bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of High Calcium Concentration on Sulfate Scale Prediction at High Temperature from 120°C to 220°C
Authors: Deng Guannan , Kan Amy T. , Dai Zhaoyi , Lu Alex Y. , Harouaka Khadouja , Zhao Yue , Wang Xin , Tomson Mason B.
Published: June 2018

High Ca concentration up to 40,000 mg/L in produced water was observed in Marcellus shale gas wells, such extremely high concentration have great impact to solubility of sulfate scales. To evaluate this impact, the virial coefficients for Ca-SO4 ion-interaction needs to be quantified in Pitzer equation for different P-T regimes. More solubility data with high Ca concentration at high temperature (>120°C) needs to be experimentally determined.

The solubility of anhydrite at Ca2+ concentration up to 1 m (mol/kg H2O) from temperature of 120°C to 220°C and at saturated vapor pressure was measured. A stainless-steel pressure proof reactor was designed to contain a Pyrex bottle, in which reagent grade anhydrite powder was mixed with salt solution of 0.25 m, 0.5 m, 0.77 m, and 1 m CaCl2. Sample was taken by using inner pressure to push solution through inline-filter, and then the Ca2+ and SO42- concentrations in the filtrate was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and compared over time to confirm when solubility equilibrium was reached.

Results shows that current Pitzer's equation model (ScaleSoftPitzer 2017) predicts saturation index (SI) values with an error of less than 0.1SI at up to 0.77 m Ca2+, but shows an error as much as −0.21 SI at 1 m Ca2+ condition. For typical produced water with less than 30,000 mg/L Ca (about 0.75 m), the current model gives a reliable prediction of anhydrite solubility. If the produced water contains greater than 30,000 mg/L Ca, the model may yield error that are as much as −0.2 SI. Further experiments are needed to correct the Pitzer equation coefficients for better scale predication at higher than 30,000 mg/L Ca.
Development of Novel Iron Sulfide Scale Control Chemicals
Authors: Li Wei , Ruan Gedeng , Bhandari Narayan , Wang Xin , Liu Ya , Dushane H. , Sriyarathne M. , Harouaka Khadouja , Lu Yi-Tsung , Deng Guannan , Zhao Yue , Kan Amy T. , Tomson Mason
Published: June 2018

Increasing production activities in sour environments with equipment and piping made of low corrosion- resistant carbon steel result in significant iron sulfides (FeS) corrosion and scaling problems. FeS scale control is challenging as FeS formation is favored in production water chemistry (extremely low solubility and fast precipitation kinetics) with complex phase transformations. Efficient chemical control of FeS scales has not been found. A polymeric compound containing amide or its derivative functionalities showed a promising effect by controlling the FeS particle size on a nano-meter scale at threshold quantities. The FeS scales were successfully managed by forming a stable FeS particle suspension in the aqueous phase without partitioning into the oil-water interface. Current development focuses on understanding the interactions between the polymeric-compound based dispersants and environmental factors such as the presence of an oil phase, as well as silica. In addition, performance improvement of the identified dispersants by new chemical additives has been explored. Our results show that biocides such as Tetrakis (hydroxymethyl) phosphonium chloride (THPS) may not be as effective as needed for FeS scale inhibition benefit. At the tested conditions, EDTA shows satisfactory FeS scale inhibition and dissolution performance. In addition, silica significantly affects wettability of FeS particles with part of the previously oil-wet FeS partitioning into the aqueous phase. The FeS inhibition and dissolution effects of EDTA are kinetically "poisoned" by silica; while FeS-dispersing effect of polymeric compounds remains unaffected. However, the previously-shown ability that polymer dispersants keep already-formed large size FeS particles in the aqueous phase is also impaired.
A Novel Approach to Identifying and Evaluating External Corrosion Using Advanced Technology
Authors: Cedeño Ramiro , Ghannam Abdullah , Nouioua Hakim , Fayyaz Muhammad
Published: June 2018

This paper discusses a novel approach to capturing the impact of corrosion in oil producers and water injection wells. This approach takes advantage of a tailor-made new technology developed for evaluating corrosion challenges based on the induced electromagnetic field principle. As a result, exceptional outcomes have been obtained from this data integration that helped accurately identify hot spots of high metal loss caused by downhole corrosion mechanisms.

Recent technology developments have enabled a successful investigative and diagnostic technique to not only appraise root causes of casing integrity failures but also to suggest optimized solutions to tackle proactively potential catastrophic scenarios. There is an increased need to correctly identify and troubleshoot these issues using the most suitable technology, promoting a clear understanding and identification of the hot spots and rank the risks where there is more likely to be potential integrity problems.

In the past, it has been impossible to identify such issues before they become potential hazards due to technology limitations. With the passage of time, proactive investment in research and development in this highly dynamic industry made possible a new generation of corrosion logging tools capable of identifying and diagnosing the extent of these types of issues, enabling the production engineering team to identifying the problem, evaluating potential risk, establishing the best possible solutions for remedial works, and improving well integrity surveillance methods.
Water Survey for Effective Souring and Corrosion Management in a German Onshore Production/Injection Plant
Authors: Dopffel Nicole , Reimann Sabrina , Jelinek Wolfgang , Sander Torben , Steigerwald Alexander , Alkan Hakan
Published: June 2018

Sulfate-reducing bacteria (SRB) can be commonly found in oil reservoirs causing H2S formation and subsequently corrosion and souring issues in associated production/injection water systems. To control and mitigate the microbial H2S formation, the production-injection loop should be monitored and the results should be implemented for effective control of H2S formation. One mitigation measure can be the injection of a biocide into produced and/or injected water killing or inactivating SRBs and other microorganisms responsible for the souring and fouling. However, the challenge often occurs to define the suitable injection spot and the required biocide concentration; not well defined biocide concentration and/or injection location can even favor SRB proliferation causing for example fouling of tanks or filters, which themselves can continously "inoculate" the system.

At the water treatment plant of of one of Wintershall's onshore oil field in Northern Germany, formaldehyde injection was started in the end of 2015. The scope of the project was to investigate the effectivness of the formaldehyde regarding the bacterial- and SRB count and to analyse the MIC (Microbially influenced corrosion) and souring potential in and around the treatment plant including the waterflood injection line. Water samples were taken under sterile and anoxic conditions at various points including production lines from the three fields, selected spots of the water treatment system and injection lines to the fields. The samples were analysed for key chemical- (pH, salt content, sulfate, formaldehyde, organic acids, H2S) and microbial parameters (bacterial, archaeal via qPCR (quantitative polymerase chain reaction) and SRB cell numbers via MPN (Most Probable Number). The obtained data can not only help the operator to optimize the biocide injection to reduce souring and fouling, but also to better understand the complex microbial growth occuring in the production facilities.
Using the Right Integrity Management Tool for the Job
Authors: Chalmers Frances , Stewart Tyler
Published: June 2018

There isn't a one size fits all solution to management of integrity. Intelligent management of integrity seeks to optimize the collection and interpretation of appropriate inspection and monitoring information. Savings can be made by making effective use of the available information to manage an asset's integrity.

Practical examples in the form of case studies are supplied to show how intelligent use of available asset integrity information can help to achieve safe, predicable production in different situations; Fix it now, training the inspection team to rectify simple pipe support issues prevents escalation of damage, reduces the overall time spent in terms of reporting, information management and execution of rectification.API fitness for service assessment (FFS), awareness of available information and ability to validate previous work against the status of an asset prevents the unnecessary expense of repeat work whilst providing assurance of continued fitness for service.Monte Carlo analysis provided a practical way to manage risks when inspection data was scarce resulting in a picture of the condition of their equipment over time. This assisted with key decisions associated with the inspection, repair and continued operation of the plant and equipment.
A Permanent Way to Prevent Corrosion on Carbon Steel
Authors: Patel Sameer , Alpert Merrick
Published: June 2018

This paper discusses a method of preventing carbon steel from corroding by alloying the surface of the steel with amorphous phosphate protective layer. Specifically discussed is a novel spray applied coating that has been developed using inorganic acid-base chemistry to create and grow a passive layer on the substrate. Detail is provided to show two main reactions occurring at the same time when EonCoat is applied on carbon steel. First, formation of a microscopic alloying layer, and second the formation of a cementitious macroscopic layer. The cementitious layer consists of a white cementitious material enriched in phosphate. The passive layer is amorphous metal phosphate of several micron in thickness. SEM and electrochemical analysis prove the chemical bond between alloying layer and the carbon steel, meaning the steel cannot further corrode. This paper describes the invention, chemistry, lab testing/findings (results and discussion), field testing and validation of the newly developed anti-corrosion technology.
Machine Learning for Evaluation of External and Internal Surface Conditions
Authors: Haas Ole-Erich , Hustad Per Sandved
Published: June 2018

Evaluation of surface condition by use of visual inspection is an important source of information to verify the integrity of assets such as process plants, chemical plants, or during fabrication. Visual inspection is a non-destructive examination (NDE) method favoured for it is low cost and efficiency, since experienced personnel quickly identifies when objects have defects or damages. Challenges to this NDE method is its lack of objective quantification and description of defects. Inspectors will interpret their observations based on their experience. Information will thus be person dependent. To mitigate this challenge, handbooks with illustrative examples can be used, showing how to quantify and describe observations. Another possibility is to use software solutions to assist the inspectors. To increase the efficiency and data quality, automatic quantification and description of observations would be valuable. Using the recent developments in machine learning (ML), image recognition, and object detection this work has investigated the feasibility of using ML on algorithms in recognizing objects and describing their condition. Googles ML framework Tensorflow was used as this is open-source software. The algorithms used for image recognition and object detection is known as convolutional neural networks (CNN). Data was produced from images taken during inspection projects, by defining typical objects in two states of condition according to a naming system. Images were tagged using an open-source tagging software, where objects are marked on the images and given a description according to the naming system. These images were used in training of the ML algorithm. The results were positive, and the algorithm can detect different objects and describe their condition. Implementing ML and CNN algorithms in software solutions for inspection can give the inspectors assistance in describing the condition of the objects. Other applications for this technology is autonomous inspection by robots or preparing augmented reality where personnel can get information about their surroundings.
Gamechanging Structural Repair Solution for FPSO Hulls with No Hot Work
Authors: Paillusseau Christophe , Errotabehere Xabier , Sayed-Ahmad Firas , Mouton Luc
Published: June 2018

An increasing number of Floating Production, Storage and Offloading Platforms (FPSO) are currently entering a mature age, requiring costly maintenance operations. Maintenance cost of the shipping industry is partly linked to corrosion management of the structural parts (incl. hull) while "Crop & Renew" of super tankers is usually taken care of during dry dock operations: FPSO hulls shall be maintained "on the field" creating challenges in terms of safety and economics. Indeed, for safety concerns, hot works on FPSO may yield to high risk simultaneous operations (SIMOPS) and/or production disruption. FPSO operators have therefore been looking for "cold work" solutions that guarantee safe and economical hull repair. This paper presents an innovative cold repair solution called ColdShield for the permanent reinforcement of steel structures in such marine environment. The purpose of ColdShield is to strengthen - in a safe and controlled manner - corroded offshore structures by eradicating the use of hot works during the whole repair process, thus avoiding downtime. The technology is based on proven techniques of bonded composite reinforcement already used in other industries such as aerospace and civil engineering. This innovation was led by COLD PAD with the support of Total, the French Petroleum Institute, and involved four different private and public laboratories.

The paper describes how this innovative technology has marinized composite reinforcement techniques throughout the three critical stages: design, installation and service life. Classical bonded composite reinforcements are usually limited by their high sensitivity to environmental marine conditions. As water is a severe degradation factor of bonded interfaces, it is well-known that bonding process in high humidity conditions, such as marine environmentswhere FPSO hulls typically are, leads to poor adhesion properties and a premature ageing of bonded reinforcements.

This led to a series of tests and simulations to finally obtain the class approval for ColdShield for hull girder strength by Bureau Veritas as a certified alternative to crop & renew.

The paper covers two field cases in West Africa comparing ColdShield with standard techniques in terms of safety, planning and savings. With an ageing fleet, the FPSO industry will face more and more corrosion challenges and COLDSHIELD proves to be a suitable tool to lower risks and costs while maximizing safety.
Exploring the Relevance of Corrosion Inhibitor Micelles to Improve Corrosion Management
Authors: Osnowski A. , Rankin S. , Carson F. , Perfect E.
Published: June 2018

Typically, the concentration of corrosion inhibitor levels in field fluids is routinely monitored. Understanding the level of corrosion inhibitor can provide information on the correct functioning of chemical injection pumps as well as determine the effects of changing system conditions, such as water cut or solids production, on chemical availability. Yet, despite the value of monitoring, the residual methods available to operators are often not sufficiently reliable or are too complex to apply in the field. A corrosion inhibitor micelle-detecting technique offers an alternative approach. A significant body of work can be found in the literature regarding the formation of micelles in model fluids and for single chemical species. The relevance of the approach for the significantly more complex field fluids and commercial corrosion inhibitor formulations is shown and discussed.
Lessons Learned from Residual Corrosion Inhibitor Measurements by LC-MS in a Mature North Sea Gas/Condensate/MEG Production System
Authors: Anthony J. , Harrington R. , Durnell C. , Sanders J. , Gerritsen D. , de Vries G. , Sonke H.
Published: June 2018

Measurement and interpretation of corrosion inhibitor residuals in a mature offshore gas/condensate field could not be reconciled with field data leading to the identification of a potential infrastructure integrity threat that mandated understanding. The field had recently transitioned from buffered pH operation to "natural" pH operation of the monoethylene glycol (MEG) loop (alongside addition of corrosion inhibitor) due to carbonate scaling caused by formation water influx. An investigation was initiated to determine the corrosion inhibitors behavior throughout the production system with focus on demonstrating the effectiveness of the inhibitor. The investigation included extensive laboratory corrosion testing using field and synthetic fluids, residual determination in field samples using liquid-chromatography mass-spectrometry (LC-MS), field implementation and confirmation of appropriate actions.

Upon completion of the investigation it was found that the intended corrosion inhibitor active components were not concentrating up in the MEG loop but were strongly partitioning to the natural gas condensate phase. This was leaving the topside facilities "under-inhibited". Obscuring this conclusion was the concentration of other benign (not corrosion inhibitor) active components present in the inhibitor formulation at very low concentrations which were giving falsely high inhibitor residuals.

After changing the inhibitor injection philosophy from batch-wise to continuous, LC-MS residuals have continued to confirm the partitioning behavior in field operation without the introduction of an unmanageable secondary property concern due to the inhibitor. Further online and laboratory corrosion studies have confirmed the integrity of the production system as proof of the effectiveness of the inhibitor. These key lessons learned challenge operators and chemical vendors to consider the MEG circuit chemistry more carefully during chemical qualification to ensure that chemical behavior is understood both before field application and that it is confirmed once applied.
Practical Galvanic Series for a More Appropriate Material Selection
Authors: Schmitt G. , Fergg B. , Schulze K. , Stanislowski M. , Berling M. , Dowengerds A. , Losacker S. , Havlik W. , Tlatlik H. , Soyk Dominok , Gommlich T. , Kuhl L.
Published: June 2018

The combination of dissimilar metals can result in corrosion due to galvanic effects. These are caused by differences in their electrode potentials. The spread difference between these potentials is the driving force for galvanic corrosion. Literature data usually refer to either standard conditions or aerated sea water at ambient temperature. However, the actual electrode potentials are influenced by a variety of factors such as temperature, pH, dissolved gases and salts, flow rates, scale formation, etc. For conditions encountered in the oil and gas industry, there are hardly any data about electrode potentials available. The aim of this work is to create a practical galvanic series under typical upstream conditions for standard oil country tubular goods (OCTG) steels, corrosion resistant alloys (CRA) as well as the gasket material graphite.

The following materials were selected for the tests, which are considered as representative for downhole and topsides equipment: J55, L80 Type 1, X52, Cr13, 316Ti, 2205, 904L and Graphite.

The electrode potentials and polarization resistances of the selected materials were measured in synthetic formation water with dissolved carbon dioxide (CO2) at temperatures between 22 and 130 °C. To account for the influence of bicarbonate and acetic acid these species were added in some of the tests.

In order to also identify overpotential effects the electric galvanic currents were determined between coupled dissimilar materials in the described media at different temperatures by electrochemical noise measurements (CoulCount-Method). For comparison, actual corrosion rates of dissimilar material couples were measured gravimetrically.

The results exhibit the influences of temperature, bicarbonate and acetic acid on the electrode potential of each material. Galvanic corrosion effects are observed between CRAs and OCTG. The highest galvanic corrosion occurs between graphite and OCTG and is also distinct between graphite and CRAs. Temperature has a strong influence on the galvanic corrosion. At high temperatures, galvanic corrosion effects occur also in couples of different CRAs.

The results show a good agreement between the measured electrode potentials, the results of electrochemical noise measurements and the gravimetric corrosion tests.

This work provides a practical galvanic series for materials and conditions that are usually encountered in the upstream oil and gas industry. Based on the results of the work presented it is possible to rate the galvanic material behavior under similar conditions. Being one of the first publications in this field of application, it represents a reference for material selection, engineering and failure analysis.
Use of Next Generation Sequencing to Identify Sources of Microbial Contamination
Authors: Chalmers Alison , Gale Andrew , Birnie Mark , Linde Anja , Millar Andrew
Published: June 2018

Management of bacteria remains a concern for most Operators and the ability for micro-organisms to generate hydrogen sulphide (H2S) that results in reservoir souring and microbiologically influenced corrosion is well documented.

This paper describes two studies carried out by Clariant Oil Services, in conjunction with an oilfield microbiology service company, where molecular techniques were utilized. These studies provided a detailed assessment of system bacterial levels in two UK North Sea platforms which had historically encountered integrity failures related to microbiologically influenced corrosion.

In each system, two methods of microbiological survey were carried out. Quantitative Polymerase Chain Reaction (qPCR) was utilized to determine the overall bacterial contamination of the system and Next Generation Sequencing (NGS) was utilized to determine the location of bacterial species capable of causing microbiologically influenced corrosion.

In system 1, qPCR showed significant H2S producing bacteria in the oil process train, closed drains drum and oily water separator. NGS indicated that the source of bacterial contamination in the closed drains drum was from the oil process train. The oily water separator, historically identified as the source of bacterial contamination of the closed drains drum, was found to contain distinctly different bacterial species to the other process vessels on the platform.

In system 2, production fluids are processed from two fields; one with seawater breakthrough and one where seawater breakthrough has not been detected. Microbiologically influenced corrosion failures have been observed downstream of where the produced fluids commingle. NGS showed predominantly sulphate reducing bacteria in the field with seawater breakthrough. Low levels of sulphate reducing bacteria were observed in the field with no seawater breakthrough, indicative of a shift in water chemistry. A moderate level of bacterial species known to cause or enhance microbiologically influenced corrosion were also detected in these field fluids.

Next Generation Sequencing has great potential to be used as a tool to identify bacterial species capable of causing microbiologically influenced corrosion in oilfield systems. These molecular techniques should be considered as a screening tool, particularly in systems which have a high frequency of failures attributed to microbiologically influenced corrosion.
Bio-Molecular Non-Corrosive Hydrogen Sulfide Scavenger
Authors: Dhulipala Prasad D. , Jani Jagrut K. , Wyatt Melanie R. , Lehrer Scott E. , Liu Zhegwei , Leidensdorf Jeremy , Chakraborty Soma
Published: June 2018

Acidithobacillus ferrooxidans (A. ferrooxidans) is a gram-negative, acidophilic and chemolithotropic bacterium that utilizes oxidation of ferrous ions, hydrogen and reduced inorganic sulfur compounds, such as H2S, as sources of energy. Sulfur oxidation in A. ferroxidans is catalyzed by the Sulfide Quinone Reductase (SQR) enzyme system. The initial step of the SQR reaction is the oxidation of sulfide to elemental sulfur or to the less-toxic polysulfide. SQR can eliminate the accumulation and persistence of H2S in waters and reservoirs contaminated with sulfur-reducing bacteria (SRB). H2S causes reservoir souring, corrosion problems, and presents a danger to oilfield personnel because of its inherent toxicity. SQR does not destroy the SRBs present in the system, but it does catalytically attack the H2S and H2S precursors produced by SRBs. As an enzyme, SQR is an environmentally compliant, sustainable, and catalytic solution to the growing H2S problem. The Sulfide Quinone Reductase enzyme (Bio-molecular scavenger-BMS) was evaluated for its efficacy as an H2S mitigation strategy. The evaluation showed that the BMS could convert H2S from different sources in liquid and gaseous phases in to nontoxic polysulfide. The studies also showed that the BMS-based H2S mitigation reactions did not cause corrosion, and the formulations are compatible with oilfield metals, plastics and elastomers.
Iron Sulfide Deposition in Sour Gas Wells: A Corrosion Induced Scale Problem
Authors: Chen Tao , Wang Qiwei , Chang Frank , Mukhles Amro
Published: June 2018

Iron sulfide is one of the exotic scales formed in the oil and gas fields, particularly for those deep sour gas wells producing from high temperature and high pressure (HTHP) reservoirs. Compared to the conventional carbonate and sulphate scale, the mitigation of iron sulfide deposition is notoriously difficult.

To develop a suitable mitigation strategy, it is essential to understand the formation mechanisms of iron sulfide in the given production system. In this work, we combined laboratorial tests, thermodynamic modelling, and field monitoring for the understanding the source of iron and the mechanisms of iron sulfide deposition in the sour gas well during acidizing treatment and production stage.

Study results indicate that iron sulfide deposition in sour gas wells is a corrosion induced scaling problem. During acidizing treatment, high concentration of iron is released from tubular due to acid attack, despite corrosion inhibitor is used in the stimulation fluid package. Large amount of iron sulfide can precipitate when spent acid mixes and reacts with H2S in the reservoir and potentially causes severe formation damage. During the production stage, the iron released from tubular due to corrosion in produced water under high temperature and high pressure is the major contribution of iron sulfide deposited at the surface of tubing. These iron sulfide deposits, although appeared as porous layer, can protect the downhole completion from the highly corrosive fluids, which leads to the unexpected long service lives of mild carbon steel tubular in many wells. However, accelerated corrosion can occur when the protective iron sulfide film or deposit is disturbed or partial.

This paper presents a fundamental study to understand the root cause of iron sulfide deposition in sour gas wells. Study results demonstrate that effective corrosion inhibition is key to mitigate the iron sulfide deposition problem in the sour gas wells.
Multifunctional H2S Scavenger and Corrosion Inhibitor: Addressing Integrity Challenges and Production Output of the Mature Field
Authors: Stipanicev Marko , Birketveit Øystein , Kvalheim Vibeke Hatloe , Hoshowski Jody , Lioliou Maria G. , Rindalsholt Tore
Published: June 2018

Production of mature oil and gas fields often requires managing the related risks and limitations imposed by reservoir souring upon assets and production integrity. The corrosive effect of H2S in combination with export gas H2S specifications, escalates operational expenditure (OPEX). The treatment of produced fluids can, in a worst-case scenario, reduce production output if the appropriate toolbox for managing elevated H2S levels are not in place. Herein presented is a case where production from a subsea field was restricted by the amount of H2S produced due to constrains in the topside gas processing system. The objective of the work was to remove significant amounts of H2S from produced fluids during transit via subsea production pipelines; scavenging H2S during multiphase flow, whilst maintaining corrosion and scale inhibition.

A novel multiphase H2S scavenger was incorporated into the incumbent subsea corrosion inhibitor. The work included identification of suitable multiphase H2S scavenging chemistry, tailoring of the multipurpose chemical to retain corrosion inhibition properties, and confirmation that this new chemistry did not deleteriously impact performance of other production chemicals used nor the production process itself. The experimental development work depicted ethylenedioxy(dimethanol) (EDDM) as capable of delivering suitable H2S scavenging capacity while maintaining corrosion inhibitor component performance. The qualification work supported a full-scale field test that demonstrated suitability of the new multipurpose chemical.

The new environmentally acceptable combined formulation of corrosion inhibitor and H2S scavenger enables higher production rates from the subsea field without modification of the chemical injection system or topside process system.
Cost Effective Material Selection for Sour and Sweet HPHT Field
Authors: Oliveira J. , Tchoundjeu S. , Néel G. , Richoux V. , Sareen D. , Bezboruah P.
Published: June 2018

Super 13Cr (S13Cr) 110ksi Specified Minimum Yield Strength (SMYS) grade, which was already supplied for previous High Pressure High Temperature (HPHT) sweet and sour gas fields, was considered for a new HPHT sweet and sour gas exploration field. After analysis, the new reservoir conditions were close to the limit of the application domain previously validated using the most stringent testing requirements, as defined in annex B of NACE MR0175/ISO 15156-3 standard. Under these circumstances, a natural switch to duplex stainless steel (22-5-3) material is usually recommended, leading to significant impact on project cost and lead-time.

This paper describes the work done between Oil Country Tubular Goods (OCTG) supplier and operator to define specific test condition based on the new reservoir environment and tubing loads. In order to qualify the material, a complete testing program was undertaken to assess Sulfide Stress Cracking (SSC), Stress Corrosion Cracking (SCC) and mass loss resistance.

In total four scenarios have been considered and analysed: shut-in and flowing conditions at both the well head and downhole locations. For these scenarios the representative applied stresses as well as reservoir fluid composition were defined.

SSC test was performed to verify the product suitability. The results showed that the material failed when using the most stringent requirements. However, when tested at specific well condition the material successfully passed the entire qualification.

Additionally, deeper SSC investigations were carried out in order to understand the influence of each parameter between initial and specific test condition, such as H2S partial pressure (ppH2S), chloride content, applied stress and material chemistry.

The benefit of this approach was to demonstrate to the operator that S13Cr was validated for the conditions of the new reservoir; thereby reducing lead time and by half the cost of purchasing duplex material during material selection phase. Generally, this methodology could be applied to all well environments requiring stainless steel materials.
Bioreactor for Accurately Assessing Biocide Effectiveness in Controlling Biogenic Souring in Mature Oil Wells
Authors: Ferreira J. A. , Almeida P. F. , Nunes dos Santos J.. , Sampaio I. C. , França Figueirêdo L.. , Tereska D.. , Chinalia F. A.
Published: June 2018

Biocide injections are used for controlling biological souring in mature oil wells, but unpredictable results of such practices are also frequently reported. To address this problem, this research aimed to quantify the effect of four new biocides, and one commonly used biocide, within a dynamic system (packed-bed bioreactor) without using batch testing. The bioreactor was operated for 591 days, and the results showed that sulfate-reducing-bacteria (SRB) activity could recover within a period that varied from 15 to 60 days. Neem-oil (NO) (1.5% vol/vol) and 3,5-dimethyl-1,3,5-thiadiazinane-2-thione (Dazomet, DZ) (0.5% vol/vol) were the most efficient in controlling SRB activity. The tests showed that the mechanistic interaction controlling souring is not only associated with the compounds’ toxicity. Immiscible biocides not only killed cells, but they also can control SRB-recovery rates after the injection of biocides.
Design of assignments using the 21st century bloom’s revised taxonomy model for development of critical thinking skills
Authors: M. Zapalska Alina , D. McCarty Miсhael , Young-McLear Kim , White Jack
Published: June 2018

Studies on the development of critical thinking skills with specific curriculum materials and instructional methods are few and have been highly theoretical and far removed from practical concerns and applications. This paper contributes to the existing literature on critical thinking pedagogy by providing examples of written assignments that are designed using the 21st century Bloom’s taxonomy model to contribute to critical thinking development. The step-wise development of critical thinking skills approach is provided. The paper argues that both focus on real problems and issues and provision of clear unambiguous instructions are critical fundamentals of critical thinking skills development. The paper also illustrates how to develop critical thinking assignments by providing five examples of course assignments within business education.
Identification of Mitochondrial Proteins of Malaria Parasite Adding the New Parameter
Authors: Yonge Feng , Weixia Xie
Published: June 2018

Malaria has been one of the serious infectious diseases caused by Plasmodium falciparum (P. falciparum). Mitochondrial proteins of P. falciparum are regarded as effective drug targets against malaria. Thus, it is necessary to accurately identify mitochondrial proteins of malaria parasite. Many algorithms have been proposed for the prediction of mitochondrial proteins of malaria parasite and yielded the better results. However, the parameters used by these methods were primarily based on amino acid sequences. In this study, we added a novel parameter for predicting mitochondrial proteins of malaria parasite based on protein secondary structure. Firstly, we extracted three feature parameters, namely, three kinds of protein secondary structures compositions (3PSS), 20 amino acid compositions (20AAC) and 400 dipeptide compositions (400DC), and used the analysis of variance (ANOVA) to screen 400 dipeptides. Secondly, we adopted these features to predict mitochondrial proteins of malaria parasite by using support vector machine (SVM). Finally, we found that 1) adding the feature of protein secondary structure (3PSS) can indeed improve the prediction accuracy. This result demonstrated that the parameter of protein secondary structure is a valid feature in the prediction of mitochondrial proteins of malaria parasite; 2) feature combination can improve the prediction’s results; feature selection can reduce the dimension and simplify the calculation. We achieved the sensitivity (Sn) of 98.16%, the specificity (Sp) of 97.64% and overall accuracy (Acc) of 97.88% with 0.957 of Mathew’s correlation coefficient (MCC) by using 3PSS+ 20AAC+ 34DC as a feature in 15-fold cross-validation. This result is compared with that of the similar work in the same dataset, showing the superiority of our work.
A Convenient Synthesis, Reactions and Biological Activities of Some Novel Thieno[3,2-e]pyrazolo[3,4-b]pyrazine Compounds as Anti-microbial and Antiinflammatory Agents
Authors: Zaki Remon M. , Zaki Remon M. , Kamal El-Dean Adel M. , Kamal El-Dean Adel M. , Radwan Shaban M. , Radwan Shaban M. , Abd ul-Malik Mokhtar A. , Abd ul-Malik Mokhtar A.
Published: June 2018

Aim and Objective: We reported in this manuscript, synthesis of novel pyrazolopyrazinothienopyrimidines.
The o-amino-thienopyrazolopyrazine-carbonitrile 4 was used as a versatile precursor for synthesis
of new heterocyclic compounds. Due to development of resistance to the current antimicrobial therapy and
non-steroidal anti-inflammatory drugs (NSAIDs), continues research for more effective agents is interesting.
Hence, the suspected promising biological activities of pyrazolopyrazine compounds persuaded us to study the
anti-microbial and anti-inflammatory activities in comparison with standard drugs.

Materials and Methods: The chemical structures of the newly synthesized compounds were confirmed by
elemental and spectral analyses. Activities of the synthesized compounds against a number of Gram-negative
and Gram-positive bacterial strains were investigated. The fungal strains were obtained from some cases of
human dermatophytosis. The antimicrobial activities were determined according to the Kwon-Chung and
Bennett method. Anti-inflammatory activity was evaluated using carrageenan induced paw edema method.

Results: The antibacterial screening of the synthesized compounds represented that the o-amino-carbonitrile 4
and triazepinone 11 have the highest activity towards E. coli & S. aureus and S. pneumonia. The amino-imino
6 was very effective against E. coli. Ring closure of 6 to triazolopyrimidine 7 increases the antibacterial activity
against E. coli & K. pneumonia, their inhibition zones were higher than ciprofloxacin. Also, the triazolopyrimidines
7 and 10 exhibited high antifungal activity against all tested strains. Compounds 6 and 11 revealed
high antifungal activity against S. racemosum and T. rubrum. The anti-inflammatory activity data indicated
that all the tested compounds 4, 6, 7, 10 & 11 revealed the highest anti-inflammatory effect after 4 hrs. of
carrageenan injection.

Conclusion: we found that most of the examined novel thieno- pyrazolopyrazine compounds exhibited promising
antibacterial, antifungal and anti-inflammatory activities which can be used as potential antibacterial,
antifungal and anti-inflammatory drugs.
Antioxidant Vitamins in Honey Samples from Different Floral Origins and Altitudes in Asir Region at the South-Western Part of Saudi Arabia
Authors: Al-Mosa Amal , Brima Eid I. , Fawy Khaled F. , AL Ghrama Hamed A. , Mohammed Mohammed E.A.
Published: June 2018

Background:

Different factors are known to affect the different physiochemical properties of bee's honey including the floral origin and climate.

Objective:

The aim of this article was to investigate the effect of floral origin and altitude on the concentration of vitamin C and A.

Methods:

Ten Ziziphus honey samples were collected from two altitudes; 113 and 511 meters. Twenty-five Acacia honey samples were included in this study from five altitudes; 14, 113, 317, 576 and 2247 meters above sea level. Vitamin C was measured by redox titration and vitamin A was estimated using the Carr-price reaction and spectrophotometer.

Results:

The mean± SD of vitamin C in the Ziziphus and Acacia honey samples were 239.2± 91.5 and 260.4± 81.1 mg\100g, respectively. Vitamin A mean value± SD in the Ziziphus and Acacia honey were 0.088± 0.126 and 0.062± 0.126 mg\ 100g, respectively. Concerning the effect of altitude, there was significant increase in vitamin C concentration in ziziphus honey with the increase of the altitude (p- value= 0.027), while an insignificant decrease was obtained in the case of vitamin A. Regarding the effect of altitude on the concentration of vitamin C in the Acacia honey, there was significant increase in the honey from the altitude of 2247 compared to the honey from all the other altitudes. Vitamin A concentration in the Acacia honey from the altitude 2247 was insignificantly decreased compared to the honey from all the other altitudes (p- value > 0.05).

Conclusion:

The floral origin insignificantly affected the concentration of vitamin C and A. The altitude significantly affected the concentration of vitamin C irrespective of the floral origin.
Development and Validation of a Stability-Indicating Chromatographic Method for the Determination of Indacaterol Maleate with Glycopyrronium Bromide in Mixture
Authors: Hassib Sonia Talaat , Hashem Hanaa Abdelmenem , Fouad Marwa Ahmed , Mohamed Nehal Essam Eldin
Published: June 2018

Introduction:

(COPD) Chronic Obstructive Pulmonary Disease is a partially reversible and
treatable lung disease, characterized by progressive limitation of airflow. It is one of the main causes of
mortality and morbidity worldwide.

Methods:

An easy, precise and selective reversed-phase liquid chromatographic method, with stabilityindicating
assay was established and validated for the determination of indacaterol maleate and glycopyrronium
bromide in the mixture. In addition, a forced degradation study was performed for indacaterol
maleate, comprised of hydrolysis by acid and base, degradation by oxidation and heat, and
photo-degradation. Separation and forced degradation were done by isocratic elution using a reversed
phase phenyl column and (methanol: phosphate buffer) at ratio (65:35, v/v) with 3.5 pH buffer as an
eluent at 1 mL min-1 as a flow rate. Quantitation was accomplished using a UV detector at 210 nm.

Results:

The method showed good separation of glycopyrronium bromide, indacaterol maleate and its
degradation products. Accuracy, linearity, and precision were acceptable over 10-160 µg mL-1 and 10-
80 µg mL-1 concentration range for indacaterol maleate and glycopyrronium bromide, respectively.

Conclusion:

The proposed method does not require any previously done separation steps, making it
applicable for the analysis of the drugs under investigation in their pharmaceutically marketed preparations.
Characterization and Identification of Isoflavonoids in the Roots of Millettia speciosa Champ. by UPLC-Q-TOF-MS/MS
Authors: Yu Dandan , Liang Xianrui
Published: June 2018

Introduction:

The root of Millettia speciosa Champ. (Leguminosae) is one of the wellknown
traditional Chinese medicines abundant in phenolic compounds and plays important roles in the
treatment of pain or numbness of the joints, blood deficiency sallow, chronic bronchitis and chronic
hepatitis.

Objective:

An ultra-high performance liquid chromatography coupled with quadrupole time-of-flight
mass spectrometry (UPLC-Q-TOF-MS/MS) based chemical profiling approach was established for the
separation and characterization of isoflavonoids in the roots of Millettia speciosa Champ.

Methods:

The roots of Millettia speciosa Champ. were prepared by ethanol extraction followed by further
extraction with chloroform. The extracts were analyzed by UPLC-Q-TOF-MS in positive and negative
electrospray ion modes at different Collision Energy (CE) values.

Results:

A total of 48 components were simultaneously detected, of which 38 components, including 21
isoflavones, 4 phenolic acids, 4 isoflavanones, 2 phenolic aldehydes, 2 flavanones, 1 aliphatic acid, 1
chalcone, 1 flavonol, 1 isoflavane and 1 pterocarpan were unambiguously identified or tentatively assigned
based on the retention time, UV spectra, characteristic molecular ions, MS/MS fragmentation
data and reference standards. The isomers of isoflavonoids were distinguished using accurate mass, the
diagnostic fragmentations of C-ring and UV spectra. The major diagnostic fragment ions of isoflavonoids
were observed and the corresponding fragmentation pathways were proposed.

Conclusion:

This investigation provides important analysis data for further quality control, pharmacological
and toxicological research on Millettia speciosa Champ.
Female healthcare workers and breast cancer screening
Authors: YALÇINTAŞ Aynur , BAYDAR ARLANTAŞ Aylin , CURA ECEVİT Püren , ÖZDEMİRKAN Tuğba , ÜSTÜ Yusuf , UĞURLU Mehmet
Published: June 2018

Aim/Background: Breast cancer is the common type of

cancer all around the world. In this study, we aimed to evaluate female

healthcare professionals’ knowledge, attitudes, behaviours and beliefs about breast cancer and breast cancer screening methods. Methods: This study was conducted in a

training and research hospital. Female healthcare professionals were included

in the study. The data were collected by questionnaires filled out through face

to face interviews. SPSS for Win. Ver. 15.0 was used for the analysis. Results: The study included 525

participants, 52.4%(n=275) of them were midwives/nurses, 31.2%(n=164) were

doctors, and 16.4%(n=86) were other allied health personnel. The doctors were

found more knowledgeable than the others about signs and symptoms of breast

cancer (p=0.001). The sensitivity subscale scores according to Breast Cancer

Health Belief Model Scale were higher in the participants whose first-degree

relatives had a history of breast cancer (p=0.001). Conclusion: Early diagnosis of breast cancer can be possible by the

implementation of screening programs effectively. For this purpose, it is

necessary to encourage healthcare professionals to be sensitive to the subject

as well as increasing the awareness of breast cancer in the community.Giriş ve Amaç: Meme kanseri tüm dünyada yaygın olarak

görülen bir kanser türüdür. Bu çalışmada kadın sağlık çalışanlarının meme

kanseri ve meme kanseri tarama metodlarıyla ilgili bilgi, tutum, davranış ve

sağlık inançlarını değerlendirmeyi hedefledik. Yöntem: Bu çalışma bir eğitim ve araştırma hastanesinde yürütülmüştür.  Veriler yüz yüze görüşme tekniği kullanılarak

doldurulan anket formları aracılığıyla toplanmıştır. Araştırmadan elde edilen

verilerin analizinde SPSS for Win. Ver. 15.0 (Statistical

PackageforSocialSciencesInc., Chicago, ILL., USA) paket programı kullanılmıştır.

Bulgular: Çalışmaya dahil edilen 525

sağlık çalışanının %52,4 (n=275)’ünü ebe/hemşire, %31,2 (n=164)’sini doktor ve

%16,4 (n=86)’ünü diğer yardımcı sağlık personeli oluşturmaktadır. Meme kanseri

belirtilerini bilme durumuna bakıldığında, doktorların diğerlerine göre meme

kanseri belirtilerini daha iyi bildikleri saptanmıştır, bu sonuç istatistiksel

olarak da anlamlıdır (χ²= 101,512; p=0,001). Birinci derece akrabalarında meme

kanseri öyküsü olanların, olmayanlara göre Meme Kanseri Sağlık İnanç Modeli

Ölçeği (MKSİMÖ) duyarlılık alt boyutundan aldıkları puan ortalaması daha yüksek

olarak bulunmuştur (p=0,001). Sonuç:

Meme kanserinde erken tanı, tarama programlarının etkin bir şekilde

yürütülmesiyle yakalanabilir. Bunun için de toplumda meme kanseri

farkındalığının artırılmasının yanında sağlık çalışanlarının konuya

hassasiyetle eğilmelerinin sağlanması gerekmektedir.