bluuebunny/crossref_metadata_2025 huggingface dataset:
Inoculation Techniques for Assessing Pathogenicity of Rhizoctonia solani, Macrophomina phaseolina, Fusarium oxysporum and Fusarium solani on Pepper Seedlings
Authors: Güler Güney İnci , Güldür Ertuğrul
Published: February 2018

In this study, surveys were carried out during 2015 and 2016 for wilt and root rot diseases caused by Rhizoctonia solani, Macrophomina phaseolina, Fusarium oxysporum, and Fusarium solani in pepper fields in Adıyaman, Diyarbakır, Mardin and Şanlıurfa provinces of Turkey. The purpose of this study was to evaluate the effects of different inoculation methods (root dip, soil infestation with wheat bran and soil infestation with rice grain) on pathogenicities of R. solani, M. phaseolina, F. oxysporum and F. solani on pepper seedlings. Inoculated pepper seedlings (cv. İnan-3363) were left to grow for three months after transplanting under growth chamber conditions. Inoculation of infective rice-grain was used to test pathogenicity of all four fungi. Root dip inoculation method was used for F. solani and F. oxysporum when the soil was infested with wheat bran method for R. solani and M. phaseolina inoculation. All tested isolates resulted in the stem and root rot, leaf chlorosis and bruising. To test the pathogenicity of fungi, soil infestation with rice grain inoculation was the most suitable method. All tested fungi induced similar foliar symptoms, root rot severity and caused a similar reduction in dry root weights when rice-grain inoculum was used. With other inoculation methods, all pathogens similarly affected root rot severity. Whereas, F. oxysporum was the least virulent pathogen among tested fungi affecting foliar symptom severity; for fresh root and plant weights, and dry root and plant weights; R. solani, M. phaseolina and F. solani were similarly virulent when these parameters were used. The results of the present study may have a useful connotation to monitor pepper seedlings against these pathogens. In conclusion, we recommend rice-grain inoculation to test pathogenicities of R. solani, M. phaseolina, F. oxysporum and F. solanion various pepper cultivars.
Antalya Sahil Koşullarında Koca Fiğ (Vicia narbonensis L.) Yetiştiriciliği İçin Uygun Ekim Normunun Belirlenmesi
Authors: ÖZYİĞİT Yaşar
Published: February 2018

Bu çalışma, Antalya sahil koşullarında koca fiğ (Vicia narbonensis L.) bitkisi için en uygun ekim normunu belirlemek
amacıyla 2014-2015 ve 2015-2016 yıllarında yürütülmüştür. Deneme, tesadüf
blokları deneme desenine göre 3 tekerrürlü olarak kurulmuş ve parsellere 5 farklı ekim
normu (5, 10, 15, 20 ve 25 kg da-1) uygulanmıştır. Araştırmada bitki boyu, bakla sayısı, baklada tane sayısı, dal sayısı,
bakla uzunluğu, 1000 tane ağırlığı, tane verimi, biyolojik verim, kes verimi ve
hasat indeksi gibi bazı agronomik veriler incelenmiştir. Çalışma sonuçları, ekim normlarının incelenen bütün
özellikler üzerine istatistiki olarak önemli etkilerinin olduğunu göstermiştir.
Ekim normları artıkça bitki boyu, biyolojik verim ve kes verimi değerlerinin
arttığı, bakla sayısı, bakla uzunluğu, dal sayısı, baklada tane sayısı, 1000 tane
ağırlığı ve hasat indeksi değerlerinin ise azaldığı tespit edilmiştir. Dane
verimi ise 15 kg da-1 uygulamasında en yüksek değerine ulaşmış, daha yüksek tohum
uygulamalarında bir düşüş gözlenmiştir. Elde edilen sonuçlar değerlendirildiğinde, Antalya sahil koşullarında koca fiğ
yetiştiriciliği için en uygun ekim normunun en yüksek tane veriminin alındığı
15 kg da-1 olduğu ve bu değerden
daha fazla veya daha az uygulanacak ekim normlarının verimde düşmeye neden
olduğu sonucuna varılmıştır.
Meme kanseri kök hücrelerinde elajik asit ile indüklenmiş miRNA’ların ifadesi ve elajik asidin apoptoz üzerine etkisi
Authors: Çağlar Hasan Onur , Yılmaz Süslüer Sunde , Kavaklı Şebnem , Gündüz Cumhur , Ertürk Biray , Özkınay Ferda , Haydaroğlu Ayfer
Published: February 2018

Amaç: Östrojen bağımlı meme kanseri tümör oluşumunda etkili miRNA’lar elajik asit (EA) uygulaması ile baskılanmaktadır. Ancak, EA uygulamasından sonra meme kanseri kök hücrelerindeki (MKKH) miRNA’ların ifade profillerinin düzenlenmesi hala belirsizdir. Bu çalışmada, MKKH’lerde EA-indüklenmiş apoptozun gösterilmesi ve EA uygulamasından sonra değişen miRNA ifade profilinin belirlenmesi amaçlanmıştır.Gereç ve Yöntem: EA’nın MKKH’lerdeki sitotoksik etkisi WST-1 testi ile incelendi. EA uygulamasından sonra apoptoz ve hücre döngüsü analizleri flow sitometri ile yapıldı. EA uygulamasından sonra, MKKH’lerin miRNA ifade profilleri RT-PCR miRNA array ile tanımlandı.Bulgular: MKKH’ler üzerinde EA’nın sitotoksik etkisi saptandı. 48. ve 72. saatlerde EA’nın IC50 konsantrasyonu 24.8 μM’dı. EA, MKKH’lerde apoptozu indüklemedi. Bununla beraber, EA’nın 24., 48. ve 72. saat uygulamalarında S fazı bloğu gözlendi. Toplamda 84 miRNA geninin 76’sının ifade profili belirlendi. hsa-miR-125b-1-3p’nin ifadesi EA uygulanmasıyla 3.59 kat arttı. Let-7 ve miR-200 aileleri dahil diğer tüm miRNA’ların ifade profili EA uygulaması nedeniyle azalış gösterdi.Sonuç: Bu çalışmada, EA’nın MKKH’de apoptozu etkilemediği ve hsa-miR-125b-1-3p’in ifadesini arttırırken, başta hsa-miR-485-5p ve hsa-miR-328-3p olmak üzere diğer miRNA’ların ifadesinde düşmeye neden olduğu görüldü. Anormal miRNA ifade profili nedeniyle MKKH’lerin EA uygulamasına direnç gösterebileceği düşünüldü.
Poor breastfeeding, complementary feeding and Dietary Diversity in children and their relationship with stunting in rural communities
Authors: Zaragoza Cortes Jessica , Trejo Osti Luis Eduardo , Ocampo Torres Moisés , Maldonado Vargas Laura , Ortiz Gress Alicia Arminda
Published: February 2018

Introduction: Stunted growth is the most common manifestation of malnutrition in México. Breastfeeding, adequate introduction of complementary feeding and Dietary Diversity can avoid this.Objective: Characterize the feeding practices in children 1–24 months of age in rural communities of Hidalgo and define their relationship with stunting.Methods: A 24-hour recall was used to obtain information. Z-scores for length-for-age (ZLA), Complementary Feeding (CF) and minimal dietary diversity (MDD) were determined. The sample was divided into breastfed and not breastfed childrenResults: One hundred eighty nine mother-child dyads were evaluated; 59.3% were breastfed and 40.7% were not. Stunting was found in 10.1% and was identified starting at the fourth month of life. This was accompanied by early CF close to the third month (57.0%) and by a reduction in exclusive breastfeeding during the second month of life to only 30%. The proportion of not breastfed children with stunting (27.5%) was almost twice that of breastfed children (12.0%) (p<0.03). By age, mean ZLA was different with a trend towards stunting increasing with age (p<0.05): 1-6 months −0.463 ± 1.445; 7-12 months −0.669 ± 1.225; and 13-24 months −0.985 ± 0.917. MDD was greater in not breastfed children (69.7%) (p<0.04) and by age greater in children 13-24 months (69.7%) (p<0.02).Conclusions: The feeding practices of most mothers did not meet WHO recommendations. It is necessary to carry out nutrition education interventions aimed at mothers in rural population.
Different Farmers’ Knowledge about Managing Soils Based on Educational Degree and Participation in Farmer Group Organization (A Descriptive Study on Sukatani and Wates Jaya Villages)
Authors: Destiyani Rani Dwi , Adisyahputra Adisyahputra , Sigit Diana Vivanti
Published: February 2018

Managing soils is a beneficial effort allowing plants to grow and have dense fruit as well as to avoid them from damaging. Lack of knowledge about soil management may be related to poor soil management performance. To identify differences on farmers’ knowledge about managing soils based on their educational degree and participation in farmer group organization, thisresearch was conducted on Villages of Sukatani, Cianjur and Wates Jaya, Bogor from November to December 2012. A descriptive method with survey technique was used. Knowledge score using a multiple choice test was obtained from 89 samples selected by simple random sampling. In prerequisite testing, data was found homogenous but in abnormal distribution. Therefore, the hypothesis testing then was carried out with non-parametric tests. The average comparative rate of farmers’ knowledge based on educational degree using the Kruskal-Wallis test showed a non significant differences (p > α at 0.393 > 0.05). This occurred because farmers gained the knowledge through parental manner. Similarly, the average comparative rate of farmers’ knowledge based on their participation in farmers’ organization using the Mann-Whitney U test also showed a non-significant differences (p > α at 0.770 > 0.05). This happened because the farmers did not receive information delivered by the organization appropriately or they did not use the organization as a source of information in managing the soils. As the conclusion, educational degree and participation in organization did not cause differences to farmers’ knowledge of soil management.
Development of Digital Comic as Learning Media on Immune System Topic in SMAN 13 Jakarta
Authors: Nurinayati Fitri , Sartono Nurmasari , Evriyani Dian
Published: February 2018

Comics are popular among teenagers in which senior high school students included. One type of comics, digital comic, has recently become a global trend, which beneficial to be utilized as an effective learning media. In order to take benefits from this great opportunity, this research was aimed to develop a digital comic on immune system topic. This study was conducted at SMAN 13 Jakarta using research and development method. Samples were consisted of students and biology teacher class XI, media expert, and material expert. A total of six steps proceeded including need assesment, objective formulation, material development, instruments development, media development, and try-out and revision. During the try out test, all samples were involved as users. The product received a very good interpretation from all samples with feasibility ranged from 81,3-90,9%. This result implied that this digital comic was qualified as learning media on immune system topic for class XI.
Perfect phase-coded pulse trains generated by Talbot effect
Authors: Fernández-Pousa Carlos R.
Published: February 2018

A perfect phase sequence is a finite and ordered set of constant-amplitude complex numbers whose periodic autocorrelation vanishes at any non-zero time shift. They find multiple applications in science an engineering as phase-coded waveforms, where the sequence defines the relative phases within a burst of electromagnetic or acoustic pulses. We show how a physical propagation effect, the so-called fractional Talbot phenomenon, can be used to generate pulse trains coded according to these sequences. The mathematical description of this effect is first reviewed and extended, showing its close relationship with Gauss perfect phase sequences. It is subsequently shown how it leads to a construction of Popović’s Generalized Chirp-Like (GCL) sequences. Essentially, a set of seed pulses with prescribed amplitude and phase levels, cyclically feeds a linear and dispersive medium. At particular values of the propagation length, multiple pulse-to-pulse interference induced by dispersion passively creates the sought-for pulse trains composed of GCL sequences, with the additional property that its repetition rate has been increased with respect to the seed pulses. This observation constitutes a novel representation of GCL sequences as the result of dispersive propagation of a seed sequence, and a new route for the practical implementation of perfect phase-coded pulse waveforms using Talbot effect.
Morfologi dan Produksi Beberapa Aksesi Sagu (Metroxylon spp.) di Distrik Iwaka, Kabupaten Mimika, Papua / Morphology and Production of Some Sago Palm Accessions in Iwaka, Mimika District, Papua Province
Authors: Ahmad Fendri , Bintoro Mochamad Hasjim , Supijatno Supijatno
Published: February 2018

Sago is a carbohydrate-producing palm witharea about 382.198 ha in Mimika Regency. So far, research on the characterization of sago palm in this area has not existed, therefore it is necessary to do. The diversity of sago accessions in Mimika District is expected to be a source of germplasm and superior sago selection to support sago development. This study aims to obtain information about morphological characters and starch production of some sago accessions. The study was conducted using observation method of seven sago accessions, namely Mbupuri, Monepikiri, Mbapare, Tuwae, Aute, Iyaremeta and Bakaketemeta in Iwaka District, Mimika Regency, Papua Province. The result showed that the seven accessions sago differed based on morphological character namely stem, leaves and spine, and starch production. The Monepikiri accession has the longest stem and large stem diametre, namely 13.75 m and 59.00 cm, respectively. Accession Mbupuri has more leaves and wider leaves than the others. Accession Monepikiri has a production potential of more than 300 kg’s dried starch/palm and accession Mbupuri more than 200 kg’s dried starch/palm. Both accessions of this sago can be further investigated the stability of yield starch to be released as superior varieties. The morphological characters, especially the length of the stem affect the starch production because the starch is present in the pith of the stem.

ABSTRAK

Sagu merupakan tanaman sumber karbohidrat dengan luas areal di Kabupaten Mimika 382.198 ha. Penelitian tentang karakterisasi aksesi sagu di Kabupaten ini belum ada, oleh karena itu perlu dilakukan. Keragaman aksesi sagu di Kabupaten Mimika diharapkan menjadi sumber plasma nutfah sagu, dan untuk seleksi sagu unggul untuk menunjang pengembangan sagu. Penelitian ini bertujuan untuk  mendapatkan informasi mengenai karakter morfologi dan produksi pati beberapa aksesi sagu. Penelitian menggunakan metode observasi terhadap tujuh aksesi sagu, yaitu Mbupuri, Monepikiri, Mbapare, Tuwae, Aute, Iyaremela dan Bakaketemeta. Penelitian dilakukan di Distrik Iwaka, Kabupaten Mimika, Provinsi Papua. Hasil penelitian menunjukkan bahwa ketujuh aksesi tersebut berbeda karaktermorfologinya, yaitu  batang, daun dan duri. Aksesi Monepikiri memiliki batang yang paling panjang dan diameter paling besar berturut-turut, yaitu 13,75 cm dan 59,00 cm. Aksesi Mbupuri memiliki jumlah daun paling banyak dan daun paling luas.Aksesi Monepikiri memiliki potensi produksi lebih dari 300 kg pati kering/pohon dan aksesi Mbupuri >200 kg pati kering/pohon. Kedua aksesi ini dapat diteliti lebih lanjut kestabilan hasilnya untuk dilepas sebagai varietas unggul. Karakter morfologi khususnya panjang batang mempengaruhi produksi, karena pati terdapat dalam empulur batang.
Measures to Control the Prevalence of Pneumoconiosis in Coal Mining: A Review of the Literature
Authors: Ayaaba Esther , Liu Yi , Li Yan , Han Lei , Yedu Quasanh Dan , Chunhui Ni
Published: February 2018

Background: There are enormous health problems associated with the use of coal as energy. Dust emitted during the mining processes is identified as a specific risk factor for Coal Worker Pneumoconiosis (CWP) and other respiratory health problems. There is little published evidence on various health measures and their effectiveness in controlling CWP. This review seeks to provide a summary of the published literature on various health measures taken to reduce CWP in coal mines.
Methods: We searched Google Scholar, PubMed, MEDLINE, EMBASE and occupational health databases for published research articles, evaluation reports, official documents and regulations. Reference lists of relevant papers were hand-searched. We retrieved a total of 1, 049 articles out of which 17 merited criteria for inclusion. Papers presenting evidence of the prevention of CWP among coal miners were included.
Results: Many technological interventions are currently available to promote primary prevention of CWP by ensuring reduction in inhalable dust. This review identified laws and regulations, surveillance, direct dust control measures, risk assessment and compensations as ways of minimizing exposure to dust among coal workers, as means of preventing CWP.
Conclusion and Implications for Translation: There is little evidence on the various measures stipulated in mining regulations that are adhered to and the extent to which they have been effective. The public health strategy that combines various health measures, including training of workers on safety measures, may be effective in preventing CWP.
 
[This article has been republished with minor changes. These changes do not impact the academic content of the article.]
 
Copyright © 2017 Ayaaba et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License CC BY 4.0.
Rapfish, Gili Labak, Coral Reefs, Sustainable Management
Authors: Muhsoni Firman Farid , Efendy Mahfud
Published: February 2018

The purpose of this research is to give direction of management of Gili Labak Island by considering multidimensional factors. The method used is Rapfish. This method uses the ecological, resource, economic, social, legal and institutional dimensions. Rapfish Gili Labak's analysis results for the ecological dimension show a value of 62.3 in a fairly sustainable category. The resource dimension shows a value of 63.07 in fairly sustainable categories. The economic dimension shows the value of 10.15 in the unsustainable category. the social dimension of value of 17.8 in the unsustainable category. Legal dimensions and institutional values of 5.36 in non-sustainable categories. Multidimensional analysis results show sustainability index in less sustainable category (value 34,24). After interference is increased it becomes quite continuous (value 74.99). This interference is described in the recommendations. Recommendations are made on the lesser dimensions, namely the legal and institutional fields, the economic field and the social field.
Knarr Field - Optimization of Wellbore Clean-Up Through Dynamic Transient Modeling
Authors: Dimude M. , Wane B. , Lu H.
Published: February 2018

Optimized well clean-up planning and procedures are crucial for the effective development of offshore subsea wells and their subsequent production stage to host facilities. The objective of the well cleanup is aimed at ensuring a successful removal of the completion fluids and drill-in fluid out of the wellbore to restore connectivity with the reservoir, maximize well productivity while minimizing tensile sand failure, and properly conditioning the sand face completion (in a standalone screen scenario). To achieve this goal, the well clean-up time, bean-up procedure, rate and fluid volumes to be produced should be appropriately estimated to properly size the surface testing equipment required for the operation.

Due to the highly dynamic and transient nature of the cleanup process, the use of a dynamic simulator was required to effectively capture the physics of the concurrent flow of the various phases present in the system. An extensive modelling and simulation of the unload process has been performed through the use of a dynamic multiphase simulator to assess the transient displacement of the various wellbore fluids according to several unload strategies. Potential clean-up times and volumes were assessed using flowrate ramp-up schedules designed for different completion fluid distributions in the wellbore. The constrained flowrate cases were considered to represent the constraint on the rig (restricted because of surface handling capacity issues).

The well clean-up procedure was developed to minimize clean-up time, avoid formation damage, and minimize volume of formation liquids on flow back during the rig well tests. During the execution, the movement of fluids along the wellbore, surface production rates, the drawdowns and duration of clean-up to predefined targets were monitored and recorded. The acquired field data from the clean-up operation was compared against simulation prediction and validated the reliability of the predictive model.

This study proves the transient multiphase simulation to be effective in capturing the physics of the multiphase flow process involved in the clean-up operation. It also demonstrates that, when appropriately done, it could be an effective tool for the planning and strategy selection for the well cleanup operation.
Quantifying Reservoir Permeability in Shale Reservoirs Using After-Closure Analysis of DFIT by Considering Natural Fractures, Fissures, and Microfractures: Field Application
Authors: Chen Zhiming , Sun He , Liao Xinwei , Wang Shuhua , Yu Wei , Zuo Lihua , Wu Keliu , Li Jing
Published: February 2018

Natural fractures, fissures, and microfractures are well-known contributors to production performance of shale reservoirs. Complex fracture geometries can be generated by either small-scale fracturing, DFIT, or large volume fracture stimulation, because the activation of pre-existing natural fractures, fissures, and microfractures plays a significant role on generation of induced hydraulic fractures. Therefore, much more attention should be paid to the model development of DFIT complexity.

In previous work, Chen et al. (2017a) built a complex fracture-network model for after-closure analysis of DIFT by considering natural fractures. Based on that, this paper introduces a generalized model with random fracture geometry caused by natural fractures, fissures, and microfractures. First, the model flexibility is demonstrated by different complex fracture cases, namely opening-fissure fracture network, tree-like fracture network, radial multiple fracture network, and mutually orthogonal fracture network. It is found that the pressure derivative reaches constant level, no matter what the fracture geometry is. Furthermore, the reservoir permeability of field examples from actual DFIT tests in Marcellus shale reservoir is quantified using the log-log diagnostic plots based on the model solutions. Finally, the Nolte G-function is applied to verify the estimated results. We find that the results from the two methods are consistent. This work primarily focuses on quantifying the reservoir permeability, while in the future more efforts will be made to identify the fracture properties using the proposed model.
A Laboratory Study of CO2 Interactions Within Shale and Tight Sand Cores - Duvernay, Montney and Wolfcamp Formations
Authors: Reynolds Murray , Britten Derek , Cui Xiaojun , Twemlow Cory , Cook Mike
Published: February 2018

The most commonly used technology for development of unconventional reservoirs is horizontal wells combined with large multi-stage hydraulic fracture treatments. However, even with these technological advancements, primary recovery factors are generally less than 10 percent of the hydrocarbon in place. Water is currently the primary fracturing fluid used in most commercial developments. There is growing interest in non-aqueous (e.g. CO2) fluid systems not only to reduce water usage, but to increase well productivity and recovery factors.

Use of carbon dioxide (CO2) as a fracturing fluid and an enhanced oil recovery (EOR) agent is also attractive from an environmental point-of-view. Organic rich shale reservoirs can be targets for carbon storage, due to their high CO2 adsorptive abilities and multiple mechanisms for gas storage. Therefore, use of CO2 can have both economic (increased recovery) and environmental (sequestration) benefits.

This laboratory study investigates the interactions of CO2 with various cores from three formations (Duvernay, Montney, and Wolfcamp). Multiple core plugs were prepared from each of the three reservoirs. The mineralogy of the samples was measured with x-ray diffraction (XRD), and total organic carbon (TOC) and thermal maturity were determined with a SRA (Source Rock Analyzer). Porosity was also measured under as-received conditions and cleaned and dried conditions with a helium pycnometer. For each sample, its initial baseline permeability to helium was tested under a full cycle of net confining pressures (1,500 psia → 4,500 psia → 1,500 psia) with pressure steps of 1,000 psia using the pressure pulse-decay method. Subsequently the sample was vacuumed for 12 hours, and was then soaked with CO2 for more than 48 hours. Afterwards, the permeability to CO2 was measured under another cycle of confining pressures. Finally, the sample was vacuumed again and the regain permeability to helium was measured.

Results indicate that the permeability to helium is generally recovered after CO2 soaking stages for tight-sand samples (e.g., Montney) and may be elevated for some samples enriched in organic matter and clay minerals (e.g., Wolfcamp). Overall the study shows favorable interaction between rock and organic material and CO2, which supports the use of CO2 as a fracturing or EOR fluid in these three reservoirs.
Pressure Depletion’s Impact on Induced Strain During Hydraulic Fracturing in Child Wells: The Key to Mitigate Fracture Hits and Pressure Interference
Authors: Vargas-Silva S. , Khodabakhshnejad A. , Paryani M. , Venepalli K. , Ouenes A.
Published: February 2018

Productivity of hydraulically stimulated unconventional wells depends greatly on the successful interconnection of the enhanced permeability and the natural fracture system. Such success is achived by proper understanding of the distribution of mechanical properties of the rock, presence of natural fractures, and regional stresses characterisitcs. With this understanding of the reservoirthe response of the rock to the stimulation can be quantified. Currrently, there are multiples approaches adopted by the industry to support such a process, making fracture designs more robust and reliable. However, theseworkflows often neglect the underlying physics of pressure wave propagation throughout the reservoir, crossing geological features such as faults, natural fractures, ash and karst layers among others.

Pressure depletion caused by production of the first well in a section (parent well) generates continuous changes in stress magnitude and orientation. Simplistic geomechanical models ignore such effects and usually are built based on original conditions, resulting in overestimation of induced strain which will be reflected in oversized hydraulic fracture jobs that negatively affect not only the subsequent wells (child wells) but also the first well in section itself. Negative effects such as frac hits are usually irreversible, and proper estimation of the potential damage needs to be quantified and understood in order to put in place a mitigation plan.

This work presents a workflow where changes in the pressure field are incorporated and taken into consideration during geomechanical modeling of induced strain using full continuum mechanics. As a result, hydraulic fracture designs are adjusted to the reservoir conditions at the time a new child well will be drilled and completed, thus reducing thepotential for negative effects such as frac hits.

A fracture design for a planned child well to be drilled after two years of production of its parentis presented under two scenarios: first, ascenario ignoring the effect of pressure depletion, second, a scenario using the full continuum geomechanical solution to account for the effects of parent depletion.

Results of the fracture design are migrated to dynamic simulation to estimate the effect on the resulting EUR.
Reconciling Empirical Methods for Reliable EUR and Production Profile Forecasts of Horizontal Wells in Tight/Shale Reservoirs
Authors: Yu Shaoyong , Jiang Zhixiang , Lee W. John
Published: February 2018

Confidently establishing single well and/or aggregated production profiles, particularly estimated ultimate recovery (EUR), is both an important and challenging process in unconventional reservoirs. Numerous papers have proposed forecasting techniques, but four fundamental approaches dominate:

Empirical decline curve analysis (DCA), such as multisegment Arps, the modified stretched exponential production decline (YM-SEPD) model, Duong's method, and power-law methods. Rate-transient analysis (RTA), which can include corrections for special dynamic mechanisms (e.g., stress-sensitivity, multiphase flow, adsorption/desorption). Numerical simulation for history-matching and forward modeling. Volumetrically determining in-place resources based on geological data and then applying a recovery factor deemed suitable for the reservoir system and depletion scheme.

Each of these approaches can be implemented using either probabilistic or single-point estimates. Seidle et al. (2016) recently outlined recommended methodologies to accurately forecast time-series volumes and ultimate recovery in unconventional systems. A key recommendation in Seidle et al. (2016) is that the multiple approaches listed previously should be reconciled to establish confidence in forecasts and ultimate recovery estimates. However, Seidle et al. (2016) does not detail the means to achieve this goal. This paper establishes a methodology/workflow to reconcile the different types of empirical DCA methods, which should serve as a starting point for the ultimate goal of reconciling the four fundamental approaches listed.

This paper compares and contrasts the DCA methods applied to various field cases in prominent Canadian [Western Canadian Sedimentary Basin (WCSB)] and US unconventional (oil and gas) plays (Bakken, Barnett, Cadomin, Eagle Ford, and Niobrara). Data sets are selectively chosen based on data quality and history length to increase confidence in the appraisal of the DCA approach. Hindcasting is applied to validate the results and conclusions.

From analysis of a number of wells in different types of reservoirs, a new workflow (methodology) is proposed and validated with hindcasting that allows practically and accurately reconciling EURs based on various empirical methods.

This manuscript is the first paper to discuss systematic reconciliation of EURs from varying approaches for horizontal wells in tight/shale reservoirs.
Dual-Permeability Matrix–Fracture Corefloods for Studying Gas Flooding in Tight Oil Reservoirs
Authors: Luo Peng , Knorr Kelvin D. , Li Sheng , Nakutnyy Petro
Published: February 2018

Laboratory evaluation of tight oil production processes requires a unique coreflood apparatus that portrays both the tight rock matrix and fractures—a dual-permeability system. However, with some tight formations such as the Bakken having no available outcrop, full-sized actual cores are very difficult and sometimes impossible to obtain. In this study, a large-volume coreflood apparatus was developed to incorporate the detailed physics of ultra-tight, dual-porosity, dual-permeability flow in porous media. Also, large synthetic cores were made to represent the permeability, porosity, and mineralogy of actual tight reservoir rocks. To generate the desired dual-permeability system, fractures are simulated by creating sand-filled branched pathways in the large synthetic core. During a coreflood test, fluids are injected through the peripheral high-permeability belt into the tight matrix and recovered through the central fracture. This simulates the flow of matrix to fracture, or vice versa, seen in an ultra-tight reservoir. As well, either continuous gas/water injection or cyclic gas injection modes can be tested with the model. Two large-volume dual-permeability corefloods were conducted to study the effectiveness of immiscible field-produced gas flooding using recombined reservoir oil and synthetic tight cores. The corefloods simulated a practical field production sequence that included primary recovery (pressure depletion), injection of field-produced gas, pressurizing and soaking with this gas, and pressure depletion. The higher-recovery run produced 28.3% original oil in place (OOIP) including primary and tertiary (enhanced) processes. The dual-permeability corefloods demonstrated more representative performance of actual field operations than do traditional one-dimensional corefloods.

The new matrix–fracture coreflood system better reflects the extreme permeability contrast between matrix and fractures that characterizes tight oil reservoirs. Therefore, history matching of its results using a numerical simulator is expected to provide much better representation in scaling up and predicting realistic field operations.
A Markov-Chain-Based Method to Characterize Anomalous Diffusion Phenomenon in Unconventional Reservoir
Authors: Liu Shuai , Li Han , Valkó Peter P.
Published: February 2018

The recent success in developing unconventional reservoirs has caused many new challenges to the theory of reservoir engineering. In this paper, we try to investigate the anomalous diffusion phenomenon caused by the heterogeneity due to the fracture network on the reservoir scale. Firstly, we revisit the physical background of the single-phase flow diffusivity equation by discussing the equivalent single particle diffusion. Combining the characteristics of single particle diffusion with complex fracture geometry, it is indicated that anomalous diffusion phenomenon will be dominant on the reservoir scale, even for single phase production behavior. Then a model based on Markov chain is presented to demonstrate the proposed anomalous diffusion by simulating the partical normal diffusion on a geometric graph and then calculating the relation of the mean square displacement vs. time in the embedding Euclidean space. Based on the simulation results, in consequence, we make a discussion on the characteristic size of the heterogeneity due to the fracture network on the reservoir scale, summarize 2 types of pattern for the anomalous diffusion, and provide a supportive argument for using the fractional diffusivity equation, in place of the classical one, to model the flow and production behavior in highly fractured unconventional reservoirs.
Evaluating Human-Machine Interaction for Automated Drilling Systems
Authors: Farhangfar A. , Torre A. M. , Shor R. J.
Published: February 2018

The efficient utilization of automation systems necessitates a clear understanding of the interaction of the human operator, the automation system and any automated routines being run. If automated routines perform actions not desirable to the human operator, time is lost as the routine is interrupted and human control re-engaged. In addition, automatic handoff back to the human operator, both due to human intervention and due to exist conditions or anomalies must also be managed. Activity data from rigs across North America is analyzed to understand automation process utilization and interrupt timing. Realtime and historic data is tagged, either automatically, semi-automatically using machine learning, or manually, to create a minute-by-minute timeline of rig operations. Operations are then classified both by operation – steering, reaming, making hole, etc. – and well plan to understand how operational demands change automation system utilization. This results in a new set of metrics which can be used to precisely quantify the performance metrics of both the human and automated drilling systems. Performance of the automation system is found to be a strong function of hole deviation with the system outperforming during simple operations and in the vertical hole, but with reduced performance while in the curve and horizontal, due to high interruption of certain tasks. It is found that standard performance metrics, such as slip to slip or weight to weight are affected by standard practices and if these are used to grade system performance, these practices must be account for. This paper presents a detailed investigation of the interaction of the driller with an automated drilling automation system and lays out the utilization of the automation system as a function of rig operations and well path. It is specially noted that standard performance metrics must consider standard practices which may differ between operations.
A New Simple Analytic Equation for Estimating Asymmetric Growth of Stimulated Reservoir Volume in Anisotropic Shales
Authors: Li Qi , Aguilera Roberto
Published: February 2018

The objective of this paper is to present the development and application of a simple equation for calculating asymmetric growth of the stimulated reservoir volume (SRV) in a shale petroleum reservoir using microseismic data.

Calculation of the SRV is a problem handled with solutions that involve different degrees of complexity. Because shale reservoirs are anisotropic, microseismic events generally develop 3D nonuniform asymmetric patterns around the injection points. This paper presents a new method with an easy to use analytic equation that allows reproducing the asymmetric growth of microseismic events as a function of time by considering reservoir anisotropy.

Asymmetric growth refers to the fact that propagation of the microseismic cloud in a given direction can be larger, equal or smaller as compared with the propagation in other directions. Accurate determination of the SRV asymmetric pattern is critical for input in specialized material balance and reservoir simulation models of shale petroleum reservoirs. This determination allows more realistic projections of reservoir performance.

The novelty of the method is the development of an easy-to-use approach for estimating SRV in a spatially nonuniform-asymmetric-anisotropic reservoir using octants in a coordinate system. The SRV is calculated from the volume of a symmetric ellipsoid divided by a constant value Vc. This in spite that the point of injection of the fracturing fluids in the asymmetric reservoir can be at, close to or far from the center of the ellipsoid. Development of Vc is presented in this paper. Use of the model is illustrated with real microseismic data of the Horn River shale in Canada for a case where Vc is equal to 1.3722.
Strategic Waterflood Optimization with Innovative Active Injection Control Devices in Tight Oil Reservoirs
Authors: Barry Kyle , McDowell Ryan , McArthur Kevin , Kozin Anton , Stretch Trena Marie , Keshishian Avo , Farid Jawad
Published: February 2018

This paper presents the successful implementation of an innovative approach for improving oil recovery by water injection optimization with Injection Control Devices (ICD's) in unconventional reservoirs. Over the past decade, operators in Southeast Saskatchewan have been continually innovating and finding efficiencies to improving water injectivity across horizontal wellbores. In late 2016, the Crescent Point Energy started a trial campaign applying ICD's in relatively low flow rate environments to offset production decline and improve recovery in the Bakken, Shaunavon and Midale formations. Early term results show greater than 25% improvement is possible in oil recovery over typical waterflood configurations.

The operator had applied waterflood as a secondary recovery method and found field trials to stabilize production decline and improve ultimate recovery. The effectiveness of waterflood in unconventional, fractured reservoirs has been debated. In some cases, short circuiting of injection water to production wells through fracture channels has occurred. This has been found to reduce sweep efficiency. The issue was evaluated and it was determined there was a need to equalize the injection profile across the horizontal wellbore. Understanding the flow profiles of injection wells was instrumental in developing diversion strategies. Applying Distributed Temperature Surveys (DTS) has been found to be an effective method of estimating flow profiles at relatively low flow rates. Using processed DTS data, a reservoir simulation model has been used to match unique injection profiles along horizontal wellbores. The results from these models supported the need to pursue injection diversion.

Several means to optimize injection profiles have been trialed, the results of which support the theory of sweep optimization. However, the limited number of isolated injection points achievable with given wellbore diameters has impeded potential for this development. The introduction of ICD injection strings allows for an optimum number of injection points, improving sweep efficiency and accelerating voidage replacement.

This paper reviews the design, execution and evaluation process used in more than 50 successful ICD installations in various fields across Saskatchewan. The performance of these ICD strings was then monitored and evaluated in collaboration with the operator and service providers.
Value-Driven Mitigation Plans for Severe Slugging in Gas-Lift Wells in Unconventional Shale Plays
Authors: Lu Haidan , Mukhanov Akhan , Nagarakanti Sekhar , Fai-Yengo Ghislain , Kwok Chun Ka , Atmaca Serdar
Published: February 2018

A major challenge when operating a gas lifted unconventional well is severe slugging. Without addressing its root causes, production fluctuation can remain for a long time and pose high risks to the entire operating system. This paper first reviews the gas lift for U.S. unconventional shale plays. Then it describes the major causes of gas lifted shale well slugging and proposes mitigation plans respectively, considering the implications on value and profitability. A systemic diagnostic workflow was developed for shale well slugging by combing production data analytics and dynamic simulation workflow. It also incorporated cost benefit analysis to evaluate incremental economic value. Transient modeling reveals key aspects of gas lift well slugging causes. A case study involving a shale well demonstrates the technical and economic impact of this transient behavior on gas-lift well performance. This study can assist operators in developing a mitigation plan for gas-lifted shale well severe slugging through transient simulation and in leading to substantial cost saving while extending asset economic life. It also demonstrates that transient multiphase flow simulation is an effective tool for the troubleshooting and the mitigation strategy selection for unconventional shale wells under gas lift.
Empowering Multivariate Statistical Analysis and Integrating it with Full Field 3D Geomodel Combined with Unconventional Fracture Modeling UFM for Production Optimization, a Montney Example
Authors: Faskhoodi Majid M. , Boskovic Drazenko , Zhmodik Alexey , Qiuguo Li , Michi Oscar P. , Ramanathan Venkateshwaran , Ogunyemi Taofeek
Published: February 2018

This paper presents a novel approach in statistical analysis of well performance of multi-stage fractured wells completed in specific part of Montney. For the first time, both geological and hydraulic fracture parameters were considered in analysis with objective of finding most influential parameters that impact deliverability of wells. Results from single point statistical analysis were further extended to unsupervised discrete classification using neural-network to bin the reservoir. Binning classification was then used to design and optimize hydraulic fracture parameters.
Promotion of Vegetative Growth in Force-ventilated Protea cynaroides L. Explants Cultured in Modified Temporary Immersion Culture Vessels
Authors: Wu How-Chiun , Kuo Mei-Ling , Chen Chia-Min
Published: February 2018

Temporary immersion culture vessels were modified to culture Protea cynaroides L. microshoots on semisolid growth medium. The effects of different ventilation treatments and sucrose concentrations on the vegetative growth and physiological characteristics of P. cynaroides L. microshoots were investigated. Three ventilation treatments were used: microshoots were either ventilated naturally or forced ventilated for 2 minutes/2 hours or 2 minutes/4 hours. In addition, two sucrose concentrations were used in the growth medium: 30 and 10 g·L−1. Significant interaction effects were found between ventilation and sucrose in the number of shoots formed. When cultured on growth medium with 10 g·L−1 sucrose, microshoots force-ventilated for 2 minutes/2 hours produced significantly higher number of shoots than those naturally ventilated or force-ventilated for 2 minutes/4 hours. In the 30 g·L−1 sucrose treatment, no significant differences in shoot numbers were observed among all ventilation treatments. The highest leaf areas were found in microshoots cultured in the 2 minutes/4 hours forced ventilation treatment, which were significantly higher than microshoots in the other ventilation treatments, irrespective of the sucrose concentration. Chlorophyll content was significantly higher in leaves of microshoots that were cultured in 30 g·L−1 sucrose compared with those grown in 10 g·L−1 sucrose in all ventilation treatments. Analysis of chlorophyll fluorescence of the leaves revealed that the Fv/Fm value of microshoots grown on 30 g·L−1 sucrose and force-ventilated for 2 minutes/4 hours was significantly higher than those naturally ventilated in the same sucrose treatment. Overall, the use of 30 g·L−1 sucrose in combination with 2 minutes/4 hours ventilation provided the best conditions for culturing P. cynaroides microshoots. This study demonstrated that these modified temporary immersion culture vessels can be used as a forced ventilation system to culture P. cynaroides microshoots and promote vegetative growth as well as improve their photosynthetic characteristics. The system described here introduces a simple and novel method of converting commercially available temporary immersion systems into force ventilation systems.
Increasing Honey Bee Hive Densities Promotes Pollination and Yield Components of Highbush Blueberry in Western Washington
Authors: Arrington Matthew , DeVetter Lisa Wasko
Published: February 2018

Yield components including fruit set and berry size in northern highbush blueberry (Vaccinium corymbosum) can be limited in key production regions like western Washington. Climactic conditions influence the activity levels of blueberry’s primary commercial pollinator, honey bee (Apis mellifera). Cool springs with frequent rainfall, which are common during the spring bloom period in western Washington, can reduce honey bee activity, pollination efficiency, and subsequent fruit set and yields. Increasing honey bee hive density may be a simple technique that growers can employ to increase the number of honey bees foraging during periods of good weather, interspersed with the poor weather, and therefore, increase fruit set and related yield components. The objective of this study was to evaluate if increased honey bee hive densities improve pollination and subsequent yield components in western Washington blueberry. Three field sites with mature ‘Duke’ plants were stocked with 10 hives/ha of honey bees (control), and three other field sites (also ‘Duke’) were stocked with 20 hives/ha (high hive density). Honey bee visitation and yield components, including fruit set and berry weight, were measured. Estimated yield, seed number/berry, and fruit firmness were also monitored. There were no significant differences in fruit set regardless of honey bee hive density. However, honey bee visitation and estimated yield increased with increased honey bee hive density. Berry weight and seed number per berry were also increased with increased honey bee hive density, although firmness was unaffected. Results indicate that increasing honey bee hive densities can help blueberry growers improve berry size and overall yields, suggesting this is a practice growers can implement if their production is constrained by insufficient pollination.