bluuebunny/crossref_metadata_2025 huggingface dataset:
The Mechanism of Leakoff Reduction of Clean Self-Diversion Acid in Acid Fracturing
Authors: Mou Jianye , Cai Xin , Liu Ming , Zhang Ye , Zhang Shicheng
Published: May 2016

Leakoff has been regarded as the main factor that limits fracture propagation and live acid penetration distance in acid fracturing. Reducing acid leakoff is a common measure to increase effective fracture length. Due to cleanness and leakoff reduction, clean self-diversion acid (VES: viscoelastic surfactant acid) has been used in acid fracturing. So far the mechanism of leakoff reduction by VES acid is interpreted qualitatively, and performance evaluation of leakoff reduction is based on laboratory results. However, laboratory results cannot be generalized to formation conditions directly. In this paper, we developed a model to simulate VES acid leakoff. The model consists of two parts: the acid invaded zone and the compressed zone. Coupling of the two zones forms the VES acid leakoff model. In the invaded zone, we built a VES wormhole model, which simulates acid flow, acid-rock reaction, porosity variation, and acid viscosity variation. The VES wormhole model predicts the pressure field, the flow field, acid concentration distribution, cation concentration distribution, VES concentration distribution, and viscosity distribution. For the viscosity variation due to acid-rock reaction, we use a correlation of viscosity as a function of pH, temperature, cation concentration, VES concentration, and shear rate based on experiment results. With the model, by extensive numerical simulation, we analyzed wormhole progation behavior under VES acid flooding and put forth the mechanism of VES acid leakoff reduction. The study shows that wormholing and viscosifying have competitive effect on leakoff. Wormholing decreases flow resistance, while the viscosifying and the increase of the width of spent acid zone raise flow resistance. Wormholes have fewer branches under VES acid compared to regular acid. For reservoirs with small compressibility, for example oil reservoirs, VES acid has relatively small effect on leakoff because compressibility has dominant effect on leakoff ; while for reservoirs with large compressibility, for example gas reservoirs, VES acid has a significant contribution to leakoff reduction because viscosity has a dominant effect on leakoff.
Natural Gas Exploration in Kuqa Foreland Thrust Belt
Authors: Xie Huiwen , Li Yong , Huang Shaoying , Lei Ganglin
Published: May 2016

The Kuqa foreland thrust belt, which has superior petroleum geological conditions and lines of structural belts, is an important target for natural gas exploration in Tarim basin. But owing to the bad surface conditions, the complex deformation of the underground structures and the poor quality of seismic data here, it is difficult to define the trap and evaluate the reservoir. Since the discovery of the Kela 2 gas field and the Dina 2 gas field, there was no further progress at one time.

Recently, a serie of technique research aimed at the targeting Cretaceous subsalt rocks strata in Kuqa foreland thrust belt has been carried out: The application of wide line and large geophone array seismic acquisition technique in complex mountainous areas can effectively improve the quality of seismic data; With 3D anisotropy seismic pre-stack migration technique, the seismic imaging and migration homing problem of the complex over-thrust and the irregular object is effectively resolved; The modeling technology of the compressive salt-related structures effectively guides the high and steep complicated structure interpretation; The technique of recognizing and forecasting of the thick conglomerate layer in shallow strata can be applied to build the seismic velocity field and confirm the traps.

The great progress in exploration technology has enriched the geological understanding and brought about three major changes in exploration: In Kelasu structure zone, the exploration target turns to deep strata from the shallow ones; In eastern Kuqa depression, it goes to tight sand gas exploration while in the western part it switches to the lithologic hydrocarbon reservoir exploration. In this way, the subsalt layer hydrocarbon exploration has made a great breakthrough, companied with a new gas exploration upsurge. In five years, Dabei-3, Keshen-2, Keshen-5, Bozi-1, Keshen-8 and many other gas reservoirs have been found. 800 billion cubic meters of natural gas has been confirmed and about 30 important traps have been reserved. The total natural gas reserves amount has exceeded 2 trillion.
Response Analysis of Pipeline Subjected to Active Fault
Authors: Jiao ZhongLiang , Wang BaoQun , Wu Bin
Published: May 2016

Aiming at the requirement of pipelines' seismic design, the code of "Seismic Technical Code for Oil and Gas Transmission Pipeline Engineering" was published, and the code presented the seismic design method of pipelines subjected to active fault, and pointed out that finite element method is necessary when pipeline is axial compressed. Based on the strain calculation method proposed by the code, this paper discuss the influence factors such as pipeline-fault angle and pipeline buried depth, then presents pipeline strain variation trend when subjected to active fault movement. Meanwhile, this paper adopts finite element method to analyze pipeline strain distribution, and points out that pipeline strain is composed of axial tension/compress strain and bend strain, which could explain the pipeline strain distribution, and the elliptic phenomenon of pipeline should be considered in the future research works and code revision. This paper provides the technical reference for pipeline seismic design.
Integrated Geological, Petrophysical and Geophysical Characterisation of a World Class Shale Gas Play, Horn River Basin, British Columbia, Canada
Authors: Potma Ken , Jonk Rene , Davie Matthew , Austin Nick
Published: May 2016

The Devonian-aged strata of the Horn River Basin, located in northeast British Columbia, Canada, host a giant shale-gas play with an estimated OGIP of 14.2 trillion cubic metres (500 TCF). Ten distinct mudstone reservoir and non-reservoir lithofacies can be recognized in core, differentiated with a suite of wireline well logs and inverted from seismic data. Reservoir lithofacies are rich in total organic carbon (TOC) and the predominant pore type is organic micro-porosity. These lithofacies are predictable within a sequence stratigraphic framework which allows us to interpret the depositional processes, map the resulting depositional geobodies and thereby optimize the development plan.

Motivation

Lithofacies classifications associate sedimentary characteristics with depositional processes. In petroleum exploration and development, lithofacies classifications are typically tied to porosity and permeability - the two key parameters that control productive capacity. A powerful tool is obtained when the lithofacies classification is constructed within a predictive sequence stratigraphic framework that integrates geological and geophysical data. Although depositional processes and environments for fine-grained, organic-rich sedimentary rocks are not as well established as those for coarse siliciclastic or for carbonate systems, herein we show how we adapted a "conventional" workflow to allow such prediction in an "unconventional" shale hydrocarbon system.
Production Transformation in Horizontal Wells
Authors: Edward B. , Katavut C. , Chantarat L. , Gordon Goh K.F. , Wachiragorn P.
Published: May 2016

Pan Orient Energy (POE) recognized that horizontal wells maximise fractures' intercept, thus improving drainage area for oil recovery. However, production data indicated horizontal wells on standalone basis, cannot guarantee the optimum performance required. The negative impact of downhole inflow imbalance along the entire horizontal wellbore is much worse in fractured reservoir due to the high contrast in permeability between macro fractures, micro-fractures and the core matrix inflow. In order to provide an inflow-control defense system downhole, ICD's application has been tested successfully in Bo Rang field and proved to normalise non-uniform influx to control water influx, thus optimising oil reciprocally.

With its single-string and one run-in-hole trip, ICD's execution is cost-effective and a low-risk yet simple operation in terms of safety, i.e. comparable to running standalone screen procedures. Upon overcoming the shallow volcanic fractured reservoir workover and lift challenges, this ground-breaking technology application success on the ICD pilot recompletion has bear fruits over the following production impact as such:Actual oil production exceeds targeted rate-improvement two-fold in Bo Rang Well A first pilotTransforming production for high water-cut well from the conventional choking-back and cyclic on-off production to the ICD's increased surface rate production with ESP lift and higher overall oil4 ICD's recompletion well installed to-date with all achieve and/or exceed oil-incremental expectation and water-cut reduction targetExisting high-water cut (WC=90%) old wells are revived with significant oil-incremental by ICD's re-distributed

Inflow across major fractures and /or micro-fractured horizontal well production

This is the first successful ICD's application in shallow fractured volcanic reservoirs worldwide, unlike in the common sandstones or carbonate fractures. The post-job production-upside significance of ICD's application in such worst-case scenario of recompleting in existing high WC wells has provided optimism and way-forwards to apply it in new sidetrack wells and the adjacent sandstones reservoir in the on-going development campaign.
Pressure Drop Reduction of Stable Water-in-Oil Emulsion Flow: Role of Water Fraction and Pipe Diameter
Authors: Al-Yaari M. , Al-Sarkhi A. , Hussein I. , Abbad M. , Chang F. , Abu-Sharkh B.
Published: May 2016

Emulsified acids provide significant benefits in stimulating oil and gas wells by slowing the reaction rate with carbonates and reducing corrosion in the tubular goods. However, pumping emulsified acids can result in high friction losses and hence reducing stimulation effectiveness. Therefore, reducing friction pressure loss is an important factor in expanding the application of emulsified acids. This experimental work aims to investigate a possible friction reduction through the control of water fraction as well as pipe diameter.

Surfactant-stabilized water-in-oil emulsions with different water fraction were created. Pressure drop measurements of the flow of all formed emulsions were conducted in a flow loop consisting of 1-in and 0.5-in horizontal pipe diameters at 77 oF emulsion temperature. Such results were explained in terms of emulsion viscosity as well as the average droplet size and distribution of the emulsion dispersed phase (water).

The results showed that stable water-in-oil emulsions are strong function of the dispersed water fraction. As water fraction increased, emulsion pressure drop increased. This was attributed to the increase in the emulsion viscosity due to an increase in the water fraction. Therefore, water-in-oil emulsion frictional pressure drop can be reduced by reducing water fraction. In addition, decreasing pipe diameter from 1-in to 0.5-in resulted in up to 74% reduction in emulsion friction factor and such dependency was clearer as water fraction increased.

Introduction

Under certain conditions, the injection of water into a crude oil pipeline results in a significant reduction of pressure loss, thereby facilitating oil transportation. Therefore, cocurrent flow of oil and water in pipelines has attracted the interest of researchers (Russel et al. (1959), Charles et al. (1961), Hasson et al. (1970), Oglesby et al. (1979), Arirachakaran et al. (1989), Valle and Kvandal (1995), Beretta et al. (1997), Angeli and Hewitt (2000), Soleimani et al. (2000) and Al-Yaari et al. (2008, 2009 & 2012)). However, the majority of studies reported in the literature, is mainly focused on either oil-water flow patterns or separated flows. The pipeline flow behavior of water-in-oil and/or oil-in-water emulsions has received less attention compared with separated flows.
Integrated Information Management to Enable Manufacturing Style E & P: Enterprise Architecture
Authors: Reagan Randy
Published: May 2016

Overview

The high well counts of the unconventional gas business of SCEPCo in China require a more efficient approach to sharing data than in a typical Exploration & Production (E&P) business. High volume well delivery requires standard, repeatable processes where inputs to each task in the process arrive in a timely, reliable manner. In addition to materials and services, the process inputs include information.

Time wasted finding and cleaning data created by different functions can be a much bigger barrier to profitability in a high well count/ low margin business, than in a conventional E&P business.

The integrated approach to information at SCEPCo relies on Enterprise Architecture for managing data that includes:Standard, quality data, shared across all subsurface, engineering, production and support functions.Interweaving the flow of information with the flow of activities in developing end to end processesMeasuring data quality where it is captured.Making information easy to find by eliminating departmental or personal data storage in favor of a few enterprise data stores.

The Enterprise Architecture (EA) approach to information is applicable across a wide variety of oil & gas business models, but is particularly valuable in high-volume, low-margin businesses.

The presentation will cover specifically what is being done in information management at SCEPCo with a focus on data that crosses processes and function.

The information presented will add knowledge of how the EA approach in other industries can be successfully applied to the petroleum industry.
A Novel, Chemistry-Based Approach to Fluid Diversion in Hydrocarbon Based Paraffin Solvent Treatments
Authors: Wiggins Chris , Quintero Harvey , Ubana Lea
Published: May 2016

Paraffin deposition is a commonly experienced problem throughout the petroleum industry, and especially in certain reservoir fluids found in the Western Canadian Sedimentary Basin (WCSB). As hydrocarbons are produced from the relatively high pressure and temperature found in the reservoir, fluids experience a thermal cooling, as well as significant pressure decreases. These alterations in the fluid thermodynamics can lead to the instability and eventual deposition of paraffins from the hydrocarbon matrix. As production continues, these paraffin deposits can result in significant flow impairment in downhole and surface facilities.

Aromatic and aliphatic compounds are commonly used as remediation methods for the dissolution of these paraffins. However, one of the most significant challenges in ensuring an effective remedial treatment is maintaining optimal fluid placement. Given a lack of diversionary placement methods, fluids will preferentially take the path of least resistance. This path does not necessarily coincide with desirable solvent placement for optimum contact with the organic solids. Instead, expensive solvents can be rendered ineffective through a lack of contact.

In order to counteract poor fluid placement, a variety of chemical and mechanical diversionary methods have been developed for use in acid or solvent treatments. Mechanical methods rely on tools or packers to force remediation fluids into the desired location. Chemical methods often rely on a viscosification to force remediation fluid from the path of least resistance into the desired areas.

To date, the majority of chemical diversion methods have been utilized for acidization treatments, while hydrocarbon based solvents have largely relied on mechanical means of isolation. This paper will provide details on the development, laboratory testing, and case study of a novel chemical system intended to provide diversion for an aliphatic and aromatic based solvent. The use of a delayed viscosifying agent can be custom tailored for each individual wellbore scenario, allowing for optimal fluid placement.
Perforation Optimisation for Long Horizontal Wells in Heterogeneous Reservoirs
Authors: Pang Wei , Zhang Tongyi , Chen Dechun , Jiang Lifu , Li Changheng
Published: May 2016

Perforated completion is one of the most common completion methods for horizontal wells and perforation density optimisation plays a crucial role in alleviating water cut of wells in water-driven reservoir. Unscientific perforation scheme may leads to ununiform production influx profile and premature water breakthrough which will shorten production period, reduce production and lower ultimate recovery. Numerous theoretical models on perforation distribution design have been proposed. However, with horizontal wellbore becoming longer and longer and heterogeneous reservoirs growing into mature (or high water cut) period, perforation density optimisation based on reservoir description becomes urgent for water breakthrough retardation as well as water crest blocking. By now, the published models haven't genuinely met this requirement.

A coupled numerical reservoir/wellbore model for horizontal wells is presented taking reservoir fluid flow in porous media, near wellbore inflow and wellbore conduit flow into consideration based on reservoir numerical simulation and wellbore dynamics, hence a perforation density optimisation method following influx-control theory is proposed. Sensitivity analysis on perforation distribution as well as influx profile of three effects including horizontal length, pressure drawdown in wellbore, and permeability heterogeneity carried out. Results show that perforation density optimisation is a compromised result of the above three parameters; the heel (toe) section filtration difference will dominate perforation optimisation when the horizontal length is short, and on the other hand, pressure drawdown will have significant effect on perforation especially when the horizontal well has fully penetrated the reservoir or the pressure drawdown is big enough; to obtain homogenized production influx profile, perforation density should be lower in high-permeability section than that in low-permeability stripe.

The research proposes an improved model for perforation design and optimisation of long horizontal wells. It also provides a basis for other completion types like inflow control device and intelligent completion.
Investigation of Waterflooding Performance of Multilayered Reservoir by Pore Scale Network Modelling and Combined Coreflooding
Authors: Zhenpeng Leng , Qingjie Liu , Zubo Zhang , Weifeng Lv
Published: May 2016

The heterogeneous property of multilayered reservoir play very important role in the waterflooding performance. At present, it is difficult in characterization of cross-flow and fingering in reservoir scale injection processes and simulating it in laboratory. Although some methods like traditional research methods, experimental physics modeling and numerical simulation of different scales, can obtain some macroscopic insights, they were not suitable to study phenomenon of cross-flow and fingering in multilayered models from micro-mechanism perspective. As a computer stochastic-simulating technology in reservoir physics, pore scale network model has been used in many fields, such as single-phase flow simulation, multi-phase flow simulation, and chemical flooding simulation, etc. A special network model which is suitable for simulation of multilayered models is introduced in this article. In order to describe heterogeneity between layers, framework of the special network model is combining of different small frameworks that represent radii distribution of pores and throats of different layers. Quasi-static flow rule is applied in this paper, which is more comprehensive than static flow rule and faster in simulation computation than dynamic flow rule. Notice that a new dimensionless variable, which is a combination of viscous forces, capillary forces and gravity forces, is introduced in this model to control cross-flow and fingering.

Two multilayered physics modeling experiment are conducted in this work. Through CT scanning method, invading front could be identified clearly at different flooding stages. Invading front shapes were almost the same when comparisons with network modeling results. It indicates that the proposed dimensionless variable described microscopic mechanism of cross-flow and fingering phenomenon well.
Advanced Geophysical Methods for Imaging Carbonate Reservoirs
Authors: Boelle J.-L. , Paternoster B. , Leclercq M. , Guilloux Y. , Landa E. , Radigon M. , Mahgoub M.
Published: May 2016

We present in this work an exhaustive seismic study which was performed on a subset of a wide azimuth Ocean Bottom Cable seismic acquisition shot over a carbonate field from the U.A.E. Most of these results were published in Guilloux et al. (2012).

A first challenge was to reprocess these data ensuring that the azimuthal information is properly preserved all along the sequence. An additional challenge is related to the very shallow water environment which brings complexity like dispersive ground-roll and water layer related guided waves, multiples which can be generated at sea-surface, sea-floor or internally, near-surface heterogeneities.

On top of that the high velocities which are encountered in these carbonate formations are detrimental to a high resolution description of reservoirs.

Two main issues are presented:Wide azimuth processing: the whole sequence was designed in order to preserve the azimuthal information. Multiples were attenuated in a cascaded approach including 3D predictive deconvolution and wide azimuth high resolution radon filtering. The Common Offset Vector strategy was followed at the imaging step to build 3D Common Image Gathers versus offset and azimuth, which enables to apply an azimuthally variant residual velocity correction and then stack all azimuthal contributions in an optimal manner.Heterogeneities and fracture characterization: we tested a newly developed technique for imaging the diffractions. This approach is not limited to description of fractures, it can describe and characterize any kind of heterogeneity, it is then well suited to describe carbonate reservoirs.

This pilot processing study enabled to set up an operational wide azimuth processing sequence on this dataset, several processing scenarii could be tested and compared. In particular the sequence for attenuation of multiples was considered efficient, bringing a lot of character to the final result.

The implementation of multi-azimuth Diffraction Imaging over this carbonate reservoir is proving very encouraging. Numerous detected features display geologically meaningful characteristics, some of them being not visible on conventional structural attributes. This study would be among the first applications of the methodology with tangible results providing more static and dynamic fracture data become available for calibration.
HPHT Well Basis of Design Case Study: Offshore Thailand Advanced Tubular Analyses Experience
Authors: Rosland Habil Akram , Effendhy E. , Park S.J.
Published: May 2016

In 2011, a major exploration and production oil company drilled and tested an HPHT well, the Tong Rang 3. This well is located in Bongkot field, Gulf of Thailand, about 722 km from Bangkok.

This paper highlights the outcome of a post-drilling review using the Tong Rang 3 as a case study with respect to the well-design models and steps that the company will be taking towards optimizing its higher degree of HPHT development wells, which include future challenging prospects in the Gulf of Thailand.

Aside from stress and pressure profiles, a good understanding of the temperature regime and heat transfer in HPHT wellbores is an important aspect of the planning process. The logs and actual well-testing operations in the Tong Rang 3 confirmed that the hydrocarbon produced contains gas condensate with 31.5% CO2. The maximum circulating temperature was diagnosed to be around 207°C while drilling to TD with a mud-cooling system in place and bottomhole temperature in excess of 227°C during well testing and a tubing-head temperature of 60°C.

To improve the quality of the well design and planning process, the company has realized the importance of a case study to establish a guideline in their well-integrity process, thereby allowing the drilling team to plan similar wells using proper engineering assumptions, including basis of design refinement, based on the company's well engineering policies. The study will not only enable aiding the wellbore and completion optimization, but can be used to improve decision making throughout the field-development campaign, thus avoiding possible underdesign and achieving long-term well integrity and cost optimization.

This paper will detail aspects of the well design incorporated in the Tong Rang 3 and provide a discussion and comparison between the plans vs. the actual design throughout the execution of this HPHT well, focusing on advanced tubular design from a temperature simulations aspect. It will also highlight the effect of tubular heat-up through comprehensive sensitivity analyses, while understanding how the currently available technology can be used to support an integrated basis of design model to successfully establish a representative HPHT wellbore configuration, subsequently signifying relevant well-construction parameters to ensure an effective and safe design for future HPHT wells.

Introduction

The casing-design process, including the production tubing string, is generally developed or reviewed by experienced personnel, and it is essential that the basis of design is designed to withstand all planned life-cycle well-loading conditions without loss of well integrity. Industry-standard casing-design software is typically used for surface, intermediate, and production casing, emphasizing in complex well-design work, which includes different well types, such as HPHT, deepwater, ERD, ultra-deep gas, sealed annulus, hydraulic fracturing or injector, and gas storage.
Multizone Tight Gas Completions in the Piceance Basin: Over a Decade of Learnings
Authors: Adeyeye Ajibola , Perez Romeo , Boyer Melanie , Wieland Deni , Benish Tim
Published: May 2016

In 1999, tight gas development began in Piceance Creek area of the Piceance Basin, Colorado by utilizing a new technology to individually fracture-stimulate over 50 stacked tight gas sand packages, spanning as much as 5000 vertical feet in each well. Through the completion of over 300 wells, the Just-in-Time-Perforating (JITP) technology matured and the efficiency of completion operations improved dramatically with the implementation of simultaneous operations, refined diversion techniques, optimization of the frac design, and improved water handling. Many of these improvements can be attributed to the unique advantages of the JITP process itself. For example, the low daily water requirement enabled the use a fully closed-loop water recycling and distribution system. This system delivers 100 percent of the requisite water to each frac site with minimal trucking and minimal storage on location, which reduced the overall environmental footprint. The project also heavily relied on a systematic science-based approach to optimize completion design. Statistical methods were used to deduce the impact of various fluid systems, chemicals, sand and water volumes, and other parameters associated with successful well stimulation. To improve long-term well productivity, a fit-for-purpose logging program was developed to identify and avoid sands with high risk of significant water production. The relentless focus on continuous improvement over the last several years resulted in notable reduction in completions cost per unit gas.
Diagenetic Geobodies: Fracture-Controlled Burial Dolomite Bodies in Outcrops from Northern Oman
Authors: Vandeginste Veerle , John Cédric , Beckert Julia
Published: May 2016

Diagenetic heterogeneities are difficult to predict in subsurface. Nevertheless, such heterogeneities can be crucial in hydrocarbon exploration. Diagenetic processes can significantly alter petrophysical properties of reservoir rocks, especially in carbonate rocks because of the reactive nature of the carbonate minerals. Dolomitization, i.e. the transformation of calcite (limestone) into dolomite, is a common diagenetic process in carbonate rocks.

Description:

an overview of the learning outcomes gained by studying fracture-related dolomite in outcrops of Oman and subsequent laboratory analysis over the last four years.

A combined structural, petrographic and geochemical approach was taken to study three dolomite systems occurring in different stratigraphic host rock intervals.

Application:

Structurally-controlled dolomitization (i.e. dolomitization along faults and fractures) typically occurs in burial conditions, and the resulting strong permeability anisotropies caused by the dolomite textures can cause major challenges for hydrocarbon exploration.

Results and Conclusions:

Dolomite bodies in the Precambrian Khufai Formation are related to N-S to NNE-SSW fractures, whereas dolomite bodies that mainly occur in the Jurassic host rocks occur along reactivated WNW-ESE normal faults. These fracture-related dolomite bodies are generally less than 15 m wide, but can be up to a few hundred meters long. Late-diagenetic dolomite bodies were also recognized in Permian host rocks, where they occur at or close to the contact between Permian limestone and early-diagenetic dolomite. This late diagenetic dolomite system can be traced laterally for at least hundreds of meters and occurs in wadi's about 40 km apart. Our data indicate that there were several dolomitization events in the geological history, generating dolomite bodies with different characteristics.

Technical Contributions:

This highlights the needs to understand the timing and structural setting of dolomite bodies in subsurface to improve reservoir management.
Unlocking Small-Scale GTL: Cost-Effective Platform for Producing Drop-in Fuel From Syngas via a Single-Loop, Catalytic Thermochemical Process
Authors: Boyajian George , Li Nan , Fang Howard , Qin Meifang , Koros Robert , Keller Arnold , Gal Eli
Published: May 2016

We describe a new gas-to-liquids technology that converts syngas to high-quality gasoline, diesel, and/or jet fuel through a catalytic thermochemical process that minimizes complexity, improves product quality and increases yield. Syngas-to-gasoline plus (STG+) converts 1 MMBtu of natural gas feed into ~5 US gallons of liquid fuels, enabling the use of cost-effective, small-scale (6,000 bpd) GTL plants. Our data are from laboratory research, pilot and demonstration plant operations, and independent laboratory testing. We also compare the two leading GTL technologies (Fischer-Tropsch and Methanol-to-Gasoline) to the STG+ process.

Our results are applicable to the GTL supply chain, development and operation of GTL plants, and end users of syngas-derived drop-in fuels. Because STG+ is cost-effective at scales as small as 400 bpd, it is particularly attractive for stranded or flared gas.

From pilot and demonstration plant operations, independent lab testing, university research, Aspen simulation and financial analyses, we show:The gasoline product has >91 octane, contains <1 ppm sulfur and ~0 benzene, and meets or exceeds other ASTM standards.It only requires ~$120M to build a 2,000 bpd commercial plant and produces high-quality gasoline at the cost of $65 per barrel crude oil because of its high yield and efficiency.STG+ is consistently more cost-effective, both in capital and overall costs, than Fischer-Tropsch and even the MTG processes at small, medium and large scales through a series of comprehensive technical and economical analyses.

This is the first in-depth presentation of the STG+ process comparing its properties and benefits with the FT and MTG processes.
CNG Application in Qatar
Authors: Kafood Ahmad Hassan
Published: May 2016

Natural gas has been considered as the most promising alternative fuel for its cleanliness and abundance. It has been widely replacing other conventional fuel in industrial applications as well as transportation. Nowadays, more than14.8 million vehicles are running on Compressed Natural Gas (CNG) globally, and the number is rapidly increasing due to increase of air pollution awareness and financial advantages.

There are numerous anticipated benefits of using CNG in transportation instead of conventional fuels in Qatar. In addition to its economic benefits, CNG will significantly reduce greenhouse gas emissions, which will consequently improve air quality in Qatar.

Qatar Petroleum is currently evaluating the logistical, technical, environmental and economic viability of utilizing CNG in a wide spectrum of transportation facilities in Qatar and free up equivalent quantities of gasoline and diesel for export. The study covers different aspects such as the distribution network, CNG supply points, modifications and supporting facilities required to convert gasoline and diesel vehicles to CNG.

CNG pilot project has been initiated in Qatar on November 2011 to address the full chain of CNG application in transportation; the pilot project will address the filling stations risk assessment, operational procedures, vehicles' maintenance and associated issues.

This paper will present the challenges and problems that might be encountered in the deployment of full scale CNG system in the State of Qatar and the way forward.
Invested in Unsustainability? On the Psychosocial Patterning of Engagement in Practices
Authors: Groves Christopher , Henwood Karen , Shirani Fiona , Butler Catherine , Parkhill Karen , Pidgeon Nick
Published: May 2016

Understanding how and why practices may be transformed is vital for any transition towards socio-environmental sustainability. However, theorising and explaining the role of individual agency in practice change continues to present challenges. In this paper we propose that theories of practice can be usefully combined with a psychosocial framework to explain how agency is biographically patterned and how this patterning is a product of attachment relationships and emergent strategies for dealing with uncertainty. Biographical interview data from the project Energy Biographies is used to illustrate the ways in which this theoretical approach can enhance understanding of how potential for practice change may be opened up or obstructed.
Coronary Angiographic Profile of Patients with Acute Non ST-Segment Elevation Myocardial Infarction with Chronic Kidney Disease
Authors: Kabir CM Shaheen , Malik Fazila Tun Nesa , Malik Abdul , Haq M Maksumul , Taimur Syed Dawood Md , Karim Md Rezaul , Jahan Mah Noor , Sharmin Elora
Published: May 2016

Background: Nearly 40% of patients presenting with Non ST-Segment Elevation Myocardial Infarction (NSTEMI) have Chronic Kidney Disease (CKD). CKD is a powerful predictor of adverse events among NSTEMI patients. CKD is associated with a high prevalence of obstructive coronary artery disease.Objectives: The purpose of the present study was to evaluate the severity of coronary artery disease in patients with Chronic Kidney Disease presenting with Non ST-Segment Elevation Myocardial Infarction. Methods: In this prospective observational study a total of 128 patients with NSTEMI were enrolled. They were divided equally in group I (NSTEMI with CKD) and group II (NSTEMI with normal renal function) on the basis of estimated glomerular filtration rate. Patients were considered to have CKD if he/she had documented history of CKD or estimated glomerular filtration rate <60 mL/min/1.73 m². Angiographic severity of CAD was assessed by evaluation of number of involved vessel, site of lesion, % of stenosis, ACC/AHA lesion classification (Type A, B, C) and TIMI flow grade between the groups.Results: Patients with CKD were significantly older, with a greater prevalence of hypertension, diabetes mellitus, lower left ventricular ejection fraction, and lower haemoglobin level compared with those without CKD. CKD was associated with an increased risk of triple vessel and left main disease.Conclusion: CKD strongly predicts severe coronary artery disease profile among NSTEMI patients.University Heart Journal Vol. 11, No. 1, January 2015; 18-25
Advances in Engineered Hemoproteins that Promote Biocatalysis
Authors: Stone Kari , Ahmed Syeda
Published: May 2016

Some hemoproteins have the structural robustness to withstand extraction of the heme cofactor and replacement with a heme analog. Recent reports have reignited interest and exploration in this field by demonstrating the versatility of these systems. Heme binding proteins can be utilized as protein scaffolds to support heme analogs that can facilitate new reactivity by noncovalent bonding at the heme-binding site utilizing the proximal ligand for support. These substituted hemoproteins have the capability to enhance catalytic reactivity and functionality comparatively to their native forms. This review will focus on progress and recent advances of artificially engineered hemoproteins utilized as a new target for the development of biocatalysts.
Observation of Whole Flushing Process of a River Sand Bar by a Flood Using X-Band Radar
Authors: Takewaka Satoshi
Published: May 2016

Morphological changes during a flood event in July 2010 were observed with X-band marine radar at the mouth of Tenryu River, Shizuoka, Japan. Radar images were collected hourly for more than 72 h from the beginning of the flood and processed into time-averaged images. Changes in the morphology of the area were interpreted from the time-averaged images, revealing that the isolated river dune was washed away by the flood, the width of the river mouth increased gradually, and the river mouth terrace expanded radially. Furthermore, image analysis of the radar images was applied to estimate the migration speed of the brightness pattern, which is assumed to be a proxy of bottom undulation of the river bed. The migration was observed to be faster when the water level gradient between the river channel and sea increased.
New Approach for Fractional Order Derivatives: Fundamentals and Analytic Properties
Authors: Karcı Ali
Published: May 2016

The rate of change of any function versus its independent variables was defined as a derivative. The fundamentals of the derivative concept were constructed by Newton and l’Hôpital. The followers of Newton and l’Hôpital defined fractional order derivative concepts. We express the derivative defined by Newton and l’Hôpital as an ordinary derivative, and there are also fractional order derivatives. So, the derivative concept was handled in this paper, and a new definition for derivative based on indefinite limit and l’Hôpital’s rule was expressed. This new approach illustrated that a derivative operator may be non-linear. Based on this idea, the asymptotic behaviors of functions were analyzed and it was observed that the rates of changes of any function attain maximum value at inflection points in the positive direction and minimum value (negative) at inflection points in the negative direction. This case brought out the fact that the derivative operator does not have to be linear; it may be non-linear. Another important result of this paper is the relationships between complex numbers and derivative concepts, since both concepts have directions and magnitudes.
Fractional Schrödinger Equation in the Presence of the Linear Potential
Authors: Liemert André , Kienle Alwin
Published: May 2016

In this paper, we consider the time-dependent Schrödinger equation: i ∂ ψ ( x , t ) ∂ t = 1 2 ( − Δ ) α 2 ψ ( x , t ) + V ( x ) ψ ( x , t ) , x ∈ R , t > 0 with the Riesz space-fractional derivative of order 0 < α ≤ 2 in the presence of the linear potential V ( x ) = β x . The wave function to the one-dimensional Schrödinger equation in momentum space is given in closed form allowing the determination of other measurable quantities such as the mean square displacement. Analytical solutions are derived for the relevant case of α = 1 , which are useable for studying the propagation of wave packets that undergo spreading and splitting. We furthermore address the two-dimensional space-fractional Schrödinger equation under consideration of the potential V ( ρ ) = F · ρ including the free particle case. The derived equations are illustrated in different ways and verified by comparisons with a recently proposed numerical approach.
Influence of Donor Age on Mouse Islet Characteristics and Transplantation
Authors: Juang Jyuhn-Huarng , Hsu Brend Ray-Sea , Kuo Chien-Hung , Yao Nan-Kuang
Published: May 2016

Old donor age has been considered as a risk factor and relative contraindication for transplantation. This study was designed to investigate the influence of donor age on islet characteristics and transplantation. Islets isolated from 8 (I-A)-, 32 (I-B)-, or 64 (I-C)-week-old C57BL/6 mice were studied for number, size, insulin content, and secretion. After syngeneically transplanting 300 islets under the kidney capsule of strep-tozotocin-diabetic mice (R-A, R-B, and R-C, respectively), we measured recipients' metabolic parameters as well as the β-cell mass and insulin content of the graft. Eight-week-old donors had better glucose tolerance than 32- and 64-week-old donors. However, 64-week-old donors had more pancreatic insulin content than 8- and 32-week-old donors. I-B and I-C were greater in number, larger in size, and higher in insulin content than I-A. But perifusion study showed I-C secreted less insulin, albeit with a similar stimulation index compared with that of I-A and I-B. After transplantation, the fall of blood glucose in R-C was faster than that in R-A and R-B. At 12 weeks, the recipients' blood glucose, body weight, HbA1c, and the β-cell mass and insulin content of the graft were comparable in all groups. However, R-C had better glucose tolerance than R-A. During follow-up, R-A and R-B maintained lifelong normoglycemia and their glucose tolerance did not deteriorate. These data indicate that islets isolated from donors with different ages have different characteristics and effects on transplantation. The islets isolated from aged donors are functioning well and can be a potential source for transplantation; however, because we transplanted a large islet mass from the aged donors, the role of the islet dose needs to be further clarified.
Remyelination of Demyelinated CNS Axons by Transplanted Human Schwann Cells: The Deleterious Effect of Contaminating Fibroblasts
Authors: Brierley C. M. H. , Crang A. J. , Iwashita Y. , Gilson J. M. , Scolding N. J. , Compston D. A. S. , Blakemore W. F.
Published: May 2016

Areas of demyelination can be remyelinated by transplanting myelin-forming cells. Schwann cells are the naturally remyelinating cells of the peripheral nervous system and have a number of features that may make them attractive for cell implantation therapies in multiple sclerosis, in which spontaneous but limited Schwann cell remyelination has been well documented. Schwann cells can be expanded in vitro, potentially affording the opportunity of autologous transplantation; and they might also be spared the demyelinating process in multiple sclerosis. Although rat, cat, and monkey Schwann cells have been transplanted into rodent demyelinating lesions, the behavior of transplanted human Schwann cells has not been evaluated. In this study we examined the consequences of injecting human Schwann cells into areas of acute demyelination in the spinal cords of adult rats. We found that transplants containing significant fibroblast contamination resulted in deposition of large amounts of collagen and extensive axonal degeneration. However, Schwann cell preparations that had been purified by positive immunoselection using antibodies to human low-affinity nerve growth factor receptor containing less than 10% fibroblasts were associated with remyelination. This result indicates that fibroblast contamination of human Schwann cells represents a greater problem than would have been appreciated from previous studies.
Phylogeographic analyses and genetic structure illustrate the complex evolutionary history of Phragmites australis in Mexico
Authors: Colin Ricardo , Eguiarte Luis E.
Published: May 2016

PREMISE OF THE STUDY:

Genetic data suggest that three lineages of Phragmites australis are found in North America: the Native North American lineage, the Gulf Coast lineage, and the Invasive lineage. In Mexico, P. australis is a common species, but nothing is known about the distribution or ecology of these lineages. We examined the phylogeography of P. australis to analyze the current geographic distribution of genetic variation, demographic history, and dispersal patterns to better understand its evolutionary history in Mexico.

METHODS:

We sampled 427 individuals from 28 populations. We used two noncoding regions of chloroplast DNA to estimate the levels of genetic variation and identified the genetic groups across the species' geographical range in Mexico. We compared the genealogical relationships among haplotypes with those previously reported. A hypothesis of demographic expansion was also tested for the Mexican P. australis lineages.

KEY RESULTS:

We found 13 new haplotypes native to Mexico that might be undergoing an active process of expansion and diversification. Genealogical analyses provided evidence that two independent lineages of P. australis are present in Mexico. The invasive lineage was not detected with our sampling. Our estimates of population expansions in Mexico ranged from 0.202 to 0.726 mya.

CONCLUSIONS:

Phragmites australis is a native species that has been in Mexico for thousands of years. Genetic data suggest that climatic changes during the Pleistocene played an important role in the demographic expansion of the populations that constitute the different genetic groups of P. australis in Mexico.
Stability and Compatibility of Antibiotics in Peritoneal Dialysis Solutions Applied to Automated Peritoneal Dialysis in the Pediatric Population
Authors: Deslandes Guillaume , Grégoire Matthieu , Bouquié Régis , Le Marec Aude , Allard Sophie , Dailly Eric , Pineau Alain , Allain-Launay Emma , Jolliet Pascale , Roussey Gwenaëlle , Navas Dominique
Published: May 2016

Objectives

Assess the stability of several antibiotics in peritoneal dialysis (PD) solutions under common conditions of use in pediatrics, particularly in automated PD.

Methods

Amoxicillin, cefazolin, cefepime, ceftazidime, imipenem, cotrimoxazole, tobramycin, vancomycin, and the association of ceftazidime + vancomycin and ceftazidime + tobramycin, were tested in 3 different PD solutions: bicarbonate/lactate solution with 2 glucose concentrations (Physioneal 1.36 and 3.86%; Baxter Healthcare Corporation, Deerfield, IL, USA) and an icodextrin-containing solution (Extraneal; Baxter Healthcare Corporation, Deerfield, IL, USA). Concentrations were those recommended in guidelines for the treatment of peritonitis in pediatrics. Physioneal bags were incubated at 37°C for 24 hours, whereas Extraneal bags were stored 12 hours at room temperature (22 ± 2°C) and then 12 hours at 37°C. Drug concentrations were determined using high performance liquid chromatography (HPLC). Each measure was taken in triplicate. Stability of antibiotics was defined as less than 10% degradation of the drug over time.

Results

Cefazolin, cotrimoxazole, tobramycin, and vancomycin were stable under studied conditions. Ceftazidime was stable 24 hours in icodextrin, 12 hours in Physioneal 1.36% and 6 hours in Physioneal 3.86%. The association of tobramycin or vancomycin did not influence the stability of ceftazidime. Cefepime and amoxicillin were stable 6 h, 4 h, and 8 h in Physioneal 1.36%, 3.86% and Extraneal, respectively. The stability of imipenem was very low: 2 h in Physioneal and 6 h in Extraneal. Moreover, an increasingly yellow coloration was observed with the use of imipenem, whereas no color change or precipitation occurred in other bags.

Conclusion

Cefazolin, tobramycin, cotrimoxazole, and vancomycin are stable in PD solutions up to 24 hours and can be administered in the PD bag for the treatment of peritonitis, even in automated PD under studied conditions. However, amoxicillin, cefepime, ceftazidime, and imipenem must be used with caution due to their lack of stability.