28 results on '"Ulisses T. Mello"'
Search Results
2. Three-Dimensional Constrained Delaunay Triangulation: a Minimalist Approach.
- Author
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Paulo Roma Cavalcanti and Ulisses T. Mello
- Published
- 1999
3. Using XML to improve the productivity and robustness in application development in geosciences.
- Author
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Ulisses T. Mello and Liqing Xu
- Published
- 2006
- Full Text
- View/download PDF
4. Uncertainty in Thermal Basin Modeling: An Interval Finite Element Approach.
- Author
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Sebastião C. Pereira, Ulisses T. Mello, Nelson F. F. Ebecken, and Rafi L. Muhanna
- Published
- 2006
- Full Text
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5. Enabling high-resolution forecasting of severe weather and flooding events in Rio de Janeiro.
- Author
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Lloyd A. Treinish, Anthony Praino, James P. Cipriani, Ulisses T. Mello, Kiran Mantripragada, Lucas Villa Real, Paula A. Sesini, Vaibhav Saxena, Thomas George, and Rashmi Mittal
- Published
- 2013
- Full Text
- View/download PDF
6. Opening New Opportunities With Fast Reservoir-Performance Evaluation Under Uncertainty: Brugge Field Case Study
- Author
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Sonia Mariette Embid Droz, David Echeverria-Ciaurri, Ruben Rodriguez Torrado, and Ulisses T. Mello
- Subjects
Reservoir simulation ,General Energy ,business.industry ,Computer science ,Field (Bourdieu) ,Environmental resource management ,Environmental economics ,Project portfolio management ,business ,General Business, Management and Accounting ,Risk management - Abstract
SummaryDecision making under uncertainty can be quite challenging, especially when complex numerical simulations are considered in the work flow and the decision has to be made relatively fast (e.g., in hours). This is the case when one needs to rank a given field portfolio within a limited budget and with acquisition constraints. If the ranking measure associated with each field is properly and rapidly evaluated, new prospect opportunities, which may lead to a favorable strategic position, can be readily identified.In this paper, we propose an efficient methodology for computing a “production-potential” measure that can be used to rank greenfield portfolios in the presence of geological uncertainty, quantifying both uncertainty and risk propagation. Next, we briefly describe the basics of the method proposed. First, uncertainty in sedimentary variability and flow behavior has to be characterized by a number of representative geological realizations. Sampling techniques are used to significantly reduce the number of realizations while preserving accuracy in the description and uncertainty propagation. Thereafter, multiple and varied field-development plans, based on primary/secondary-recovery mechanisms, are automatically generated while accounting for key parameters related to the number, drilling locations, and drilling sequence of wells. In these plans the reservoir is clustered by areas with similar production/injection potential, and the well locations and drilling schedules are obtained accordingly. The well controls are determined through estimations of the field-recovery factor. By means of experimental-design techniques a relatively small number of field-development plans are selected to capture the most significant production profiles. Each of these development plans is simulated for the realizations sampled previously, and the production-potential measure [e.g., average net present value (NPV) over all sampled realizations] is computed for all the plans. The highest of these measures (i.e., the best development plan) can be used for ranking the greenfield in the portfolio. Response-surface procedures are considered to perform additional analysis computations within iterative optimization procedures. It is important to note that other statistics related to the exploitation potential (e.g., standard deviation of the NPV) can also be used to complement the ranking, thereby mitigating the decision makers’ risk tolerance. The methodology has been tested on the Brugge Field benchmark, which presents 104 realizations of multiple geological parameters. The benchmark has been modified to simulate a greenfield scenario. The ranking measure is the (discounted) NPV averaged over the 104 realizations. The proposed work flow yields a ranking measure of USD 5.43 billion, and the computational cost is approximately 1,900 simulations (performed in a parallel-computing environment). This NPV is somewhat higher than those found for the Brugge benchmark (with similar modified settings) by other researchers. To validate the results, we performed more-exhaustive checking by use of approximately 17,000 simulations, and the ranking measure found was USD 5.51 billion.The new work flow presented allows one to efficiently and in a sufficiently accurate manner support decision making in greenfield-portfolio evaluation. Fast reservoir-performance-evaluation engines open new prospect opportunities that, with traditional decision-making techniques, may be frequently lost.
- Published
- 2015
- Full Text
- View/download PDF
7. Modeling of discrete intersecting discontinuities in rock mass using XFEM/level set approach
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Sandeep Singh Sandha, Kamal C. Das, Ulisses T. Mello, Nubia Aurora Gonzalez, P. E. Vargas, J SeguraSerra, Mookanahallipatna Ramasesha Lakshmikantha, Ignacio Carol, and Eduardo R. Rodrigues
- Subjects
Level set (data structures) ,Geotechnical engineering ,Classification of discontinuities ,Rock mass classification ,Geology ,Extended finite element method - Published
- 2016
- Full Text
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8. A control-volume finite-element method for three-dimensional multiphase basin modeling
- Author
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André L. Rossa, Jose Rodrigues, and Ulisses T. Mello
- Subjects
Partial differential equation ,Preconditioner ,Stratigraphy ,Multiphase flow ,Mineralogy ,Geology ,Oceanography ,Generalized minimal residual method ,Physics::Geophysics ,symbols.namesake ,Geophysics ,Linearization ,Basin modelling ,Heat transfer ,symbols ,Applied mathematics ,Economic Geology ,Newton's method - Abstract
In this paper we describe a 3D control-volume finite-element method to solve numerically the coupled partial differential equations (PDEs) governing geological processes involved in the evolution of sedimentary basins. These processes include sediment deposition and deformation, hydrocarbon generation, multiphase fluid flow, and heat transfer in deforming porous media. These integrated processes possess a wide range of time-scales, indicating the need for implicit methods. In addition, sedimentary basins are geometrically complex environments, requiring unstructured tetrahedral meshes to adequately represent the problem realistically without the need for an excessive number of mesh elements. Here, we also present a general formulation for problems involving back-oil, thermal, or compositional models using overall component mass concentrations, and an arbitrary Lagrangian–Eulerian (ALE) formulation to deal with salt motion conservatively. The Newton method is used to solve the sparse Jacobian systems resulting from the linearization of the coupled non-linear PDEs for multiphase flow and energy transfer. These systems are solved with the generalized minimal residual method (GMRES) method with an incomplete lower–upper (ILU) preconditioner for faster inner iteration convergence rates. We applied this model to a sedimentary basin and we describe the results for this basin.
- Published
- 2009
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9. Exploring Efficient Alternatives for High Performance Computing Requirements in Coupled Fluid-Flow and Stress Simulations for the Oil & Gas Industry
- Author
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Eduardo R. Rodrigues, J.M. Serra Segura, P. Vargas Mendoza, M. R. Lakshmikantha, Kamal C. Das, Ulisses T. Mello, and Roberto F. Ausas
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Stress (mechanics) ,Engineering ,Petroleum engineering ,business.industry ,Fluid dynamics ,business ,Supercomputer - Abstract
Numerical simulation is becoming an indispensable tool for the Oil & Gas industry. In order to simulate large numerical models, common practice is to rely on parallel computing. Here, we present key concepts for the development of numerical application intended to be parallel from start. Design and implementation of numerical simulators require many decisions. However, engineers do not consider parallelization priority. This is not a good decision and we present three factors that affect the implementation and performance of a numerical tool. Memory usage: workstations have very large amounts of memory. It is tempting to "splurge" on that resource. However, parallel machines have less memory per processor (e.g. BlueGene and GPU). Reducing the memory footprint in order to parallelize an existing numerical tool is time-consuming and error prone. Conversely, developing numerical code in such environment means that they can run with fine-grained parallelism when needed, but still run in fatter nodes. I/O: Usually the numerical core is the focus of parallelization. Nonetheless, as applications scale to large processor counts, I/O becomes a bottleneck. As an efficient alternative, I/O routines can be implemented in HDF5. This has two main advantages: (1) it is parallel and relies on the underlying parallel I/O system (e.g. GPFS); (2) and it is an open standard. Adopting it at a later stage would mean a different file format in the workflow that would require converters that can become a bottleneck. Solvers: Discretization of the governing equations leads to large systems that need to be assembled and solved several times during the computation. This requires efficient iterative solvers. Interchangeable interfaces for standardized libraries add flexibility. This is fundamental for ill-conditioned problems found in coupled fluid flow and stress phenomenon.
- Published
- 2014
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10. Regional slope stability and slope-failure mechanics from the two-dimensional state of stress in an infinite slope
- Author
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Ulisses T. Mello and Lincoln F. Pratson
- Subjects
Extensional deformation ,Slope failure ,Pore water pressure ,Line of greatest slope ,Geochemistry and Petrology ,Slope stability ,Geology ,Mechanics ,Slip (materials science) ,Oceanography ,Slope stability analysis ,Headwall - Abstract
Rapid estimates of regional submarine slope stability can be obtained using 1-D infinite-slope analysis or empirical 2-D analyses, such as the log-spiral or φ-circle methods. In these methods, slope stability is evaluated along a pre-defined slip surface because the principal stresses in the slope and the slip-plane directions they control are undefined. However, where these pre-defined slip surfaces are not a good approximation of the surface along which a slope failure actually occurs, the analyses cannot explain the physics and observed geometry of the failure. Here we present an alternative, 2-D analytical solution for the state of stress in an infinite slope that incorporates cohesion and constant pore pressure, and yields the principal stresses and possible slip-plane directions along which the slope can fail. As a result, the analysis provides a framework for understanding the general geometry and relative motion of mass movements not addressed by 1-D infinite-slope analysis or the empirical 2-D analyses. We use our 2-D infinite-slope analysis to show that if the compressive stresses in the lower part of a slope are great enough, slope failure will occur along a basal plane, which in turn will permit extensional deformation along a steeper, headwall plane farther upslope. We then discuss how such failure can be facilitated on slopes of low inclination by excess pore pressure. Based on this discussion, we suggest that if pore pressure becomes high enough, slope failure can be initiated at a lower pore pressure and along a lower-angle basal plane than predicted by 1-D infinite-slope analysis.
- Published
- 1999
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11. Techniques for including large deformations associated with salt and fault motion in basin modeling
- Author
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Michael E. Henderson and Ulisses T. Mello
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geography ,geography.geographical_feature_category ,Stratigraphy ,Mineralogy ,Geology ,Context (language use) ,Geometry ,Fault (geology) ,Sedimentary basin ,Structural basin ,Oceanography ,Displacement (vector) ,Physics::Geophysics ,Geophysics ,Basin modelling ,Economic Geology ,Fault block ,Salt dome - Abstract
Modeling large deformations such as non-vertical fault displacement and salt motion have been a major obstacle for the improvement of regional basin modeling studies. Because salt has a large thermal conductivity and is practically impervious, and faults can act as conduits or seals during the evolution of sedimentary basins, they are critical in making accurate predictions of the generation, migration and accumulation of hydrocarbons within salt-bearing basins. To model numerically the evolution of salt structures is not a trivial task and one of the major difficulties in modeling the motion of salt and faults is the management of numerical meshes that are severely corrupted with large deformations. In this study, we use a topological framework for the representation of complex geological structures that makes it possible to model geological processes with large deformation within sedimentary basins and the lithosphere. This framework greatly facilitates the automatic meshing and remeshing required during modeling because meshes, like lithology and physical properties, are treated as attributes of subregions of the model. In this context, we developed a series of techniques to classify fault blocks in order to model the displacement of multiple faults simultaneously in the correct order. In addition, we show that this framework allows the decomposition of the basin model along geological discontinuities and makes it suitable for parallel computation of the solution of differential equations governing generation and migration of hydrocarbons.
- Published
- 1997
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12. Generation of an Accurate Conceptual Model for Green Fields
- Author
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Sonia Embid, Debarun Bhattacharjya, Ruben Rodriguez Torrado, Ulisses T. Mello, and G. De Paola
- Subjects
Geography ,Reservoir modeling ,Conceptual model (computer science) ,Geotechnical engineering ,Geostatistics ,Civil engineering - Abstract
A proper quantification and propagation of geological and geophysical uncertainty during phase of technical and economic appraisal of a reservoir is of primary importance to evaluate the potential and the risks associated with a new prospect. In this paper we propose an innovative methodology to define a conceptual model for different levels of available information particularly appealing for cases with limited data – such as that of a green field. The proposed methodology aims to construct multiple reservoir realizations which are geologically consistent with the the available data and constrain, and capable to propagate the uncertainty inherent to a given target reservoir specifications. The uncertainty is characterized using analogous reservoirs which are, in the present case, evaluated from an in-house database. The methodology can be resumed in a sequence of well defined steps. First, based on the quality and availability of the information, an optimization problem is formulated and solved to ensure that the generated realizations obey the petro-physical property statistics of the target reservoir. Outputs of the optimization process are the facies proportions yielding to the conditional probability distributions of properties. The physical distribution of the petrophysical properties are then generated based on these inputs using multipoint geostatistical techniques. To correctly propagate the uncertainty in the reservoir model the sensitive controlling variables input to the geostatistical algorithm are defined within a variability range. The selection of the relevant input parameters can be selected based on sensitivity analysis techniques. The stochasticity proper of the geostatistical algorithms used for the property distribution requires special care for the correct application and interpretation of the problem reduction techniques. Static and dynamic objective functions have been used to evaluate the statistical distribution of the generated realizations. From a static point of view the reservoir volumetric has been ranked using the field original-oil-in-place. The dynamic response of the generated realizations upon a simple pattern has been implemented as measure of connectivity. As proof of concept the field-oil-production-rate for an inverted-five-spot pattern under voidage replacement was chosen as dynamic ranking. The methodology has been applied to the Brugge field benchmark which presents 104 geological realizations (Peters et al (2010), Peters et al (2009)). The benchmark was modified in order to simulate a green field, therefore only mean values for the petro-physical properties were extracted and used as input to the methodology whils the complete geological realizations results of the full-field-model (FFM) have been used for validation. A list of equiprobable analogous reservoirs has been identified from the database. Thereof, a number of conceptual models have been created respecting the key static parameters statistics defined. To validate the workflow first the predicted original-oil-in-place from the analogues and from the generated realizations respectively has been positively compared with the benchmark realizations. Due to the absence of structural uncertainty in the benchmark realizations the brute volume and the mean original-oil-in-place compute from the analogues have been set and a large number of geological realizations have been simulated. Results indicate that the trends obtained by the conceptual model for a given production strategy is in agreement with the FFM and the FFM results are located within the produced realizations. The computational time associated with the conceptual model, due to its simplicity, was also very attractive compared to the full model. Noteworthy, the methodology provides important insight on the sensitivity of the geological model to several uncertain static and dynamic parameter and configurations which can be the base for a risk analysis or to quantify the value of additional information.
- Published
- 2013
- Full Text
- View/download PDF
13. Fast Reservoir Performance Evaluation Under Uncertainty: Opening New Opportunities
- Author
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David Echeverría Ciaurri, Ruben Rodriguez Torrado, Ulisses T. Mello, and Sonia Embid
- Subjects
Engineering ,Risk analysis (engineering) ,business.industry ,Risk analysis (business) ,Environmental resource management ,Field development ,Project portfolio management ,business - Abstract
Decision-making under uncertainty can be quite challenging, especially when complex numerical simulations are considered in the workflow and the decision has to be made relatively fast (e.g. in hours). This is the case when one needs to rank a given field portfolio within a limited budget and with acquisition constraints. If the ranking measure associated with each field is properly and rapidly evaluated, new prospect opportunities, that may lead to a favorable strategic position, can be readily identified.In this paper, we propose an efficient methodology for computing a ‘production potential’ measure that can be used to rank field portfolios in the presence of geological uncertainty, quantifying both uncertainty and risk propagation. Next, we briefly describe the basics of the method proposed. In the first place, uncertainty in sedimentary variability and flow behavior has to be characterized by a number of representative geological realizations. Sampling techniques are used to significantly reduce the number of realizations while preserving accuracy in the description and uncertainty propagation. Thereafter, multiple and varied field development plans, based on primary/secondary recovery mechanisms, are automatically generated whilst accounting for key parameters related to the number, drilling locations and drilling sequence of wells. In these plans the reservoir is clustered by areas with similar production/injection potential, and the well locations and drilling schedules are obtained accordingly. The well controls are determined through estimations of the field recovery factor. By means of experimental-design techniques a relative small number of field development plans are selected to capture the most significant production profiles. Each of these development plans is simulated for the realizations sampled previously, and the production potential measure [e.g. average net present value (NPV) over all sampled realizations] is computed for all the plans. The highest of these measures (i.e. the best development plan) can be used for ranking the field in the portfolio. Response surface procedures are considered to perform additional analysis computations within iterative optimization procedures. It is important to note that other statistics related to the exploitation potential (e.g. standard deviation of the NPV) can also be used to complement the ranking, thereby mitigating the decision-makers risk tolerance. The methodology has been tested on the Brugge field benchmark which presents 104 realizations of multiple geological parameters. The benchmark has been modified in order to simulate a green-field scenario. The ranking measure is the (discounted) NPV averaged over the 104 realizations. The proposed workflow yields a ranking measure of $5.43 billion, and the computational cost is around 1,900 simulations (performed in a parallel computing environment). This NPV is somewhat higher than those found for the Brugge benchmark (with similar modified settings) by other researchers. In order to validate the results, we performed more exhaustive checking using around 17,000 simulations, and the ranking measure found was $5.51 billion.The new workflow presented allows one to efficiently, and in a sufficiently accurate manner, support decision making in field portfolio evaluation. Fast reservoir performance evaluation engines open new prospect opportunities that, with traditional decision-making techniques, may be frequently lost.
- Published
- 2013
- Full Text
- View/download PDF
14. Studies of Mass-Movement Processes on Submarine Slopes
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Jacques Locat, Kenneth Isreal, Marcelo H. Garcia, Jeffrey D. Parsons, Bernard Coakley, Sun Uk Choi, David Mohrig, Gary Parker, Homa J. Lee, Ulisses T. Mello, and Lincoln F. Pratson
- Subjects
Paleontology ,Mass movement ,Submarine ,Oceanography ,Geology - Published
- 1996
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15. Role of salt in restraining the maturation of subsalt source rocks
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Garry D. Karner, Roger N. Anderson, and Ulisses T. Mello
- Subjects
geography ,geography.geographical_feature_category ,Evaporite ,Salt glacier ,Stratigraphy ,Mineralogy ,Geology ,Diapir ,Sedimentary basin ,Oceanography ,Salt tectonics ,Structural evolution of the Louisiana gulf coast ,Dome (geology) ,Geophysics ,Economic Geology ,Petrology ,Salt dome - Abstract
The presence of salt within a sedimentary basin can potentially modify its temperature distribution and history. In particular, the positive thermal anomaly associated with the top of salt domes has attracted considerable attention in the past. The role of the lesser appreciated negative thermal anomaly associated with the base of salt domes in modifying the maturation history of subsalt source rocks is explored. The finite element method was used to model the transient and steady-state conductive temperature perturbations induced by salt layers, domes and pillows. The results indicate that the modification of the thermal regime due to evolving salt domes may significantly affect the maturation level of source rocks in the vicinity of the domes. Modelling the temperature structure of various salt structures has shown that, in general, the refraction of heat flow induces a dipole-shaped temperature anomaly; a positive anomaly located towards the top of the salt structure and a negative anomaly located towards its base. These dipole anomalies can be strongly asymmetrical, the degree of asymmetry depending on the shape of the salt structure and the proximity of the top of the salt structure to the surface of the basin. However, when the salt structure reaches the surface, the dipole-shaped temperature anomaly collapses to a monopole. Below the salt structure, all sediments, independent of their depth and lithology, are colder relative to a section with no salt. Similarly, salt domes that reach the surface very efficiently drain the heat from below and from the side of the dome. These negative thermal anomalies may extend for a considerable depth beneath the base of the salt dome and may reach values of −85°C locally. Because of the large contrast in thermal conductivity between the highly porous sediments and salt at lower temperatures, the efficiency of a salt dome to channel heat increases the closer the salt dome is to the surface. These results indicate that deep sedimentary basins containing salt are more prospective than basins without salt and/or salt diapirism. In addition to the structural traps associated with salt tectonics, salt domes and tongues connected to their source dissipate heat more efficiently and thus keep deeper regions of the basin relatively colder and potentially within the oil window for a longer time. This cooling effect is maximized when the top of the salt dome remains close to the surface of the sedimentary basin for a significant period of time and may be especially important for continental margins such as Brazil and offshore West Africa, where most of the source rocks lie beneath extensive evaporite deposits. In contrast, it was found that for the Gulf of Mexico basin, pre- and Early Tertiary salt diapirism and sheet emplacement may have caused significant delays in the maturation of subsalt source rocks in the deeper regions of the Gulf basin, but the maturation is likely to be relatively insensitive to the Late Miocene-Pliocene stage of salt mobilization because the time interval has been too short (
- Published
- 1995
- Full Text
- View/download PDF
16. Adjoint-based History-Matching of Production and Time-lapse Seismic Data
- Author
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Justyna Katarzyna Przybysz-jarnut, Lior Horesh, Andrew R. Conn, Sippe G. Douma, Gijs Van Essen, Paul van den Hoek, Eduardo Jimenez, and Ulisses T. Mello
- Subjects
Data assimilation ,Workflow ,Mean squared error ,Computer science ,Temporal resolution ,Fluid dynamics ,Inversion (meteorology) ,Ensemble Kalman filter ,Spatial analysis ,Algorithm - Abstract
Time-lapse (4D) seismic attributes can provide valuable information on the fluid flow within subsurface reservoirs. This spatially-rich source of information complements the poor areal information obtainable from production well data. While fusion of information from the two sources holds great promise, in practice, this task is far from trivial. Joint Inversion is complex for many reasons, including different time and spatial scales, the fact that the coupling mechanisms between the various parameters are often not well established, the localized nature of the required model updates, and the necessity to integrate multiple data. These concerns limit the applicability of many data-assimilation techniques. Adjoint-based methods are free of these drawbacks but their implementation generally requires extensive programming effort. In this study we present a workflow that exploits the adjoint functionality that modern simulators offer for production data to consistently assimilate inverted 4D seismic attributes without the need for re-programming of the adjoint code. Here we discuss a novel workflow which we applied to assimilate production data and 4D seismic data from a synthetic reservoir model, which acts as the real yet unknown reservoir. Synthetic production data and 4D seismic data were created from this model to study the performance of the adjoint-based method. The seamless structure of the workflow allowed rapid setup of the data assimilation process, while execution of the process was reduced significantly. The resulting reservoir model updates displayed a considerable improvement in matching the saturation distribution in the field. This work was carried out as part of a joint Shell-IBM research project. Introduction In history matching, production measurements are assimilated to obtain a dynamical reservoir model that is consistent with historical data; see e.g. Oliver et al (2008). However, production measurements – although generally of a high temporal resolution – provide only very localized spatial information about the subsurface around the wells, especially in the early production phase when wateror gas-breakthrough has not yet occurred in the producers. After breakthrough, somewhat more insight can be gained into the reservoir model parameters that influence the mismatch between measured and simulated data. At that time however the benefits of using a pro-active reservoir management strategy have often diminished considerably. Interpreted time-lapse (4D) seismic data can provide information on the areal distribution of pressure and saturation changes due to fluid production or injection. The seismic data are generally more noisy and uncertain than production data, but due to the field-wide distribution of the data, very valuable additional information on the subsurface can be gathered; see e.g. Calvert (2005). In production data assimilation, the quality of the updated model is usually evaluated with a cost function defined as the summed squared error between the observations (measurements) and simulated production data, sometimes weighted by a measure of the accuracy of the observations. Ensemble Kalman filter (EnKF) methods (Naevdal et al. (2005); Evensen (2009); Aanonsen et al. (2009)), streamline-based methods (Vasco et al. (1999); Wang and Kovscek (2000).) and adjoint-based methods (Chen et al. (1974), Chavent et al. (1975); Li et al. (2003); Rodrigues (2006); Oliver et al. (2008)) are the most common data-assimilation techniques reported in literature to deal with the history matching problem. All these methods update the reservoir model using the sensitivities of a least-squares cost function with respect to model parameters, but differ in the considered measurement types, model parameters and derivation of the sensitivities. Of these three methods, the adjointbased method is the preferred method, because
- Published
- 2012
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17. Integrating Mathematical Optimization and Decision Making in Intelligent Fields
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David Echeverría Ciaurri, Andrew R. Conn, Ulisses T. Mello, and Jerome E. Onwunalu
- Subjects
Computer science ,Intelligent decision support system ,Industrial engineering - Abstract
In this paper a decision-making approach that can be applied to problems that are relevant to the oil and gas industry is presented. This methodology is supported by state-of-the-art mathematical optimization algorithms, and is based on the formal integration of the decisions in question with well-studied optimization procedures. The integration of the methodology with the application adds to its robustness. Two different types of problems are formulated and solved. The first kind is based on deciding which wells have to be shut in during a given production interval whilst simultaneously optimizing the controls for each selected well. The second category involves deciding for a group of wells which ones have to be injectors or producers, and at the same time searching for optimal well locations. In all the results obtained we can systematically see that the set of decisions proposed by the integrated approach mean substantial improvement in field production. For example, in the first class of problems studied, the production oil target is satisfied, and up to 50 percent of produced water is saved with respect to the reference case. The huge amount of information available, for example, in Intelligent/Smart Fields or Closed-Loop Reservoir Management can be utilized for rigorously making solid decisions. In this work we put an emphasis on integration of real-life decisions with a realistic simulation-based mathematical optimization framework. This framework can be also useful for establishing a common language for decision makers and researchers within a given organization, and as a consequence endowing the decision-making process with agility and robustness. It should be stressed that ultimately it is human interpretation and intuition that drives the making of crucial decisions. Automated tools should be understood as an additional (and hopefully valuable) source of information for making these important decisions.
- Published
- 2012
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18. Achieving Excellence in Offshore Logistics
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Ulisses T. Mello, Bruno Da Costa Flach, Dirk A. Claessens, and Jose R. Favilla
- Subjects
Engineering management ,Excellence ,media_common.quotation_subject ,Systems engineering ,Submarine pipeline ,Business ,media_common - Abstract
New frontiers in deep water oil exploration have imposed a number of challenges for the oil industry. One of these challenges is to provide high service level to the oil platforms and drilling units to keep them operating 24/7 in the most cost effective manner. Thousands of people have to be transported to and from the platforms on a monthly basis and also food, maintenance parts, diesel and other fluids. Helicopters and special vessels are used. Drilling operations require allocation of very expensive equipments and their needs are sometimes less predictable. Complex onshore logistics, composed of suppliers, warehouses, ports, heliports, etc. are required to support the offshore operations. Currently, most of the offshore logistics are still conducted in a traditional way, breaking the logistics chain in silos with little synchronization across the entire process. The proposed approach enables a paradigm change, bringing together the concept of integrated operations, leading supply chain practices and advanced enabling technologies. The concepts presented are being discussed and adopted by leading offshore operators. Dramatic improvement in service levels and significant cost reduction can be realized, enabling the offshore operators to achieve logistics excellence.
- Published
- 2012
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19. A physical explanation for the positioning of the depth to the top of overpressure in shale-dominated sequences in the Gulf Coast basin, United States
- Author
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Roger N. Anderson, Ulisses T. Mello, and Garry D. Karner
- Subjects
Atmospheric Science ,Compaction ,Soil Science ,Aquatic Science ,Oceanography ,Hydraulic conductivity ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Fluid dynamics ,Geotechnical engineering ,Petrology ,Earth-Surface Processes ,Water Science and Technology ,geography ,geography.geographical_feature_category ,Ecology ,Paleontology ,Forestry ,Sedimentary basin ,Overpressure ,Permeability (earth sciences) ,Geophysics ,Space and Planetary Science ,Clastic rock ,Sedimentary rock ,Geology - Abstract
A one-dimensional model of fluid pressure and porosity evolution is used to investigate the physical processes that control the development and maintenance of overpressure in a compacting sedimentary basin. We show that for shale-dominated sequences the variation of the hydraulic diffusivity in both space and time is such that it produces a minimum between 2 and 4 km depth, consistent with observations from the Gulf Coast basin. This minimum inhibits the upward flow of fluid by acting as a “bottleneck” and thus determines the shallowest position of the depth to the top of overpressure. Above this region of bottleneck, overpressure does not develop because the porosity is sufficiently large to maintain high values of hydraulic diffusivity that are conducive to the rapid dissipation of excess fluid pressure. Within the overpressured shales, compaction propagates downward through the section, releasing fluids from the upper part of the section while continuing to restrain the upward flow of fluids from deeper within the section. As such, overpressures are predicted to be maintained within the deeper regions of a basin for tens to hundreds of millions of years. Further, fluid viscosity plays an important role in defining the depth behavior of hydraulic diffusivity as a function of time. Assuming a temperature-dependent fluid viscosity guarantees that the hydraulic diffusivity minimum will always exist during the development of the basin. On the basis of our results, we find that the depth at which the porosity equals 14±4% correlates with the depth to the local hydraulic diffusivity minimum and thus the depth to the top of overpressure. Moreover, we interpret that the 14±4% represents the threshold porosity for which a shale actually begins to act as a seal. Within the Gulf Coast basin, the gross sediment facies consists of lower massive shales across which deltaic systems have prograded allowing the deposition of an alternating series of sandstones and shales that grade vertically into massive sandstones. The massive sandstones are highly permeable and are connected hydrologically to the surface. We conclude that these sandstones play little role in the development of overpressure because of their high permeability except to the extent that the base of the massive sandstones marks the minimum depth possible for the top of overpressure. In contrast, overpressuring is observed to develop within either the shale-dominated sequence or the region of interspersed/interfingering sands and clays. The clay-encompassed sands play only a passive role in the development and maintenance of overpressure because it is the low-permeability clays that control the movement of fluids into and out of the sands.
- Published
- 1994
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20. Rock Physics and Depositional History from Seismic Matching – A Model Study
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Andrew R. Conn, Hongchao Zhang, Ulisses T. Mello, Stewart A. Levin, Katya Scheinberg, L. Xu, and Vanessa Lopez
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Sedimentary depositional environment ,Regional geology ,Matching (statistics) ,Stratigraphy ,Engineering geology ,IBM ,Palaeogeography ,Geomorphology ,Geology ,Seismology ,Environmental geology - Abstract
F031 Rock Physics and Depositional History from Seismic Matching – A Model Study S.A. Levin* (Halliburton Energy Services) U. Mello (IBM) V. Lopez (IBM) L. Xu (IBM) A.R. Conn (IBM) K. Scheinberg (IBM) & H. Zhang (IBM) SUMMARY In this study we apply advanced numerical optimisation techniques to extend the work of Imhof and Sharma (2005 2006) to integrate geological and geophysical data and infer the sedimentary parameters that produce a match to seismic data. In particular we seek to match not just event timing (phase) but also reflection strength (amplitude). This inverse problem of quantitatively matching present-day measurements of
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- 2007
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21. Assisted seismic matching: Joint inversion of seismic, rock physics, and basin modeling
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Liqing Xu, Stewart A. Levin, Katya Scheinberg, Michael E. Henderson, Andrew R. Conn, Ulisses T. Mello, Vanessa Lopez, and Hongchao Zhang
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Petroleum engineering ,Stratigraphy ,Basin modelling ,Petrophysics ,Reflection (physics) ,Seismic inversion ,Inverse problem ,Joint (geology) ,Seismic to simulation ,Seismology ,Physics::Geophysics - Abstract
In this study, we apply advanced numerical optimization techniques to extend the work of Imhof and Sharma (2005, 2006) to integrate geological and geophysical data and infer the sedimentary parameters that produce a match to seismic data. In particular, we seek to match not just event timing (phase) but also reflection strength (amplitude). This inverse problem of quantitatively matching present-day measurements of structure, stratigraphy, petrology and/or fluids is inherently ill-posed and computationally difficult. In our approach we automatically adjust parameters, which control numerical forward models such as numerical basin models, petrophysical models, and seismic acoustic models, to match observed seismic data and observed stratigraphy. Note that the problem we tackle is more complex than traditional seismic inversion, which “just” estimates the velocity and reflectivity model that fits the seismic data. Here we also estimate the geological layer composition, as well as rock physics parameters controlling the relationships defining the bulk rock density and velocity.
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- 2007
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22. On Integrating Salt Motion in Basin Modeling: A Hybrid Approach for Goal-Oriented Salt Flow
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Jose Rodrigues, Jorge M. de Mendonça, Ulisses T. Mello, and Sebastião C. A. Pereira
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Petroleum engineering ,Goal orientation ,Flow (mathematics) ,Salt (cryptography) ,Basin modelling ,Geotechnical engineering ,Hybrid approach ,Geology ,Motion (physics) - Published
- 2004
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23. Optimization of Reservoir Simulation and Petrophysical Characterization in 4D Seismic
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Wei He, Gilles Guerin, Roger N. Anderson, Ulisses T. Mello, and Liqing Xu
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Reservoir simulation ,Petroleum engineering ,Petrophysics ,Geology ,Characterization (materials science) - Abstract
Abstract 4D seismic has become a widely accepted technique to interpret changes between successive 3D seismic surveys in terms of fluid substitution and pressure depletion in a producing reservoir. However, most time-lapse studies have been mostly qualitative and based on simplified reservoir representation in order to adjust to the time constraints of today's oil market. In this paper, we present how reservoir simulation constrained by stochastic characterization and non-linear optimization can be used in an integrated series of tools to refine 4D interpretation. Because of its direct relationship with pore fluid content and properties, we use seismic impedance rather than seismic amplitude as the primary data between the various steps of our 4D interpretation loop. Non-linear inversion of the 3D seismic data sets allows a preliminary interpretation. Stochastic simulation of the lithology and porosity, constrained by these "observed" impedance volumes and by well logs, provide the static reservoir characterization for the reservoir simulator. Once simulated production matches the recorded production history, empirical or Biot/Gassmann-type petrophysical models are used to calculate the "simulated" impedance volume from the fluid saturation and pressure distribution calculated by the reservoir simulator. Non-linear optimization is used iteratively to improve first the production history match and next the agreement between "simulated" and "observed" impedance volumes over time. This optimization is performed over a limited set of poorly constrained parameters in the permeability calculation and petrophysical models. In the case study presented here, the analysis of a turbidite reservoir in the South Timbalier 295 field, our results show how stochastic characterization helps reproducing the complexity of reservoir fluid dynamics while the results of the optimization underlines the robustness of the 4D interpretation despite the large amount of unknowns. Introduction Time-lapse, or 4-D, seismic monitoring is an integrated reservoir exploitation technique based on the analysis of successive 3D seismic surveys. Differences over time in seismic attributes are directly related to changes in pore fluids and pore pressure during the drainage of a reservoir under production. The detection of areas with significant changes or with unaltered hydrocarbon-indicative attributes, can be used to determine drilling targets where hydrocarbons remain trapped after several years of production. Making sure that seismic differences are related to fluid flows is critical for a complete time-lapse seismic study. Noise associated with differences in acquisition can generate seismic differences between surveys that are not related to the reservoir drainage pattern. In this paper, we describe how reservoir simulation can be used to generate independent impedance maps to validate or constrain 4-D impedance maps obtained from the inversion of successive legacy data sets. A complete 4D analysis is an iterative loop where the original interpretation can be refined along the later steps. First, we summarize the steps preceding the reservoir simulation, including the 3D seismic processing and inversion, and the preliminary time-lapse interpretation. We then describe the elastic models, the properties of reservoir fluids and the reservoir characterization that can be used to link the impedance volumes to fluid and lithology distributions in the reservoir.
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- 2000
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24. 4‐D seismic reservoir simulation in a South Timbalier 295 turbidite reservoir, Gulf of Mexico
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Ulisses T. Mello, Wei He, Roger N. Anderson, Gilles Guerin, and Albert Boulanger
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Pressure drop ,Reservoir simulation ,business.industry ,Water injection (oil production) ,Fossil fuel ,Fluid dynamics ,Reservoir modeling ,Drilling ,Petrology ,business ,Geology ,Seismology ,Turbidite - Abstract
4-D seismic reservoir simulation combines the analysis of 4-D (time-lapse) seismic changes measured in an oil and gas field with 3D elastic seismic modeling, reservoir characterization and fluid flow simulation to better understand drainage patterns of oil, gas and water into wells and to identify bypassed pay. We have solved this poorly constrained, inverse problem and arrived at a selfconsistent reservoir simulation that minimizes error and predicts 4-D seismic changes similar in space, time, and magnitude to those observed in a complex, intertwined, turbidite channel reservoir in the South Timbalier 295 field, Gulf of Mexico. Particle flow produced from the seismic reservoir simulation predicts that drainage was complex, with a pressure drop in the reservoir to below the bubble point producing a gas cap nearby the producing wells. Brightened seismic amplitudes both downdip and updip of the wells indicate that the gas coming out of solution filled the most permeable of the tubular turbidite channels. Poor oil migration downdip suggests the need for water injection, which the operator instituted in 1997 to recover this downdip oil and repressurize the reservoir. Additional production drilling must be placed precisely to target the tubular turbidite channels not filled with gas. The seismic reservoir simulation suggests that this enhanced recovery strategy should be successful. As we get better and better at 4-D seismic reservoir simulation, we should get more and more of the original oil-in-place from complex reservoirs.
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- 1998
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25. Time‐dependent reservoir characterization of the LF sand in the South Eugene Island 330 field, Gulf of Mexico
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Roger N. Anderson, Ulisses T. Mello, Wei He, and Gilles Guerin
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Hydrology ,Geophysics ,Field (physics) ,Reservoir modeling ,Geology ,Geomorphology - Abstract
One of the most important features of time‐dependent reservoir characterization is the added additional constraints that can be incorporated to update the initial reservoir model. Uncertainty of the model may be gradually reduced as the iteration of time‐dependent reservoir characterization continues.
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- 1997
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26. Enabling high-resolution forecasting of severe weather and flooding events in Rio de Janeiro
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Vaibhav Saxena, Paula Aida Sesini, Praino Anthony Paul, Lloyd A. Treinish, Ulisses T. Mello, Thomas George, L. C. Villa Real, James P. Cipriani, Kiran Mantripragada, and Rashmi Mittal
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General Computer Science ,Meteorology ,Severe weather ,Prognostic chart ,Environmental science ,Terrain ,Storm ,Numerical weather prediction ,Surface runoff ,Surface weather observation ,Ponding - Abstract
Safe operation of many cities is affected by relative extremes in weather conditions. With precipitation events, local topography and weather influence water runoff and infiltration, which directly affect flooding. Hence, the availability of highly focused predictions has the potential to mitigate the impact of severe weather on a city. Often, such information is simply unavailable. The initial step to address this gap is the application of state-of-the-art weather models at an urban scale calibrated to address this mismatch. The generation of operational forecasts at such a scale for the Rio de Janeiro metropolitan area suggests a horizontal resolution of approximately 1 km and a vertical resolution in the lower boundary layer of tens of meters. Forecasting impacts from storm-driven flooding events requires the development of a coupled hydrological model that operates at a street scale with resolution of approximately 1 m, capturing local terrain effects and simulating surface flow and water accumulation, especially for overland flow and ponding depth. This coupled approach has enabled operational prediction of storm impacts on local infrastructure, as well as measurement of the model error associated with such forecasts.
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- 2013
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27. Development of Sediment Overpressure and Its Effect on Thermal Maturation: Application to the Gulf of Mexico Basin
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Garry D. Karner and Ulisses T. Mello
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geography ,geography.geographical_feature_category ,Energy Engineering and Power Technology ,Sediment ,Geology ,Sedimentary basin ,Fluid transport ,Petroleum reservoir ,Pore water pressure ,Fuel Technology ,Source rock ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Sedimentary rock ,Progradation ,Petrology ,Geomorphology - Abstract
High sedimentation rates can potentially lead to overpressuring and sediment undercompaction within basins. Sediments with anomalously high porosity, in turn, induce low thermal conductivities and so tend to act as a thermal insulator to the flow of heat. In the Gulf of Mexico basin (Gulf basin), the generation of overpressure is caused mainly by the inability of pore pressure fluids to escape at a rate commensurate with sedimentation. We modeled the generation and dissipation of abnormal sediment pore pressure due to variations in sedimentation rate, facies, formation porosity, and permeability within the Gulf basin using finite-element techniques to solve the differential equations of both heat and fluid transport within compacting sediments. We assume that the porosity effective stress relationship within the sediment follows a negative exponential steady-state form when the pore pressure is hydrostatic. An important feature of our modeling approach is the assumption that sediments are incapable of significant expansion in response to increasing pore pressure. Sediments are assumed to hydrofracture when the pore pressure approaches the lithostatic pressure, rather than a common assumption of porosity expansion even in lithified sediments. From our modeling, we conclude that significant overpressures have been created (and dissipated) at various times within the Gulf basin and track, in general, the west to east migration of sediment loads deposited since the Cretaceous. Although predicted overpressures of more than 0.75 kpsi (i.e., an equivalent excess hydraulic head of 500 m) of Campanian-Maastrichtian age remain to the present day, the main phase of overpressure development in the Gulf basin is predicted to have occured during the Miocene-Holocene. Maximum overpressures (~13.6 kpsi; excess hydraulic head of 9.4 km) are predicted for the present day. Overpressure development during the Miocene-Quaternary, a consequence of rapid sediment deposition associated with the Mississippi delta system, is also predicted to be associated with undercompaction. This undercompaction led to increased temperature gradients during the Miocene and Quaternary despite the fact that the anomalous basal heat flow engendered by extension had practically dissipated. We further predict that by the end of the Neogene, temperatures would have been approaching s eady state over broad regions of the Gulf basin implying that the highest temperatures occur in the deepest parts of the basin. In contrast, during the Quaternary, the rapid progradation of overpressured and undercompacted sediments resulted in a thick section that has yet to reach thermal equilibrium and thus is anomalously cold with respect to its present depth. The predicted vitrinite reflectance indicates that for most of the Gulf basin history, the depth to the top of the oil window remained at approximately 2.5±0.5 km below sea floor (bsf). Similarly, the depth to the base of the oil window ranged from 3.5 to 6.5 km bsf. This relatively constant position of the top of the oil window defines a maturation "front" that propagated from the offshore into the End_Page 1367------------------------------ onshore regions of the northern Gulf basin as a function of time. As such, hydrocarbon generation is predicted to have occurred continuously within the Jurassic and Cretaceous sections of the onshore region during the entire Cenozoic. Prior to this, maturation fronts within each of the onshore basins resulted in maturation of Upper Jurassic source rocks during the Early Cretaceous. In the offshore Gulf Coast area, pre-Tertiary source rocks are predicted to be overmature for liquid hydrocarbons at present. In the offshore regions affected by Quaternary sedimentation, the depth to the top of the oil window has been significantly depressed in response to sediment loading and subsidence.
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- 1996
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28. On isostasy at the equatorial margin of Brazil
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Ulisses T. Mello and Andre Adriano Bender
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Margin (machine learning) ,Isostasy ,General Earth and Planetary Sciences ,Geodesy ,Geology - Published
- 1988
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