37 research outputs found
Heavy oil recovery efficiency using SAGD, SAGD with propane co-injection and STRIP-SAGD
No full textPrimary oil recovery methods in heavy oil basins generally extract 5-10% of the available resource, with the vast majority left in the ground and recoverable only through Enhanced Oil Recovery (EOR) methods. Traditional EOR methods, such as SAGD and solvent-assisted SAGD, generate steam in surface facilities and inject it underground to mobilize the oil for production. However, these methods can have considerable energy losses that significantly impact process performance. In contrast, the Solvent Thermal Resource Innovation Process (STRIP) technology, which uses down hole combustion of methane to produce CO2 and steam, reduces the operating and capital costs of surface facilities, saving more than 50% of the energy typically required for thermal production. In this work, simulations of conventional SAGD, SAGD with a non-condensing solvent (propane), and STRIP-SAGD for a typical bitumen reservoir in the Fort McMurray region in Alberta, Canada were performed using the combined software system ADGPRS/GFLASH. SAGD simulations used steam injection with a quality of 0.8 while STRIP simulations injected a vapor-liquid mixture with a quality of 0.8. Furthermore, both solvent-based EOR methods required longer operation periods than conventional SAGD to recover a similar amount of oil. However, when compared on the basis of cumulative oil produced for the same overall energy input, it is shown that STRIP-SAGD recovered more oil per kJ of energy input to the reservoir than either SAGD or SAGD with propane co-injection
Nonlinear Convergence for Near-Miscible Problem: A Mystery Unveiled for Natural Variable Simulator
No full textAbstract
In reservoir simulation, the nonlinear solver is used to solve the nonlinear system of conservation and phase-equilibrium equations at each time step. The convergence behavior of this solver is vital for the robustness and performance of any reservoir simulator.
Based on the basic solution variables used in a reservoir simulator, we have natural variable based simulators with phase-dependent solution variables (e.g. phase saturations), and mass/overall variable based simulators without phase-dependent solution variables. The nonlinear convergence behavior between these two types of simulators has been compared previously. It has been found that natural variable based simulator works well for immiscible and miscible flow, while sometimes it has apparent convergence issues for near-miscible flow.
In this paper, we analyze the fundamental physical and numerical causes for the nonlinear convergence difficulty encountered for near-miscible flow for a natural variable based simulator and study why the same issues do not appear in both immiscible and miscible flow. Based on our analysis, some carefully designed user tuning parameters can be applied to partially alleviate the convergence issue for near-miscible flow. Unfortunately this is neither general nor good enough. To fundamentally solve this issue, we propose a straightforward nonlinear solver modification which is applicable for all types of displacements (immiscible/miscible/near-miscible/mixed). We demonstrate improvements on the real field cases with different types of flow. For near-miscible and mixed type of displacements, the improvements in Newton iterations can be significant, while for the other types, our nonlinear solver modification does not show the adverse effect. For reference, we also compared the convergence behavior of the proposed solver with that from a standard mass variable based commercial simulator.</jats:p
Full-EoS based thermal multiphase compositional simulation of CO<sub>2</sub> and steam injection processes
No full textSeveral compositional reservoir simulators based on equations of state (EoS) have been designed. Yet, few of them can deal with thermal processes such as steam injection and no fully compositional thermal simulation of the steam injection process has been proposed with extra-heavy oils yet. Those simulations appear essential and will offer better tools to decide whether to carry out the exploitation of a heavy oil field or not. In those processes, the accurate modelling of the water/steam phase plays an important role and accurate multiphase equilibrium calculations are necessary. Thermodynamics generate highly nonlinear problems. Besides, in reservoir simulation a huge amount of phase equilibrium calculations is required, and a single failure may cause significant error propagations leading to false solutions. This study presents several improvements leading to a more robust and efficient phase equilibrium calculation (stability and flash) program. A general multiphase flash implementing all the developed algorithms is presented and tested against experimental and literature data. It can handle any number of phases; a numerical example consists in a four-phase simulation of CO2 injection. Simulations of steam flooding are performed with highly heterogeneous reservoirs. Besides, a fully compositional simulation of the SAGD process for an extra heavy bitumen is performed, which appears to be the one of the first simulation of the kind in the literature.Reservoir Engineerin
In Memory of a Friend
No full textThe article is dedicated to the memory of Rustem Sultanovich Gabyashev (1941-2010), an outstanding Kazan archeologist. He was one of the renowned experts in the Mesolithic and the Neolithic of the Volga-Kama region. The author, the researcher’s colleague and friend, narrates about his scientific and, first of all, expedition activities, offers some biographical data and characterizes his personal qualitie
Fully Compositional and Thermal Reservoir Simulations Efficiently Compare EOR Techniques
No full textPrimary oil recovery methods in Saskatchewan\u27s heavy oil basin extract 5 to 10% of the available resource with the vast majority left in the ground and recoverable only through Enhanced Oil Recovery (EOR) methods. Traditional EOR generates steam in surface facilities and injects it underground to mobilize the oil for production with considerable energy losses inherent in the process. R.I.I. North America\u27s Solvent Thermal Resource Innovation Process (STRIP) technology moves the steam generator underground, reducing the operating and capital costs of a surface thermal production facility by 30% and 50% respectively, and saving more than 30% of the energy typically required for thermal production. STRIP technology combusts methane to produce in situ CO 2 and steam. Because CO2 acts as a co-solvent, STRIP outperforms traditional steam-injection technology. This is demonstrated using a breakthrough modeling technique that couples fully compositional and thermal reservoir flow simulation capabilities. This new approach couples FlashPoint\u27s equation-of-state solver for the multiphase, multi-component, isothermal, isobaric flash problem, GFLASH, with Stanford\u27s Automatic Differentiation General Purpose Research Simulator for thermal reservoir flow simulations. This new computational framework exploits advanced techniques for skipping phase-identification computations and only uses exact phase equilibria from GFLASH when needed, reducing computational times by one to two orders of magnitude compared to the full rigorous solution. Copyright 2013, Society of Petroleum Engineers
Co-aligning user-centered design and software engineering courses: A case study
No full textIntroducing students to different perspectives and roles in the development process allows them to engage in the work of cross-disciplinary diverse teams and even can enable them to change roles in designer-developer interactions. Industry work often places recent graduates in preexisting polarized relationship dynamics between different participants in the design and development process. This paper describes a two-stage attempt at co-alignment of software engineering and user-centered design courses: from full alignment with topic intersections and joint project to partial alignment through separate activities. We discuss challenges of both ways including time or technical constraints, increased effort from the program developers and instructors, students' and instructors' frustrations. We finalize by describing benefits of providing students with early experience identifying trade-offs between design requirements and architecture and opportunities for diverse group with different background in computer science.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Internet of Thing
Mehmed Senai: A Crimean Historian at Sarai of Khan Islam Giray »
No full textThe article is devoted to the creative work of Mehmed Senai – the Crimean chronicler at the serai of the khan Islam Geray III, as well as his chronicle “Tarih-i Islam Geray khan” (“History of the khan Islam Geray III”, 1651). The researcher gives biographical information about the author and a brief description of the source. The identity of the writer is defined and based on the text of the Preface to the Chronicle: background, education, position, religious status. The meaning of the pseudonym of Senai is under the study, the text of the chronogram in which it occurs is reproduced. Especially noted thing is the originality of the artistic structure of the Chronicle “Tarih-i Islam Geray khan”.The Chronicle “Tarih-i Islam Geray khan” is the panegyric to the Crimean khan Islam Geray whose reign represents the brilliant epoch in the history of the Crimean Khanate. The writing consists of the ceremonies of public appointments, episodes of military campaigns and making treaties, the text of khan Islam Geray’s pedigree (shejere), construction and repair of buildings.
There is the brief information about the Chronicle and about M. Senai in “Catalogue of the Turkish Manuscripts in the British Museum” (1888). The primary work on writing was conducted by Polish orientalists who prepared the edition of the original text, its translation and processing, backed with comments.
At the time of writing the Chronicle, Mehmed Senai was in his old age, he served as the kadi (religious judge). In his youth he worked as munshi (decorator of papers) in the khan’s office. He got education in the Ottoman Empire, and was engaged in the implementation of diplomatic correspondence. The prospect of identification of the author on the basis of other sources is important to clarify the hypothesis of identifying M. Senai with such Crimean Tatar author as Dzhanmuhammed.
The Chronıcle’s plot consists of the diary notes on the military expeditions, eyewitness accounts (including those of the author). The author of the work focuses the historical events of 1648–1651 covering the Crimean Tatar-Ukrainian-Polish relations. The bulk of the official documents used by Senai was narrow. Details and brevity in the coverage of events indicates that certain materials were available to the author, while others were unavailable.
The aesthetic peculiarities of the Chronicle are also notable as well as historical. The author created the vivid images of the central characters in the writing – Islam Geray, Sefer Gazi aga and Tugay bey. The work is characterized by the use of various expressive means for the purpose of idealization of the images and emotional perception of characters and events
PRE-ISLAMIC WORLD VIEWS OF THE KAZAKH PEOPLE: FROM THE END OF THE 19TH TO THE BEGINNING OF THE 21ST CENTURY
No full textThis article analyses the problems of the traditional world views and beliefs of the Kazakh people. The main purpose of the article is to show the features of such cultural phenomena as âreligious syncretismâ and âhybrid worldviewâ. The author pays attention to the cosmogonic and cosmological beliefs, the perception and feeling of place and time, religious consciousness and national identity, folk customs and traditions, cultural branding. The farming and cattle-breeding practices in the harsh climatic conditions of wide steppe spaces influenced the formation of a special type of culture and unique worldview. In the long history of the nomadic peoples who inhabited the Eurasian steppes, the history of the development of the religious worldview occupies a special place. Being in the crossroad of civilization, Central Asia has been a region of interaction between different world religious traditions, such as Zoroastrianism, Buddhism, Christianity (in their earliest forms as Nestorianism), ManiÑhaiesm, and Islam. However, the Kazakh people did not break ties with nature due to their way of life, so peopleâs beliefs and superstitions were based on the animistic, totemistic beliefs and magic. The author concludes that the cornerstone of the entire system of worldview was the faith in the opportunity to transform the world for the good of peopleâs traditions and it was reflected in the special rites, traditions, and practices
Transport Properties of Mixed-Matrix Membranes: A Kinetic Monte Carlo Study
No full textKinetic Monte Carlo (KMC) simulations are used to study transport of guest molecules in a two-phase medium in which the minority phase forms closed regions. This type of model system resembles compositions of mixed-matrix membranes (MMMs) made of a matrix and imbedded filler particles with different permeabilities. Based on an ideal filler-matrix composite morphology as defined in [H. Vinh-Thang, S. Kaliaguine, Chem. Rev. 113, 4980, 2013], the effects of the filler-particle volume fraction, particle size, shape (aspect ratio), and the spatial particle distribution on gas transport through MMMs are addressed. The results obtained for nonoverlapping and randomly placed spherical filler particles are found to be in good agreement with the analytical models available in the literature and have proven their good accuracy also for thin membranes where finite-size effects are expected to play an appreciable role. Furthermore, the prominent influence of the aspect ratio for nonspherical particles on the effective permeability is shown and scenarios are discussed where the alignment of the asymmetric filler particles give rise to anisotropic transport properties potentially favorable for the performance of MMMs. The KMC approach developed guides the optimal spatial arrangement and orientation of the filler particles for the different strategies to increase the membrane permeability and separation selectivity by transport enhancement or inhibition.ChemE/Catalysis Engineerin
