Integrating multiple clusters for compute-intensive applications

Multicluster grids provide one promising solution to satisfying the growing computational demands of compute-intensive applications. However, it is challenging to seamlessly integrate all participating clusters in different domains into a single virtual computational platform. In order to fully utilize the capabilities of multicluster grids, computer scientists need to deal with the issue of joining together participating autonomic systems practically and efficiently to execute grid-enabled applications. Driven by several compute-intensive applications, this theses develops a multicluster grid management toolkit called Pelecanus to bridge the gap between user\u27s needs and the system\u27s heterogeneity. Application scientists will be able to conduct very large-scale execution across multiclusters with transparent QoS assurance. A novel model called DA-TC (Dynamic Assignment with Task Containers) is developed and is integrated into Pelecanus. This model uses the concept of a task container that allows one to decouple resource allocation from resource binding. It employs static load balancing for task container distribution and dynamic load balancing for task assignment. The slowest resources become useful rather than be bottlenecks in this manner. A cluster abstraction is implemented, which not only provides various cluster information for the DA-TC execution model, but also can be used as a standalone toolkit to monitor and evaluate the clusters\u27 functionality and performance. The performance of the proposed DA-TC model is evaluated both theoretically and experimentally. Results demonstrate the importance of reducing queuing time in decreasing the total turnaround time for an application. Experiments were conducted to understand the performance of various aspects of the DA-TC model. Experiments showed that our model could significantly reduce turnaround time and increase resource utilization for our targeted application scenarios. Four applications are implemented as case studies to determine the applicability of the DA-TC model. In each case the turnaround time is greatly reduced, which demonstrates that the DA-TC model is efficient for assisting application scientists in conducting their research. In addition, virtual resources were integrated into the DA-TC model for application execution. Experiments show that the execution model proposed in this thesis can work seamlessly with multiple hybrid grid/cloud resources to achieve reduced turnaround time

A multiperiod optimization model to schedule large-scale petroleum development projects

This dissertation solves an optimization problem in the area of scheduling large-scale petroleum development projects under several resources constraints. The dissertation focuses on the application of a metaheuristic search Genetic Algorithm (GA) in solving the problem. The GA is a global search method inspired by natural evolution. The method is widely applied to solve complex and sizable problems that are difficult to solve using exact optimization methods. A classical resource allocation problem in operations research known under Knapsack Problems (KP) is considered for the formulation of the problem. Motivation of the present work was initiated by certain petroleum development scheduling problem in which large-scale investment projects are to be selected subject to a number of resources constraints in several periods. The constraints may occur from limitations in various resources such as capital budgets, operating budgets, and drilling rigs. The model also accounts for a number of assumptions and business rules encountered in the application that motivated this work. The model uses an economic performance objective to maximize the sum of Net Present Value (NPV) of selected projects over a planning horizon subject to constraints involving discrete time dependent variables. Computational experiments of 30 projects illustrate the performance of the model. The application example is only illustrative of the model and does not reveal real data. A Greedy algorithm was first utilized to construct an initial estimate of the objective function. GA was implemented to improve the solution and investigate resources constraints and their effect on the assets value. The timing and order of investment decisions under constraints have the prominent effect on the economic performance of the assets. The application of an integrated optimization model provides means to maximize the financial value of the assets, efficiently allocate limited resources and to analyze more scheduling alternatives in less time

Development of a petroleum knowledge tutorial system for university and corporate training

The increasingly rapid development of the disciplines of petroleum engineering and petroleum geology has led to new methodologies and interpretation techniques forming new knowledge that should be offered quickly and efficiently to modern engineers and geologists. This need is equally important for students as well as for young professionals. Access and training to all scientific information is necessary to ensure success in their future careers. Today, e-learning has become a common medium for the management and distribution of on-line educational content. Learning Management Systems (LMSs) were not only developed to handle a large variety of multimedia content that provides an organized knowledge repository used to accelerate access to information and skill acquisition; but, LMSs can also keep detailed statistics on the use of the available material offering a powerful training and educational tool. In this document, the Petroleum Knowledge Tutorial System, an LMS platform offering a variety of online educational and training options to petroleum engineers and geologists, is presented. It was created using Moodle, open-source software that can be used to create on-line courses. The platform covers fundamental educational concepts in a structured way. It follows an optimized "workflow" that can be applied not only to solve a specific exercise but also any similar problem encountered over the course of one's career. The platform was designed to offer a repository of learning material in various forms and to favor user-platform interactions. It can be used for training and evaluation purposes through exercises and problem solving that the user can perform online by using browsing software along with internet access. Special tools were created and implemented on the platform to assist the user in completing a variety of tasks including performing exercises involving calculations with given data and plots of points or lines on graphs without leaving the learning environment. Furthermore, videos with detailed explanations follow each learning module and provide the full solution to every exercise. The LMS automatically keeps a large statistical database including the users' access to activities on the platform that can be exported and further processed to improve the platform functionality and evaluate the users' performance

Environmental Crisis and the Paradox of Organizing

Public organizations, including those involved in contingency planning, have tremendous influence over the ultimate scale and scope of an environmental crisis. Yet our understanding of how organizational behavior can either rein in or exacerbate crises continues to lag behind advances in technology. This Article considers the role of public organizations in the blowout of the Macondo well in the Gulf of Mexico. Its theoretical lens is the “paradox of organizing,” a frame that I suggest should be applied to interorganizational responses to low-probability, high-consequence events. The struggle to differentiate tasks and subunits and then piece them together during moments of great uncertainty can challenge and strain contingency planning, such as what is envisioned by the National Contingency Plan. Through the paradox of organizing, the organizational roots of a crisis, such as the accidental release of oil or hazardous substances, are recreated and amplified during an interorganizational response to that crisis. I discuss several dynamics that were reproduced by the response system awakened by the Deepwater Horizon oil spill. They included risk amplification and system degradation due to the structure of the response, through processes including “anarchy,” “drift,” and “fire fighting.” They also involved the tasks of making sense of information within the response effort, which erases detail, limits whether data can be used to detect anomalies, and encourages responders to develop their own plausible rationales for equivocal data so that they can resume interrupted tasks. These dynamics go beyond the narratives that dominate standard regulatory accounts of accidents. They point to how multiagency response can intensify the paradox of organizing

Oil Spill Prevention and Response in the U.S. Arctic Ocean: Unexamined Risks, Unacceptable Consequences

Examines the risks, challenges, and potential impact of oil spills from Arctic oil and gas exploration and production. Recommendations include ecosystem mapping, oil spill trajectory models, blowout prevention measures, and response gap analysis

Zero-thickness interface elements in petroleum geomechanics : sand production and hydraulic fracture

Aplicat embargamet des de la data de defensa fins el dia 20 de setembre de 2019This thesis describes the extension of the Finite Element Method with zero-thickness interface elements (FEM+z) to 3D, large and complex problems in geomaterials, with special interest in petroleum geomechanics. This general objective has led to specific developments and applications such as the 3D code implementations and parallelization, and the specific petroleum geomechanics studies, both the macroscale (hydraulic fracture) and microscale (sand production). The extension to 3D of the hydro-mechanical formulation of double node zero-thickness interface elements proposed earlier, has been developed and implemented in the computer code, with satisfactory results in the verification examples. From the theoretical viewpoint, the formulation is generalized via the definition of \quotes{transport} matrices for both mechanical and hydraulic formulations, so that the two levels of the formulation can be separated: the nodal variables of the interface element, and the mid-plane variables. The formulation described is successfully validated with benchmarking examples based on analytical expressions of a hydraulic fracture. The parallelization of the code DRAC is achieved through the implementation of public domain library PETSc. The new code structure is conceived to perform a correct subdivision of tasks associated to each processor. For this purpose, a domain decomposition strategy has been implemented, which is crucial for an efficient matrix generation and assembly. The results obtained show a good degree of parallelization, demonstrated with a cube benchmark test. The applications to hydraulic fracture have served a dual purpose. First, the examples of a single fracture have been used to validate the proposed formulation, since it has been possible to compare the results with the predictions of analytical expressions such as GDK or PKN, and to other numerical results from the literature. Second, the examples of multiple interacting fractures have shown the capabilities to analyze large and complex cases. The studies performed have shown a number of relevant aspects of multiple fracturing such as the effect of geometry (distance between injections) and the effect of in situ stresses. Finally the thesis is devoted to the micromechanical analysis of sand production, including the generation and testing of micromechanical models based on the use of zero-thickness interface elements. Micromechanical (mesoscopic level) analysis with FEM+z has been successfully used to model the mechanical behavior of rock materials, using a similar approach as used previously for other heterogeneous materials. The rock grains are modeled as a group of continuum elastic elements and the cement (or matrix) is modeled with zero-thickness interfaces. This kind of modeling has been successfully used in uniaxial and triaxial compression test simulations. These numerical tests have been used for calibration purposes, comparing the macroscopic results obtained with the existing laboratory data. Due to the availability of experimental data, the simulation of sand production has been focused on the modeling of the hollow cylinder test. The simulations have been divided into two parts. First, using a prototype material, the sensitivity of the method to geometric and microstructural variations has been analysed, and the effect of the perforation size is clearly observed. The second part deals with the analysis of a real case of rock sanding, that includes micromechanical tests for parameter calibration and the simulation of sand production. The results, despite the intrinsic variability of the samples, have shown a satisfactory agreement with average experimental results, both in terms of the rock sanding initiation and of sand production.En aquesta tesi es presenta l'extensió del mètode d'elements finits amb elements junta d'espessor zero (FEM+z) a casos en 3D, per geometries grans i amb fenòmens complexos de fracturació per geomaterials, amb especial interès en la geomecànica del petroli. Aquest objectiu general ha donat lloc al desenvolupament i la generació aplicacions específiques, com ara les implementacions del codi a 3D i la paral·lelització, i els estudis específics de geomecànica del petroli, tant a macroescala (fractura hidràulica) com a microescala (producció de sorra). L'extensió a 3D de la formulació hidromecànica d'elements junta de doble nus proposada anteriorment, s'ha desenvolupat i implementat en el codi de càlcul, amb resultats satisfactoris en els exemples de verificació. Des del punt de vista teòric, la formulació s'ha generalitzat mitjançant la definició de matrius de transport per les dues formulacions, la mecànica i la hidràulica, de manera que es poden separar els dos nivells de la formulació: les variables nodals de l'element junta i les variables del pla mig. La paral·lelització del codi DRAC s'ha assolit mitjançant la implementació de la llibreria en codi lliure PETSc. La nova estructura del codi s'ha concebut per tal de realitzar una subdivisió correcta de les tasques associades a cada processador. Així, s'ha implementat una estratègia de descomposició de dominis, que és fonamental per a la generació i assemblatge de matrius de manera eficient. Els resultats obtinguts mostren un bon grau de paral·lelització. Les aplicacions de fractura hidràulica han tingut un doble propòsit. En primer lloc, s'han utilitzat els exemples d'una sola fractura per tal de validar la formulació proposada, ja que s'han pogut comparar els resultats amb les prediccions d'expressions analítiques com GDK o PKN i altres resultats numèrics de la literatura. En segon lloc, els exemples d'interacció entre fractures múltiples han demostrat la capacitat d'analitzar casos grans i complexos. Els estudis realitzats han mostrat una sèrie d'aspectes rellevants de la fractura múltiple, com l'efecte de la geometria (distància entre les injeccions) i l'efecte de les tensions in situ. Per finalitzar, la tesi presenta l'anàlisi micromecànic de la producció de sorra, que inclou la generació i la verificació dels models micromecànics basats en l'ús d'elements junta d'espessor zero. L'anàlisi micromecànic (nivell mesoscòpic) fet amb FEM+z s'ha utilitzat amb èxit per modelitzar el comportament mecànic de les roques. Els grans de roca es modelen com un grup d'elements elàstics de continu i el ciment (o matriu) es modelitza amb les juntes d'espessor zero. Aquest tipus de modelització s'ha utilitzat amb èxit en les simulacions d'assaigs a compressió uniaxial i triaxial. Les simulacions numèriques han servit per calibrar els paràmetres del model, comparant els resultats macroscòpics obtinguts amb les dades del laboratori existents. Degut a la disponibilitat de dades experimentals, la simulació de la producció de sorra s'ha centrat en la modelització de l'assaig de cilindres buits. Les simulacions s'han dividit en dues parts. En primer lloc, mitjançant l'ús d'un material prototip, s'ha analitzat la sensibilitat del mètode a les variacions geomètriques i microestructurals, on s'observa clarament l'efecte de mida de la perforació. La segona part ha tractat l'anàlisi d'un cas real de producció de sorra, que inclou assaigs micromecànics per la cal·libració dels paràmetres i la simulació de la producció de sorra. Els resultats, tot i la variabilitat intrínseca de les mostres, han demostrat un semblança satisfactòria amb els resultats experimentals, tant pel que fa a la iniciació com a la producció de sorra.Postprint (published version

Application of ERTS-1 data to integrated state planning in the state of Maryland

There are no author-identified significant results in this report