This paper describes miscible displacement upon air injection in a porous medium saturated with oil corresponding to conditions of high-pressure air injection (HPAI). We assume that injection fluids and produced fluids are fully miscible with the oil at the prevailing high pressure. We use three pseudo-components, viz., oxygen, oil, and an inert component, which includes nitrogen, carbon dioxide, etc

Efficient and safe production of hydraulically fractured reservoirs benefits from the prediction of their geometrical attributes. Geophysical methods have the potential to provide data that are sensitive to fracture geometries, alleviating the typically sparse nature of in situ reservoir observations. Moreover, surface-based methods can be logistically and economically attractive since they avoid operational

Though geologic carbon storage (GCS) is widely recognized as a promising strategy to reduce emissions of greenhouse gas (GHG), the potential for mobilization of radioactive uranium (U) from U-bearing minerals in deep subsurface due to CO2 injection remains a concern. In this study, supercritical CO2 and brine flowing through a fracture surrounded by reservoir rock containing uranium is simulated so

Permeability and its anisotropy are of central importance for groundwater and hydrocarbon migration. Existing fluid dynamics methods for computing permeability have common shortcomings, i.e., high computational complexity and long computational time, reducing the potential of these methods in practical applications. In view of this, a 3D CNN-based approach for rapidly estimating permeability in anisotropic

We develop a staggered finite element procedure for the coupling of a free viscous flow with a deformable porous medium, in which interface phenomena related to the skin effect can be incorporated. The basis of the developed simulation procedure is the coupled Stokes-Biot model, which is supplemented with interface conditions to mimic interface-related phenomena. Specifically, the fluid entry resistance

Geostatistical seismic inversion methods use stochastic sequential simulation as the model generation and perturbation technique. These stochastic simulation methods use a global variogram model to express the expected spatial continuity pattern of the subsurface elastic properties of interest. The conditioning to a single variogram model is not suitable for complex and non-stationary geological environments

Predicting the petrophysical properties of rock samples using micro-CT images has gained significant attention recently. However, an accurate and an efficient numerical tool is still lacking. After investigating three numerical techniques, (i) pore network modeling (PNM), (ii) the finite volume method (FVM), and (iii) the lattice Boltzmann method (LBM), a workflow based on machine learning is established

The general field development optimization problem is complex due to the potentially large number of controls of mixed type and discontinuities in the objective function related to varying numbers and types of wells being placed in a discretized grid. This may make the problem challenging or even unsuitable for certain types of optimization methods that rely on, e.g., the availability of (adjoint)

Numerical modeling of geochemistry associated with geologic CO2 storage involves many conceptual and quantitative uncertainties. In this study, a time efficient arbitrary polynomial chaos (aPC) expansion approach was proposed to do global sensitivity analysis of mineral dissolution and precipitation modeling in geologic carbon storage scenarios. To demonstrate the workflow of the aPC approach, a numerical

In this study, a 3D coupled FEM-DEM method was adopted to study the influence of thermal-induced damage on the mechanical properties of fractured rock mass. In this method, the rock matrix was discretized into bulk elements bridged by cohesive elements, and the preexisting fractures were represented by cohesive elements. The thermal-induced damage process was modeled through two parts, i.e., thermal

The phenomenon of flow-channeling, or the existence of preferential pathways for flow in fracture networks, is well known. Identification of the channels (“backbone”) allows for system reduction and computational efficiency in simulation of flow and transport through fracture networks. However, the purpose of machine learning techniques for backbone identification in fractured media is two-pronged

This paper presents a numerical simulation tool for the analysis of coupled processes related to subsurface operations. The tool combines the open-source scientific code OpenGeoSys with the reservoir simulator Eclipse enabling the coupling of thermal, hydraulic, mechanical and geochemical processes. While the coupling of multiphase flow with heat and reactive geochemical component transport has been

Model-based production optimization relies on a dynamic model that simulates the fluid flow in the oil reservoirs, and an economic objective function that assigns an economic measure to the recoverable oil reserves. An optimization algorithm utilizes the dynamic model to find the production scenario which maximizes the economic measure of profit. However, due to incompleteness and doubtfulness of available

We are concerned with the efficiency of stochastic gradient estimation methods for large-scale nonlinear optimization in the presence of uncertainty. These methods aim to estimate an approximate gradient from a limited number of random input vector samples and corresponding objective function values. Ensemble methods usually employ Gaussian sampling to generate the input samples. It is known from the

Poroelasticity theory can be used to analyse the coupled interaction between fluid flow and porous media (matrix) deformation. The classical theory of linear poroelasticity captures this coupling by combining Terzaghi’s effective stress with a linear continuity equation. Linear poroelasticity is a good model for very small deformations; however, it becomes less accurate for moderate to large deformations

In this study, imbibition process is investigated in heterogeneous hydrocarbon reservoir using the non-classical (effective viscous finger) model equations proposed by Luo et al. (SPE Res. Eval. Engineering, 20(4), 1–16 2017). Counter-current spontaneous imbibition is analyzed in different heterogeneous porous media. The heterogeneity is mainly due to the spatial variation of the porosity and absolute

Modeling of hydraulic fracturing processes is of great importance in computational geosciences. In this paper, a phase-field model is developed and applied for investigating the hydraulic fracturing propagation in saturated poroelastic rocks with pre-existing fractures. The phase-field model replaces discrete, discontinuous fractures by continuous diffused damage field, and thus is capable of simulating

We developed a generalized multiphase-field modeling framework for addressing the problem of brittle fracture propagation in quartz sandstones at microscopic length scale. Within this numerical approach, the grain boundaries and crack surfaces are modeled as diffuse interfaces. The two novel aspects of the model are the formulations of (I) anisotropic crack resistance in order to account for preferential

Borehole resistivity measurements are routinely employed to measure the electrical properties of rocks penetrated by a well and to quantify the hydrocarbon pore volume of a reservoir. Depending on the degree of geometrical complexity, inversion techniques are often used to estimate layer-by-layer electrical properties from measurements. When used for well geosteering purposes, it becomes essential

Prior to the estimation process of channelized reservoirs, in the context of any Assisted History Matching method, the parameterization of facies field is a necessary task. The parameterization of the facies field consists of defining a numerical field (parameter field) on the reservoir domain so that, using a projection function, we are able to recover the facies field from the values of parameter

The fully implicit method is the most commonly used approach to solve black-oil problems in reservoir simulation. The method requires repeated linearization of large nonlinear systems and produces ill-conditioned linear systems. We present a strategy to reduce computational time that relies on two key ideas: (i) a sequential formulation that decouples flow and transport into separate subproblems, and

A novel upscaling approach was previously introduced using pressure transient concepts which allowed us to distinguish between well-connected, weakly connected, and disconnected pay in the local upscaling region. The current work applies these same concepts to benchmark the upscaling formulation against existing upscaling techniques to test the impact of localization. The local flow field generated

Subsurface reservoir models have a high degree of uncertainty regarding reservoir geometry and structure. A range of conceptual models should therefore be generated to explore how fluids-in-place, reservoir dynamics, and development decisions are affected by such uncertainty. The rapid reservoir modelling (RRM) workflow has been developed to prototype reservoir models across scales and test their dynamic

For most history matching problems, the posterior probability density function (PDF) may have multiple local maxima, and it is extremely challenging to quantify uncertainty of model parameters and production forecasts by conditioning to production data. In this paper, a novel method is proposed to improve the accuracy of Gaussian mixture model (GMM) approximation of the complex posterior PDF by adding

We present a novel nonlinear formulation for modeling reactive-compositional flow and transport in the presence of complex phase behavior due to a combination of thermodynamic and chemical equilibria in multi-phase systems. We apply this formulation to model precipitation/dissolution of minerals in reactive multiphase flow in subsurface reservoirs. The proposed formulation is based on the consistent

In cases with significant density difference between the injection mixture and the reservoir fluids, segregation can take place on short temporal scales relative to the typical time-step lengths of the simulation. A fully resolved 3D description is computationally demanding and is often difficult to achieve with buoyancy segregated flow. Vertical equilibrium (VE) is one possible technique for effective

In reservoir simulations, the radius of a well is inevitably going to be small compared to the horizontal length scale of the reservoir. For this reason, wells are typically modelled as lower-dimensional sources. In this work, we consider a coupled 1D–3D flow model, in which the well is modelled as a line source in the reservoir domain and endowed with its own 1D flow equation. The flow between well

Distributed Gauss-Newton (DGN) optimization method has been proved very efficient and robust for history matching and uncertainty quantification (HM&UQ). The major bottleneck for performance enhancement is the expensive computational cost of solving hundreds of Gauss-Newton trust-region (GNTR) subproblems in each iteration. The original GNTR solver applies the less efficient iterative Newton-Raphson

There is strong interest to design sequential fully implicit (SFI) methods for compositional flow simulations with convergence properties that are comparable to fully implicit (FI) methods. SFI methods decompose the fully coupled system into a pressure equation and a transport system of the components. During the pressure update, the compositions are frozen, and during the transport calculations, both

Algebraic multiscale (AMS) is a recent development for the construction of efficient linear solvers in reservoir simulations. It employs upscaling ideas to coarsen the respective linear system and provides a high amount of inherent parallelism. However, it has the drawback that it can so far only be applied to scalar problems, e.g., a pressure sub-problem. Moreover, AMS relies on the availability of

The fluid injection in sedimentary formations may generate geochemical interactions between the fluids and the rock minerals, e.g., CO2 storage in a depleted reservoir or a saline aquifer. To simulate such reactive transfer processes, geochemical equations (equilibrium and kinetics equations) are coupled with compositional flows in porous media in order to represent, for example, precipitation/dissolution

Transient well test analysis provides valuable information about reservoir characteristics such as permeability and the hydraulic diffusivity coefficient. It is based on the solution of diffusivity equation, which describes mass transfer in porous media. On the whole, analytical solutions are used for interpreting well test data. However, all these solutions were obtained under the condition of reservoir

Multiphase flow simulation in fractured reservoirs at field scale is a significant challenge. Despite recent advances and a wide range of applications in both hydrology and hydrocarbon reservoir engineering, discussing efficient methods that cover computational complexity, accuracy, and flexibility aspects is still of paramount importance for a better understanding of these complex media. In this work

Abstract Relating the attenuation and velocity dispersion of seismic waves to fluid pressure diffusion (FDP) by means of numerical simulations is essential for constraining the mechanical and hydraulic properties of heterogeneous porous rocks. This, in turn, is of significant importance for a wide range of prominent applications throughout the Earth, environmental, and engineering sciences, such as

Abstract The coupled THMC model, interface for pressure solution analysis under coupled conditions, IPSACC, that was proposed by the authors and can describe the long-term evolution in rock permeability due to mineral reactions (i.e., pressure solution and free-face dissolution/precipitation) within rock fractures, was upgraded in the present study by incorporating the processes of fracture initiation/propagation

Abstract A common method of imaging with seismic data is reverse time migration (RTM) in which recorded data are back-propagated to form an image of the subsurface. Least-squares RTM (LSRTM) extends this method to an iterative method that minimizes a data misfit term. An appropriate regularization term such as a sparsity-promoting functional (e.g., total variation (TV)) is required to stabilize the

Abstract This paper focuses on the modeling of heat transfer between fluid flowing in a well and the surrounding rock mass and proposes an efficient domain decomposition approach to solve this problem. The importance of such a method is illustrated by the study of the modeling of underground gas storage in salt caverns.

Abstract In this work, we present a new conceptual model to describe fluid flow in a porous media system in presence of a large fault. Geological faults are often modeled simply as interfaces in the rock matrix, but they are complex structures where the high strain core is surrounded by the so called damage zones, characterized by the presence of smaller fractures which enhance the permeability of

Abstract When simulating borehole resistivity measurements in a reservoir, it is common to consider an oil-water contact (OWC) planar interface. However, this consideration can lead to an unrealistic model since in the presence of capillary actions, the mix of two immiscible fluids (oil and water) often appears as an oil-water transition (OWT) zone. These transition zones may be significant in the

Abstract Large discontinuities (jumps) in coefficients often appear when modelling physical problems involving inhomogeneous media. An example of this is the geophysical electromagnetic (EM) problem, where these jumps occur at interfaces which separate regions of (high) conductivity contrasts. These interfaces, along with other problem features, such as singular EM sources, motivate the use of adaptive

Abstract We compare numerically the performance of reversible and non-reversible Markov Chain Monte Carlo algorithms for high-dimensional oil reservoir problems; because of the nature of the problem at hand, the target measures from which we sample are supported on bounded domains. We compare two strategies to deal with bounded domains, namely reflecting proposals off the boundary and rejecting them

Abstract A sequential inversion methodology for combining geophysical data types of different resolutions is developed and applied to monitoring of large-scale CO2 injection. The methodology is a two-step approach within the Bayesian framework where lower resolution data are inverted first, and subsequently used in the generation of the prior model for inversion of the higher resolution data. For the

Abstract Reservoir engineers use large-scale numerical models to predict the production performance in oil and gas fields. However, these models are constructed based on scarce and often inaccurate data, making their predictions highly uncertain. On the other hand, measurements of pressure and flow rates are constantly collected during the operation of the field. The assimilation of these data into

Abstract Fluid flow in rough fractures and the coupling with the mechanical behaviour of the fractures pose great difficulties for numerical modeling approaches due to complex fracture surface topographies, the non-linearity of hydro-mechanical processes and their tightly coupled nature. To this end, we have adapted a fictitious domain method to enable the simulation of hydro-mechanical processes in

Abstract The disposal of heat-generating nuclear waste in salt host rock generates a thermal gradient around the waste package that may cause brine inclusions in the salt grains to migrate toward the waste package. In this study, a dual-continuum model is developed to analyze such a phenomenon. In this model, fluid flow in terms of advective and diffusive fluxes in the interconnected pore space and

Abstract The paper is motivated by a strong interest in numerical analysis of flow in fractured porous media, e.g., rocks in geo-engineering applications. It follows the conception of porous media as a continuum with fractures which are represented as lower dimensional objects. In the paper, the finite element discretization of the flow in coupled continuum and fractures is used; fluid pressures serve

Abstract The effect of fluid flow on tissue adaptation was the focus of many research works during the last years. Moreover, the use of poroelasticity models to simulate and understand the interstitial flow movement has taken interest due to the possibility to include the fluid effect on mechanical simulations. In particular, shear stresses induced by bone canalicular fluid flow are suggested to be

Abstract We propose two postprocessing procedures (Patch method and Stitch method) to recover local conservation of velocity fields produced by multiscale approximations that are only conservative in coarse scales. These procedures operate on small overlapping regions and are designed to be implemented in parallel, which makes them relatively inexpensive. We investigate the applicability of such methods

Abstract This benchmark provides the first rigorous test of a three-isotope system [12C, 13C, and 14C] subject to the combined effects of radioactive decay and both stable equilibrium and kinetic fractionation. We present a series of problems building in complexity based on the cycling of carbon in both organic and inorganic forms. The key components implement (1) equilibrium fractionation between

Abstract CO2 huff and puff (CO2 huff-n-puff) with multistage hydraulic fracture has been proven to be a feasible approach to enhance oil recovery in shale/tight formations. The present study investigates the effect of pore confinement on the incremental recovery of the CO2 huff-n-puff process in shale formation. The results demonstrate that neglecting nanopore confinement has a large impact on production

Abstract This paper aims to present the initial concept of modified net present value (MNPV) and its first results. The main goal of this study is to propose a production strategy aimed at maximizing the revenue of a reservoir using the best choice of reservoir inputs. The MNPV was tested with two widely used reservoir benchmarks in the oil industry: Egg Model and SAIGUP. This new strategy modifies

Abstract A method to manage geological uncertainty as part of an expensive simulation-based optimization process is presented. When the number of realizations representing the uncertainty is high, the computational cost to optimize the system can be considerable, and often prohibitively, as each forward evaluation is expensive to evaluate. To overcome this limitation, an iterative procedure is developed

Imbibition is an important process encountered in many porous media applications. At the pore scale, pore network models (PNM) are computationally efficient and can model drainage accurately. However, using PNM to model imbibition still remains a challenge due to the complexities encountered in understanding pore-scale flow phenomena related to pore body filling (PBF) and snap-off along with the relative