bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inter Well Tracer Test Results in the Mature Oil Field La Cira Infantas
Authors: Morales Victor Alfonso , Ramirez Leyla Kristle , Garnica Sandy Vanessa , Rueda Luz Adriana , Gomez Vicente , Gomez Adriana , Bejarano Maria Angelica , Shook G. Michael 
Published: March 2018

Abstract
La Cira Infantas is the oldest oil field in Colombia with approximately 100 years of production history, located in the Middle Magdalena Valley Basin. The field production comes from the C zone reservoir of Mugrosa Formation where the depositional environment is a fluvial meandering system. The reservoir has a high heterogeneity and it is defined as an interbedding of sandstones, shales and siltstones with an average thickness of 600 ft and a permeability range from 80 mD to 2 Darcy. The field has been under secondary recovery since the 1960's and in 2005 a redevelopment of the water flooding process began. The field has approximately 400 patterns and 1,000 active producer wells, 95% of which are under a water flooding process. Injector wells have a selective string completion, composed of mandrels and packers, independently injecting in different sand units. Currently, there are patterns with low areal efficiency and consequently lower than expected recovery factor. An interwell tracer project was executed in a six pattern pilot sector, composed of 16 distinct mandrels, in order to validate the need of a conformance treatment to improve current conditions and have a better understanding of the reservoir connectivities. In each selected mandrel a unique tracer family was used in order to accurately intepret breakthough results.
The workflow in the project starts by using the results of the tracer test to estimate swept volume and flow geometry in all patterns. The swept zone represents the thief zone in each pattern and provides an insight of how poor the areal efficiency of the pattern is. Flow geometry is represented in an F- Φ curve and the tangent is related to the residence time of an arbitrary flow line, which is used to first recognize the need for a conformance job and then to calculate the fraction of the swept volume needed to treat. The last step of the workflow is to estimate the incremental oil production rates derived from treating the thief zone. Two analytic methods were derived for the incremental oil production rate estimates. The conformance candidates were ranked according to treatment volume vs. incremental oil recovered over a two-year timeframe. Those results are in process of being analyzed.
The results of the inter-well tracer showed that conformance is needed in 6 individual mandrels and there is a strong relationship between the facies architecture and the flow distribution of the injected water. Also, it will improve the definition of the job portfolio for the conformance project which considers 80 candidates and 2.7 MMBO resources.
The application of conformance treatments is a novelty in multilayer mature oil fields under water flooding process in Colombia, and the study of inter well tracers is essential for the success of this IOR technology.
Assessing Productivity Impairment of Surfactant-Polymer EOR Using Laboratory and Field Data
Authors: Izadi M. , Vicente S. E. , Zapata Arango J. F. , Chaparro C. , Jimenez J. A. , Manrique E. , Mantilla J. , Dueñas D. E. , Huertas O. , Kazemi H. 
Published: March 2018

Abstract
Surfactant-polymer (SP) flooding (also known as micellar flooding) is an enhanced oil recovery (EOR) process resulting from the interaction of three mechanisms: (1) oil solubilization, (2) interfacial tension reduction, and (3) aqueous-phase mobility reduction by polymer. Surfactant-polymer flooding has been studied both in the laboratory and field pilot tests for several decades. In SP flooding, traditionally a tapered polymer solution follows the injected surfactant slug. However, in recent years, co-injection of surfactant and a relatively high concentration of polymer solution has been used in several field trials. Despite a significant increase in oil recovery in several surfactant-polymer flood projects, the increased oil production period has been of short duration.
The first objective of this paper is to present two field pilot tests which encountered productivity impairment, and the second objective is to describe the probable causes of the productivity impairment. The third objective of the paper is to present a methodology, using field and laboratory data, to anticipate the nature of long-term problems. To shed light on the issues, we will present two pilot tests located in the Illinois basin in the United States and San Francisco Field in Colombia. The results of the pilot tests and several laboratory experiments will be presented to address the productivity loss observed in the two pilot projects. Laboratory measurements to determine crude oil propensity for emulsions, with and without surfactants, are not part of the routine chemical EOR protocol in the industry. Nonetheless, understanding the cause and type of emulsion formation in crude oil, brine, and polymer at different salinities is critical and will be presented in the paper. In addition, in the paper, we will present the results of a numerical simulator to evaluate experimental laboratory results and the field test performance. In conclusion, because of the experience with numerous laboratory experiments and the conduct of associated field tests, we will be able to shed light on the complexity of surfactant-polymer EOR field applications.
Beneficial Relative Permeabilities for Polymer Flooding
Authors: Seright R. S. , Wang Dongmei , Lerner Nolan , Nguyen Anh , Sabid Jason , Tochor Ron 
Published: March 2018

Abstract
This paper examines oil displacement as a function of polymer solution viscosity during laboratory studies in support of a polymer flood in the Cactus Lake reservoir in Canada. When displacing 1610-cp crude oil from field cores (at 27°C and 1 ft/d), oil recovery efficiency increased with polymer solution viscosity up to 25 cp (7.3 s-1). No significant benefit was noted from injecting polymer solutions more viscous than 25 cp. Much of the paper explores why this result occurred. That is, was it due to the core, the oil, the saturation history, the relative permeability characteristics, emulsification, or simply the nature of the test? Floods in field cores examined relative permeability for different saturation histories—including native state, cleaned/water-saturated first, and cleaned/oil-saturated first. In addition to the field cores and crude oil, studies were performed using hydrophobic (oil-wet) polyethylene cores and refined oils with viscosities ranging from 2.9 to 1000 cp. In nine field cores, relative permeability to water (krw) remained low—less than 0.03 for water saturations up to 0.42. Relative permeability to oil (kro) remained reasonably high (greater than 0.05) for most of this range. At a given water saturation, krw values for 1000-cp crude oil were about ten times lower than for 1000-cp refined oil. These observations help explain why only 25- cp polymer solutions were effective in recovering the viscous crude oil. In contrast to results found for the Daqing polymer flood, no evidence was found that high-molecular-weight (Mw) HPAM solutions mobilized trapped residual oil in our application. The results are discussed in light of ideas expressed in recent publications. The relevance of the results to field applications is also examined. Although 25-cp polymer solutions were effective in displacing oil during our core floods, the choice of polymer viscosity for a field application must consider reservoir heterogeneity and the risk of channeling/viscous fingering in a reservoir.
Measuring Relative Permeability in Cores at Reservoir Pressures Using a Gravity Drainage Method
Authors: Churchwell Lauren , DiCarlo David 
Published: March 2018

Abstract
Three-phase relative permeabilities are typically measured in cores using either steady-state or Johnson Bossier, and Naumann (JBN) methods. These methods require assumptions that can lead to erroneous relative permeability data. One alternative approach is a gravity drainage method, which has previously been used in sandpacks and recently extended to cores at atmospheric conditions. Here, we test a gravity drainage method that can be used to measure relative permeability in cores at elevated pressures. To achieve this, nitrogen gas is injected to the core at a low flow rate to overcome capillary pressure. We test the method by measuring two-phase water relative permeability in a Berea sandstone core using two gas flow rates: one that is low enough that gravity is a significant driving force for the flow, and a higher flow rate for comparison. During drainage, water saturation is measured along the length of the core at different times using a CT scanner, and pressure drops are measured across five sections of the core. The relative permeability of water is calculated using data points in regions of the core where the saturation is changing in time but not space, allowing capillary end effects and capillary pressure gradients to be ignored. Relative permeability data from the low flow rate experiment are scattered widely; the low gas flow rate likely hindered the free drainage of the water. Relative permeability data from the higher flow rate experiment formed a distinct curve. More flow rates will need to be tested to determine an optimum flow rate for gravity drainage experiments at reservoir pressures.
Development of a Field Scale Polymer Project in Argentina
Authors: Hryc A. , Hochenfellner F. , Best R. Ortíz , Maler S. , Freedman P. 
Published: March 2018

Abstract
After 6 years of continous polymer injection in El Corcobo Norte field, pilot's preliminar evaluation showed promising results. Although the evaluation is still ongoing, polymer technology economics look good enough to sustain a project expansion.
Located in the Neuquén Basin, El Corcobo Norte field is an unconsolidated, underpressurized, strongly water-wet sandstone reservoir, producing medium-heavy oil from the Centenario Formation. Reservoir drive is waterflood, which has been implemented since the beginning of the field's development. Up to date the field has more than 650 producers and 350 injectors, mostly developed under 20 acres, inverted 7-spot patterns. Main challenge for this field's operation is sand production and chanelling issues that leave bypassed or undrained oil zones.
Since 2008 EOR technologies were evaluated in order to increase ultimate recovery factor. As a results of this screening, polymer injection was chosen as the first candidate to test in the field. Polymer pilot design and execution was described in SPE 160078 ("Desing and Execution of a Polymer Injection Pilot in Argentina") and pilot preliminar evaluation was presented in SPE 181210 ("Evaluation of a Polymer Injection Pilot in Argentina").
Based on the pilot's learnings, an expansion project was designed to maximize the use of the available capacity and upscale polymer injection as efficiently as possible, considering field's current operational conditions.
The present article will focus on describing the upscale of the polymer pilot and the strategy to optimize the project's operation.
Experimental Investigation of Cross-Flow in Stratified Reservoirs During Polymer Flooding
Authors: Alshawaf Mohammed H. , Muggeridge Ann , Krevor Same 
Published: March 2018

Abstract
In this paper we investigate the contribution of capillary and viscous cross-flow to oil recovery during secondary polymer flooding. Cross-flow can be an important mechanism in oil displacement processes in vertically communicating stratified reservoirs. Using polymers will change the balance of these contributions. Previous numerical investigations have shown that the amount of viscous cross-flow is controlled by the layer permeability contrast and a dimensionless number that characterises the combined effects of water, polymer and oil viscosities. The highest viscous cross-flow values were observed during favourable mobility ratio floods in reservoirs with a layer permeability ratio close to 3.
The purpose of the laboratory study was to validate previous numerical studies of cross-flow performed using commercial reservoir simulators. A series of experiments were performed in glass beadpack using analogue fluids comprising water, glycerol solution (to represent the polymer) and paraffin oil. All porous medium and fluid properties (including relative permeabilities and capillary pressure curves) needed for the numerical simulations were determined independently of the displacement experiments. Two beadpacks were constructed of two layers of different permeabilities parallel to the principal flow direction. In one of the packs a barrier was placed between the two layers to prevent cross-flow. Comparing the recoveries from these enabled us to quantify the contribution of cross-flow to oil recovery. The mobility ratios examined in the experiments ranged from very unfavourable to very favourable. The layer permeability ratio was approximately 2.5.
Good agreement was obtained between experiments and simulations, without the need for history matching, demonstrating that the simulation correctly captures the physics of crossflow. The incremental oil recoveries attributable to cross-flow and mobility control both fell within the error margins of the experimentally calculated values. The experiments showed that capillary cross-flow dominated over viscous cross-flow on laboratory length scales. Having validated the simulator, we then used it to show that wettability (with and without capillary pressure) can modify the impact of cross-flow on oil recovery.
An Investigation of Retention and Unusually High Apparent Viscosity of Hydrophobically Associative Polymer in Porous Media
Authors: Han Xu , Zhang Guoyin , Yu Jianjia , Chen Zhao , Kurnia Ivan 
Published: March 2018

Abstract
In this study, we investigated the influence of polymer retention (both irreversible and reversible retentions) on the unusually high resistance factor provided by hydrophobically associative polymers (AP) in porous media. As a comparison, a commercial partially hydrolyzed polyacrylamide (HPAM) was also tested. Coreflood or dynamic method was used to assess retention (both irreversible and reversible) and resistance factor in sandstone cores at a flux of around 11 ft/d. To make fair comparison, in some corefloods, HPAM solutions was injected in the same core after the completion of associative polymer injection cycle. The results indicated: (1) the retention of fresh associative polymer was nearly four times of that from fresh HPAM and this was indicated by the residual resistance factor measurement. Resistance factor provided by fresh associative polymer was almost ten times higher than that from HPAM even though they showed similar viscosity property in a viscometer; (2) Compared with fresh HPAM, a substantial excess reversible retention (44.6 μg/g rock) was detected for fresh associative polymer that was comparable to its irreversible retention (41.0 μg/g rock); (3) Degraded associative polymer showed reduced irreversible retention (32.7% less) and almost no reversible retention difference was observed between associative polymer and HPAM. The resistance factor by degraded associative polymer was almost half of that from fresh solution. In the absence of excess irreversible and reversible retentions caused by HPAM, the degraded associative still provided much higher resistance factor than HPAM; (4) The unusually high resistance factor from associative polymer could be ascribed to the irreversible retention that caused permeability reduction, reversible retention which provided resistance to polymer flow in porous media without affecting core permeability, and also the intermolecular association between hydrophobic monomers in associative polymer.
Assessing the Effects of Short-Term Culture and Language Immersion Program: A Hong Kong Case
Authors: Du-Babcock Bertha 
Published: March 2018

<p><span style="font-family: Times New Roman;"><span style="font-size: medium;">The current study examines the effects of a four-week short-term culture and language immersion program. The Program involves four key curricular components and covered three phases: the pre-trip planning and preparations, implementation of the Program, and the post-trip debriefings. </span><span style="font-size: medium;">D</span><span style="font-size: medium;">ata were collected prior to, during, and after the students’ taking their four-week immersion program. A 360-degree assessment of the Program was employed to evaluate its effectiveness. The assessment involves </span><span style="font-size: medium;">triangulation of </span><span style="font-size: medium;">quantitative and qualitative data. </span></span></p><p><span style="font-family: Times New Roman; font-size: medium;"> </span></p><p><span style="font-family: Times New Roman;"><span style="font-size: medium;">Two statistical measurements (Analysis and Variance and Pearson Correlation Coefficient tests) were employed to assess the Program effectiveness. </span><span style="font-size: medium;">The results show that the for-week short-term culture and language immersion program achieved all its learning objectives.</span><span style="font-size: medium;"> </span><span style="font-size: medium;">By all measures, the students experienced increased confidence in using English, demonstrated a greater awareness of culture, were able to identify and explain cultural differences between Hong Kong and the host culture, and learned to apply language learning strategies and to begin to develop intercultural communication skills.</span></span></p>
Terpenes, Phenylpropanoids, Sulfur and Other Essential Oil Constituents as Inhibitors of Cholinesterases
Authors: Burčul Franko , Blažević Ivica , Radan Mila , Politeo Olivera 
Published: March 2018

:
Essential oils constituents are a diverse family of low molecular weight organic
compounds with comprehensive biological activity. According to their chemical structure,
these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes,
and "others". In addition, they may contain diverse functional groups according
to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic
hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes,
ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing
compounds (thioesters, sulfides, isothiocyanates, nitriles, and others).

:
Compounds that act as cholinesterase inhibitors still represent the only pharmacological
treatment of Alzheimer´s disease. Numerous in vitro studies showed that some compounds,
found in essential oils, have a promising cholinesterase inhibitory activity, such as α-pinene,
δ-3-carene, 1,8-cineole, carvacrol, thymohydroquinone, α- and β-asarone, anethole, etc.

:
Essential oils constituents are a diverse family of low molecular weight organic
compounds with comprehensive biological activity. According to their chemical structure,
these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes,
and "others". In addition, they may contain diverse functional groups according
to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic
hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes,
ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing
compounds (thioesters, sulfides, isothiocyanates, nitriles, and others).
Aggregation-Induced Emission Enhancement of CdSe QDs by Protamine and its Application to Sensitively and Selectively Detect Heparin
Authors: Liu Jin-Xia , Wu Mei-Xia , Ding Shou-Nian 
Published: March 2018

Background:
Heparin, it is commercially used as an anticoagulant in surgical procedures for
the prevention of blood clotting. However, overdose and prolonged use of heparin often induce potentially
fatal bleeding complication. So, it is of crucial importance to monitor closely heparin levels for
the sake of health. In this work, a sensitive fluorescence sensing platform to detect heparin was set up
based on MPA-CdSe QDs (quantum dots) and protamine enhanced fluorescent system.

Methods:
The image of CdSe QDs was taken on a JEM-2100 transmission electron microscope (JEOL
Ltd.). The fluorescence spectrum was recorded on a FluoroMax-4 fluorescence spectrophotometer
(Horiba, USA). UV–vis absorption spectrum was recorded using a Shimadzu UV-2450 Spectrophotometer
(Tokyo, Japan). A vortex mixer IKA MS3 digital was selected to mix the solution.

Results:
Under optimized conditions, the linear response to detect heparin ranges from 0.06 to 14 µg
mL-1 with a detection limit of 8 ng mL-1. The approach showed a highly selective response to heparin in
the presence of 16 interfered substances.

Conclusion:
A simple method for the detection of heparin was developed based on MPA-CdSe QDs
and protamine enhanced fluorescent system. The electrostatic effect between MPA-CdSe QDs and protamine
resulted in strong fluorescence enhancement from the MPA-CdSe QDs. Moreover, the addition
of heparin could cause a significant fluorescence decrease due to the strong affinity of protamine and
heparin. Under optimal conditions, this method displayed a low detection limit and good selectivity
over other substances.
Analytes’ Structure and Signal Response in Evaporating Light Scattering Detector (ELSD)
Authors: Dalavitsou Antonia , Vasiliadis Alexandros , Mordos Michail D. , Kouskoura Maria G. , Markopoulou Catherine K. 
Published: March 2018

Background:
Working with an Evaporative Light Scattering Detector (ELSD), the target
components are converted to a suspension of particles in a gas phase by a nebulizer and heated while
the mobile phase is evaporated. Then, the incident light is directed at the remaining particles which are
scattered and detected.

Methods:
The signal response of an ELS detector is studied through the correlation of the signal intensity
of 65 compounds (at 30, 45 and 80°C) with their structural and physicochemical characteristics.
Therefore, 67 physicochemical properties as well as structural features of the analytes were inserted as
X variables and they were studied in correlation with their signal intensity (Y variable).

Results:
The collected data were statistically processed with the use of partial least squares method. The
results proved that several properties were those that mainly affected the signal intensity either increasing
or decreasing this response.

Conclusion:
The derived results proved that properties related to vapor pressure, size, density, melting
and boiling point of the analytes were responsible for changes in the signal intensity. The light detected
was also affected by properties relevant to the ability of a molecule to form hydrogen bonds (HBA and
HBD) and its polarizability or refractivity, but at a lower extent.