bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Scaling and Corrosion Inhibitors on the Static Adsorption of an Anionic Surfactant on a Carbonate Rock
Authors: Gutierrez Mary Ellen , Gaona Silvia Juliana , Calvete Fernando Enrique , Botett Jesus Alberto , Ferrari Jean Vicente
Published: March 2019

About half of the world's oil reserves are in carbonate reservoirs, and most of these formations are mixed-wet or oil-wet and fractured, with extremely heterogeneous porosities and permeabilities. Implementation of enhanced oil recovery (EOR) techniques in this kind of reservoir is essential to achieve peak oil production and increase the recovery factor. Chemical EOR (CEOR) processes have been studied for many years in carbonate reservoirs but are not usually economically viable. Surfactant flooding has been considered as one of the most promising techniques among the chemical recovery methods due to the capacity of some surfactants to alter the carbonate rocks' wettability. However, the process is economically feasible only when losses of surfactant caused by adsorption into the porous media are decreased. Adsorption of surfactants can be affected by the surface charge on the rock surface and fluid interfaces. In general, the adsorption of cationic surfactants on carbonates is lower in comparison with other surfactants. Nevertheless, the high cost of cationic surfactants compared to anionic ones has led to studies aiming to evaluate the injection of the latter in the presence of a sacrificial agent in order to reduce the adsorption caused by interaction between the negative charges of the surfactant and positive charges on the carbonate surface. This work aims to study the effect of the presence of two chemicals, normally applied as scaling and corrosion inhibitors, on reducing the static adsorption of an anionic sodium olefin sulfonate surfactant on a carbonate rock. Water soluble poly(sodium methacrylate) (PSM) and diethanolamine (DEA) were evaluated as sacrificial agents in concentrations close to their scaling and corrosion inhibitor functions, respectively, to verify their sacrificial role in a co-injection chemical scenario. Adsorption studies were carried out using a pulverized carbonate rock in which low-salinity water was used as the base medium. Aqueous stability tests were carried out, which made it possible to select the correct salinity for the solutions of surfactant. Surface tension measurements were used as an indirect approach to study the adsorption of the surfactant in the presence and absence of PSM and DEA. Individually, PSM presented the best performance in reducing the adsorption of the anionic surfactant, while the DEA showed an almost null effect. However, when the chemicals were mixed, a synergistic effect was observed. The performance of PSM can probably be attributed to a steric effect of an adsorbed layer of polymer. It will be shown that even at lower concentrations, co-injection chemicals which are used for targeting other issues, such as scaling and corrosion inhibitors, may play the role of a sacrificial agent in reducing the adsorption of anionic surfactants, which is a concern in application to carbonate reservoirs.
Strategies for Squeezing Co-Mingled Wells in the Same Flow Line in Sub-Sea and Deepwater Environments - Guidelines for Scale Inhibitor Selection and Effective Treatment Strategies and Design
Authors: Heath Stephen , Gjøsund Nina , Dugué Dominique
Published: March 2019

As the oil and gas industry continues to operate in more complex and deeper water environments downhole scale control via scale squeeze treatments becomes an ever-increasing technical challenge. It is therefore essential that effective scale management strategies are adopted which incorporate suitable scale inhibitor (SI) selection, analysis and treatment design procedures to provide optimal and cost-effective squeeze treatment lifetimes to maximise oil production and reduce well intervention costs.

In this paper key factors are evaluated in order to provide a guidance to selecting a suitable treatment strategy for downhole scale control in co-mingled sub-sea well and the impact of chemical retention, minimum inhibitor concentration (MIC), limit of quantifiable detection (LOQD) and well dilution factors on treatment design and strategy are discussed. The pros and cons of different treatment strategies are presented in this paper and consideration is given to following three treatment strategies: Treating all wells with the same chemical and over designing the chemical treatment lifetime ie 18 months and then re-treating all wells after 12 months;Treating individual wells with tagged versions of the same scale inhibitor chemical;Treating individual wells with different scale inhibitors.

Options (ii) and (iii) offer the ability to design similar treatment lifetimes for each well but have the flexibility to monitor wells individually and re-squeeze when required.

Examples are provided for treatment options (ii) and (iii) based upon a field example to illustrate the design concepts for fluorescent (F) and phosphorus (P) tagged polymers in two co-mingled wells and a theoretical example for treating three co-mingled wells with different scale inhibitors, one of which could be a phosphonate with two tagged polymers.

This paper presents an overview of the key factors that influence chemical selection and treatment design for co-mingled wells in the same flow line. In addition, it will highlight important concepts to provide guidance for the design of effective treatment strategies for squeezing co-mingled wells in sub-sea and deepwater environments.
Effect of Calcium Carbonate on Barite Solubility Using a Chelating Agent and Converter
Authors: Abdelgawad Khaled , Mahmoud Mohamed , Elkatatny Salaheldin , Patil Shirish
Published: March 2019

Barium Sulfate (Barite) is one of the common oil and gas field scales formed inside the production equipment and in the reservoir. Barite is also a common weighting material used during drilling oil and gas wells. Barium sulfate scale may exist as well in carbonate formations. The removal of barium sulfate from calcium carbonate formation is a challenging problem because of the solubility of calcium carbonate is higher compared to that of barium sulfate in different acids. In addition, barium sulfate is not soluble in the regular acids such as hydrochloric (HCl) acid and other organic acids.

In this paper, the effect of calcium carbonate on barium sulfate solubility in a chelating agent and converter catalyst was investigated using solubility experiments at 80°C as a function of time. 20 wt.% DTPA with 6 wt.% potassium carbonate (converter) were used at pH of 12. The effect of calcium chelation on the barium sulfate solubility was studied in two scenarios. The first scenario when Barium sulfate is dissolved first then the solution reacts with calcium carbonate. The second scenario when both calcium carbonate and barium sulfate are exposed to the DTPA solution at the same time. In addition, the effect of calcium carbonate loading on the barium sulfate solubility was determined using 25, 50, 75, and 100 wt.% of the scale as calcium carbonate. As an evaluation criterion, inductively coupled plasma (ICP) was used to analyze the cation concentration and determine the solubility of each scale type.

For the two scenarios of barium sulfate dissolution, the presence of calcium carbonate had a significant effect on the solubility of barium sulfate. When DTPA solution got saturated first with barium cations after 24 hours, and the addition of calcium carbonate to the solution will cause immediate barium drop of solution (concentration drop from 2140 to 1984 ppm in 30 min in 50 ml solution) which cause precipitation of barium sulfate. In addition, simultaneous chelation of both calcium carbonate and barium sulfate showed a low barium sulfate solubility compared to calcium carbonate. This can be explained by the high affinity of DTPA to calcium compared to barium.

It is highly recommended to account for the presence of any calcium source during the design of the chemical formulation for barium sulfate scale removal using DTPA. Therefore, DTPA treatment formulation is recommended in sandstone formations. Field results can be completely different from laboratory results if Ca2+ chelation from carbonate rocks is ignored.
Water Chemistry Application in Reservoir Management and Production
Authors: Wei Wei , Wang Wei , Clinch Simon
Published: March 2019

This paper presents novel approaches and comprehensive field case examples on applying water chemistry in reservoir management and production. Systematic field water sampling and analysis, data integration, and water chemistry fingerprinting techniques are utilized for various important applications such as Original Oil In Place (OOIP) estimate, water source identification, prediction/prevention/management of oilfield scale and other water-related production/operation problems. Field case study examples show significant value creation achieved by utilizing water chemistry-based approaches. Results show subsurface water heterogeneity can significantly impact the calculation of OOIP, water sampling and analysis is critical to identify "unexpected" scaling risk at initial water breakthrough and monitor seawater breakthrough ensuring management/treatment in place as needed, systematic water data collection and integration and understanding can be used as a reliable/efficient/cost-effective approach to identify water source/water breakthrough from a new formation zone. Significant value creation was achieved for projects via our novel and systematic water chemistry-based approach discussed in this paper.
A Novel Biochemical-Based Paraffin Wax Removal Program Providing Revenue Generation and Asset Enhancement
Authors: Raney Kirk , Alibek Ken , Shumway Martin , Karathur Karthik , Stanislav Terry , West Gary , Jacobs Marc
Published: March 2019

New biochemically-derived products for the removal of paraffin wax from oil wells do not require additional capex nor heat and do not utilize bacteria. They contain inactivated microbial cells, biosurfactants and biosolvents, and other components harvested as microbial byproducts that emulsify and dissolve paraffin from rock pores and from the well surfaces over wide temperature, salinity, depth, and pH ranges. Additionally, they increase oil recovery by remediating near-wellbore formation damage, reducing interfacial tension, altering rock surfaces and changing their wettability, and reducing oil viscosity. The product application is environmentally superior to well treatments using hot oil/water and aromatic solvents and is economical due to low capital and operating costs required for product synthesis. Specifically, product preparation is achieved using a modular fermentation system that is installed near the points of application. This insures highly efficient and low-cost production and logistics, as well as reducing time from generation to application which maximizes potency. With sufficient space, water, and electricity, the initial manufacture of the dispersal products can occur within a few weeks.

The treatment products utilized were initially developed and tested in laboratory studies, which showed that dispersion rates of the relevant paraffin samples were comparable to those achieved with toluene. The paraffin dispersal products exhibit a very high level of efficacy and safety when deployed in the Appalachian and Permian Basins. The potency of these products has led to outstanding paraffin removal results as indicated by reduced well failures in both vertical and horizontal wells and by visual observation of sucker rods removed from the wells. In addition, tank sludge and wax deposits in pipelines can be removed through either residual product flowing from the well or through direct application. Growth of detrimental bacteria and formation of biofilms are inhibited by the product application thereby reducing corrosion risk.

Specifically, details of an almost two-year 70-well study in the Appalachian Basin are reported in which no well failures were observed due to paraffin buildup and 95% of the wells exhibited an enhanced oil recovery effect during the paraffin remediation treatments. This resulted in an approximate 50% average increase in sustained production rate over baseline. Analysis of the results forecasts a substantial increase in future production, thereby significantly enhancing the value of the producing wells. Importantly, longer times between required treatments and the increased recovery rates have transformed the paraffin maintenance program into a documented revenue generator for the operator.
A New Approach to Testing Scale Inhibitors in Mild Scaling Brines – Are Dynamic Scale Loop Tests Needed?
Authors: Barber Miriam , Heath Stephen
Published: March 2019

Static jar tests are widely known and used in the oil and gas industry for quantitative screening and determining the minimum effective dose (MED) for scale inhibitors. However, when dealing with very low saturated brines, challenges are faced in the laboratory to replicate the same scaling environment found in the oilfield facilities and often brines have to be stressed in order to induce scaling in the laboratory tests. This paper proposes an efficient approach for quick chemical selection and recommendation for low scaling environments.

The method proposed has been developed and successfully applied for the selection and recommendation of scale inhibitors in low to mild saturated brines. This technique involves the combination of the standard static jar test with Scanning Electron Microscopy (SEM) and UV-Visible Spectrophotometry (UV/VIS).

The two case studies presented here shows two fields with low to mild barium sulphate (BaSO4) and calcium carbonate (CaCO3) scaling issues. This novel approach of has been used to screen and identify the best scale inhibitor in terms of cost effective peformance. Post-experimental analyses such as the Scanning Electron Microscope/Energy Dispersive X-Ray Diffraction Spectrometry (SEM/EDXS) permitted the investigation and assessment of the type of scale formed, and the mechanisms of inhibiton for each scale inhibitor chemistry tested.

This combined approach removed any discrepancies obtained by visual observations and/or Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) efficiency measurements. Furthermore, the UV-Visible Spectrophotometry was used in conjunction to the static SEM/EDXS method, in order to reassess the MED for the scale inhibitor candidates using the kinetic turbidity test (KTT) method. Results obtained from the KTT method complimented those from the combined static with ICP and SEM imaging, providing a quick understanding of the scale formation kinetics and inhibition efficiency.

To summarise, results have shown that different techniques can be used as a fast screening process for the MED using different scale inhibitors at low scaling regimes. Therefore, the static SEM and KTT methods are recommended as a thorough screening process for determining the optimum MED and selection of the best fit for purpose scale inhibitor. This opposes the conventional dynamic scale loop (DSL) approach, which would require severe alterations to the brine chemistry in order to get a scaling blank within a minimum 2-hour-period.
A Placement Case Study for a Well in the North Sea Field
Authors: Kaur Amarpreet , Stalker Robert , Graham Gordon
Published: March 2019

This paper considers the placement challenge in selected wells in a North Sea Field and presents the importance of understanding reservoir properties such as relative permeability, mobility and fluid in place when attempting to simulate treatments in complex wells such as these. The work presents the challenges and solutions offered to minimise the scale risk in this mature field as a result of changes in the overall drainage strategy.

Many wells in the North Sea Field are complex and produce from multiple heterogeneous formations which makes them difficult to treat, and so effective placement is vital to mitigate downhole scaling. The wells highlighted in this paper were originally planned for minimal interventions. However as the field development plan matured an increased (albeit mild) sulphate scaling risk became evident in several production wells. Therefore, pre-emptive squeeze treatments were planned to mitigate downhole barium sulphate scaling. Given the heterogeneity in the formation this resulted in potential risks in the event that squeeze treatments could not be designed to give effective placement.

This paper presents the placement challenge that is seen in these wells in addition to potential methods of overcoming these challenges. Effective placement does not necessarily mean placement into all producing layers, but means placement of inhibitor into layers upstream of any potential mixing point of scaling brines. Therefore, this work highlights the necessary placement required for effective inhibition and the corresponding treatment designs that may achieve this. One treatment injection strategy to assist effective placement is the use of a staged diversion treatment which is simulated using a near-wellbore placement model.

This paper documents a case study of modelling placement, and the corresponding squeeze return, in a mature North Sea Field. It highlights the important influence of reservoir properties such as relative permeability effects (in addition to permeability, porosity, fluid mobility etc.) and how these are used such that chemical treatments in complex heterogeneous wells can be readily simulated without the necessity of using complex full field reservoir simulators.
Enhancing Scale Inhibitor Squeeze Retention in HT/HP & High Water Rate Wells - Laboratory to Field Case Study
Authors: Sutherland Louise , Jordan Myles
Published: March 2019

The practice of squeeze treatments to oil/gas production wells to prevent inorganic scale formation has been applied for over 30 years and during that period different mechanisms to retain the inhibitor chemical have been evaluated. The simple mechanism of inhibitor retention, adsorption/desorption has been complemented over the years by enhanced adsorption via mutual solvent and full precipitation of the active inhibitor onto the mineral surface of the reservoir.

Previously published studies have shown that the retention of phosphonate scale inhibitors in sandstone reservoirs can be enhanced through the addition of a ‘squeeze life enhancer’. This chemical, typically, a highly charged, low molecular weight polymer can be applied in either the preflush or overflush stage of the scale squeeze treatment. To date these studies have been conducted using low temperature (85°C) sandpack testing.

This paper details the laboratory work carried out under high temperature (146°C) field conditions to qualify the use of the squeeze life enhancer for field application.

The results of the formation damage/inhibitor return corefloods using an MEA phosphonate (EABMPA, Ethanolaminebis(Methylene Phosphonic Acid)) and polymeric squeeze life enhancer additive are presented. The coreflood results indicated that the addition of the additive within the overflush stage of the squeeze program resulted in a 19% extension of the inhibitor lifetime. The ability to extend the squeeze treatment was translated into reduced injected squeeze fluid treatment volume as injected fluid volumes was an issue for the wells being treated and therefore reduced associated oil deferment costs.

The paper will also present field data obtained from the initial two field trial treatments which were carried out in a North Sea field. The trial well had been treated more than ten times previously with the same MEA phosphonate as applied in the enhancer trial making direct comparison of the treatment performance possible. The treatment program applied to the wells resulted in no change to the clean-up rates of the treated well and no process upset during well reflow. The initial scale inhibitor returns from the field trial treatments showed the expected improvement suggested from the coreflood study.

The study brings value to the industry by providing the process to follow for qualifying and trialling a new technology in a challenging high temperature scaling environment with the results from the field supporting the carefully designed chemical selection and evaluation program.
Permanent Removal of Condensate Banking in Tight Gas Reservoirs Using Thermochemicals
Authors: Hassan Amjed , Mahmoud Mohamed , Al-Majed Abdulaziz , Al-Nakhli Ayman , BaTaweel Mohammed , Elktatany Salaheldin
Published: March 2019

Condensate banking is a common problem in tight gas reservoirs because it diminishes the gas relative permeability and reduces the gas production rate significantly. CO2 injection is a common and very effective solution for condensate removal in tight gas reservoirs. The problem with CO2 injection is that it is a temporary solution and has to be repeated frequently in the field in addition to the supply limitations of CO2 in some areas. Also, the infrastructure required at the surface to handle CO2 injection makes it expensive to apply CO2 injection for condensate removal.

In this paper, a new permanent technique is introduced to remove the condensate by using a thermochemical technique. Two chemicals will be used to generate in-situ CO2, nitrogen, steam, heat, and pressure. The reaction of the two chemicals downhole can be triggered either by the reservoir temperature, or a chemical activator. Two chemicals will start reacting and produce all the mentioned reaction products after 24 hrs. of mixing and injection. Also, the reaction can be triggered by a chemical activator and this will shorten the time of reaction. Coreflooding experiments were carried out using actual condensate samples from one of the gas fields. Tight sandstone cores of 0.9 mD permeability were used.

The results of this study showed that, the thermochemical reaction products removed the condensate and reduced its viscosity due to the high temperature and the generated gases. The novelty in this paper is the creation of micro-fractures in the tight rock sample due to the in-situ generation of heat and pressure from the thermochemical reaction. These micro-fractures reduced the capillary forces that hold the condensate and enhanced its relative permeability. The creation of micro-fractures and in turn the reduction of the capillary forces can be considered as permanent condensate removal.
Investigation into the Synergistic Interaction of a Range of Generic Scale Inhibitors for Improved Sulphate Scale Control in North Sea Topside Processes
Authors: Jordan Myles , Temple Erin , Sham Anita , Williams Helen , McCallum Catriona
Published: March 2019

Inorganic scale control of sulphate and carbonate scales with polymer, phosphonate and phosphate ester scale inhibitors is well established within the oilfield service industry. The environments in which these chemical work best have been published such as vinyl sulphonates are known to be very effective for sulphate scale control in low temperatures whereas phosphonates are much less effective under these same conditions but improve at higher temperatures. What is less well understood is the potential for synergistic interaction with blends of polymers/phosphonates/phosphate esters to give reduced treatment rates, lower chemical discharge volumes and potentially lower treatment cost.

In this paper evaluation of two North Sea produced waters will be outlined. Both produced brines have a high barium sulphate scale tendency but differ in the temperature at which the fluids arrive and depart the topside process one case with a temperature of 20C and the other at 90C. Static bottle test data will be presented to evaluate the crystal growth performance of single scale inhibitors and the improvements observed when blends of these same inhibitors are applied. Select dynamic tube blocking tests data to evaluate nucleation inhibition will also be presented so that mechanism of inhibition for the blended chemicals can clearly be highlighted.

The generic inhibitor evaluated included vinyl sulphonates co polymer, phosphate esters, poly aspartic acid. In the lower temperature environment, it was observed that a vinyl sulphonate/phosphate ester blend was more effective than either of the components by themselves. Poly aspartic acid blende with phosphate ester also give a synergistic interaction but the performance of this chemical required higher treatment rates than the vinyl sulphonate co polymer blend. At higher temperature the overall treatment rates were reduced as the sulphate scale saturation values were reduced and the synergistic effects of the polymers and phosphate ester blends were evident.

As well as classic static bottle tests performance tests were carried out in the presence of reservoir solids with stirring to further understand if the interaction of the generic chemicals within the blends with suspended solids would reduce the observed performance in the solids free test solutions.

The current regulatory challenges with REACH mean that the methods outlined in this study offer the potential to reduce chemical treatment rate, cost and environmental impact by evaluating the synergistic interaction of the current range of commercially available scale inhibitors so cutting out the very high registration costs/ time delays to the market associated with new molecule development.
Tuning Ionic Liquids for Simultaneous Dilution and Demulsification of Water-in-Bitumen Emulsions at Ambient Temperature
Authors: Abdelfatah Elsayed , Chen Yining , Berton Paula , Rogers Robin D , Bryant Steven
Published: March 2019

Thermal and flotation processes are widely used to produce bitumen from oil sand in Alberta. However, bitumen contains many surface-active components that tend to form water-in-oil emulsion stabilized by fines and/or asphaltenes. Although several demulsifiers have been proposed in the literature to treat such emulsions, these chemicals are sometimes not effective. We propose ionic liquids whose composition has been designed to enable effective treatment of these emulsions.

Different ionic liquids were synthesized and tested for their efficiency in treating bitumen emulsion obtained from a field in Alberta. Ionic liquids tested are mixtures of organic bases with acids. Mixtures of ionic liquids and bitumen emulsion were prepared at several mass ratios. The two components were mixed under ambient conditions. After mixing, segregation of different components in the mixture was accelerated by centrifugation for rapid assessment of the degree of emulsion breaking. Optical microscopy, rheology, thermal gravimetric analysis, and viscosity measurements were used to assess the effect of ionic liquids on bitumen emulsions.

The first set of ionic liquids with cations of different alkyl chain lengths were able to separate the water from the emulsion. However, these ionic liquids tend to form a gel when mixed with water. The number and length of alkyl chains proved critical for avoiding gel formation. Ionic liquids with multiple long chains on the cation were immiscible with the separated water. These ionic liquids were very efficient in diluting and demulsifying bitumen emulsion. The emulsion droplet sizes increased upon addition of the ionic liquid. The ionic liquid mixes into the bitumen phase released from the emulsion, yielding a viscosity at ambient temperature close to the pipeline specifications.

This work demonstrates that ionic liquids can be tailored to break bitumen emulsions effectively without heat input. The process developed in this paper can replace current practice for the demulsification and dilution of bitumen emulsions, which requires the emulsion to be heated significantly. Hence the ionic liquid process reduces the heat requirements and hence greenhouse gas emissions.
Kinetics and Thermodynamics of Iron Sulfide, Precipitation, Deposition and Control
Authors: Wang Xin , Ko Saebom , Liu Ya , Lu AlexYi-Tsung , Zhao Yue , Harouaka Khadouja , Deng Guannan , Paudyal Samridhdi , Dai Chong , Kan Amy T. , Tomson Mason B.
Published: March 2019

Iron sulfide scaling is a severe problem in flow assurance and asset integrity in oil and gas and deep-water production. FeS scale control is challenging due to the extremely low solubility, fast precipitation kinetics and complexity of ferrous iron and sulfide chemistry. Despite the ubiquity of FeS, we have limited understanding about the kinetics and thermodynamics of iron sulfide. To address this problem, we have developed a reliable anoxic plug flow reactor using argon gas to remove oxygen and PIPEs or MES buffer to control pH. The FeS (mackinawite) solubility, precipitation kinetics and phase transformation were the focus of this study. The impact of temperature (25 – 90°C), pH (5.92 – 6.91), ionic strength (0.15 – 4.30 M), Fe(II) to S(-II) ratio, dispersant and chelating reagent have been investigated. It was found that mackinawite is always the first FeS precipitated and could be stable for a week. It was suggested that low pH, high temperature and low ionic strength could accelerate the FeS phase transformation. FeS precipitation is under diffusion control at pH lower than 6.1, which could be accelerated by high temperature and high ionic strength. But the precipitation kinetics would be faster at higher pH. Some evidence suggests the importance of neutral FeS(aq) species at pH 6 −7. A polymeric compound containing amide functional group showed a promising effect by controlling the FeS particle size and reducing FeS scale retention rate. EDTA showed satisfactory FeS scale inhibition effect, as well as reducing FeS scale retention and H2S corrosion rate.
Application of Advanced Fluorescence Detection Technology to Improve Scale Management in Both Conventional and Sub-Sea Fields
Authors: Heath Stephen , Toivonen Susanna , Vuori Vesa , Puupponen Salla
Published: March 2019

Scale inhibitor (SI) analysis is an extremely important part of scale management and, in recent years, much work has been done on the development of specialist scale inhibitor analysis techniques like Liquid Chromatography Mass Spectroscopy (LCMS) to push the boundaries of low level scale inhibitor detection. However, LCMS requires costly and complex instrumentation and there was therefore still a need for the development of other advanced techniques like fluorescence (F) and Time resolved Fluorescence (TRF) that can be used on site to provide near "on line" data.

Fluorescence techniques are particularly suited to tagged polymers and naturally fluorescent molecules like polyamines whereas the operation principle of TRF is based on interactions between lanthanide ions and various functional groups of polymer or phosphonate scale inhibitors.

Both techniques work individually or in combination and this provides a distinct advantage for multiple scale inhibitor analysis in produced brines that enable the design of packages of different products for specific field applications. In addition, TRF and fluorescence techniques offer the capability of on-site detection compared to the majority of scale inhibitor analysis techniques and other advanced methods like LC-MS.

The ability to detect both phosphonate and polymeric scale inhibitors at very low MIC (<1ppm) has the potential for significantly extending scale squeeze lifetimes. This has now also allowed highly efficient, F tagged polymers, to be used in field situations where scale squeezing was either stopped or the lifetime was significantly compromised because of the lack of confidence in the residuals analysis.

Specific field and theoretical examples from both sub-sea and conventional wells will be presented where the application of both advanced fluorescence and TRF techniques has shown significant improvements in scale management.

This paper will compare and contrast the pros, cons and limitations of both fluorescence and TRF techniques for both phosphonate and polymeric scale inhibitors. In addition, it will highlight examples where scale management significantly improves through the application of Fluorescence and/or TRF scale inhibitor analysis techniques in complex production scenarios.
Peripapillary retinal artery in first diagnosed and untreated normal tension glaucoma
Authors: RONG XIN , Cai Yu , Li Mei , Fang Yuan , Tian Tian , Pan Yingzi
Published: March 2019

Backgroud

Glaucoma, an important cause of visual impairment in many countries, remains a common eye condition due to difficulties in its early diagnosis. We analyzed the characteristics of retinal arteries to add a valuable technology for helping the normal tension glaucoma (NTG) diagnosis.

Methods

This study included 51 patients with newly diagnosed NTG with hemifield defects and 60 age-matched controls. Peripapillary retinal arteriolar calibers (PRACs) photoed by non-mydriatic retinal camera were measured using ImageJ by two masked readers. We also performed spectral-domain optical coherence tomography to evaluate retinal nerve fiber layer thickness (RNFLT) and optic disc parameters. Their relations to retinal arteriolar calibers were investigated by univariate and multivariate linear regression. The area under the receiver operating characteristic curve (AUROC) was used to confirm the powers to detect NTG by PRACs.

Results

PRACs in four quadrants were significantly reduced in individuals with first diagnosed NTG (82 ± 15.1 μm, 80 ± 13.6 μm, 71 ± 11.6 μm, and 64 ±10.0 μm) compared with those in age-matched controls (101 ± 9.8 μm, 105 ± 8.7 μm, 90 ± 7.5 μm, and 82 ± 9.8 μm). Superotemporal and inferotemporal PRACs in the visual field-affected hemifield were narrower than those in the unaffected hemifield in NTG group (P≤0.004). Temporal PRACs in the RNFL unaffected hemifield were significantly narrower than in healthy eyes (P<0.001). Superotemporal PRAC showed a significant correlation with superior RNFLT (β=0.551, P<0.001), and a similar relationship was found between inferotemporal PRAC and inferior RNFLT (β=0.296, P=0.050). These associations were independent of IOP. The diagnostic capability of temporal PRACs was satisfactory (superotemporal PRAC; AUROC 0.983, cut-off value 84.7 μm, inferotemporal PRAC; AUROC 0.946, cut-off value 94.2 μm).

Conclusions

Superotemporal PRAC and inferotemporal PRAC are valid parameters for discriminating patients with NTG. And it is likely that narrowed peripapillary vessels preceded the RNFL damage detected by digital retinal camera.
Moroccan Facebook Visual Narratives and Cultural Production
Authors: Faddouli Driss
Published: March 2019

In this paper, I argue that the creation and circulation of the visual narratives within Facebook groups by Moroccan Facebookers largely entail and substantiate a stronger process of cultural production that has its own logic and praxis. I argue that this process of cultural production has two major facets: an aestheticization of everyday life and promulgation of specific modes of consciousness. Through the aestheticization of everyday life, I posit that Moroccan youth’s acts of cultural production increasingly blur the formal boundaries between the Internet, art, and popular culture; an aspect which fundamentally empowers their creative online input. Through the promulgation of specific modes of consciousness, I argue that the visual narratives attempt to develop and enhance the cultural sensibilities which better champion their perceptions and stances. Taken together, I claim that these major manifestations of the process of cultural production, while being deeply wedded to the Gramscian and Foucauldian perception of power dynamics, set the tone for an underlying struggle over power and meaning-making in the Moroccan society, thus seeking to intervene and exploit the gaps and contradictions in these power dynamics in society.
Power law in tails of bourse volatility – evidence from India
Authors: Ghosh Bikramaditya , C. Krishna M.
Published: March 2019

Inverse cubic law has been an established Econophysics law. However, it has been only carried out on the distribution tails of the log returns of different asset classes (stocks, commodities, etc.). Financial Reynolds number, an Econophysics proxy for bourse volatility has been tested here with Hill estimator to find similar outcome. The Tail exponent or α ≈ 3, is found to be well outside the Levy regime (0 < α < 2). This confirms that asymptotic decay pattern for the cumulative distribution in fat tails following inverse cubic law. Hence, volatility like stock returns also follow inverse cubic law, thus stay way outside the Levy regime. This piece of work finds the volatility proxy (econophysical) to be following asymptotic decay with tail exponent or α ≈ 3, or, in simple terms, ‘inverse cubic law’. Risk (volatility proxy) and return (log returns) being two inseparable components of quantitative finance have been found to follow the similar law as well. Hence, inverse cubic law truly becomes universal in quantitative finance.
Intergenerational management in the group of people subjected to job reintegration as a form of maintaining social security potential in Poland
Authors: Sapiński Aleksander
Published: March 2019

The aim of this paper is to present a theoretical reflection and results of a pilot study research on intergenerational management in the group of participants of Centrum Integracji Społecznej (later called: Social Integration Centre) in Jeleśnia who underwent job reintegration and can socially improve the social potential of internal security. The concept of national identity and intergenerational awareness in terms of ensuring the social security potential of the country depends in reintegration groups on the broadly understood level of diversity of the team. An important feature of intergenerational management in socially reintegrated groups is situational awareness, mutual respect and a sense of group unity with the leader and vice versa. The mere fact that intergenerational management in relation to security management, the essence of which is to ensure social security potential, is becoming an indispensable issue from a practical point of view (Cf. Ponomarenko & Khudolei, & Prokopenko, & Klisinski, 2018). On the other hand, however, research in the area of management, which is also in the humanities area (Kostera, 2005, 2015), makes it possible to discover new methods and opportunities for the development of social security potential through intergenerational cooperation based on the methods of social education philosophy The article therefore has a quasi-empirical and interdisciplinary nature, as it uses terminology, concepts and thematic scope from the fields of management, security, and elements of upbringing studies.
The Substitution Effect of Avocado Seed Flour on The Organoleptic Properties of Sponge Cake
Authors: Megarani Sarah , Srimiati Mia
Published: March 2019

The aims of this study was to determine the substitution effect of avocado seed flour on the organoleptic properties of sponge cake. Method: This was experimental study where the substitution rate of wheat flour with avocado seeds was treated. There were 3 treatments, F1 (15% of avocado seed flour), F2 (25% of avocado seed flour), F3 (40% of avocado seed flour) and F0 (control). The substitution of avocado seed flour had a significant effect (P <0.05) on the organoleptic properties. The F1 (15%) was the best formula with the highest acceptability compared to other formulas determined by hedonic test. The characteristics of the sponge cake were sweet taste, very fragrant aroma, very soft texture, and have a yellow colour. The product contained 44.77% (w/w) of carbohydrates, 17.97% (w/w) fat, 8.04% (w/w) protein, 28.02% (w/w) water, and 1.2% (w/w) ash. To get the best acceptability of the sponge cake, the maximum substitution of avocado seed flour in the sponge cake is 15%.
Establishment of Novel Cells Stably Secreting Various Human IL-18 Recombinant Proteins
Authors: Kumagai Asuka , Shimizu Kenji , Kurata Riho , Cui Xiaofeng , Isagawa Takayuki , Harada Masamitsu , Nagai Jun , Yoshida Yasuhiro , Ozaki Kei-ichi , Takeda Norihiko , Semba Hiroaki , Yonezawa Tomo
Published: March 2019

Background:

The immunotherapies against cancer, autoinmmune diseases or infection are remarkable development. These days programmed cell death (PD)-1 antibody-induced immune checkpoint blockade or chimeric antigen receptor-T cells (CAR-T) have been shown to have eminent therapeutic effects on tumor development. We have focused on adoptive transfer with human gamma delta T cells for novel immunotherapies. Additionally, IL-18 is one of the cytokines that enhances cytokine secretion and cytotoxicity of human gamma delta T cells.

Method:

Thus, we established novel cell lines stably expressing and secreting various types of human recombinant IL-18 proteins to their culture supernatants using episomal vector. We also differentiated primary cultured human gamma delta T cells from peripheral blood mononuclear leukocytes to validate biological activity of the IL-18 proteins using measuring IFN-γ by ELISA.

Results and Conclusion:

Finally, we demonstrated that the supernatant could activate human gamma delta T cells using monitoring interferon gamma in culture medium.
Real-World Use of Do-it-Yourself Artificial Pancreas Systems in Children and Adolescents: Self-Reported Clinical Outcomes (Preprint)
Authors: Braune Katarina , O'Donnell Shane , Cleal Bryan , Lewis Dana , Tappe Adrian , Willaing Ingrid , Hauck Bastian , Raile Klemens
Published: March 2019

BACKGROUND

Patient-driven initiatives have made uptake of Do-it-Yourself Artificial Pancreas Systems (DIYAPS) increasingly popular amongst people with diabetes of all ages. Observational studies show improvements in glycemic control and quality of life amongst adults. However, there remains a lack of research examining experiences of children and adolescents with DIYAPS in everyday life and their social context.

OBJECTIVE

This study assesses self-reported clinical outcomes of the pediatric population using DIYAPS in real-world use.

METHODS

An online survey was distributed to caregivers, assessing HbA1c and Time in Range (TIR) before and after, and problems during DIYAPS use.

RESULTS

209 caregivers from 21 countries responded. Children were 47.4% female with a median age of 10y; a mean diabetes duration of 5.1y ±3.9 and 10.3m ±10.0 experience with DIYAPS. Clinical outcomes improved significantly, including HbA1c (from 6.91% ±0.88 to 6.27% ±0.67; P<.001) and TIR (from 64.2% ±15.94 to 80.68% ±9.26; P<.001).

CONCLUSIONS

Improved glycemic outcomes were found across all pediatric age groups including adolescents and very young children. These findings are in line with clinical trial results from commercially developed closed-loop systems.

CLINICALTRIAL

The study was approved by the Charité ethics committee (EA2/140/18).
Continuous Measurement of Reconnaissance Marines in Training With Custom Smartphone App and Watch: Observational Cohort Study (Preprint)
Authors: Saxon Leslie , DiPaula Brooks , Fox Glenn R , Ebert Rebecca , Duhaime Josiah , Nocera Luciano , Tran Luan , Sobhani Mona
Published: March 2019

BACKGROUND

Specialized training for elite US military units is associated with high attrition due to intense psychological and physical demands. The need to graduate more service members without degrading performance standards necessitates the identification of factors to predict success or failure in targeted training interventions.

OBJECTIVE

The aim of this study was to continuously quantify the mental and physical status of trainees of an elite military unit to identify novel predictors of success in training.

METHODS

A total of 3 consecutive classes of a specialized training course were provided with an Apple iPhone, Watch, and specially designed mobile app. Baseline personality assessments and continuous daily measures of mental status, physical pain, heart rate, activity, sleep, hydration, and nutrition were collected from the app and Watch data.

RESULTS

A total of 115 trainees enrolled and completed the study (100% male; age: mean 22 years, SD 4 years) and 64 (55.7%) successfully graduated. Most training withdrawals (27/115, 23.5%) occurred by day 7 (mean 5.5 days, SD 3.4 days; range 1-22 days). Extraversion, positive affect personality traits, and daily psychological profiles were associated with course completion; key psychological factors could predict withdrawals 1-2 days in advance (P=.009).

CONCLUSIONS

Gathering accurate and continuous mental and physical status data during elite military training is possible with early predictors of withdrawal providing an opportunity for intervention.
Persistence and adherence of biologics in US patients with psoriatic arthritis: analyses from a claims database
Authors: Oelke Kurt R , Chambenoit Olivier , Majjhoo Amar Q , Gray Stephani , Higgins Kate , Hur Peter
Published: March 2019

Aim:To evaluate the persistence and adherence of subcutaneous biologics in patients with psoriatic arthritis (PsA).Patients & methods:Psoriatic arthritis patients who initiated adalimumab, certolizumab pegol, etanercept, golimumab or secukinumab between 15 January 2016 and 31 July 2017 were identified in the Truven Databases. Outcomes included discontinuation rate, persistence and adherence over 12 months.Results:Of 1558 patients included, the 12-month discontinuation rate was lowest with secukinumab (36.5%), followed by adalimumab, golimumab, etanercept and certolizumab pegol (42.6–51.6%). Mean persistence ranged from 240.7 (certolizumab pegol) to 282.8 days (secukinumab). The mean proportion of days covered was highest with secukinumab (0.67) and lowest with certolizumab pegol (0.49).Conclusion:Patients who initiated secukinumab had the lowest discontinuation rate and highest persistence and adherence over 12 months.
Una historiografía de la independencia mexicana, anónima, de 1884
Authors: Lemoine Villicaña Ernesto
Published: March 2019

Este artículo se refiere a un folleto y una compilación de documentos relativos a la guerra de Independencia, de Juan E. Hernández y Dávalos. Igualmente, reproduce y analiza un texto publicado en 1884 cuyo objeto de estudio es la obra de Lucas Alamán y otros historiadores.
La Junta de Representantes o Consejo de los Departamentos, 1841-1843
Authors: Moreno Valle Lucina
Published: March 2019

La autora analiza la creación y el funcionamiento de la Junta de Representantes o Consejo de los Departamentos que fue concebida con el objeto de contar con una representación nacional que legalizara la elección de Antonio López de Santa Anna como presidente provisional de la República Mexicana. Señala que el orden constitutivo de esta junta emanó de las Bases de Tacubaya, firmadas el 28 de septiembre de 1841 por Santa Anna y otros generales que desconocían el gobierno de Anastasio Bustamante.
Charles W. Johnson, México en el siglo XX (Bibliografía política y social de publicaciones extranjeras, 1900-1969)
Authors: Matute Álvaro
Published: March 2019

Reseña
¿Quién se amparó en el seudónimo Un Cura de Michoacán?
Authors: Cortés Arreola Raúl
Published: March 2019

Raúl Arreola Cortés intenta encontrar a la persona o personas que, bajo el seudónimo de Un cura de Michoacán, cuestionaron en diversas ocasiones la representación de Melchor Ocampo en el Congreso de Michoacán, y provocaron una de las escisiones más notables entre Estado e Iglesia que se recuerde en esa zona del país.
Ideas políticas y sociales de Salvador Alvarado
Authors: Valadés Diego
Published: March 2019

Diego Valadés da a conocer el ideario político y social de Salvador Alvarado, expresado en su obra La reconstrucción de México. Este último, tras ser enviado por Venustiano Carranza a Yucatán para desactivar la rebelión argumedista, propuso un socialismo de Estado que regulara las cuestiones económicas, financieras y educativas en la península yucateca.
Barry Carr, El movimiento obrero y la política en México, 1910-1929
Authors: López Villafañe Víctor
Published: March 2019

Reseña
La Historia de Oaxaca del presbítero José Antonio Gay
Authors: Martínez Ríos Jorge
Published: March 2019

Jorge Martínez Ríos presenta un panorama breve de la historiografía de Oaxaca, en el cual coloca a José Antonio Gay como un personaje relevante, mas no aislado, en la serie de estudiosos sobre aquella región. Examina la obra de este historiador, quien siempre fue consecuente con sus ideas, y afirma que el valor de aquélla radica en que fue la respuesta de un religioso al embate liberal, hecho que le valió antipatías tanto del lado liberal como del eclesiástico.