physical processes. Our goal is to use dynamic data and process-based simulation to update structural uncertainty in a Bayesian inverse approach. We propose a stochastic fault model where the number and features of faults...

The modeling of subsurface geometry and properties is a key element to understand Earth processes and manage natural hazards and resources. In this paper, we suggest this field should evolve beyond pure data fitting approaches by integrating geological concepts to constrain interpretations or test their consistency. This process necessarily calls f...

Structural restoration is commonly used to assess the deformation of geological structures and to reconstruct past basin geometries. Classically, restoration is formulated as a geometric or mechanical problem driven by geometric boundary conditions to flatten the top surface. This paper investigates the use of boundary conditions in restoration to...

Faults are crucial subsurface features that significantly influence the mechanical behavior and hydraulic properties of rock masses. Interpreting them from seismic data may lead to various scenarios due to uncertainties arising from limited seismic bandwidth, possible imaging errors, and human interpretation noise. Although methods addressing fault...

We propose and evaluate methods for the integration of automatic implicit geological modelling into the geophysical (potential field) inversion process. The objective is to enforce structural geological realism and to consider geological observations in a level set inversion, which inverts for the location of the boundaries between rock units. We p...

Structural restoration is commonly used to assess the deformation of geological structures and to reconstruct past basin geometries. For this, most methods use numerical simulations to compute the deformation of geological models from a chosen deformation mechanism for each geological layer, and conditions applied on the boundaries depending on geo...

We propose a workflow for updating 3D geological meshed models to test different layering scenarios and to assess their impact on the simulation of CO2 injection. This workflow operates on a tetrahedral mesh that encodes rock unit information as well as rock physical properties. The alternative layering meshes are built by modifying the input mesh...

Sedimentary strata are essential archives of the past conditions of the earth, and host significant natural resources in the subsurface. However, inferring the features of strata at depth (e.g., geometry, connectivity, physical or geological properties), remains a challenge prone to many uncertainties. Classically, the layers and their geometry are...

Variations in the migration velocity model directly affect the position of the imaged reflectors in the subsurface, leading to structural imaging uncertainties. These uncertainties are not explicitly addressed when trying to deterministically build an adequate velocity model. This paper presents a new stochastic geology-controlled velocity modeling...

We propose and evaluate methods for the integration of automatic implicit geological modelling into the geophysical (potential field) inversion process. The objective is to enforce structural geological realism in level-set inversion, which inverts for the location of boundaries between rock units. We propose two approaches. In the first one, a geo...

Horizontal drilling is useful to target subsurface formations for injection or recovery of fluids in subsurface reservoirs. However, drilling with a low angle relatively to the stratigraphic dip can be a significant cause of targeting error and sub-optimal drilling process. Real-time consistency between the drill bit and the subsurface model is, th...

Assisted well correlation aims at complementing sedimentological expertise with computational rigor to increase automation, improve reproducibility and assess uncertainties during stratigraphic correlation. In this work, a computer-assisted method is proposed to automatically generate possible well correlations based on facies interpretation, dipme...

The exploration and exploitation of deep geothermal resources require to understand and conceptualize their functioning in all its complexity (scales and processes), to define the associated uncertainties and to evaluate their consequences in order to make decisions. A solution is proposed to meet this objective based on the results, the multidisci...

The purpose of this article is to discuss several modern aspects of remeshing, which is the task of modifying an ill-shaped tetrahedral mesh with bad size elements so that it features an appropriate density of high-quality elements. After a brief sketch of classical stakes about meshes and local mesh operations, we notably expose (i) how the local...

We introduce a method for 3D implicit geological structural modeling from sparse sample points, where several conformable geological surfaces are represented by one single scalar field. Laplacian and Hessian regularization energies are discretized on a tetrahedral mesh using finite elements. This scheme is believed to offer some geometrical flexibi...

In this work, we propose a local updating method to test different contact depth scenarios and assess their impact on wave propagation in the subsurface. We propose to locally modify a 2D geological model and run time-dependent elastic simulations. The input model triangulation is conforming to geological structures. The 2D meshed model is locally...

The numerical simulation of seismic wave propagation in realistic heterogeneous media, as sedimentary basins, is a key element of seismic hazard estimation. Many numerical methods in two dimensions are based on unstructured triangular meshes and explicit time schemes. However, the presence of thin layers and tangential stratigraphic contacts in sed...

Without properly accounting for both fault kinematics and observations of a faulted surface, it is challenging to create 3D geological models of faulted geological units. Geometries where multiple faults interact, where the faulted surface geometry significantly deviate from a flat plane and where the geological interfaces are poorly characterised...

Computer-assisted stratigraphic correlation can help to produce several scenarios reflecting interpretation uncertainties. In this work, we propose a method which translates sedimentary concepts into a correlation cost for each possible stratigaphic correlation. All these correlation costs are used to populate a cost matrix in order to apply the Dy...

Without properly accounting for both fault kinematics and faulted surface observations, it is challenging to create 3D geological models of faulted geological units that are seen in all tectonic settings. Geometries where multiple faults interact, where the faulted surface geometry significantly deviate from a flat plane and where the geological in...

The characterization of geological faults from geological and geophysical data is often subject to uncertainties, owing to data ambiguity and incomplete spatial coverage. We propose a stochastic sampling algorithm which generates fault network scenarios compatible with sparse fault evidence while honoring some geological concepts. This process is u...

Structural restoration is commonly used to assess the deformation of geological structures and to reconstruct past basin geometries. For this, geomechanical restoration considers faults as frictionless contact surfaces. To bring more physical behavior and better handle large deformations, we build on a reverse-time Stokes-based method, previously a...

Well-log interpretation and chronostratigraphic well correlation are essential steps in the basin and reservoir modeling, as they provide clues for the quantification of depositional history and flow units. At the sub-seismic scale (1 to 100 meters), correlations affect the layer geometry and the geobodies connectivity but are subject to many uncer...

We introduce a new method for implicit structural modeling. The main developments in this paper are the new regularization operators we propose by extending inherent properties of the classic one-dimensional discrete second derivative operator to higher dimensions. The proposed regularization operators discretize naturally on the Cartesian grid usi...

In the petroleum industry, time-lapse (4D) studies are commonly used for reservoir monitoring, but are also useful to perform risk assessment for potential overburden deformations (e.g., well shearing, cap rock integrity). Although complex anisotropic velocity changes are predicted in the overburden by geomechanical studies, conventional time-lapse...

Uncertainties related to permeability heterogeneity can be estimated using geostatistical simulation methods. Usually, these methods are applied on regular grids with cells of constant size, whereas unstructured grids are more flexible to honor geological structures and offer local refinements for fluid-flow simulations. However, cells of different...

Abstract. Structural restoration is commonly used to assess the deformation of geological structures and to reconstruct past basin geometries. To replace geometric criteria, linear elastic behavior and frictionless fault contact assumptions used in existing restoration approaches, we study the possibility of using a creeping flow behavior in geomec...

The sedimentary record of meandering rivers contains a diverse and complex set of lithological heterogeneities, which impact natural resource management. Different methods exist to model such accumulated successions present in the subsurface by integrating knowledge of system evolutionary behaviour and geometries visible on seismic time or stratal...

Loop is a new open source 3D geological and geophysical modelling platform in full development. The new platform consists of 4 main work packages: • Knowledge Management: use of AI techniques for knowledge extraction from literature, maps and reports using geological ontology. Geological rules will be encoded to ensure proper knowledge extraction....

Seismic structural interpretation involves highlighting and extracting faults and horizons that are apparent as geometric features in a seismic image. Although seismic image processing methods have been proposed to automate both fault and horizon interpretation, each of which today still requires significant human effort. We improve automatic struc...

We have developed an implicit method to automatically generate several possible models of salt top surfaces with varying geometries and topologies. This method can be conditioned to available data such as well markers and seismic picks. As seismic imaging of salt is prone to velocity uncertainty and Fresnel zone effects, the input of the method is...

The logic of sedimentary channelized systems is only partly preserved in the depositional record. We propose a new method to reconstruct 3D channelized systems from incomplete observations made on surface or subsurface images that integrates the uncertainty on meander abandonment chronology. Starting with the youngest channel path observed and the...

Time-lapse studies not only allow to monitor the reservoir but are also useful to access risk in the overburden. They usually assume that the velocity change during reservoir depletion is isotropic, but, from a geomechanical perspective, velocity changes have no reason to be isotropic. Numerous authors observe that the velocity changes in the overb...

Underground fluid flow in hydrocarbon reservoirs (or aquifers) is difficult to predict accurately due to geological and petrophysical uncertainties. To quantify that uncertainty, several spatial statistical methods are often used to generate an ensemble of subsurface models representing and sampling these uncertainties. However, to predict the unce...

Structural uncertainty exists when associating sparse fault interpretations made from two-dimensional seismic lines or limited outcrop observations. Here, a graph formalism is proposed that describes the problem of associating spatial fault evidence. A combinatorial analysis, relying on this formalism, shows that the number of association scenarios...

In this paper, an implicit structural modeling method using locally defined moving least squares shape functions is proposed. The continuous bending energy is minimized to interpolate between data points and approximate geological structures. This method solves a sparse problem without relying on a complex mesh. Discontinuities such as faults and u...

Incorporating prior geological knowledge in geophysical process models often meets practical meshing challenges and raises the question of how much detail is to be included in the geometric model. We introduce a strategy to automatically repair and simplify geological maps, geological cross-sections and the associated meshes while preserving elemen...

Structural interpretation of seismic images can be highly subjective, especially in complex geologic settings. A single seismic image will often support multiple geologically valid interpretations. However, it is usually difficult to determine which of those interpretations are more likely than others. We have referred to this problem as structural...

As part of the GEOTREF research project, a cost-effective approach, relying on innovative software tools, is proposed to carry out prefeasibility studies prior drilling based on numerical conceptual models associated with phenomenological modelling and well layout optimization. The numerical conceptual models are intended to be 3D structural, geolo...

In geology, implicit structural modelling constructs the geometry of geological structures (e.g. layers) by interpolating between sparse field data. A model is represented by a volumetric scalar field which is discontinuous on structural discontinuities such as faults or stratigraphic unconformities. The management of such discontinuities may invol...

Geologists and geophysicists often approach the study of the Earth using different and complementary perspectives. To simplify, geologists like to define and study objects and make hypotheses about their origin, whereas geophysicists often see the earth as a large, mostly unknown multivariate parameter field controlling complex physical processes....

Geomechanical restoration methods are dependent on boundary conditions to ensure geological consistency of the restored model in terms of geometry and strain. Classical restoration boundary conditions, such as flattening a datum horizon, may lead to inconsistent displacement and strain fields. We restore a laboratory structural sandbox model with k...

The Earth below ground is the subject of interest for many geophysical as well as geological investigations. Even though most practitioners would agree that all available information should be used in such an investigation, it is common practice that only a part of geological and geophysical information is actually integrated in structural geologic...

Fault-related displacements impact oil and gas flow predictions at reservoir scales. In this contribution, we integrate a quantitative description of fault-related deformation directly embedded into the structural modeling workflow. Consistent fault displacements are produced by using numerical fault operators that deform horizons in accordance wit...

We discuss the sampling and the volumetric impact of stratigraphic correlation uncertainties in basins and reservoirs. From an input set of wells, we evaluate the probability for two stratigraphic units to be associated using an analog stratigraphic model. In the presence of multiple wells, this method sequentially updates a stratigraphic column de...

A recent method for modeling folds uses a fold frame with coordinates based on the structural geology of folds: fold axis direction, fold axial surface and extension direction. The fold geometry can be characterised by rotating the fold frame by the pitch of the fold axis in the axial surface and the angle between the folded foliation and the axial...

Geological heterogeneities directly control underground flow. In channelized sedimentary environments, their determination is often underconstrained: it may be possible to observe the most recent channel path and the abandoned meanders on seismic or satellite images, but smaller-scale structures are generally below image resolution. In this paper,...

We present a structural modeling method that uses an object model of fault to produce consistent fault-related deformations. Our numerical fault operator relies on geometric and kinematic parameters that are determined by numerical optimization to fitting interpretations points in the fault neighborhood. We use our operator sequentially to model fa...

RINGMesh is a C++ open-source programming library for manipulating discretized geological models. It is designed to ease the development of applications and workflows that use discretized 3D models. It is neither a geomodeler, nor a meshing software. RINGMesh implements functionalities to read discretized surface-based or volumetric structural mode...

Well-seismic ties allow rock properties measured at well locations to be compared with seismic data and are therefore useful for seismic interpretation. Numerous methods have been proposed to compute well-seismic ties by correlating real seismograms with synthetic seismograms computed from velocity and density logs. However, most methods tie multip...

Three-dimensional structural modeling is gaining importance for a broad range of quantitative geoscientific applications. However, existing approaches are still limited by the type of structural data they are able to use and by their lack of structural meaning. Most techniques heavily rely on spatial data for modeling folded layers, but are unable...

Well-seismic ties allow rock properties measured at well locations to be compared to seismic data, and therefore are useful for seismic interpretation. We propose to simultaneously tie multiple wells to the seismic image by first flattening synthetic and real seismograms so that all seismic reflectors are horizontally aligned. By doing this, we tur...

The identification of structural geometries in the vicinity of fault is a difficult challenge in seismic interpretation. In this paper, we propose a quantitative numerical model of fault-related deformation. This model considers localized slip along a fault surface together with a ductile deformation of the strata away from the fault plane. This di...

We propose a 3D modelling strategy of the encased mini-basin of Inceyol in Sivas (Turkey). The challenge lies in the combination of sparse outcrop data and the complex interpretive geometry of geological structures that comes from salt tectonics. We succeeded in modelling the convoluted salt surface using an explicit indirect surface patch construc...

download : https://hal.univ-lorraine.fr/hal-01492512/document ----------------- Stochastic discrete fracture networks (DFNs) are classically simulated using stochastic point processes which neglect mechanical interactions between fractures and yield a low spatial correlation in a network. We propose a sequential parent-daughter Poisson point proce...

Corner-point gridding is widely used in reservoir and basin modeling but generally yields approximations in the representation of geological