bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experience of Using the Foamed Cement Technology for Difficult Lost Circulation Control
Authors: Bikmukhametov A. , Iliasov S. , Okromelidze G. , Garshina O. , Chugaeva O. 
Published: April 2016

Abstract
Experience of using the foamed cement technology for difficult lost circulation control at Perm Krai fields (Russia) was summarized. Properties of foamed cement material and results of its applications were shown. Effectiveness of the foamed cement technology for difficult lost circulation control was estimated. Geological factors, which decrease effectiveness of the foamed cement lost circulation control technology, were investigated. Different techniques of foaming base material were investigated and the optimal conditions for the application of these techniques were identified and described. The effect of applying spacers on the technology efficiency was analyzed. Oil-base mud environments were investigated especially.
The foamed cement material is intended for a lost circulation control: –for rocks of any lithology;–for rocks with fractures and secondary cavities formed along fractures, with effective disclosure to 2 cm;–for the intensity loss of circulation to 100 m3/h;–for the low static level of the drilling fluid;–for BHST from 0 to 40 °C;–for the vertical depth of the lost circulation zone up to 3000 m;
The foamed cement material is not intended for a lost circulation control in the high intensity flow of brine waters.
Effectiveness of the foamed cement technology for lost circulation control is 80%. The density of the foamed cement material can be adjusted within a wide range, but some geological conditions require application of the same material without foaming. The optimal technique for foaming base cement material in the field is the ejecting pressurized air or nitrogen. The most efficiency of application the foamed cement lost circulation control technology is with using certain volumes special spacers before and after main material.
The foamed cement material has several important advantages: adjustable density, energy of pressurized gas and adjustable thixotropy (time of coagulation structure formation).
Field Scale Injection Efficiency Optimization Based On Combined Analysis Of Finite Difference And Streamline Simulation: Case study
Authors: Algdamsi H. A. , Amtereg A. A. , Agnia A. 
Published: April 2016

Abstract
Within the framework of reservoir management streamline simulation finds one of its typical applications as one of the effective tool to improve gasflood and pressure maintance performance. Streamlines provide an instantaneous visualization of flow patterns as a function of reservoir heterogeneity. Additionally they also provide an estimation of the well allocation factors (WAFs) between injection and producing wells. Such information is a default outcome from streamline models but not from finite difference simulation and it is particularly useful in optimizing and balancing well patterns and field scale injection rates. However finite difference simulation has the advantage of implicitly taking into account all the details of an existing simulation model, especially advanced well management strategy. In this paper we demonstrate a straightforward workflow for optimizing injection rate based on a comprehensive analysis of two key parameters: injector efficiency (IE) metric and WAFs. The optimization approach consists of a three step procedure starting with streamline analysis using commercial software which combines the power of finite difference simulators and streamline technology to derive streamlines from the flux field generated by the finite difference simulation that represent a snapshot of the flow pattern within the reservoir, well drainage region information and fluid allocation changes with the flood progression. Second using a simple analytical calculation to compute weighting factors for injection/production rate targets from a derived ranking of the wells (IE). Finally reallocation of injected fluid volumes from low-efficiency to high-efficiency injectors improves volumetric displacement and sweep efficiency in the less swept areas of the reservoir. The application of this workflow is demonstrated with a real-field example of an onshore tight sandstone reservoir where the pattern balancing has led to incremental production of 3.5 % over the 5 year forecast in which the IE average of the field is the benchmark for whether more or less injection volumes were required while obeying facility constraints.
Challenges and Rewards in the Resource Evaluation and Flow Modeling of Transition Zone
Authors: Masoudi Rahim , Altunbay Michael Mehmet , Karkooti Hooman , Hajizadeh Alireza , Makentharan Kokulananda , Salmi Norbashinatun 
Published: April 2016

Abstract
Advances in well and completion design together with higher oil prices and increased depletion trends of maturing assets have been the driving force behind developing marginal fields. The remaining hydrocarbons in marginal accumulations mostly located in the transition zones. There are numerous examples of water-free oil production from zones that are interpreted as transition zones from logs. These observations have caused debates over the concept, definition and potential of capillary-transition-zone (CTZ), especially for Low Resistivity reservoirs with high-clay content, where the distinction between the capillary-driven and apparent transition zone (ATZ) is not clear. Apart from environmental effects on Wireline logs, there may be other artefacts affecting the ATZ characterization such as laboratory procedures, wettability variation and hysteresis effect, water salinity changes, rock type and mineralogy.
The complications in detection of CTZ, resource estimation and modelling flow dynamics in these reservoirs, hugely impact the development potential of these projects. The reliable resource assessment and flow dynamics predictions as well as the understanding of the mobile/immobile oil/water saturation and distributions and avoiding early water-breakthroughs are key components for the success of such developments.
This study elaborates on integrated log interpretation, rock characterization/mineralogy, and digital core analysis for generating and up-scaling relative permeability and capillary pressure data, production tests and SCAL data to identify and characterize the CTZ rather than relying on ATZ from visual observation of logs. Identification of ATZ (with water-free oil production potential) versus CTZ (with two phase flow) is a key question to be answered before the development. The paper demonstrates an extensive elaboration of the transition zone (TZ) concept and the developed workflow and guidelines in the resource/reserve assessment, flow modelling and production predictions in the CTZ intervals.
Going to the Root of Incidents with Structured Approach
Authors: Al Saadi Jamal , Duguay Alexandra , AL Saabri Hassan 
Published: April 2016

Abstract
Learning from incident is a key process to ensure that risk of recurrence is reduced or even eliminated.
At TOTAL ABK, one mean for learning and improve from incident is to perform a Cause Tree Analysis (CTA), ie a structured approach to identifying the factors that resulted in the incident. It helps identify what behaviors, actions/inactions, or conditions that need to be changed to prevent recurrence of similar harmful outcomes. In order words, it is a method used to determine what, how and most importantly why an incident occurred.
It is therefore easily understandable that the outcome of CTA is highly dependent on the performer's expertise, experience and overall management of the investigation process. When reviewing past CTAs, a difference was witnessed depending on who led the CTA and often this difference would foster a bias towards always requesting the same CTA leader.
In an effort to improve and standardize its incident investigation and cause tree analysis, TOTAL ABK assessed various tools available in the market. This review aimed at understanding whether available third-party tools will help to improve both in the effective investigation of incidents and in the determination of true root causes.
Major Accidents and their impact - The EU Directive for Offshore Safety
Authors: Pat-El I. E. , Meijlink L. , Mol P. 
Published: April 2016

Abstract
In the oil and gas industry several major accidents caused an impact that resulted in new legislation for improvement of safety. These are Piper Alpha, BP Texas refinery, Buncefield terminal, BP Macondo. Piper Alpha resulted in the extensive Safety Case regulations as implemented in the North Sea countries with offshore oil & gas activities (Norway, UK, The Netherlands). The Macondo accident led to the European Directive that is in fact a further development of the Safety Case regulations. BP Texas refinery showed the vulnerability of construction workers on site. The accident introduced more stringent codes and standards for safety distances and regulations requiring approval for siting of temporary accommodation on site. The accident also revealed the requirement for additional performance indicators for process safety as these were only developed for occupational safety. The Buncefield fire confirmed the requirement for more structured management (with KPI's) of process safety in the complete life cycle of the plant. In addition the accident showed that explosion effects can be much more severe than was assumed for a normal oil terminal. This paper evaluates the impact of these accidents and indicated by examples how this has influenced the legislation and regulation. After the latest major accident, the BP Macondo Deepwater Horizon accident, the European Parliament and Council approved in June 2013 a new EU Directive on safety of offshore oil and gas operations. The EU countries have 2 years' time to transpose this Directive into national legislation. The impact on the oil and gas industry will be different dependent on the country in which the operations take place. The Directive introduces the requirement of major hazards reports and emergency response plans, not only for accidents with safety but also with environmental impact. Matters such as competence of authorities, licensing, third party independent verifications, and liability are addressed. This paper evaluates the potential impact of the Directive and indicates possible actions oil & gas companies can take to anticipate on these impacts.
Improving ESP Design Through Advanced Measurement and Unsteady Simulation of Internal Flows Within Stages
Authors: Dusting J.. , Dupoiron M.. , Monmont F.. 
Published: April 2016

Abstract
As a result of the trend towards more difficult operating environments, there is an increasing demand for improved ESP performance and reliability under a range of flow conditions. This poses significant challenges for pump designers, however stage design can benefit greatly from improved understanding, and consequently modelling, of the internal flow behaviour. To some extent this has been successfully achieved, at least for steady, single-phase conditions, through the use of commercial Computational Fluid Dynamics (CFD) packages. However, the complexity of the flows in realistic, unsteady conditions means that more advanced CFD and experimental tools are required for accurate flow characterisation. Here, we will demonstrate how laboratory-based, optical measurement techniques such as Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) provide new insight into flow behaviour under a range of operating conditions. We also present examples of highly resolved, quantitative velocity fields acquired within impeller and diffuser passages. This information provides improved understanding of the fluid mechanics and can be used directly for design purposes or for validation of CFD models. In addition, unsteady flow computations performed using in-house Large Eddy Simulation (LES), adaptive meshing and immersed boundary methods will be presented. Finally, we will summarise the potential benefits of these new methodologies in the context of pump design.
Co-digestion of press liquids of source-sorted municipal organic waste in anaerobic sludge treatment of municipal wastewater treatment plants
Authors: Effenberger Johannes , Jahn Lydia , Kuehn Volker 
Published: April 2016

Abstract
This paper describes a semi-continuous laboratory-scale investigation of a potential co-substrate for mesophilic anaerobic sludge digestion in a municipal wastewater treatment plant. A feed liquid produced from source-sorted municipal organic waste by pretreatment with a screw press was subjected to the investigation. Quantities produced in press trials as well as the composition of the feed liquid are presented. Mass balances for N, P and chemical oxygen demand are given in order to verify the methane production of the feed liquid in co-digestion with sewage sludge at mesophilic conditions. Hydraulic retention time of the reactors were 14.7 to 16 d and organic loading rates were 1.5 to 2.7 kg volatile solids (VS) per cubic metre per day. The pretreatment by screw press is compared to the production of feed liquids with pulper-based pretreatment processes. While the addition of the feed liquid increased methane production by about 345 ml CH4/g VSin, total solids of the feed liquid were reduced to about 63%. With respect to co-digestion at municipal wastewater treatment plants, several risks associated with the investigated feed liquid are outlined.
Evaluation of the energetic potential of sewage sludge by characterization of its organic composition
Authors: Schaum C. , Lensch D. , Cornel P. 
Published: April 2016

AbstractThe composition of sewage sludge and, thus, its energetic potential is influenced by wastewater and wastewater treatment processes. Higher or lower heating values (HHV or LHV) are decisive factors for the incineration/gasification/pyrolysis of sewage sludge. The HHV is analyzed with a bomb calorimeter and converted to the LHV. It is also possible to calculate the heating value via chemical oxygen demand (COD), total volatile solids (TVS), and elemental composition. Calculating the LHV via the COD provides a suitable method. In contrast, the correlation of the HHV or LHV with the TVS is limited. One prerequisite here is a constant specific energy density; this was given with the types of sewage sludge (primary, surplus/excess, and digested sludge) investigated. If the energy density is not comparable with sewage sludge, for instance with the co-substrate (bio-waste, grease, etc.), the estimation of the heating value using TVS will fail. When calculating the HHV or LHV via the elemental composition, one has to consider the validity of the coefficients of the calculation equation. Depending on the organic composition, it might be necessary to adjust the coefficients, e.g. when adding co-substrates.
Metabolism, Protein Binding, and Renal Clearance of Microbiota–Derived p-Cresol in Patients with CKD
Authors: Poesen Ruben , Evenepoel Pieter , de Loor Henriette , Kuypers Dirk , Augustijns Patrick , Meijers Björn 
Published: April 2016

Background and objectives
Colonic microbial metabolism substantially contributes to uremic retention solutes in CKD. p-Cresyl sulfate is the main representative of this group of solutes, relating to adverse outcomes. Other than sulfate conjugation, p-cresol is subjected to endogenous glucuronide conjugation. Whether the balance between sulfate and glucuronide conjugation is relevant in CKD is unexplored.

Design, setting, participants, & measurements
We prospectively followed 488 patients with CKD stages 1–5 (enrollment between November of 2005 and September of 2006; follow-up until December of 2010). Serum and urine levels of p-cresyl sulfate and p-cresyl glucuronide were measured using liquid chromatography-mass spectrometry. Total amount of microbial p-cresol was calculated by the sum of serum p–cresyl sulfate and p-cresyl glucuronide. Outcome analysis was performed for mortality and cardiovascular disease.

Results
Serum p–cresyl sulfate was a median of 193.0-fold (interquartile range, 121.1–296.6) higher than serum p–cresyl glucuronide, with a significant correlation between eGFR and proportion of serum p–cresyl sulfate to glucuronide (rho=0.23; P=0.001). There was also a significant correlation between eGFR and proportion of 24-hour urinary excretion of p-cresyl sulfate to glucuronide (rho=0.32; P<0.001). Higher serum p–cresol and lower proportion of serum p–cresyl sulfate to glucuronide were jointly and significantly associated with mortality (hazard ratio per SD higher, 1.58; 95% confidence interval, 1.10 to 2.29; P=0.01 and hazard ratio, 0.65; 95% confidence interval, 0.47 to 0.89; P<0.01, respectively) and cardiovascular disease (hazard ratio, 1.68; 95% confidence interval, 1.27 to 2.22; P<0.001 and hazard ratio, 0.55; 95% confidence interval, 0.42 to 0.72; P<0.001, respectively) after adjustment for eGFR, Framingham risk factors, mineral bone metabolism markers, C-reactive protein, and albumin.

Conclusions

p-Cresol shows a preponderance of sulfate conjugation, although a relatively diminished sulfotransferase activity can be suggested in patients with advanced CKD. Along with total p–cresol burden, a relative shift from sulfate to glucuronide conjugation is independently associated with mortality and cardiovascular disease, warranting increased focus to the dynamic interplay between microbial and endogenous metabolism.
In–Center Nutrition Practices of Clinics within a Large Hemodialysis Provider in the United States
Authors: Benner Debbie , Burgess Mary , Stasios Maria , Brosch Becky , Wilund Ken , Shen Sa , Kistler Brandon 
Published: April 2016

Background and objectives
Eating during hemodialysis treatment remains a controversial topic. It is perceived that more restrictive practices in the United States contribute to poorer nutritional status and elevated mortality compared with some other parts of the world. However, in–center food practices in the United States have not been previously described.

Design, setting, participants, & measurements
In 2011, we conducted a survey of clinic practices and clinician (dietitian, facility administrator, and medical director) opinions related to in–center food consumption within a large dialysis organization. After the initial survey, we provided clinicians with educational materials about eating during treatment. In 2014, we performed a follow-up survey. Differences in practices and opinions were analyzed using chi-squared tests and logistic regression.

Results
In 2011, 343 of 1199 clinics (28.6%) did not allow eating during treatment, 222 clinics (18.2%) did not allow drinking during treatment, and 19 clinics (1.6%) did not allow eating at the facility before or after treatment. In 2014, the proportion of clinics that did not allow eating during treatment had declined to 22.6% (321 of 1422 clinics), a significant shift in practice (P<0.001). Among the 178 (6.8%) clinics that self-reported that eating was “more allowed” in 2014, the main reason for this shift was an increased focus on nutritional status. Among clinicians, a higher percentage encouraged eating during treatment (53.1% versus 37.4%; P<0.05), and facility administrators and medical directors were less concerned about the seven reasons commonly cited for restricting eating during treatment in 2014 compared with 2011 (P<0.05 for all).

Conclusions
We found that 28.6% and 22.6% of hemodialysis clinics within the United States restricted eating during treatment in 2011 and 2014, respectively, a rate more than double that found in an international cohort on which we previously published. However, practices and clinician opinions are shifting toward allowing patients to eat. Additional research is warranted to understand the effect that these practices have on patient outcomes and outline best practices.
Proximal Hamstring Tendinopathy: Clinical Aspects of Assessment and Management
Authors: Goom Thomas S.H. , Malliaras Peter , Reiman Michael P. , Purdam Craig R. 
Published: April 2016

Synopsis Proximal hamstring tendinopathy (PHT) typically manifests as deep buttock pain at the hamstring common origin. Both athletic and nonathletic populations are affected by PHT. Pain and dysfunction are often long-standing and limit sporting and daily functions. There is limited evidence regarding diagnosis, assessment, and management; for example, there are no randomized controlled trials investigating rehabilitation of PHT. Some of the principles of management established in, for example, Achilles and patellar tendinopathy would appear to apply to PHT but are not as well documented. This narrative review and commentary will highlight clinical aspects of assessment and management of PHT, drawing on the available evidence and current principles of managing painful tendinopathy. The management outline presented aims to guide clinicians as well as future research. J Orthop Sports Phys Ther 2016;46(6):483–493. Epub 15 Apr 2016. doi:10.2519/jospt.2016.5986
A DEEP SEARCH FOR PROMPT RADIO EMISSION FROM THERMONUCLEAR SUPERNOVAE WITH THE VERY LARGE ARRAY
Authors: Chomiuk Laura , Soderberg Alicia M. , Chevalier Roger A. , Bruzewski Seth , Foley Ryan J. , Parrent Jerod , Strader Jay , Badenes Carles , Fransson Claes , Kamble Atish , Margutti Raffaella , Rupen Michael P. , Simon Joshua D. 
Published: April 2016

ABSTRACT
Searches for circumstellar material around Type Ia supernovae (SNe Ia) are some of the most powerful tests of the nature of SN Ia progenitors, and radio observations provide a particularly sensitive probe of this material. Here, we report radio observations for SNe Ia and their lower-luminosity thermonuclear cousins. We present the largest, most sensitive, and spectroscopically diverse study of prompt (

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t
≲
1

years) radio observations of 85 thermonuclear SNe, including 25 obtained by our team with the unprecedented depth of the Karl G. Jansky Very Large Array. With these observations, SN 2012cg joins SN 2011fe and SN 2014J as an SN Ia with remarkably deep radio limits and excellent temporal coverage (six epochs, spanning 5–216 days after explosion, implying

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, assuming

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). All observations yield non-detections, placing strong constraints on the presence of circumstellar material. We present analytical models for the temporal and spectral evolution of prompt radio emission from thermonuclear SNe as expected from interaction with either wind-stratified or uniform density media. These models allow us to constrain the progenitor mass loss rates, with limits in the range of

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