bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cumulative-Gas-Production Distribution on the Nikanassin Tight Gas Formation, Alberta and British Columbia, Canada
Authors: Solano Nisael , Zambrano Liliana , Aguilera Roberto 
Published: May 2011

Summary271 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, have been evaluated with a view to determine the distribution of cumulative gas production and the possibilities of intensive infill drilling.The Upper Jurassic to Lower Cretaceous Nikanassin formation is generally characterized as a tight gas formation with low values of permeability (typically a fraction of millidarcy) and low porosities (usually less than 6%). It is likely that natural microfractures and slot pores dominate the productivity of the formation. The study area was divided into six smaller narrow areas (A through F) approximately parallel to the northwest/southeast-trending thrust belt of the Canadian Rocky Mountains. Area A is located to the west of the deformation edge, Area B is on the deformation edge, and Areas C through F are located to the east. Area C is the deepest and closest to the thrust belt, whereas Area F is the shallowest and farthest from the thrust belt.Cumulative production characteristics within each area were evaluated with a variability distribution model (VDM) developed recently for naturally fractured reservoirs. The evaluation of each one of the six areas (271 wells) resulted in coefficients of determination, R2 greater than 0.99 in all cases. The results indicate that the gas cumulative production distribution per well is more homogeneous along the deformation edge (Area B), in which 80% of the wells contribute approximately 50% of the cumulative production. The highest heterogeneity was found in Area F (the shallowest), with 80% of the wells contributing only 25% of the cumulative gas production. Areas A, C, D, and E have more or less the same distribution with 80% of the wells contributing between 35 and 45% of the cumulative gas production. In preliminary terms, there is an association between the cumulative-production distribution and lateral variations of borehole breakouts in the Nikanassin formation on a transect perpendicular to the deformation belt of the WCSB.Analysis of the distributions leads to the conclusion that the Nikanassin is a very heterogeneous formation and that there is significant potential for massive drilling to efficiently drain the formation. The possibilities of horizontal wells and multistage hydraulic-fracturing jobs are being investigated at this time.
Study of Alkaline/Polymer Flooding for Heavy-Oil Recovery Using Channeled Sandpacks
Authors: Wu Yongge , Dong Mingzhe , Shirif Ezeddin 
Published: May 2011

Summary
For heavy oils with viscosities ranging from 1000 to 10 000 mPa·s in western Canada, primary production and waterflood together can recover only 8–15% of original oil in place (OOIP) at their economic limits because of the adverse mobility ratio, severe water channeling, low reservoir pressure, and formation voidage. These heavy oils usually have a relatively high content of acids that can react with alkalis to form in-situ surfactants. The loosely consolidated sandstone formations in which these oils are deposited are characterized by high porosity, high permeability, and low reservoir temperature. These reservoir conditions are favorable for polymer application. Therefore, there is a potential to improve waterflood in these reservoirs by applying alkaline/polymer (A/P) flooding.
This paper presents the results of a laboratory study of A/P flooding for heavy-oil recovery, including viscosity measurements, flood tests conducted in channeled sandpacks, residual-resistance-factor (FRR) determination, and residual-oil-distribution tests. A heavy oil with a viscosity of 1,202 cp and an acid number of 1.07 (mg of KOH/g of oil) and produced brine collected from a heavy-oil reservoir in Alberta are used in this study. We found that the distribution of the injected chemical solution within the high-permeability channels leads to the diversion of the subsequently injected chemical solution to low-permeability zones with higher oil saturation because of the formation of blockage in the channel zones. Consequently, pressure buildup during chemical-slug injection is the key to the improvement of displacement efficiency. Flood tests also show that A/P flooding is more efficient than either alkaline flooding or polymer flooding. The optimal formulation for the heavy oil used in this study is 0.4% NaOH + 0.2% Na2CO3 + 1000 mg/L polymer, with a tertiary oil recovery of 25–30% of OOIP above that from waterflooding. Analysis of the results of the residual-oil distributions in the channeled sandpacks at the end of A/P flooding show that A/P flooding can effectively improve the sweep efficiency of waterflooding for the heavy oil.
Rate-Decline Analysis for Fracture-Dominated Shale Reservoirs
Authors: Duong Anh N. 
Published: May 2011

Summary
Traditional decline methods such as Arps’ rate/time relations and their variations do not work for wells producing from supertight or shale reservoirs in which fracture flow is dominant. Most of the production data from these wells exhibit fracture-dominated flow regimes and rarely reach late-time flow regimes, even over several years of production. Without the presence of pseudoradial and boundary-dominated flows (BDFs), neither matrix permeability nor drainage area can be established. This indicates that matrix contribution is negligible compared with fracture contribution, and the expected ultimate recovery (EUR) cannot be based on a traditional concept of drainage area.
An alternative approach is proposed to estimate EUR from wells in which fracture flow is dominant and matrix contribution is negligible. To support these fracture flows, the connected fracture density of the fractured area must increase over time. This increase is possible because of local stress changes under fracture depletion. Pressure depletion within fracture networks would reactivate the existing faults or fractures, which may breach the hydraulic integrity of the shale that seals these features. If these faults or fractures are reactivated, their permeabilities will increase, facilitating enhanced fluid migration. For fracture flows at a constant flowing bottomhole pressure, a log-log plot of rate over cumulative production vs. time will yield a straight line with a unity slope regardless of fracture types. In practice, a slope of greater than unity is normally observed because of actual field operations, data approximation, and flow-regime changes. A rate/ time or cumulative production/time relationship can be established on the basis of the intercept and slope values of this log-log plot and initial gas rate.
Field examples from several supertight and shale gas plays for both dry and high-liquid gas production, and for oil production were used to test the new model. All display the predicted straightline trend, with its slope and intercept related to reservoir types. In other words, a certain fractured flow regime or a combination of flow types that dominate a given area or play because of its reservoir-rock characteristics and/or fracture-stimulation practices all produce a narrow range of intercepts and slopes. An individualwell performance or EUR can be derived that is based on this range if the best 3-month average or the initial production rate of the well is already known or estimated. The results show that this alternative approach is easier to use, gives a reliable EUR, and can be used to replace the traditional decline methods for unconventional reservoirs. The new approach is also able to provide statistical methods to analyze production forecasts of resource plays and to establish a range of results of these forecasts, including probability distributions of reserves in terms of P90 (lower side) to P10 (higher side).
Innovative Alternative to Full-Field Compositional Modeling-Case Study of the North Kuwait Jurassic Complex
Authors: Ghorayeb Kassem , Aziz Rafi Mohammad , Limsukhon Manoch , Al-Anzi Ealian 
Published: May 2011

Summary
The North Kuwait Jurassic complex (NKJC) consists of six fields with four potential reservoirs in a naturally fractured Jurassic carbonate formation. Current understanding of the complex has led to 12 subdivisions of the area and potentially 48 separate compartments (segments) in the complex. These subdivisions are defined by fault boundaries supported by a combination of variations in fluid composition, initial pressures, and free-water levels estimated from capillary pressure and log saturation data.
Multiscenario production forecasts based on integrated full-field modeling were needed in the process of building a field-development plan (FDP) for the NKJC. An integrated asset modeling (IAM) framework is adopted in which multiple separate reservoir models are coupled through global constraints to meet gas-delivery targets.
We present the results of a feasibility study to select the optimal modeling strategy for the complex. We discuss available options to simulate multiple reservoirs, which, although isolated based on the current understanding of compartmentalization, need to meet global production targets. We show that using multiple-reservoirs integration through a controller to couple the separate reservoir models through global production targets/limits provides an optimal simulation framework for the NKJC—the flexibility and computational efficiency of multiple segment models and the comprehensiveness of full-field simulation modeling.
The solution uses a black-oil delumping technique to obtain compositional wellstreams while running black-oil simulation models. The feasibility study demonstrated that black-oil delumping enables the composition and component molar rates of a producing well from a black-oil reservoir simulation to be reconstituted accurately. Comparison of results obtained from a compositional model to those obtained from a black-oil model using black-oil delumping shows excellent agreement.
The adopted simulation framework provided us with all the benefits of a compositional full-field simulation model while adding two advantages (i.e., computational speed and flexibility). Full computational advantages of black-oil modeling are obtained while preserving the reservoir details required for an accurate prediction of well and reservoir behavior.
Rent Control Rationing and Community Composition: Evidence from Massachusetts
Authors: Sims David P 
Published: May 2011

Abstract
This paper investigates whether rent control affects community socioeconomic composition. In particular, do rent controls increase the presence of poor and minority residents in a locale? Theoretically, the effect of rent control on community composition is ambiguous, as it depends upon several factors including willingness to occupy controlled apartments, landlord imposed rationing mechanisms, and spillover effects of rent controlled housing on uncontrolled units. Using census data on how Cambridge, Massachusetts and nearby communities responded to the state imposed end of rent control, I find evidence that rent control increased the presence of minority residents but also decreased the proportion of poor residents. This evidence is robust to alternate control areas and several specification checks. I also find that despite its positive impact on minority membership, rent control is associated with an increase in traditional measures of residential segregation.
Association between anthropometric indexes and cardiovascular risk factors
Authors: Luksiene Dalia , Petkeviciene Janina , Jureniene Kristina , Klumbiene Jurate , Smalinskiene Alina , Tamosiunas Abdonas 
Published: May 2011

Abstract
The aim of this study was to assess the associations of the body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) with ischemic heart disease (IHD) and risk factors of IHD in the Lithuanian population aged 25 to 70 years. The cross-sectional health survey was carried out in Kaunas, which is the second largest city in Lithuania, and in five regions randomly selected from the northern, southern, eastern, western and central parts of Lithuania. Data from 2048 subjects (936 men and 1112 women) were analyzed. In both sexes, the odds ratios for reduced high density lipoprotein cholesterol, elevated triglycerides, high fasting blood glucose, and hypertension rose with an increasing quartile of BMI, WC, and WHtR. The likelihood of having IHD was statistically significantly higher in the fourth quartile of these anthropometric measures when compared to the first one. Comparison of the logistic regression models revealed that the models with WHtR best fit the prediction of IHD risk. Compared with BMI and WC, WHtR showed a stronger association with IHD and its risk factors in the Lithuanian adult population.
Light induced silver and copper plating on silver screen-printed contacts of silicon solar cells
Authors: Tutashkonko S. , Kaminski-Cachopo A. , Boulord C. , Arès R. , Aimez V. , Lemiti M. 
Published: May 2011

AbstractIn this paper we present the results of solar cell’s screen printed contacts thickening by light induced plating (LIP) of Cu and Ag. Light-induced and light-assisted plating techniques are compared. Plating bath current versus illumination intensity, the potentials of metallic anode, front and back surfaces of the solar cell were measured and analyzed for all possible plating modes. The current-voltage behaviour of cells under illumination in a plating bath for the cases of electrically insulated and non-insulated back-surface of a cell is analyzed and discussed. Finally, the exact values of current/voltage/illumination intensity for optimal depositions and a general recipe for their determination for different plating materials are given.The quality of deposited layers, state of contact-line and anti-reflective coating surface were controlled after plating by cross-section and planar-view SEM observations. The electrical properties of plated contacts and their effect on overall efficiency of solar cell were investigated by measuring contact-line resistance and dark- and light I–V solar cell measurements. The absence of short-circuits was verified by imaging with an infra-red camera.
A new family of leafy liverworts from the middle Eocene of Vancouver Island, British Columbia, Canada
Authors: Steenbock Christopher M. , Stockey Ruth A. , Beard Graham , Tomescu Alexandru M. F. 
Published: May 2011

•Premise of the study: Morphology is a reflection of evolution, and as the majority of biodiversity that has lived on Earth is now extinct, the study of the fossil record provides a more complete picture of evolution. This study investigates anatomically preserved bryophyte fossils from the Eocene Oyster Bay Formation of Vancouver Island. While the bryophyte fossil record is limited in general, anatomically preserved bryophytes are even more infrequent; thus, the Oyster Bay bryophytes are a particularly significant addition to the bryophyte fossil record.•Methods: Fossils occur in two marine carbonate nodules collected from the Appian Way locality on the eastern shore of Vancouver Island, British Columbia, and were prepared using the cellulose acetate peel technique.•Key results: The fossils exhibit a novel combination of characters unknown among extinct and extant liverworts: (1) three‐ranked helical phyllotaxis with underleaves larger than the lateral leaves; (2) fascicled rhizoids associated with the leaves of all three ranks; (3) Anomoclada‐type endogenous branching.•Conclusions: A new liverwort family, Appianacae fam. nov., is established based upon the novel combination of characters. Appiana gen. nov. broadens the known diversity of bryophytes and adds a hepatic component to one of the richest and best characterized Eocene floras.
An annual pattern of native embolism in upper branches of four tall conifer species
Authors: McCulloh Katherine A. , Johnson Daniel M. , Meinzer Frederick C. , Lachenbruch Barbara 
Published: May 2011

• Premise of the study: The Pacific Northwest of North America experiences relatively mild winters and dry summers. For the tall coniferous trees that grow in this region, we predicted that loss in the hydraulic conductivity of uppermost branches would be avoided because of difficulty reversing accumulated emboli in xylem that is always under negative pressure.• Methods: To test this hypothesis, we measured native percent loss in hydraulic conductivity (PLC; the decrease of in situ hydraulic conductivity relative to the maximum) monthly throughout 2009 in branches at the tops (∼50 m) of four species in an old growth forest in southern Washington.• Key results: Contrary to our prediction, freeze–thaw cycles resulted in considerable native PLC. Branches showed hydraulic recovery in the spring and after a moderate increase in native embolism that was observed after an unusually hot period in August. The September recovery occurred despite decreases in the leaf and stem water potentials compared to August values.• Conclusions: Recoveries in branches of these trees could not have occurred by raising the water potential enough to dissolve bubbles simply by transporting water from roots and must have occurred either through water absorption through needles and/or refilling under negative pressure. Excluding the August value, native embolism values correlated strongly with air temperature of the preceding 10 d. For three species, we found that branches with lower wood density had higher specific conductivity, but not greater native PLC than branches with higher wood density, which calls into question whether there is any hydraulic benefit to higher wood density in small branches in those species.
Relationship between Polymorphisms of the Inosine Triphosphatase Gene and Anaemia or Outcome after Treatment with Pegylated Interferon and Ribavirin
Authors: Kurosaki Masayuki , Tanaka Yasuhito , Tanaka Keisuke , Suzuki Yuichiro , Hoshioka Yoshihide , Tamaki Nobuharu , Kato Tomoji , Yasui Yutaka , Hosokawa Takanori , Ueda Ken , Tsuchiya Kaoru , Kuzuya Teiji , Nakanishi Hiroyuki , Itakura Jun , Takahashi Yuka , Asahina Yasuhiro , Matsuura Kentaro , Sugauchi Fuminaka , Enomoto Nobuyuki , Nishida Nao , Tokunaga Katsushi , Mizokami Masashi , Izumi Namiki 
Published: May 2011

Background A genome-wide association study revealed an association between variants of the inosine triphosphatase ( ITPA) gene and ribavirin (RBV)-induced anaemia. The aim of this study was to replicate this finding in an independent Japanese cohort and to define a method to allow pretreatment prediction of anaemia in combination with other factors. Methods Genotype 1b chronic hepatitis C patients ( n=132) treated with pegylated interferon (PEG-IFN)-α and RBV for 48 weeks were genotyped for ITPA rs1127354 and examined for anaemia and treatment outcome. Results Variants of the ITPA gene protected against severe anaemia throughout the 48-week treatment period and were associated with lower incidence of anaemia-related RBV dose reduction. A combination of the ITPA genotype with baseline haemoglobin (Hb) and creatinine clearance (CLcr) levels predicted severe anaemia with high accuracy (90% sensitivity and 62% specificity). Among a subset of patients with the IL28B genotype of TT at rs8099917, patients with variants of the ITPA gene were associated with a higher rate of receiving >80% of the expected RBV dose, a higher rate of sustained virological response (SVR), and a lower rate of relapse. Conclusions The variants of the ITPA gene, which could protect against haemolytic anaemia and RBV dose reduction, were associated with a high rate of SVR by standard PEG-IFN and RBV therapy in a subset of Japanese patients with the favourable TT genotype at rs8099917 of IL28B. A combination of ITPA genetic polymorphisms with baseline Hb and CLcr levels further improves the predictive accuracy of severe anaemia.
Influence of HIV Infection on Cytomegalovirus-Specific Immunity: T-Cell Responses to Pp65 and Ie1 before and after Haart May Refect Altered Cytomegalovirus Biology
Authors: Scherrenburg Jolanda , Schellens Ingrid MM , van Baarle Debbie 
Published: May 2011

Background Data are inconclusive whether treatment with HAART induces functional recovery of HIV-specific T-cells. Since the introduction of HAART, a marked decrease of cytomegalovirus (CMV) disease – for which untreated HIV-infected individuals are at increased risk – is observed, suggesting that this treatment influences CMV-specific T-cell immunity. Methods To study potential functional recovery of HIV-and CMV-specific T-cells, CD4+ and CD8+ T-cell responses were measured longitudinally after in vitro expansion using gag, pp65 and IE1 peptide pools, during HIV infection and after long-term HAART. Results HIV-specific T-cell function, measured by interferon (IFN)-γ production, was low after initiation of HAART. Interestingly, the cytotoxic function – measured by CD107a expression – of these T-cells temporarily increased after start of treatment, suggesting some functional recovery. The pp65-specific CD8+ T-cell responses tended to decrease during HIV infection, whereas pp65-specific CD4+ T-cell responses decreased upon treatment with HAART. Both pp65-specific CD4+ and CD8+ T-cell responses were low after initiation of HAART compared to healthy controls. By contrast, IE1-specific CD4+ T-cell responses increased during the course of HIV infection. After initiation of HAART, IE1-specific T-cell responses decreased, but IE1-specific CD8+ T-cells seemed increased compared to healthy controls. Conclusions This study suggests that HIV-infection leads to an altered CMV biology, affecting pp65- and IE1-specific T-cell responses in a different way, which is not restored by treatment with long-term HAART.
Efficacy and Safety of Nevirapine Extended-Release Once Daily versus Nevirapine Immediate-Release Twice-Daily in Treatment-Naive HIV-1-Infected Patients
Authors: Gathe Joseph , Andrade-Villanueva Jaime , Santiago Steven , Horban Andrzej , Nelson Mark , Cahn Pedro , Bogner Johannes , Spencer David , Podzamczer Daniel , Yong Chan-Loi , Nguyen Thuy , Zhang Wei , Drulak Murray , Quinson Anne-Marie 
Published: May 2011

Background This study (VERxVE) compared the efficacy and safety of the new nevirapine extended-release (NVP XR) formulation dosed once daily with NVP immediate release (IR) twice daily in treatment-naive patients. Methods Randomized, double-blind, double-dummy, parallel group study of HIV-1-infected adult patients with baseline viral load (VL) ≥1,000 copies/ml and CD4+ T-cell count of >50-<400 (males) and >50-<250 cells/mm3 (females). Patients stratified by baseline VL (≤100,000/>100,000 copies/ml) were randomized 1:1 to NVP XR 400 mg once daily (plus placebo) or NVP IR 200 mg twice daily (plus placebo), both combined with tenofovir disoproxil fumarate (TDF) 300 mg and emtricitabine 200 mg once daily. Primary endpoint was sustained virological response (<50 copies/ml) through week 48 using the time to loss of virological response algorithm. Non-inferiority of NVP XR to NVP IR was tested using Cochran's statistic incorporating baseline VL stratum with pre- specified, non-inferiority margin of -10%. Results Among 1,011 patients randomized and treated, virological response at week 48 was 81.0% (409/505) for NVP XR and 75.9% (384/506) for NVP IR with adjusted difference of 4.9% in favour of NVP XR (95% CI -0.1– 10.0%), demonstrating non-inferiority of NVP XR to NVP IR. This finding was supported by secondary endpoints. The safety profile of NVP XR was similar to NVP IR, but showed numerically fewer treatment-related adverse events. Conclusions NVP XR in combination with TDF and emtricitabine was shown to be non-inferior in efficacy to NVP IR with a similar safety and adverse event pro-file, with the potential for the added convenience of once-daily dosing. Trial registration: ClinicalTrials (NCT): NCT00561925.