Browsing by Subject "Streamline"
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Item A Hierarchical Multiscale Approach to History Matching and Optimization for Reservoir Management in Mature Fields(2012-10-19) Park, Han-YoungReservoir management typically focuses on maximizing oil and gas recovery from a reservoir based on facts and information while minimizing capital and operating investments. Modern reservoir management uses history-matched simulation model to predict the range of recovery or to provide the economic assessment of different field development strategies. Geological models are becoming increasingly complex and more detailed with several hundred thousand to million cells, which include large sets of subsurface uncertainties. Current issues associated with history matching, therefore, involve extensive computation (flow simulations) time, preserving geologic realism, and non-uniqueness problem. Many of recent rate optimization methods utilize constrained optimization techniques, often making them inaccessible for field reservoir management. Field-scale rate optimization problems involve highly complex reservoir models, production and facilities constraints and a large number of unknowns. We present a hierarchical multiscale calibration approach using global and local updates in coarse and fine grid. We incorporate a multiscale framework into hierarchical updates: global and local updates. In global update we calibrate large-scale parameters to match global field-level energy (pressure), which is followed by local update where we match well-by-well performances by calibration of local cell properties. The inclusion of multiscale calibration, integrating production data in coarse grid and successively finer grids sequentially, is critical for history matching high-resolution geologic models through significant reduction in simulation time. For rate optimization, we develop a hierarchical analytical method using streamline-assisted flood efficiency maps. The proposed approach avoids use of complex optimization tools; rather we emphasize the visual and the intuitive appeal of streamline method and utilize analytic solutions derived from relationship between streamline time of flight and flow rates. The proposed approach is analytic, easy to implement and well-suited for large-scale field applications. Finally, we present a hierarchical Pareto-based approach to history matching under conflicting information. In this work we focus on multiobjective optimization problem, particularly conflicting multiple objectives during history matching of reservoir performances. We incorporate Pareto-based multiobjective evolutionary algorithm and Grid Connectivity-based Transformation (GCT) to account for history matching with conflicting information. The power and effectiveness of our approaches have been demonstrated using both synthetic and real field cases.Item Effective Reservoir Management Using Streamline-Based Reservoir Simulation, History Matching and Rate Allocation Optimization(2014-08-28) Tanaka, ShuseiThe use of the streamline-based method for reservoir management is receiving increased interest in recent years because of its computational advantages and intuitive appeal for reservoir simulation, history matching and rate allocation optimization. Streamline-based method uses snapshots of flow path of convective flow. Previous studies proved its applicability for convection dominated process such as waterflooding and tracer transport. However, for a case with gas injection with strong capillarity and gravity effects, the streamline-based method tends to lose its advantages for reservoir simulation and may result in loss of accuracy and applicability for history-matching and optimization problems. In this study, we first present the development of a 3D 3-phase black oil and compositional streamline simulator. Then, we introduce a novel approach to incorporate capillary and gravity effects via orthogonal projection method. The novel aspect of our approach is the ability to incorporate transverse effects into streamline simulation without adversely affecting its computational efficiency. We demonstrate our proposed method for various cases, including CO2 injection scenario. The streamline model is shown to be particularly effective to examine and visualize the interactions between heterogeneity which resulting impact on the vertical and areal sweep efficiencies. Next, we apply the streamline simulator to history matching and rate optimization problems. In the conventional approach of streamline-based history matching, the objective is to match flow rate history, assuming that reservoir energy was matched already, such as pressure distribution. The proposed approach incorporates pressure information as well as production flow rates, aiming that reservoir energy are also reproduced during production rate matching. Finally, we develop an NPV-based optimization method using streamline-based rate reallocation algorithm. The NPV is calculated along streamline and used to generate diagnostic plots of the effectiveness of wells. The rate is updated to maximize the field NPV. The proposed approach avoids the use of complex optimization tools. Instead, we emphasize the visual and the intuitive appeal of streamline methods and utilize flow diagnostic plots for optimal rate allocation. We concluded that our proposed approach of streamline-based simulation, inversion and optimization algorithm improves computational efficiency and accuracy of the solution, which leads to a highly effective reservoir management tool that satisfies industry demands.Item Fast history matching of finite-difference model, compressible and three-phase flow using streamline-derived sensitivities(Texas A&M University, 2006-10-30) Cheng, HaoReconciling high-resolution geologic models to field production history is still a very time-consuming procedure. Recently streamline-based assisted and automatic history matching techniques, especially production data integration by ??????travel-time matching,?????? have shown great potential in this regard. But no systematic study was done to examine the merits of travel-time matching compared to more traditional amplitude matching for field-scale application. Besides, most applications were limited to two-phase water-oil flow because current streamline models are limited in their ability to incorporate highly compressible flow in a rigorous and computationally efficient manner. The purpose of this work is fourfold. First, we quantitatively investigated the nonlinearities in the inverse problems related to travel time, generalized travel time, and amplitude matching during production data integration and their impact on the solution and its convergence. Results show that the commonly used amplitude inversion can be orders of magnitude more nonlinear compared to the travel-time inversion. Both the travel-time and generalized travel time inversion (GTTI) are shown to be more robust and exhibit superior convergence characteristics. Second, the streamline-based assisted history matching was enhanced in two important aspects that significantly improve its efficiency and effectiveness. We utilize streamline-derived analytic sensitivities to determine the location and magnitude of the changes to improve the history match, and we use the iterative GTTI for model updating. Our approach leads to significant savings in time and manpower. Third, a novel approach to history matching finite-difference models that combines the efficiency of analytical sensitivity computation of the streamline models with the versatility of finite-difference simulation was developed. Use of finite-difference simulation can account for complex physics. Finally, we developed an approach to history matching three-phase flow using a novel compressible streamline formulation and streamline-derived analytic sensitivities. Streamline models were generalized to account for compressible flow by introducing a relative density of total fluids along streamlines and a density-dependent source term in the saturation equation. The analytical sensitivities are calculated based on the rigorous streamline formulation. The power and utility of our approaches have been demonstrated using both synthetic and field examples.Item Streamline-based modeling and interpretation of formation-tester measurements(2013-12) Hadibeik Nishaboori, Abdolhamid; Torres-Verdín, Carlos; Sepehrnoori, Kamy, 1951-Formation testing is a critical component of modern petrophysical analysis for determining pore pressure, pressure gradients, and reservoir connectivity, and for estimating static and dynamic formation properties. However, petrophysicists tend to avoid the analysis of transient formation-tester measurements because of the physical and mathematical complexities involved, including time-consuming numerical simulations, rock heterogeneity, anisotropy, presence of mud-filtrate invasion, and saturation-dependent properties. Additional technical challenges arise when modeling formation-tester measurements in heterogeneous reservoirs penetrated by high-angle wells. A new method is developed in this dissertation to efficiently simulate formation-tester measurements acquired in heterogeneous reservoirs penetrated by vertical and deviated wells. The method is based on tracing flow streamlines from the reservoir into the formation tester’s probe. Before tracing streamlines, an initial reservoir condition is imposed due to the pressure-saturation field resulting from mud-filtrate invasion. Subsequently, the spatial distribution of pressure is calculated via finite differences to account for the negative flow-rate source originating from the tester’s probe. Streamlines are retraced at various time intervals upon updating the pressure distribution resulting from dynamic fluid flow toward the source. The streamline-based simulation method is efficient and flexible in accounting for various probe configurations, including dual packers and point focused-sampling probes. Streamlines are also used to trace reservoir fluid and contamination into sample probes. In addition, graphical rendering of streamlines permits rapid assessment of flow regimes as a function of time. Simulation results obtained with finite-difference and streamline methods agree well, although the streamline-based method is computationally more efficient. However, the streamline method is not well suited for complicated fluid displacement, such as that arising in the presence of highly compressible flow, strong capillary-pressure effects, and variable phase behavior. Furthermore, criteria for enforcing pressure updates with finite differences raise additional difficulties in accurately modeling formation-tester measurements. Despite these limitations, forward simulation results indicate that both faster computation time and reduced computer-memory requirements resulting from use of the streamline-based method are ideal for inversion of formation-tester measurements used in estimating static and dynamic petrophysical properties. Synthetic and field examples of streamline-based inversion are considered to estimate petrophysical properties from transient data acquired with packer and probe-type formation testers. The method is applied to measurements acquired in two offshore field reservoirs penetrated by vertical and deviated wells to estimate permeability, anisotropy, and relative permeability. In the documented examples, each streamline-based simulation used to calculate the Jacobian matrix is up to 8.7 times faster than that obtained by using the finite-difference method. Inversion results also indicate that streamline trajectories are valuable in ascertaining the sensitivity of estimated formation properties in the presence of variable pressure/fluid sampling locations, variable wellbore orientations with respect to formation bedding, and reservoir heterogeneity in deviated and horizontal well models.Item Streamline-based simulation of water injection in naturally fractured reservoirs(Texas A&M University, 2004-09-30) Al-Huthali, AhmedThe current streamline formulation is limited to single-porosity systems and is then not suitable for application to naturally fractured reservoirs. Describing the fluid transport in naturally fractured reservoirs has been recognized as a main challenge for simulation engineers due to the complicated physics involved. In this work, we generalized the streamline-based simulation to describe the fluid transport in naturally fractured reservoirs. We implemented three types of transfer function: the conventional transfer function (CTF), the diffusion transfer function (DTF), and the empirical transfer function (ETF). We showed that these transfer functions can be implemented easily in the current single-porosity streamline codes. These transfer functions have been added as a source term to the transport equation that describes the saturation evolution along the streamlines. We solved this equation numerically for all types of transfer functions. The numerical solution of the continuity equation with DTF and ETF requires discretizing a convolution term. We derived an analytical solution to the saturation equation with ETF in terms of streamline TOF to validate the numerical solution. We obtain an excellent match between the numerical and the analytical solution. The final stage of our study was to validate our work by comparing our dual-porosity streamline simulator (DPSS) to the commercial dual-porosity simulator, ECLIPSE. The dual-porosity ECLIPSE uses the CTF to describe the interaction between the matrix-blocks and the fracture system. The dual-porosity streamline simulator with CTF showed an excellent match with the dual-porosity ECLIPSE. On the other hand, dual-porosity streamline simulation with DTF and ETF showed a lower recovery than the recovery obtained from the dual-porosity ECLIPSE and the DPSS with CTF. This difference in oil recovery is not due to our formulation, but is related to the theoretical basis on which CTF, DTF, and ETF were derived in the literature. It was beyond the scope of this study to investigate the relative accuracy of each transfer function. We demonstrate that the DPSS is computationally efficient and ideal for large-scale field application. Also, we showed that the DPSS minimizes numerical smearing and grid orientation effects compared to the dual-porosity ECLIPSE.Item Streamline-based three-phase history matching(Texas A&M University, 2008-10-10) Oyerinde, Adedayo StephenGeologic models derived from static data alone typically fail to reproduce the production history of a reservoir, thus the importance of reconciling simulation models to the dynamic response of the reservoir. This necessity has been the motivation behind the active research work in history matching. Traditionally, history matching is performed manually by applying local and regional changes to reservoir properties. While this is still in general practice, the subjective overtone of this approach, the time and manpower requirements, and the potential loss of geologic consistency have led to the development of a variety of alternative workflows for assisted and automatic history matching. Automatic history matching requires the solution of an inverse problem by minimizing an appropriately defined misfit function. Recent advances in geostatistics have led to the building of high-resolution geologic models consisting of millions of cells. Most of these are scaled up to the submillion size for reservoir simulation purposes. History matching even the scaled up models is computationally prohibitive. The associated cost in terms of time and manpower has led to increased interest in efficient history matching techniques and in particular, to sensitivity-based algorithms because of their rapid convergence. Furthermore, of the sensitivity-based methods, streamline-based production data integration has proven to be extremely efficient computationally. In this work, we extend the history matching capability of the streamline-based technique to three-phase production while addressing in general, pertinent issues associated with history matching. We deviate from the typical approach of formulating the inverse problem in terms of derived quantities such as GOR and Watercut, or measured phase rates, but concentrate on the fundamental variables that characterize such quantities. The presented formulation is in terms of well node saturations and pressures. Production data is transformed to composite saturation quantities, the time variation of which is matched in the calibration exercise. The dependence of the transformation on pressure highlights its importance and thus a need for pressure match. To address this need, we follow a low frequency asymptotic formulation for the pressure equation. We propose a simultaneous inversion of the saturation and pressure components to account for the interdependence and thus, high non-linearity of three phase inversion. We also account for global parameters through experimental design methodology and response surface modeling. The validity of the proposed history matching technique is demonstrated through application to both synthetic and field cases.Item Understanding reservoir mechanisms using phase and component streamline tracing(2009-05-15) Kumar, SarweshConventionally streamlines are traced using total flux across the grid cell faces. The visualization of total flux streamlines shows the movement of flood, injector-producer relationship, swept area and movement of tracer. But they fail to capture some important signatures of reservoir dynamics, such as dominant phase in flow, appearance and disappearance of phases (e.g. gas), and flow of components like CO2. In the work being presented, we demonstrate the benefits of visualizing phase and component streamlines which are traced using phase and component fluxes respectively. Although the phase and component streamlines are not appropriate for simulation, as they might be discontinuous, they definitely have a lot of useful information about the reservoir processes and recovery mechanisms. In this research, phase and component streamline tracing has been successfully implemented in three-phase and compositional simulation and the additional information obtained using these streamlines have been explored. The power and utility of the phase and component streamlines have been demonstrated using synthetic examples and two field cases. The new formulation of streamline tracing provides additional information about the reservoir drive mechanisms. The phase streamlines capture the dominant phase in flow in different parts of the reservoir and the area swept corresponding to different phases can be identified. Based on these streamlines the appearance and disappearance of phases can be identified. Also these streamlines can be used for optimizing the field recovery processes like water injection and location of infill wells. Using component streamlines the movement of components like CO2 can be traced, so they can be used for optimizing tertiary recovery mechanisms and tracking of tracers. They can also be used to trace CO2 in CO2 sequestration project where the CO2 injection is for long term storage in aquifers or reservoirs. They have also other potential uses towards study of reservoir processes and behavior such as drainage area mapping for different phases, phase rate allocations to reservoir layers, etc.