bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Natural Fracture Density on Production Variability of Individual Wells in the Tight Gas Nikanassin Formation
Authors: Gonzalez Laureano , Aguilera Roberto 
Published: November 2011

Abstract
A statistical model with a strong correlation has been developed to determine average fracture density on the basis of production variability of 271 individual wells producing exclusively from the Nikanassin and equivalent formations in a very large area of more than 15,000 km2 in the Western Canada Sedimentary basin (WCSB), Alberta and British Columbia, Canada.
Fractional production variability plots published by Nelson (2001) have been used successfully in the past in many naturally fractured reservoirs around the world. Up to now, the generation of such graphs has been based on empirical observations from field production data. The variability of the graphs is qualitatively interpreted as a measure of reservoir heterogeneities.
This paper presents a sequential methodology to reproduce the empirical fractional variability plots of the Nikanassin tight gas formation using real data, an empirical variability distribution model (VDM) and dual-porosity numerical simulation. Different simulation approaches and multiple sensitivities were generated from the simplest to the most detailed cases to understand what causes the curvature of the fractional production variability plot (FPVP) in Nikanassin wells. The base simulation case is a homogeneous dual porosity model where porosity and permeability are set constant for matrix and fractures. A second case accounts for a heterogeneous dual porosity model generated through statistical distributions of porosity and permeability. Finally, Discrete Fracture Network (DFN) methodology is used to generate multiple fracture models from where stochastic fracture properties are generated for the simulation model.
It is concluded that curvature of the variability plot is mainly affected by the occurrence of natural fracture density. This finding permits estimating fracture density approximately parallel to the northwest/southeast-trending thrust belt of the Canadian Rocky Mountains in both the west and east side of the deformation wedge. An unexpected result is that for a significant change in fracture permeability and porosity with constant fracture density, the fractional production variability curve is not affected significantly in the case of gas reservoirs. Although the method is applied specifically to the Nikanassin tight gas formation, the theory is developed in detail in such a way that the methodology can be applied in other tight gas reservoirs around the world. Findings from this work are in good agreement with the geological description of the Nikanassin formation and with a previous production analysis performed in the six study areas based on the cumulative number of wells versus yearly cumulative gas production.
SeTES: A Self-Teaching Expert System for the Analysis, Design, and Prediction of Gas Production From Unconventional Gas Resources
Authors: Moridis George J. , Kuzma Heidi Anderson , Reagan Matthew T. , Blasingame Thomas A. , Huang Y. Wayne , Santos Ralph , Boyle Katie , Freeman Craig M. , Ilk Dilhan , Cossio Manuel , Bhattacharya Srimoyee , Nikolaou Michael 
Published: November 2011

Abstract
SeTES is a self-teaching expert system that (a) can incorporate evolving databases involving any type and amount of relevant data (geological, geophysical, geomechanical, stimulation, petrophysical, reservoir, production, etc.) originating from unconventional gas reservoirs, i.e., tight sands, shale or coalbeds, (b) can continuously update its built-in ‘public’ database and refine the its underlying decision-making metrics and process, (c) can make recommendations about well stimulation, well location, orientation, design, and operation, (d) offers predictions of the performance of proposed wells (and quantitative estimates of the corresponding uncertainty), and (e) permits the analysis of data from installed wells for parameter estimation and continuous expansion of its database. Thus, SeTES integrates and processes any available information from multiple and diverse sources on a continuous basis to make recommendations and support decision making at multiple time-scales, while expanding its internal database and explicitly addressing uncertainty. It receives and manages data in three forms: public data, that have been made available by various contributors, semi-public data, which conceal some identifying aspects but are available to compute important statistics, and a user’s private data, which can be protected and used for more targeted design and decision making. SeTES can be a vital and easy-to-use tool in gas production from unconventional gas resources, and presents a new paradigm for communicating research and technology to the public and distributing scientific tools and methods. It is expected to result in a significant improvement in reserve estimates, and increases in production by increasing efficiency and reducing uncertainty.
Reservoir Quality Mapping Based on IDC Analyses and Hydraulic Frac Size
Authors: Kuppe Frank , Carlson Patrick 
Published: November 2011

Abstract
A three part process has been developed to generate a correlation which can be used to 1) map representative ∅h in the Kakwa Cadotte reservoir and 2) optimize the design of hydraulic fracture treatments. This same process can be applied to multi-fractured horizontal wells, completed in the Upper Montney reservoir, to generate a relationship between Estimated Ultimate Recovery (EUR), ∅h and total hydraulic fracture tonnage.
The initial stage of the process required the application of IDC (Inverted Decline Curve) technology to determine independent quantities of 1) reservoir quality (kh) and 2) hydraulic fracture placement (as measured by fracture half length = Xf). Using this IDC technique to differentiate between the better and lesser quality wells we can find a correlation between Estimated Ultimate Recovery (EUR) and some function of porosity, net pay and fracture tonnage (the second step in this process).
The physics behind this relationship essentially correlates to hydraulic fracture volumetrics and effective insitu permeability within each well’s drainage area. Wells that do not match the trend established by the "clear majority" of wells (data points) can now be readily flagged and included in the established correlation by modifying ∅h and/or frac tonnage until they match the trend. This adjustment would of course have to be rationalized by either a change in 1) possible kh, throughout the well drainage area, or 2) the effective frac tonnage displaced for the well. Given that most of the two dozen wells evaluated established an excellent correlation, this technique became very useful in narrowing the range of possible kh or effective Xf, within each well’s drainage area. After establishing the relative contribution to EUR of 1) reservoir quality and 2) hydraulic fracture effectiveness, we could map a representative kh distribution to optimize future well locations.
Finally, the process (for developing this correlation) was also tested on 46 Upper Montney horizontal wells producing from the Swan reservoir. Although producing into multiple hydraulic fractures, the linear trend of the inverted decline curve, for these wells, still yields a reliable indicator of permeability and/or fracture placement effectiveness. An excellent correlation exists between IDC slopes and independently determined EURs but more work is required to differentiate between the relative contributions of reservoir quality (kh) and hydraulic fracture effectiveness (Xf). This reservoir surveillance technique will be useful for the placement of horizontal wells, particularly unconventional Montney wells, and the optimization of hydraulic fracture treatments, along the entire Montney trend.
Simulation of Noncondensable Gases in SAGD Steam Chambers
Authors: Gittins Simon , Gupta Subodh , Zaman Maliha 
Published: November 2011

Abstract
Cenovus Energy has been very successfully developing the Foster Creek and Christina Lake projects using the Steam Assisted Gravity Drainage (SAGD) process. The SAGD process at both these projects has been operated at well above the initial reservoir pressure for extended periods of time and this has been adequately simulated using dead oil models which omit solution gas from the simulations.
As we move into later stages in the life of the more mature well pairs at these projects it is important to better understand the role of non-condensable gases on the development of the steam chambers in order to optimize the methane co-injection, steam ramp-down and ultimately blow-down phases of operations. Cenovus also plans on implementing reduced pressure SAGD and Solvent Aided Processes (SAP) at future projects and non-condensable gas is expected to play a significant role in these processes.
Hence, understanding the flow behavior of non-condensable gases in SAGD steam chambers could have far-reaching consequences for lowering the energy intensity and associated costs as well as reducing the environmental impact of bitumen production while potentially increasing reserves.
This paper presents the results of some recent simulations which are improving our understanding of the role of solution gas in SAGD and the impact of non-condensable gases on steam chamber development.
Microseismic Evaluation of Stage Isolation With a Multiple-Fracport, Openhole Completion
Authors: Maxwell S. C. , Chen Z. , Nizkous I. , Parker R. , Rodionov Y. , Jones M. 
Published: November 2011

Abstract
Multiple, mechanically-activated, sliding-sleeve fracports is a common completion used for horizontal wells in unconventional reservoirs. Characteristic seismic signals have been observed at approximately the same time as pressure spikes associated with balls dropped to open the sliding sleeves. The ‘ball drop’ seismic signals are high amplitude, low frequency, multiple discrete events with a short period of time, with each event locating at the fracport. The seismic radiation characteristics are consistent with an axial displacement along the treatment well. The seismic signals are attributed to the sleeve sliding open, which results in sufficient energy to account for the high amplitude signals. The occurance of the ball drop events can therefore be used to diagnose if the ball seated and the sleeve opened at the expected location, and along with the pressure and microseismic response can be used to validate the expected actions of the completion. Several case studies are also presented illustrating successful stage isolation with proper completion operation, response of the sleeve not opening properly and stage overlap associated with both hydraulically connected fracture networks in the reservoir and connected fracture ports.
Synthesis, structure, and luminescent properties of two novel polynuclear complexes of 1,3-di(pyridin-2-yl)propane-1,3-dione
Authors: Tan Jin-Ting , Zhao Wen-Jie , Chen San-Ping , Li Xia , Lu Ying-Li , Feng Xing , Yang Xu-Wu 
Published: November 2011

AbstractTwo complexes, {[Cd6(o-dppd)2(µ2-Cl)6(µ3-Cl)2(DMF)2(H2O)2Cl2]·DMF·CH3OH}n (I) (DMF = N,N-dimethylformamide; o-dppdH = 1,3-di(pyridin-2-yl)propane-1,3-dione) and [Cu4(o-dppd)2(OAc)4(OH)2]·4H2O (II), were synthesised and characterised by single-crystal X-ray diffraction, elemental analysis, IR, solid fluorescence and TGA. The results showed that complex I had a rodshaped polynuclear chain with hexacoordinating Cd atoms bridged by oxygen, µ2-Cl and µ3-Cl; complex II was a tetranuclear oligomer. In general, supramolecular architectures are constructed through hydrogen-bonding and π-π stacking interactions. I shows luminescence.
Neutralizing IL-6 Reduces Human Arterial Allograft Rejection by Allowing Emergence of CD161+ CD4+ Regulatory T Cells
Authors: Fogal Birgit , Yi Tai , Wang Chen , Rao Deepak A. , Lebastchi Amir , Kulkarni Sanjay , Tellides George , Pober Jordan S. 
Published: November 2011

AbstractPerioperative injuries to an allograft exacerbate graft rejection, which in humans is primarily mediated by effector memory T cells. IL-6 transcripts in human coronary artery segments rapidly increase posttransplantation into immunodeficient mouse hosts compared with those of pretransplant specimens and fall dramatically by 30 d. Adoptive transfer of human PBMCs allogeneic to the artery 2 d postoperatively results in T cell infiltrates and intimal expansion 4 wk later. Ab neutralization of human IL-6 reduces the magnitude of intimal expansion and total T cell infiltration but increases the relative expression of CD161 while decreasing other Th17 markers. Coculture of MHC class II-expressing human endothelial cells (ECs) with allogeneic CD4+ memory T cells results in T cell activation and EC secretion of IL-6. Neutralizing IL-6 in primary allogeneic T cell–EC cocultures results in enhanced T cell proliferation of CD161+ CD4+ T cells, reduces total T cell proliferation upon restimulation in secondary cultures (an effect dependent on CD161+ T cells), increases expression of FOXP3 in CD161+ T cells, and generates T cells that suppress proliferation of freshly isolated T cells. These data suggest that IL-6 released from injured allograft vessels enhances allogeneic T cell infiltration and intimal expansion in a model of human allograft rejection by inhibiting an increase in CD161+ regulatory T cells.
IL-15 Regulates Homeostasis and Terminal Maturation of NKT Cells
Authors: Gordy Laura E. , Bezbradica Jelena S. , Flyak Andrew I. , Spencer Charles T. , Dunkle Alexis , Sun Jingchun , Stanic Aleksandar K. , Boothby Mark R. , He You-Wen , Zhao Zhongming , Van Kaer Luc , Joyce Sebastian 
Published: November 2011

Abstract
Semi-invariant NKT cells are thymus-derived innate-like lymphocytes that modulate microbial and tumor immunity as well as autoimmune diseases. These immunoregulatory properties of NKT cells are acquired during their development. Much has been learned regarding the molecular and cellular cues that promote NKT cell development, yet how these cells are maintained in the thymus and the periphery and how they acquire functional competence are incompletely understood. We found that IL-15 induced several Bcl-2 family survival factors in thymic and splenic NKT cells in vitro. Yet, IL-15–mediated thymic and peripheral NKT cell survival critically depended on Bcl-xL expression. Additionally, IL-15 regulated thymic developmental stage 2 to stage 3 lineage progression and terminal NKT cell differentiation. Global gene expression analyses and validation revealed that IL-15 regulated Tbx21 (T-bet) expression in thymic NKT cells. The loss of IL-15 also resulted in poor expression of key effector molecules such as IFN-γ, granzyme A and C, as well as several NK cell receptors, which are also regulated by T-bet in NKT cells. Taken together, our findings reveal a critical role for IL-15 in NKT cell survival, which is mediated by Bcl-xL, and effector differentiation, which is consistent with a role of T-bet in regulating terminal maturation.
Granzyme B Regulates Antiviral CD8+ T Cell Responses
Authors: Salti Suzan M. , Hammelev Erin M. , Grewal Jenny L. , Reddy Sreelatha T. , Zemple Sarah J. , Grossman William J. , Grayson Mitchell H. , Verbsky James W. 
Published: November 2011

Abstract
CTLs and NK cells use the perforin/granzyme cytotoxic pathway to kill virally infected cells and tumors. Human regulatory T cells also express functional granzymes and perforin and can induce autologous target cell death in vitro. Perforin-deficient mice die of excessive immune responses after viral challenges, implicating a potential role for this pathway in immune regulation. To further investigate the role of granzyme B in immune regulation in response to viral infections, we characterized the immune response in wild-type, granzyme B-deficient, and perforin-deficient mice infected with Sendai virus. Interestingly, granzyme B-deficient mice, and to a lesser extent perforin-deficient mice, exhibited a significant increase in the number of Ag-specific CD8+ T cells in the lungs and draining lymph nodes of virally infected animals. This increase was not the result of failure in viral clearance because viral titers in granzyme B-deficient mice were similar to wild-type mice and significantly less than perforin-deficient mice. Regulatory T cells from WT mice expressed high levels of granzyme B in response to infection, and depletion of regulatory T cells from these mice resulted in an increase in the number of Ag-specific CD8+ T cells, similar to that observed in granzyme B-deficient mice. Furthermore, granzyme B-deficient regulatory T cells displayed defective suppression of CD8+ T cell proliferation in vitro. Taken together, these results suggest a role for granzyme B in the regulatory T cell compartment in immune regulation to viral infections.
An MHC Class Ib-Restricted CD8+ T Cell Response to Lymphocytic Choriomeningitis Virus
Authors: Chen Lili , Jay David C. , Fairbanks Jared D. , He Xiao , Jensen Peter E. 
Published: November 2011

Abstract
Conventional MHC class Ia-restricted CD8+ T cells play a dominant role in the host response to virus infections, but recent studies indicate that T cells with specificity for nonclassical MHC class Ib molecules may also participate in host defense. To investigate the potential role of class Ib molecules in anti-viral immune responses, Kb−/−Db−/−CIITA−/− mice lacking expression of MHC class Ia and class II molecules were infected with lymphocytic choriomeningitis virus (LCMV). These animals have a large class Ib-selected CD8+ T cell population and they were observed to mediate partial (but incomplete) virus clearance during acute LCMV infection as compared with Kb−/−Db−/−β2-microglobulin−/− mice that lack expression of both MHC class Ia and class Ib molecules. Infection was associated with expansion of splenic CD8+ T cells and induction of granzyme B and IFN-γ effector molecules in CD8+ T cells. Partial virus clearance was dependent on CD8+ cells. In vitro T cell restimulation assays demonstrated induction of a population of β2-microglobulin–dependent, MHC class Ib-restricted CD8+ T cells with specificity for viral Ags and yet to be defined nonclassical MHC molecules. MHC class Ib-restricted CD8+ T cell responses were also observed after infection of Kb−/−Db−/−mice despite the low number of CD8+ T cells in these animals. Long-term infection studies demonstrated chronic infection and gradual depletion of CD8+ T cells in Kb−/−Db−/−CIITA−/− mice, demonstrating that class Ia molecules are required for viral clearance. These findings demonstrate that class Ib-restricted CD8+ T cells have the potential to participate in the host immune response to LCMV.
Hepcidin Is Regulated during Blood-Stage Malaria and Plays a Protective Role in Malaria Infection
Authors: Wang Hai-Zhen , He Ying-Xin , Yang Chun-Ju , Zhou Wei , Zou Cheng-Gang 
Published: November 2011

Abstract
Hepcidin is one of the regulators of iron metabolism. The expression of hepcidin is induced in spleens and livers of mice infected with pathogenic bacteria. Recent studies have indicated that serum hepcidin level is also increased in human subjects infected with Plasmodium falciparum. The mechanism of the regulation of hepcidin expression and its role in the infection of malaria remains unknown. In this study, we determined the expression of hepcidin in livers of mice infected with Plasmodium berghei. The expression of hepcidin in the liver was upregulated and downregulated during the early and late stages of malaria infection, respectively. Inflammation and erythropoietin, rather than the iron-sensing pathway, are involved in the regulation of hepcidin expression in livers of infected mice. Meanwhile, we investigated the effect of hepcidin on the survival of mice infected with P. berghei. Treatment of malaria-infected mice with anti-hepcidin neutralizing Abs promoted the rates of parasitemia and mortality. In contrast, lentiviral vector-mediated overexpression of hepcidin improved the outcome of P. berghei infection in mice. Our data demonstrate an important role of hepcidin in modulating the course and outcome of blood-stage malaria.
Leukemic Priming of Resting NK Cells Is Killer Ig-like Receptor Independent but Requires CD15-Mediated CD2 Ligation and Natural Cytotoxicity Receptors
Authors: Sabry May , Tsirogianni Maria , Bakhsh Ismail A. , North Janet , Sivakumaran Janani , Giannopoulos Konstantinos , Anderson Robert , Mackinnon Stephen , Lowdell Mark W. 
Published: November 2011

Abstract
Resting human NK cells require a two-stage activation process that we have previously described as “priming” and “triggering.” NK-sensitive tumor cells provide both priming and triggering signals. NK-resistant tumors evade lysis, mostly by failure to prime; however, we recently reported a tumor cell line (CTV-1) that primes resting NK cells but fails to trigger lysis. In this article, we report two additional leukemia cell lines that prime NK cells but are resistant to lysis. Tumor-mediated NK priming is via CD2 binding to a ligand within CD15 on the tumor cell. NK-resistant RAJI cells became susceptible to NK lysis following transfection and expression of CD15. Blockade of CD15 on K562 cells or on CD15+ RAJI cells significantly inhibited lysis, as did blockade of CD2 on resting NK cells. NK priming via CD2 induced CD16 shedding, releasing CD3ζ to the CD2, leading to its phosphorylation and the subsequent phosphorylation of linker for activation of T cells and STAT-5 and synthesis of IFN-γ. Blockade of C-type lectin receptors significantly suppressed the tumor-mediated priming of NK cells, whereas blockade of Ig-superfamily–like receptors had no effect at the NK-priming stage. Tumor priming of resting NK cells was irrespective of HLA expression, and blockade of HLA–killer Ig-like receptor interactions did not influence the incidence or degree of priming. However, CD15–CD2 interactions were critical for NK priming and were required, even in the absence of HLA-mediated NK inhibition. Tumor-mediated priming led to a sustained primed state, and the activated NK cells retained the ability to lyse NK-resistant tumors, even after cryopreservation.
Structural Basis of Diverse Peptide Accommodation by the Rhesus Macaque MHC Class I Molecule Mamu-B*17: Insights into Immune Protection from Simian Immunodeficiency Virus
Authors: Wu Yan , Gao Feng , Liu Jun , Qi Jianxun , Gostick Emma , Price David A. , Gao George F. 
Published: November 2011

Abstract
The MHC class I molecule Mamu-B*17 has been associated with elite control of SIV infection in rhesus macaques, akin to the protective effects described for HLA-B*57 in HIV-infected individuals. In this study, we determined the crystal structures of Mamu-B*17 in complex with eight different peptides corresponding to immunodominant SIVmac239-derived CD8+ T cell epitopes: HW8 (HLEVQGYW), GW10 (GSHLEVQGYW), MW9 (MHPAQTSQW), QW9 (QTSQWDDPW), FW9 (FQWMGYELW), MF8 (MRHVLEPF), IW9 (IRYPKTFGW), and IW11 (IRYPKTFGWLW). The structures reveal that not only P2, but also P1 and P3, can be used as N-terminal anchor residues by Mamu-B*17–restricted peptides. Moreover, the N-terminal anchor residues exhibit a broad chemical specificity, encompassing basic (H and R), bulky polar aliphatic (Q), and small (T) residues. In contrast, Mamu-B*17 exhibits a very narrow preference for aromatic residues (W and F) at the C terminus, similar to that displayed by HLA-B*57. Flexibility within the whole peptide-binding groove contributes to the accommodation of these diverse peptides, which adopt distinct conformations. Furthermore, the unusually large pocket D enables compensation from other peptide residues if P3 is occupied by an amino acid with a small side chain. In addition, residues located at likely TCR contact regions present highly flexible conformations, which may impact TCR repertoire profiles. These findings provide novel insights into the structural basis of diverse peptide accommodation by Mamu-B*17 and highlight unique atomic features that might contribute to the protective effect of this MHC I molecule in SIV-infected rhesus macaques.