bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Interimplant Distance (2 and 3 mm) on the Height of Interimplant Bone Crest: A Histomorphometric Evaluation
Authors: Elian Nicolas , Bloom Mitchell , Dard Michel , Cho Sang‐Choon , Trushkowsky Richard D. , Tarnow Dennis
Published: March 2011

Background: Implants restored according to a platform‐switching concept (implant abutment interface with a reduced diameter relative to the implant platform diameter) present less crestal bone loss than implants restored with a standard protocol. When implants are placed adjacent to one another, this bone loss may combine through overlapping, thereby causing loss of the interproximal height of bone and papilla. The present study compares the effects of two interimplant distances (2 and 3 mm) on bone maintenance when bone‐level implants with platform‐switching are used.

Methods: This study evaluates marginal bone level preservation and soft tissue quality around a bone‐level implant after 2 months of healing in minipig mandibles. The primary objective is to evaluate histologically and histomorphometrically the affect that an implant design with a horizontally displaced implant–abutment junction has on the height of the crest of bone, between adjacent implants separated by two different distances.

Results: Results show that the interproximal bone loss measured from the edge of the implant platform to the bone crest was not different for interimplant distances of 2 or 3 mm. The horizontal position of the bone relative to the microgap on platform level (horizontal component of crestal bone loss) was 0.31 ± 0.3 mm for the 2‐mm interimplant distance and 0.57 ± 0.51 mm above the platform 8 weeks after implantation for the 3‐mm interimplant distance.

Conclusions: This study shows that interimplant bone levels can be maintained at similar levels for 2‐ and 3‐mm distances. The horizontally displaced implant–abutment junction provided for a more coronal position of the first point of bone–implant contact. The study reveals a smaller horizontal component at the crest of bone than has been reported for non‐horizontally displaced implant–abutment junctions.
Living Cellular Construct for Increasing the Width of Keratinized Gingiva: Results From a Randomized, Within‐Patient, Controlled Trial
Authors: McGuire Michael K. , Scheyer E. Todd , Nevins Marc L. , Neiva Rodrigo , Cochran David L. , Mellonig James T. , Giannobile William V. , Bates Damien
Published: March 2011

Background: The standard of care for increasing keratinized gingiva adjacent to teeth that do not require root coverage is the free gingival graft (FGG). A pilot study indicated that the use of a living cellular construct (LCC) could be effective in this clinical scenario.

Methods: A pivotal, multicenter, randomized, within‐patient, controlled, open‐label trial was conducted (N = 96 patients). After removing the mucosa and keratinized gingiva from the test site, either an LCC or FGG was applied. The primary efficacy endpoint was the ability of the LCC to regenerate ≥2 mm keratinized gingiva at 6 months. Secondary measures were the same color and texture as the adjacent tissue, a 1‐mm width of keratinized gingiva at 6 months, patient treatment preference, surgical site sensitivity at 1 week, and patient‐reported pain after 3 days. Safety was assessed by reports of adverse events.

Results: At 6 months, the LCC regenerated ≥2 mm of keratinized gingiva in 95.3% of patients (81 of 85 patients; P <0.001 versus a 50% predefined standard). As expected, the FGG generated more keratinized gingiva than the LCC (4.57 ± 1.0 mm versus 3.2 ± 1.1 mm, respectively). The gingiva regenerated with the LCC matched the color and texture of the adjacent gingiva. All patients achieved ≥1 mm keratinized gingiva with the LCC treatment by 6 months, and more patients preferred treatment with the LCC than with the FGG. No difference in sensitivity or pain was noted between the treatments. The treatments were well tolerated, and reported adverse events were typical for this type of periodontal surgery.

Conclusion: The use of an LCC may provide a safe and effective therapy for augmenting the zone of keratinized gingiva.
Interactions of Enamel Matrix Derivative and Biomechanical Loading in Periodontal Regenerative Healing
Authors: Nokhbehsaim Marjan , Deschner Birgit , Bourauel Christoph , Reimann Susanne , Winter Jochen , Rath Björn , Jäger Andreas , Jepsen Søren , Deschner James
Published: March 2011

Background: Although enamel matrix derivative (EMD) has been shown to promote periodontal regeneration, it is unknown whether the actions of EMD are modulated by occlusal loading. This in vitro study was performed to investigate whether biomechanical forces regulate the response of periodontal ligament (PDL) cells to EMD.

Methods: Human PDL cells were treated with EMD in the presence and absence of cyclic tensile strain (CTS) of various magnitudes for ≤14 days. Synthesis of transforming growth factor (TGF)‐β1, vascular endothelial growth factor (VEGF), growth factor receptors, collagen, and runt‐related transcription factor 2‐ (RUNX2), cell numbers and adhesion, wound fill rate, and calcium accumulation were analyzed by real‐time polymerase chain reaction, enzyme‐linked immunosorbent assay, a wound healing assay, and alizarine red S staining.

Results: Wound fill rate, cell numbers and adhesion, and expression of TGF‐β1, VEGF, collagen, and RUNX2 were significantly increased by EMD. In the presence of CTS, the EMD‐induced effects were significantly reduced. The inhibition of the EMD‐upregulated VEGF expression by CTS was blocked by a specific inhibitor of nuclear factor‐kappa B signaling. Moreover, CTS downregulated receptors for growth factors involved in the actions of EMD. CTS also antagonized significantly the EMD‐induced calcium deposition.

Conclusions: These in vitro findings suggest that the beneficial actions of EMD on PDL cell functions critical for periodontal regeneration are jeopardized by biomechanical loading. Clinical studies should clarify whether protection of teeth against occlusal forces in the early healing stage may positively affect the outcome of regenerative therapy with EMD.
Detection of Periodontal Bacteria in Atheromatous Plaque by Nested Polymerase Chain Reaction
Authors: Figuero Elena , Sánchez‐Beltrán María , Cuesta‐Frechoso Susana , Tejerina Jose María , del Castro Jose Antonio , Gutiérrez Jose María , Herrera David , Sanz Mariano
Published: March 2011

Background: In recent years, increasing evidence regarding the potential association between periodontal diseases and cardiovascular diseases has been identified. The available evidence underlines the importance of detecting periodontal pathogens on atheromatous plaque as the first step in demonstrating the causal relationship between the two conditions. The main aim of this investigation is to detect periodontitis‐associated bacteria from carotid artery atheromatous plaque from patients who received an endarterectomy using strict sample procurement and laboratory procedures.

Methods: Atheromatous plaque from endarterectomies from carotid arteries were scraped and homogenized, and bacterial DNA was extracted. To obtain a representative concentration of amplicons, two amplifications of the bacterial 16S ribosomal‐RNA gene were carried out for each sample with universal eubacteria primers by a polymerase chain reaction (PCR). A nested PCR with specific primers for the target bacteria was performed next. Statistical tests included the χ2 test.

Results: Forty‐two atheromatous plaque were analyzed. All of them were positive for ≥1 target bacterial species. The bacterial species most commonly found was Porphyromonas gingivalis (78.57%; 33 of 42), followed by Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) (66.67%; 28 of 42), Tannerella forsythia (previously T. forsythensis) (61.90%; 26 of 42), Eikenella corrodens (54.76%; 23 of 42), Fusobacterium nucleatum (50.00%; 21 of 42), and Campylobacter rectus (9.52%; four of 42). The simultaneous presence of various bacterial species within the same specimen was a common observation.

Conclusion: Within the limitations of this study, the presence of DNA from periodontitis‐associated bacteria in carotid artery atheromatous plaque retrieved by endarterectomy is confirmed.
Method To Generate Full-Bore Images Using Borehole Images and Multipoint Statistics
Authors: Hurley Neil F. , Zhang Tuanfeng
Published: March 2011

Borehole-image logs, which are produced by tools being lowered into a well, provide oriented electrical and acoustic maps of the rocks and fluids encountered in the borehole. Electrical borehole images in water-based (conducting) and oil-based (nonconducting) muds are generated from electrodes arranged in fixed patterns on pads that are pressed against the borehole wall. Depending on the borehole diameter, gaps nearly always occur between pads. Because of these gaps, it is common to have nonimaged parts of the borehole wall.

Full-bore images are complete, 360° views of the borehole wall. They are generated by "filling in the gaps" between the pads in borehole-image logs. This method uses the Filtersim algorithm of multipoint statistics (MPS) to generate models, or realizations. Measured (incomplete) borehole images themselves are used as "training images." Recorded data are perfectly honored (i.e., the models are conditioned to the real data). Gaps are filled with patterns similar to those seen elsewhere in the log. Patterns in the gaps match the edges of the pads. The frequency distribution of continuously variable pixel colors in the gaps matches the distribution of pixel colors in the measured images.

Full-bore images facilitate visualization and interpretation of borehole-image logs in any lithology, although case studies shown in this paper are developed in vuggy and fractured rocks. These images can be used to draw closed contours around electrically resistive or nonresistive patches in the borehole wall. Full-bore images can be used to repair logs with bad electrodes, low pad pressure, or poor acoustic reflections. Therefore, they can be used to enhance any commercially available electrical or acoustic borehole images.
A New Well-Pattern-Optimization Procedure for Large-Scale Field Development
Authors: Onwunalu J.E.. E. , Durlofsky L.J.. J.
Published: March 2011

The optimization of large-scale multiwell field-development projects is challenging because the number of optimization variables and the size of the search space can become excessive. This difficulty can be circumvented by considering well patterns and then optimizing parameters associated with the pattern type and geometry. In this paper, we introduce a general framework for accomplishing this type of optimization. The overall procedure, which we refer to as well-pattern optimization (WPO), includes a new well-pattern description (WPD) incorporated into an underlying optimization method. The WPD encodes potential solutions in terms of pattern types (e.g., five-spot, nine-spot) and pattern operators. The operators define geometric transformations (e.g., stretching, rotating) quantified by appropriate sets of parameters. It is the parameters that specify the well patterns and the pattern operators, along with additional variables that define the sequence of operations, that are optimized. A technique for subsequent well-by-well perturbation (WWP), in which the locations of wells within each pattern are optimized, is also presented. This WWP represents an optional second phase of WPO. The overall optimization procedure could be used with a variety of underlying optimization methods. Here, we combine it with a particle-swarm-optimization (PSO) technique because PSO methods have been shown recently to provide robust and efficient optimizations for well-placement problems.

Detailed optimization results are presented for several example cases. In one case, multiple reservoir models are considered to account for geological uncertainty. For all examples, significant improvement in the objective function is observed as the algorithm proceeds, particularly at early iterations. The use of well-by-well perturbation (following determination of the optimal pattern) is shown to provide additional improvement. Limited comparisons with results using standard well patterns of various sizes demonstrate that the net present values (NPVs) achieved by the new algorithm are considerably larger. Taken in total, the optimization results highlight the potential of the overall procedure for use in practical field development.
Inflow Performance of a Cyclic-Steam-Stimulated Horizontal Well Under the Influence of Gravity Drainage
Authors: Wu Z.. , Vasantharajan S.. , El-Mandouh M.. , Suryanarayana P.V.. V.
Published: March 2011

In this paper, we present a new, semianalytical gravity-drainage model to predict the oil production of a cyclic-steam-stimulated horizontal well. The underlying assumption is that the cyclic steam injection creates a cylindrical steam chamber in the upper area of the well. Condensed water and heated oil in the chamber are driven by gravity and pressure drawdown toward the well. The heat loss during the soak period and during oil production is estimated under the assumption of vertical and radial conduction. The average temperature change in the chamber during the cycle is calculated using a semianalytical expression. Nonlinear, second-order ordinary differential equations are derived to describe the pressure distribution caused by the two-phase flow in the wellbore. A simple iteration scheme is proposed to solve these equations. The influx of heated oil and condensed water into the horizontal wellbore is calculated under the assumption of steady-state radial flow.

The solution from the semianalytical formulation is compared against the results from a commercial thermal simulator for an example problem. It is shown that the model results are in good agreement with those obtained from reservoir simulation. Sensitivity studies for optimization of wellbore length, gravity drainage, bottomhole pressure, and steam-injection rate are conducted with the model. Results indicate that the proposed model can be used in the optimization of individual-well performance in cyclic-steam-injection heavy-oil development. The semianalytical thermal model presented in this work can offer an attractive alternative to numerical simulation for planning heavy-oil field development.
Optimizing Fracture Spacing and Sequencing in Horizontal-Well Fracturing
Authors: Roussel Nicolas P. , Sharma Mukul M.
Published: March 2011

Horizontal wells with multiple fractures are now commonly used in unconventional (low-permeability) gas reservoirs. The spacing between perforations and the number and orientation of transverse fractures all have a major impact on well production.

The opening of propped fractures results in the redistribution of local Earth stresses. In this paper, the extent of stress reversal and reorientation has been calculated for fractured horizontal wells using a 3D numerical model of the stress interference induced by the creation of one or more propped fractures. The results have been analyzed for their impact on simultaneous and sequential fracturing of horizontal wells.

Our results demonstrate that a transverse fracture initiated from a horizontal well may deviate away from the previous fracture. The effect of the reservoir's mechanical properties on the spatial extent of stress reorientation caused by an opened crack has been quantified. The paper takes into account the presence of layers that bound the pay zone but have mechanical properties different from those of the pay zone. The fracture vertical growth into the bounding layers is also examined.

It is shown that stress interference, or reorientation, increases with the number of fractures created and depends on the sequence of fracturing. Three fracturing sequences are investigated for a typical field case in the Barnett shale: (a) consecutive fracturing, (b) alternative fracturing, and (c) simultaneous fracturing of adjacent wells. The numerical calculation of the fracture spacing required to avoid fracture deviation during propagation, for all three fracturing techniques, demonstrates the potential advantages of alternate fracture sequencing and zipper fracs to improve the performance of stimulation treatments in horizontal wells.
Design Methodology and Operational Practices Eliminate Differential Sticking
Authors: Dupriest Fred E. , Elks William C. , Ottesen Steinar
Published: March 2011

This paper discusses a successful initiative begun 6 years ago to eliminate differential sticking across global operations. In the 5-year period from 2004 through 2008, there were only three differential-sticking events in 3,476 wells drilled with the recommended practices. There were an additional 17 sticking events with designs that did not conform to recommended practices, and 14 of these were freed. The drilling environment was diverse. Overbalances in excess of 1,000 to 2,000 psi were common in multidarcy rock and at high angle, and depleted reservoirs have been drilled with overbalance as high as 7,800 psi in vertical wells.

The early focus of the stuck-pipe-avoidance practices was the elimination of differential sticking. However, some level of sticking occurs routinely in drilling operations, and these events become problematic only if the force required to initiate pipe movement exceeds what can be delivered to the stuck point. It is now accepted that sticking cannot be prevented and that elimination of sticking is not a proper design objective. The philosophical objective has now shifted from elimination of sticking to "maintaining conditions that allow the pipe to be pulled free," assuming that it will become differentially stuck. The desire to maintain this ability to move the pipe has required the implementation of a range of practices, some of which were not common in the industry.

Changes were made in bottomhole assembly (BHA) design, fluid design, real-time cake-shear-strength recognition, and realtime cake-remediation practices. A finite-element (FE) model was also applied to redesign new systems or applications that lie outside the operator's previous experience. The stochastic model predicts cake growth and sticking force and the probability that it will be possible to deliver a force that can free the pipe for any given still-pipe time. The model inputs were calibrated through pullout tests with a variety of fluids to determine mechanical cake-strength properties, the rate at which those properties develop, changes in the pressure transient through the cake as it matures, and the cake contact areas and geometry at any point in time.

Engineering and operations training also contributed greatly and allowed relatively uniform implementation to be achieved across a large, globally diverse operation in less than 1 year. A small number of noncompliant designs continued to be used, and these contributed greatly to the incidence of stuck pipe in the first 3 years. Last year, there was only one incident of stuck pipe with a noncompliant design.

The paper describes the underlying sticking concepts, the engineering design and field practices used, the modeling capability, and the field results.
Automation of Mud-Pump Management: Application to Drilling Operations in the North Sea
Authors: Cayeux Eric , Daireaux Benoît , Dvergsnes Erik Wolden
Published: March 2011

Drilling in the North Sea is confronted with an ever more challenging pressure-management issue because of narrow geopressure windows in depleted reservoirs. Further, the occurrence of packoffs can cause serious damage to the formation and contribute to nonproductive time. To address these problems, automation of mud-pump management has been developed over the last 4 years to minimize the chance of fracturing the formation while starting the mud pumps or circulating. To account for abnormal flow restrictions in the annulus, automatic actions are also an integral part of the mud-pump automation described in this paper.

Since the downhole conditions are continuously changing (e.g., depth, temperature, flow-rate, gel time, cuttings proportion), the necessary safeguards to operate the mud pumps need to be updated constantly. Advanced transient temperature and hydraulic models are used to estimate, in real-time, the downhole situation. On the basis of the current context, evaluations of maximum pump rates and acceptable flow accelerations are performed and sent to the mud-pump control system to be used as an envelope of protection. Furthermore, to assist the driller during connections, the pump-startup procedure has been semiautomated to decrease connection time. Finally, an automatically triggered pump-shutdown procedure is also available to minimize the consequences of a packoff on formation fracturing.

A first version of the system has been tested during the drilling of one well in 2008 in the North Sea. Based on the initial experience, a revised version has been used during the drilling of three wells drilled on the Norwegian continental shelf in 2009. The feedback from the drillers involved in the testing has been used to improve the user friendliness of the system. The automation of the mud-pump management has been well accepted by the drilling crews. However, the testing has shown that additional instrumentation at the rigsite is necessary before such automation can be rolled out safely.
The Influence of Data Quality on Workflows and Decision Making in Well Delivery
Authors: Sawaryn S.J.. J. , Whiteley N.. , Deady A.. , Borresen A.. , Gibson N..
Published: March 2011

The paper discusses how data quality influences workflows and decision making in drilling and completions and examines the use of semiautomated processes for quality assurance. With poor data, additional steps are required and workflows must be repeated. In even relatively simple situations, controlled tests suggest that small changes or omissions may have a significant influence on the work efficiency or outcome.

In earlier work, the quality of any data stream has been described in terms of identity, presence, measurement frequency, accuracy, continuity, units, and associated metadata. For some of these, a degree of self-checking is possible, applying simple algorithms to the data stream to detect presence and bounds, with alarms to alert the operator if these are transgressed. In other cases, such as the change in drag and torque with depth, the stream must be checked against a trend, called a pseudolog, determined from the physics. These calculations are performed by "smart agents" directly in real time on the wellsite information transfer standard markup language (WITSML) data feed from the rig. The paper describes the early work in developing smart agents to address data quality and structure of the associated tool kit that can be used to construct more- complex agents from a wider selection of data sources, including system-generated ones. The computational resources required are also discussed.

The increase in digital data and skills shortage makes manual assurance of all the data streams neither practical nor cost effective. Because current applications are not tolerant of errors and omissions, a step change in data quality is needed if more-automated workflows are to be achieved. Greater assurance of the data at source and an improved understanding of the workflows will help.
Hybrid Bits Offer Distinct Advantages in Selected Roller-Cone and PDC-Bit Applications
Authors: Pessier Rolf , Damschen Michael
Published: March 2011

Early concepts of hybrid drill bits go back to the 1930s, but the development of a viable drilling tool has become feasible only with the recent advances in polycrystalline-diamond-compact (PDC) cutter technology. This paper describes a new generation of hybrid bits that is based on proven PDC-bit designs with rolling cutters on the periphery of the bit. Laboratory and field results will be presented that compare the performance of hybrid bits with that of conventional PDC and roller-cone bits. A hybrid bit can drill shale and other plastically behaving formations two to four times faster than a roller cone bit by being more aggressive and efficient. The penetration rate of a hybrid bit responds linearly to revolutions per minute (RPM) unlike that of roller-cone bits, which exhibit an exponential response with an exponent of less than unity. In other words, the hybrid bit will drill significantly faster than a comparable roller-cone bit in motor applications. Another benefit is the effect of the rolling cutters on the bit dynamics. Compared with conventional PDC bits, torsional oscillations are as much as 50% lower, and stick/slip is reduced at low RPM and whirl at high RPM. This gives the hybrid bit a wider operating window and greatly improves toolface control in directional drilling. The hybrid drill bit is a highly application-specific drill bit aimed at (1) traditional roller-cone applications that are rate-of-penetration (ROP) limited, (2) large-diameter PDC-bit and roller-cone-bit applications that are torque or weight-on-bit (WOB) limited, (3) highly interbedded formations where high torque fluctuations can cause premature failures and limit the mean operating torque, and (4) motor and/or directional applications where a higher ROP and better build rates and toolface control are desired.
The Influence of Salt Concentration in Injected Water on Low-Frequency Electrical-Heating-Assisted Bitumen Recovery
Authors: Bogdanov I.I.. I. , Torres J.A.. A. , Akhlaghi H.A.. A. , Kamp A.M.. M.
Published: March 2011

Steam injection is often not a good alternative for oil recovery from shallow bitumen reservoirs. For instance, the thin caprock creates the danger of steam breakthrough. For deeper reservoirs, the heat losses from injection wells may be prohibitive. A technology that may be better suited is oil recovery aided by low-frequency electrical heating of the reservoir. This technology, well known for environmental remedial applications, has been field tried recently, yielding promising results. The process uses electric conductivity of connate water to propagate an alternating current between electrodes, inducing the Joule heating of the reservoir. An associated problem is the appearance of hot spots around the electrodes that may be relieved by water circulation. However, the water circulation may have a significant effect on the heating process because the electric conductivity of the circulated water depends on its salt content.

To find out the influence of salt concentration on process efficiency, we have studied the process of salt-water recirculation around an electrode using numerical simulation. The physical properties and operational data for Athabasca bitumen have been collected from the literature. The model built with Computer Modelling Group's STARS simulator and tested first with available analytical solutions has been validated, and the proper choice of the underlying grid and numerical tuning parameters has been verified. The process was also simulated at field scale for a common pattern of electrodes and production wells. The salt penetrated into the reservoir, far beyond the major water-circulation zone around the electrodes. This process increases the electric conductivity in a large region between electrodes, which improves the heating of the reservoir. The single-electrode simulation studies using different tools yielded similar results for a simple problem. More-complex (and more-realistic) field-scale simulations show that adding salt enhances the oil production. In practice, an upper concentration limit may be given by corrosion problems at the electrodes.

The reservoir simulation of bitumen recovery assisted by low-frequency heating is a challenging multiphysics problem. The understanding of the influence of salt concentration on the circulated water provided by this work is an important key in process-design considerations.
Deployment, Monitoring, and Optimization of a Scale Inhibitor and Associated Corrosion Inhibitor Within a Deepwater Subsea Facility Offshore Brazil
Authors: Jordan M.. , Linares-Samaniego S.. , Afonso M. Santos
Published: March 2011

This paper presents field results and lessons learned from a floating production, storage, and offloading (FPSO) vessel, offshore Brazil where a scale and combination scale inhibitor (SI) and corrosion inhibitor (Cl) has been applied subsea to control both the deposition of scale and associated corrosion.

The paper outlines the problems encountered when the initial scale-inhibitor formulation was deployed in the field related to materials compatibility with the subsea manifold and the steps taken to develop and monitor an improved formulation. Problems that can affect product application in a subsea environment—including deposition of suspended solids within the chemical, hydrate formation, and incompatibility of the chemicals with umbilical material and produced fluid—will all be addressed. The laboratory methods used to select the product along with measurement methods used in the field are also discussed. The validation of the laboratory selection methods in the field required the development of a monitoring program to establish baseline control and to assess the degree of protection from scale deposition and corrosion across the process.

The use of novel real-time scale monitoring, as well as water-chemistry tracking, proved vital to understanding the efficiency of flow assurance within the processes and understanding how treatment rates of the scale inhibitor and corrosion inhibitor could be optimized.

This paper will outline in detail the particular issues associated with chemical injection to a subsea facility, many of which are currently being developed in the Gulf of Mexico, offshore West Africa, and offshore Brazil. This case study is a good example of lessons learned and sharing of best practices from another oil basin.
Improved Polymer-Flood Management Using Streamlines
Authors: Clemens Torsten , Abdev Joseph , Thiele Marco R.
Published: March 2011

Recently, modern streamline (SL) simulation has been extended to polymer flooding. In this work, we extend the applicability of SL simulation further for efficient management of polymer-injection projects. We first present our method and then demonstrate the applicability of our approach using a Romanian field as an example. Owing to the price of polymers, an optimized injection strategy is crucial to minimize costs, maximize sweep, and thereby ensure profitability of a polymer flood. The biggest advantage of SL simulation in comparison to traditional finite-difference (FD) modeling is that polymer floods can be optimized on an individual-well-pattern basis. By being able to plot cumulative oil produced as a function of polymer injected for an individual well pattern, underperforming patterns—injectors and associated offset producers—can be indentified easily and rates, concentration, and slug size can be modified to improve the local efficiency of the flood. In this paper, we introduced a new metric—the polymer-injection efficiency as a function of time for each pattern—and we show how it is central to containing costs while improving oil recovery. We demonstrate our management method on a Romanian oil field that has been operating since 1961 with 21 injectors and 136 producers. We show that the utility factor (UF) (mass of polymers injected per volume of incremental oil produced) can be reduced while sustaining oil recovery. We conclude with a discussion on SL simulation as an enabling technology for reservoir-management decisions for polymer floods.
Numerical Investigation of Potential Injection Strategies To Reduce Shale Barrier Impacts on SAGD Process
Authors: Li Weiqiang , Mamora Daulat , Li Yamin , Qiu Fangda
Published: March 2011

It is well known that shale barriers significantly reduce steam-assisted gravity drainage (SAGD) performance in Athabasca fields. An extensive 2D simulation study shows that the flow resistance at the end of shale barriers and the extra heat absorbed by the residual water inside the unproductive shale barrier are the main reasons for the shale barrier effects. Long continuous shale barriers located vertically above or near the wellbore delay production performance significantly.

We investigated potential strategies, including solvent coinjection, top injector application, or a combination of both, to reduce the shale barrier impacts. Solvent in the vapour phase can pass through the narrow flow path at the end of a shale barrier. Meanwhile, because the phase condenses from vapour to liquid, solvent efficiently reduces the flow resistance of the shale barrier. Liquid solvent coinjection can accelerate the near-wellbore flow and reduce the residual oil saturation at the wellbore vicinity. Coinjecting a multicomponent solvent can flush out the oil at different areas with different drainage mechanisms from vaporized and liquid components. Additional injector application at the top of the reservoir results in only marginal improvement.
Prediction of Frictional Pressure Gradient in Horizontal Oil/Water Dispersion Flow
Authors: Vielma Jany Carolina , Shoham Ovadia , Mohan Ram S. , Gomez Luis E.
Published: March 2011

A novel model has been developed for the prediction of frictional pressure gradient in unstable turbulent oil/water dispersion flow in horizontal pipes. This model uses the friction-factor approach, based on the law of the wall, to predict the pressure gradient. Modification of both the von Karman coefficient κ' and the parameter B' have been carried out in the law of the wall to include the effect of the dispersed phase—namely, the dispersed-phase volume fraction and the characteristic-droplet-size diameters. The developed model applies to both dilute and dense flows, covering the entire range of water cuts. Model predictions have been compared with a comprehensive experimental database collected from literature, resulting in an absolute average error of 9.6%. Also, the comparisons demonstrate that the developed model properly represents the physical phenomena exhibited in unstable turbulent oil/water dispersions. These include drag reduction, increase in frictional pressure gradient with increasing dispersed-phase volume fraction, and the peak in the frictional pressure gradient at the oil/water phase-inversion region.
Optimum Utilization of Edge Pairs
Authors: Miller Karl A. , Xiao Yi
Published: March 2011

Nearly all of Husky's SAGD projects in the Lloydminster, Saskatchewan area are in reservoirs with bottomwater. While operating several projects in this region, Husky observed that in some reservoir settings, the outer SAGD pair had significantly decreased performance compared to inner SAGD pairs. When the outer pair was shut in to improve overall pilot performance, the performance of the now exposed adjacent pair rapidly decreased.

It was hypothesized that operating the edge pairs protected inner pairs from the detrimental effects of bottomwater. Numerical simulation runs have confirmed this behaviour. The conclusions reached are that in many bottomwater settings, poorer-performing edge SAGD pairs protect and preserve the performance of inner SAGD pairs; and this should be taken into consideration during facilities' design, development of operational strategy, and production forecasting.
Changes in Student Motivation During Online Learning
Authors: Kim Kyong-Jee , Frick Theodore W.
Published: March 2011

Self-directed e-learning (SDEL) refers to electronic learning environments where there are often no peer learners or instructors regularly available. Past studies suggest that lack of time and lack of motivation are primary causes of learner attrition in online settings. However, little is known about what influences motivational change during SDEL. We surveyed 368 adult learners from both higher education and corporate settings who had used commercial SDEL products. Results from stepwise regression analysis indicated that the best predictors of motivation to begin SDEL were perceived relevance, reported technology competence, and age. The best predictors of motivation during SDEL were perceived quality of instruction and learning (e-learning is right for me) and motivation to begin. Motivation during SDEL was the best predictor of positive change in motivation, which in turn predicted learner satisfaction with SDEL. Instructional design principles for sustaining learner motivation in SDEL are identified from the findings of the present study.
Technology Integration Through Professional Learning Community
Authors: Cifuentes Lauren , Maxwell Gerri , Bulu Sanser
Published: March 2011

We describe efforts to build a learning community to support technology integration in three rural school districts and the contributions of various program strategies toward teacher growth. The Stages of Adoption Inventory, classroom observations, the Questionnaire for Technology Integration, interviews, STAR evaluation surveys, a survey of teachers' perceptions regarding the impact of the project on student achievement, and force field analysis revealed the positive impacts, including a shift toward student-centered learning, and limitations of those strategies. This study contributes to the learning theory regarding professional learning communities and technology integration by demonstrating the power of learning community and support for Roblyer's technology integration model.
Professional Growth Through Online Mentoring: A Study of Mathematics Mentor Teachers
Authors: McAleer Deanna , Bangert Art
Published: March 2011

This article explores how patterns of engagement and program design impact professional learning and development of mathematics mentor teachers as they participate in an asynchronous mentoring program, e-Mentoring for Student Success (eMSS). In specific, this study: 1) sought to determine if activity level was related to mentors' perceived professional growth; 2) explored the effect of program design on a mentors' perceived growth and over what domains this growth occurred; and 3) sought evidence of the mentor teachers' professional growth in the online dialogue. Results of the study indicate that a mentor's activity level does positively relate to perceived professional growth and that much growth occurs “behind the scenes” and may not be evident in participants' posts. The mentor mathematics teachers reported growth in all assessed domains, particularity in their reflective practices, and attributed their growth to participation in the Content Forum discussion areas more than the other assessed areas.
The Global Economic Crisis and Developing Countries: Effects, Responses and Options for Sustainable Recovery
Authors: Naudé Wim
Published: March 2011

Following the financial crisis that broke in the U.S. and other Western economies in late 2008 and lead to a global economic crisis, there is now worldwide concern about its effect on the developing countries. One year into the crisis, this paper discusses its unfolding during 2008‐2009 and traces its effect on developing countries. The paper takes note of the greater resilience of man developing countries this time around (as opposed to previous global recessions) and discusses the global responses to the crisis during 2008 and 2009, concluding that the weak response of the rich world to help developing countries may contribute to a paradigm shift in international development.
Racial Disparities in Poverty Status among Families of Individuals with Spinal Cord Injury
Authors: Dismuke Clara E , Krause James S , Terza Joseph V
Published: March 2011

Background: Poverty rates among individuals with disabilities are much higher than for the general U.S. population. However, little is known about the likelihood of poverty among families of those with Spinal Cord Injury (SCI). Objectives: Examine the association of pre‐injury and post‐injury education with the likelihood of familial poverty by race/ethnicity for 1,405 adults between the ages of 18 and 64 who had a traumatic spinal cord injury at least one year prior to the study interview (2003). Methods: Based on reported household income in 2002, familial poverty status of individuals with a SCI was determined based on United States (U.S.) Federal Poverty Guidelines during the year of reported income. Based on a conceptual model of human capital loss and acquisition, a model of the likelihood of poverty was estimated separately for Non‐Hispanic White and Black/Hispanic families. Results: 18.33% of Non‐Hispanic White families and 42.35% of Black/Hispanic families with a member having SCI were found to be living below the poverty level. Bachelor's degree education attainment was the most important factor and was significantly associated with a lower likelihood of familial poverty for Non‐Hispanic White (‐0.10) and for Black/Hispanic families (‐0.27). Conclusions: We have proposed that the Social Security Administration grant presumptive disability eligibility for SCI, guarantee continued medical benefits after employment and pilot an online college degree reimbursement plan to reduce poverty among families of individuals with SCI.
The History and Politics of Health Care in America: From the Progressive Era to the Patient Protection and Affordable Care Act
Authors: Skidmore Max J.
Published: March 2011

Max J. Skidmore surveys the history and politics of the development of health care delivery in the United States, and reviews Health Care Reform and American Politics: What Everyone Needs to Know, by Lawrence R. Jacobs and Theda Skocpol. This study, by two prominent scholars of health care in America, is a detailed analysis of the process that led to adoption of the Patient Protection and Affordable Care Act of 2010, and of the details of the Act.
Review of Understanding The Social Security Act: The Foundation of Social Welfare for America in the Twenty‐First Century
Authors: Brazelton W. Robert
Published: March 2011

Dr. W. Robert Brazelton divides this work into three parts and offers an analytical assessment of its value within the American social welfare realm.
In Response to Professor Dobelstein's Respectful Critique of A Tale of Three Commissions: The Good, the Bad, and the Ugly
Authors: Kingson Eric
Published: March 2011

Eric R. Kingson responds to Andrew Dobelstein's position with regard to “A Tale of Three Commissions: The Good, The Bad, and the Ugly,” which was published in Poverty & Public Policy Volume 2, Issue 3.
The Current Battle in the Long‐Running War Over Social Security
Authors: Altman Nancy J
Published: March 2011

Nancy J. Altman responds to Andrew Dobelstein's position with regard to “A Tale of Three Commissions: The Good, The Bad, and the Ugly,” which was published in Poverty & Public Policy Volume 2, Issue 3.
Poverty: Israel's Greatest Threat
Authors: Frankel Jackie
Published: March 2011

Jackie Frankel, a fund raising coordinator for the Jaffa Institute, a Non‐Profit Organization in the Tel Aviv‐Jaffa area of Israel, offers this op‐ed piece in which she asserts that poverty, and not the Israeli/Palestinian conflict, is the greatest threat to Israel and calls on that country's government to make sweeping changes in order to supplant these concerns.
Editor's Letter
Authors: Skidmore Max J.
Published: March 2011

Editor‐in‐Chief Max J. Skidmore shares his introductory thoughts about the first issue of PPP's Third volume.
The problem of corporal punishment of children and role of experts in its solving
Authors: Srna Jelena , Stevanovic Ivana
Published: March 2011

Corporal punishment of children is a serious social problem and as such more
and more recognized around the world and in recent years in our environment
as well. The aim of this paper is to highlight the current contribution of
experts of different profiles to the perception and understanding of these
issues, as well as possible directions for their further, more active,
professional and socially engaged involvement in its solving.
Legal protection of child victims of sexual violence in Serbia
Authors: Tanjevic Natasa
Published: March 2011

Violence against children is not a new phenomenon. In this regard, the forms
in which it occurs as well as methods that allow it to have taken on an
astonishing scale worldwide. Certainly, in this sense, sexual violence leaves
the hardest and most complicated effects on the victim. Bearing in mind the
complexity of sexual violence against children in the work we are going
through an analysis of the criminalization of certain creatures that protect
the sexual integrity of children from various forms of sexual violence, and
analysis of his position of criminal attempt to answer the question of how
the criminal justice system of protection that exists in our country can
respond to this case.
Public attitudes toward child sexual abuse in Serbia
Authors: Petkovic Nikola , Djordjevic Mirjana , Balos Vasilije
Published: March 2011

Bringing public attention to the topic of sexual harrassment of children in
Serbia during 2010 as well as the series of arrests of persons suspected of
?peadophilia?, encouraged authors to conduct a study which will analyze the
public opinion about sexual child abuse. The study is conducted using a
sample of 804 people in three comparative categories, laymans, professionals
who work with potential victims and sexual abusers, and students of the
Belgrade university. Besides assessing how well the persons in question are
informed and assessing their concrete knowledge, the authors will evaluate
standpoints in five dimensions questioning the perception of the term child,
the term abuser and cause often abusing, stands regarding punative measures
for sexual delinquents, stands regarding victimization of children with
developmental disorders and finally the perception of the child regarding the
abuse.
Self-reported pain associated with the use of intermaxillary elastics compared to pain experienced after initial archwire placement
Authors: Tuncer Zeynep , Ozsoy Faik Serhat , Polat-Ozsoy Omur
Published: March 2011

Objective:

To evaluate the pain during the use of intermaxillary elastics and to compare it with that of initial archwire placement.

Materials and Methods:

Sixteen orthodontic patients who underwent initial bonding (7 girls, 13 boys; mean age 16.75 ± 2.61 years) and 19 patients who would be using intermaxillary elastics for the first time (13 girls, 7 boys; mean age 16.21 ± 3.01 years) were enrolled in this prospective study. A visual analog scale form was given to each patient to measure the pain levels, and these were measured by the same investigator using a digital caliper. Data were evaluated using Mann Whitney U-test.

Results:

The pain started to increase 2 hours after the application of elastics. The highest levels were achieved at the sixth hour and the same night. The pain levels started to decrease at day 2. Although the pain levels of the elastic group started to decrease after the second day, the pain levels of the initial bonding group were still significantly high.

Conclusions:

Intermaxillary elastics cause similar amounts of pain compared with initial archwire placement, but the pain of the elastics did not last as long as the pain felt after initial bonding.
Nasal obstruction causes a decrease in lip-closing force
Authors: Sabashi Kishio , Washino Kaei , Saitoh Issei , Yamasaki Youichi , Kawabata Atsushi , Mukai Yousuke , Kitai Noriyuki
Published: March 2011

Objective:

To investigate the relationship between nasal obstruction and lip-closing force.

Materials and Methods:

Nasal airway resistance and lip-closing force measures were recorded for 54 Japanese females. The subjects were classified into normal and nasal obstruction groups according to nasal airway resistance values. Differences between the normal and nasal obstruction groups in lip-closing force were tested statistically. Correlation coefficients were calculated between the measures for the normal and nasal obstruction groups.

Results:

Lip-closing force for the nasal obstruction group was significantly less than for the normal group (P < .05). In the normal group, nasal airway resistance did not correlate with lip-closing force, while in the nasal obstruction group a significant negative correlation was found between nasal airway resistance and lip-closing force (P < .05).

Conclusions:

Nasal obstruction is associated with a decrease in lip-closing force. When the severity of nasal obstruction reaches a certain level, the lip-closing force is weakened.