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Joint Optimization of Well Placement and Controls for Petroleum Field Development
Get PDFIn this thesis we optimize the drilling location and operational controls of wells in a joint
manner to improve the overall development strategy for a petroleum field. In particular,
in this thesis we treat the integrated problem of searching for an improved well placement
configuration while also taking into account the control settings of the production
and/or injector wells planned for the development of the hydrocarbon asset. In oil field
development, the well placement and well control problems are commonly performed in a
sequential manner. However, this type of sequential approach cannot be expected to yield
optimal solutions because it relies on handling well production controls using heuristic
techniques during the well placement part of the procedure. In this work, we develop a
nested (joint) optimization approach that seeks to capture the interdependency between
the well configuration and the associated controls during the optimization search.
This thesis summarizes the development of the joint approach; from establishing the
methodology while using relatively simple cases and performing thorough comparisons
against sequential approaches, to further extending and finally testing the methodology
using a real field case model. This progression naturally divides the work in this thesis
into two parts with different research focus. The first part of this work (Chapter 2)
focuses chiefly on creating proper definitions and on establishing the proposed methodology
against common approaches. The second part of this thesis (Chapters 3 and 4), on
the other hand, focuses mainly on applying the developed methodology within a real field
case scenario involving the North Sea Martin Linge oil reservoir. The dual aim of this
application work is both to further develop the methodology, and to produce and test optimization
solutions that may serve as decision–support to engineering efforts within the
development work process of the Martin Linge field.
Chapter 2 establishes the core of the methodology followed in this thesis. This chapter
introduces the joint and sequential approaches as different ways to solve for the coupled
well placement and control problem. The joint approach embeds the well control
optimization within the search for optimum well placement configurations. Derivative–
free methods based on pattern search are used to solve for the well–positioning part of
the problem, while the well control optimization is solved by sequential quadratic programming
using gradients efficiently computed through adjoints. Compared to reasonable
sequential approaches, the joint optimization yields a significant increase in net present
value of up to 20%. Compared to the sequential procedures, though, the joint approach
requires about an order of magnitude increase in the total number of reservoir simulations
performed during optimization. This increase, however, is somewhat mitigated by the parallel implementation of some of the pattern search algorithms used in this work.
Chapter 3 focuses on extending and applying the methodology developed in the previous
chapter within a real field development scenario. A work process loop is set up to
guide the entire application effort; from work model validation and problem definition,
to optimization effort and solution testing. Results from the optimization effort, using an
approximated work model, yield a mean increase in FOPT of close to 33% for solutions
developed using the joint approach. In comparison, solutions developed using a sequential
approach yield a mean increase in FOPT of almost 26%. Moreover, cost function
evolution data for the joint runs using the field case work model, show that the performance
of less promising locations during the well placement search may be improved
significantly due to the embedded control routine. This supports the notion that the nested
routine may contribute to a smoothing of the outer loop optimization surface with respect
to the well placement variables, and that this smoothing may add some robustness to the
well placement search conducted by the joint approach. Furthermore, as seen previously
in Chapter 2, the cost of the joint approach is still substantially higher compared to the
computation required by the sequential alternatives. For the application work in Chapter
3, the mean total number of reservoir simulations required by the joint runs is almost 7
times higher than the mean total number of reservoir simulations needed by the sequential
runs.
In Chapter 4, the well placement solutions obtained using the work model are transferred
and tested on to the original field case model for the Martin Linge oil reservoir. A
main result from the overall testing shows that those well placement configurations with
B wells that aggressively target the eastern lobe of the Martin Linge oil reservoir yield
the greatest increases in field oil production total. Furthermore, the various well placement
solutions are tested for two realistic field development considerations that were not
included in the optimization effort, i.e., the original larger production time frame and a
multiple realizations field case scenario. Compared to the initial well configuration for the
single–realization case, the best–performing well placement solution yields an increase in
field oil production total of, respectively, 25.5% for the time frame used in the optimization
procedure, and of 13% for the original (larger) production horizon. However, we note
that we performed the optimization effort using only a single realization. Consequently,
the solutions developed from this procedure are observed to lose most of their gains once
these well configurations are implemented for both the larger production time frame and
over the multiple realization case. This final test result underscores the importance for
future work of both improving the computational performance of the overall optimization
procedure (e.g., through surrogate techniques) and of including geological uncertainty
within the search routine
Joint Optimization of Well Placement and Controls for Petroleum Field Development
No full textIn this thesis we optimize the drilling location and operational controls of wells in a joint
manner to improve the overall development strategy for a petroleum field. In particular,
in this thesis we treat the integrated problem of searching for an improved well placement
configuration while also taking into account the control settings of the production
and/or injector wells planned for the development of the hydrocarbon asset. In oil field
development, the well placement and well control problems are commonly performed in a
sequential manner. However, this type of sequential approach cannot be expected to yield
optimal solutions because it relies on handling well production controls using heuristic
techniques during the well placement part of the procedure. In this work, we develop a
nested (joint) optimization approach that seeks to capture the interdependency between
the well configuration and the associated controls during the optimization search.
This thesis summarizes the development of the joint approach; from establishing the
methodology while using relatively simple cases and performing thorough comparisons
against sequential approaches, to further extending and finally testing the methodology
using a real field case model. This progression naturally divides the work in this thesis
into two parts with different research focus. The first part of this work (Chapter 2)
focuses chiefly on creating proper definitions and on establishing the proposed methodology
against common approaches. The second part of this thesis (Chapters 3 and 4), on
the other hand, focuses mainly on applying the developed methodology within a real field
case scenario involving the North Sea Martin Linge oil reservoir. The dual aim of this
application work is both to further develop the methodology, and to produce and test optimization
solutions that may serve as decision–support to engineering efforts within the
development work process of the Martin Linge field.
Chapter 2 establishes the core of the methodology followed in this thesis. This chapter
introduces the joint and sequential approaches as different ways to solve for the coupled
well placement and control problem. The joint approach embeds the well control
optimization within the search for optimum well placement configurations. Derivative–
free methods based on pattern search are used to solve for the well–positioning part of
the problem, while the well control optimization is solved by sequential quadratic programming
using gradients efficiently computed through adjoints. Compared to reasonable
sequential approaches, the joint optimization yields a significant increase in net present
value of up to 20%. Compared to the sequential procedures, though, the joint approach
requires about an order of magnitude increase in the total number of reservoir simulations
performed during optimization. This increase, however, is somewhat mitigated by the parallel implementation of some of the pattern search algorithms used in this work.
Chapter 3 focuses on extending and applying the methodology developed in the previous
chapter within a real field development scenario. A work process loop is set up to
guide the entire application effort; from work model validation and problem definition,
to optimization effort and solution testing. Results from the optimization effort, using an
approximated work model, yield a mean increase in FOPT of close to 33% for solutions
developed using the joint approach. In comparison, solutions developed using a sequential
approach yield a mean increase in FOPT of almost 26%. Moreover, cost function
evolution data for the joint runs using the field case work model, show that the performance
of less promising locations during the well placement search may be improved
significantly due to the embedded control routine. This supports the notion that the nested
routine may contribute to a smoothing of the outer loop optimization surface with respect
to the well placement variables, and that this smoothing may add some robustness to the
well placement search conducted by the joint approach. Furthermore, as seen previously
in Chapter 2, the cost of the joint approach is still substantially higher compared to the
computation required by the sequential alternatives. For the application work in Chapter
3, the mean total number of reservoir simulations required by the joint runs is almost 7
times higher than the mean total number of reservoir simulations needed by the sequential
runs.
In Chapter 4, the well placement solutions obtained using the work model are transferred
and tested on to the original field case model for the Martin Linge oil reservoir. A
main result from the overall testing shows that those well placement configurations with
B wells that aggressively target the eastern lobe of the Martin Linge oil reservoir yield
the greatest increases in field oil production total. Furthermore, the various well placement
solutions are tested for two realistic field development considerations that were not
included in the optimization effort, i.e., the original larger production time frame and a
multiple realizations field case scenario. Compared to the initial well configuration for the
single–realization case, the best–performing well placement solution yields an increase in
field oil production total of, respectively, 25.5% for the time frame used in the optimization
procedure, and of 13% for the original (larger) production horizon. However, we note
that we performed the optimization effort using only a single realization. Consequently,
the solutions developed from this procedure are observed to lose most of their gains once
these well configurations are implemented for both the larger production time frame and
over the multiple realization case. This final test result underscores the importance for
future work of both improving the computational performance of the overall optimization
procedure (e.g., through surrogate techniques) and of including geological uncertainty
within the search routine
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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