Decision-Making for Well Placement Optimization in Oil Field Development

Well placement is a method to improve oil recovery by drilling new infill wells in a reservoir. Drilling new wells is a critical yet very challenging task in field development, because the optimal well locations are rarely known and difficult to decide in practice due to complex reservoir and depletion situations. This dissertation focuses on the development of mathematical optimization techniques to assist decision-making for well planning and placement. The following topics are included in this dissertation. 1. To study and develop two stochastic approximated gradient-based approaches: the ensemble based optimization method (EnOpt) and the fixed-gain simultaneous perturbation stochastic approximation (FSP) for well placement; Evaluate the performance and effectiveness of these two methods on case studies. 2. To develop an efficient method to decide optimal number of wells and the corresponding locations, evaluate the performance on study cases. 3. To handle geological uncertainty and decision-making risk, propose a new workflow for multi-objective well placement optimization. 4. To ensure an efficient decision-making and a fast turnaround time, the use of engineering prior knowledge and a few acceleration routines are discussed in the context of optimization. All approaches are evaluated on synthetic reservoir models, some are performed on real field-like cases. This dissertation provides various optimization methods with an enhanced capability of addressing geological uncertainty for well placement in oilfield development. However, it should also be noted that while the techniques proposed in this dissertation are applicable to a diverse set of reservoirs with no known limitations, the additional value of this dissertation lies in its ability to address well placement needs for highly complex reservoirs. For reservoirs that lack the complexity seen, for example, in deepwater basins, conventional well placement methods may be sufficient

Improvements on the Individual Logarithm Step in Extended Tower Number Field Sieve

The hardness of discrete logarithm problem over finite fields is the foundation of many cryptographic protocols. When the characteristic of the finite field is medium or large, the state-of-art algorithms for solving the corresponding problem are the number field sieve and its variants. There are mainly three steps in such algorithms: polynomial selection, factor base logarithms computation, and individual logarithm computation. Note that the former two steps can be precomputed for fixed finite field, and the database containing factor base logarithms can be used by the last step for many times. In certain application circumstances, such as Logjam attack, speeding up the individual logarithm step is vital. In this paper, we devise a method to improve the individual logarithm step by exploring subfield structures. Our method is based on the extended tower number field sieve algorithm, and achieves more significant improvement when the extension degree has a large proper factor. We also perform some experiments to illustrate our algorithm and confirm the result

Model for route planning of freight buses

This paper introduces freight buses as a novel solution for city logistics, aiming to replace other freighters currently operated by various private logistics firms within city centers. The focus lies on investigating the route planning challenge associated with integrating freight buses into an city distribution framework. Each freight bus follows a predefined route, repeatedly traversing from a distribution center to multiple depots before returning to the distribution center. All depots are serviced by multiple freight buses on a consistent basis. This route planning problem presents a fresh iteration of the periodic vehicle routing problem. To tackle this challenge, the paper proposes a Mixed-Integer Linear Programming model, serving as a fundamental framework for future research endeavors concerning freight buses

Carbapenemase-Producing Escherichia coli among Humans and Backyard Animals

Background: The rapidly increasing dissemination of carbapenem-resistant Enterobacteriaceae (CRE) in both humans and animals poses a global threat to public health. However, the transmission of CRE between humans and animals has not yet been well studied. Objectives: We investigated the prevalence, risk factors, and drivers of CRE transmission between humans and their backyard animals in rural China. Methods: We conducted a comprehensive sampling strategy in 12 villages in Shandong, China. Using the household [residents and their backyard animals (farm and companion animals)] as a single surveillance unit, we assessed the prevalence of CRE at the household level and examined the factors associated with CRE carriage through a detailed questionnaire. Genetic relationships among human- and animal-derived CRE were assessed using whole-genome sequencing–based molecular methods. Results: A total of 88 New Delhi metallo-β-lactamases –type carbapenem-resistant Escherichia coli (NDM-EC), including 17 from humans, 44 from pigs, 12 from chickens, 1 from cattle, and 2 from dogs, were isolated from 65 of the 746 households examined. The remaining 12 NDM-EC were from flies in the immediate backyard environment. The NDM-EC colonization in households was significantly associated with a) the number of species of backyard animals raised/kept in the same household, and b) the use of human and/or animal feces as fertilizer. Discriminant analysis of principal components (DAPC) revealed that a large proportion of the core genomes of the NDM-EC belonged to strains from hosts other than their own, and several human isolates shared closely related core single-nucleotide polymorphisms and blaNDM genetic contexts with isolates from backyard animals. Conclusions: To our knowledge, we are the first to report evidence of direct transmission of NDM-EC between humans and animals. Given the rise of NDM-EC in community and hospital infections, combating NDM-EC transmission in backyard farm systems is needed. https://doi.org/10.1289/EHP525

Transplantation of Human Undifferentiated Embryonic Stem Cells into A Myocardial Infarction Rat Model

Human embryonic stem (hES) cells hold great therapeutic potential for cell transplantation. To date, it remains uncertain whether undifferentiated hES cells can differentiate into cardiac lineage in vivo during myocardial infarction. Here we provide the first report that undifferentiated hES cells can survive in rat hearts during myocardial infarction without the formation of teratoma using undifferentiated green fluorescent protein (GFP)-transgenic hES cells. Using a laser-capture microscope to dissect the GFP-positive cell area from the hES-injected hearts, we documented the expression of human cardiac-specific genes, including GATA-4, Nkx-2.5, and cardiac troponin I. Taken together, our results demonstrate that undifferentiated hES cells can be driven to the cardiac lineage under the local injured environment in the heart, which may provide a potential method for regenerating de novo myocardium to treat myocardial infarction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63274/1/scd.2006.110206.pd

Profiling Plasma Peptides for the Identification of Potential Ageing Biomarkers in Chinese Han Adults

Advancing age is associated with cardiovascular disease, diabetes mellitus and cancer, and shows significant inter-individual variability. To identify ageing-related biomarkers we performed a proteomic analysis on 1890 Chinese Han individuals, 1136 males and 754 females, aged 18 to 82 years, using weak cation exchange magnetic bead based MALDI-TOF-MS analysis. The study identified 44 peptides which varied in concentration in different age groups. In particular, apolipoprotein A-I (ApoA1) concentration gradually increased between 18 to 50 years of age, the levels of fibrinogen alpha (FGA) decreased over the same age span, while albumin (ALB) was significantly degraded in middle-aged individuals. In addition, the plasma peptide profiles of FGA and four other unidentified proteins were found to be gender-dependent. Plasma proteins such as FGA, ALB and ApoA1 are significantly correlated with age in the Chinese Han population and could be employed as indicative ageingrelated biomarkers

A study on the reasonable dietary trajectory of elderly people in the community and its correlation with body mass index

ObjectiveTo explore the reasonable dietary trajectory of elderly people in the community and to test the correlation between different dietary trajectories and body mass index (BMI) of the elderly people in the community to provide a reference for these individuals to formulate scientific interventions and cultivate healthy living habits.MethodsThe data of The Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 2011 to 2018 were used to evaluate the dietary status of elderly people in the community according to their diet, and body mass index was calculated according to height and weight. The latent variable growth mixed (LGMM) model was used to analyze the development trajectory of diet in elderly people, and the multivariate logistic regression model was used to test the relationship between different dietary development trajectories and BMI changes as well as to test the correlation between different dietary trajectories and BMI of the elderly people in the community.ResultsThe LGMM fit four dietary trajectories of elderly individuals: the continuous reasonable diet group (37.81%), the dietary behavior decline group (28.84%), the continuous unreasonable diet group (20.16%), and the dietary behavior improvement group (13.19%). The results showed that factors including male sex, rural setting, being spouseless, nonformal education status, not being wealthy, living alone, and having tooth loss were more likely to be classified as the “persistently unreasonable diet group” (p < 0.05). The logistic regression results showed that the “continuous reasonable diet group” and the “dietary behavior improvement group” were significantly correlated with the development of obesity to a normal BMI.ConclusionThe dietary behavior of the elderly was significantly correlated with BMI value, and improving the reasonable dietary behavior of the elderly could reduce the high BMI to the normal range, but could not restore the low BMI to the normal range, indicating that reasonable dietary behavior is an important measure to prevent and improve overweight or obesity in the elderly. There is significant heterogeneity in the dietary behavior of the elderly, and community medical staff should identify the risk factors of various dietary behaviors of other groups as soon as possible, and provide corresponding intervention strategies to help them change their poor dietary behaviors and improve their nutritional status

Emerging roles of i-motif in gene expression and disease treatment

As non-canonical nucleic acid secondary structures consisting of cytosine-rich nucleic acids, i-motifs can form under certain conditions. Several i-motif sequences have been identified in the human genome and play important roles in biological regulatory functions. Due to their physicochemical properties, these i-motif structures have attracted attention and are new targets for drug development. Herein, we reviewed the characteristics and mechanisms of i-motifs located in gene promoters (including c-myc, Bcl-2, VEGF, and telomeres), summarized various small molecule ligands that interact with them, and the possible binding modes between ligands and i-motifs, and described their effects on gene expression. Furthermore, we discussed diseases closely associated with i-motifs. Among these, cancer is closely associated with i-motifs since i-motifs can form in some regions of most oncogenes. Finally, we introduced recent advances in the applications of i-motifs in multiple areas