bluuebunny/crossref_metadata_2025_split huggingface dataset:
When Is Induced Fracture Complexity Necessary for Unconventionals Stimulation?
Authors: Wilson Adam 
Published: February 2016

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 168976, “Induced Fracture Complexity—When Is It Really Required in Unconventional Reservoir Stimulation?” by Leopoldo Sierra, SPE, and Mike Mayerhofer, SPE, Pinnacle—A Halliburton Service, prepared for the 2014 SPE Unconventional Resources Conference—USA, The Woodlands, Texas, USA, 1–3 April. The paper has not been peer reviewed.
Induced-fracture-complexity maximization in addition to the primary hydraulic fractures has been accepted and fully implemented to improve recovery efficiency or productivity in unconventional reservoirs. This paper aims to develop criteria for identifying situations in which induced fracture complexity and sustained conductivity are or are not required. The results show that the fracture complexity and sustained conductivity are generally important for reservoir permeabilities lower than 100 nd for gas production and 500 nd for liquid production.
Introduction
The industry-implemented completion strategy for unconventional gas- or liquid- producing reservoirs considers increased reservoir contact to maximize productivity and hydrocarbon recovery through the following methods:
Drilling long horizontal wellbores
Optimizing the horizontal-wellbore placement to maximize the vertical coverage of the prospective formation
Placing multiple transverse fractures by perforating the most-brittle and -prospective areas to generate complex fractures
Alternating fractures in parent horizontal wellbores to induce stress interference that could result in more-complex fractures
Engineering stimulation fluids to help induce complex fractures
Although the existing completion strategy for each shale play has been optimized or is in the optimization process, a correlation between production and the perceived fracture surface area was not observed in some cases. Assuming the stimulation process is adequate and properly implemented in the field, the observed production behavior might be related to the combination of unknown reservoir permeability and induced fracture complexity.
This paper investigates the benefits of induced fracture complexity in the stimulation of unconventional gas-or liquid-producing reservoirs for a wide range of reservoir permeabilities (10 nd to 0.001 md) and with a variable stimulation efficiency. Ultimately, this paper aims to answer the question of when induced fracture complexity is really necessary.
Finding Optimal Hydraulic-Fracture Angles in Productivity-Maximized Shale Well Design
Authors: Wilson Adam 
Published: February 2016

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 170965, “Optimal Hydraulic-Fracture Angle in Productivity-Maximized Shale Well Design,” by Nadav Sorek, SPE, Jose A. Moreno, Ryan Rice, Guofan Luo, and Christine Ehlig-Economides, SPE, Texas A&M University, prepared for the 2014 SPE Annual Technical Conference and Exhibition, Amsterdam, 27–29 October. The paper has not been peer reviewed.
In general, hydraulic fractures propagate perpendicular to the horizontal-well axis whenever drilling is parallel to the minimum principal-stress plane. However, operators frequently drill horizontal wells parallel to lease boundaries, resulting in slanted hydraulic-fracture planes at angles less than 90° from the well axis. This study provides a model for the inclined fracture case. It applies and further extends the unified-fracture-design approach for rectangular drainage areas, relating the dimensionless proppant number to the maximum productivity index in pseudosteady-state conditions.
Introduction
Industry experience suggests that horizontal shale-gas development is enhanced by drilling in the direction parallel to the local minimum principal horizontal stress. Because US mineral leases frequently are rectangular areas with north/south and east/west boundaries, operators often drill parallel to the lease boundaries, prioritizing well saturation over optimum fracture-length propagation. This practice leads to the creation of hydraulic-fracture planes that are slanted at an angle less than 90° with respect to the well axis.
Extensive research has investigated the effects of angled fractures on well productivity. Theoretical and empirical data have been used to address the effect of wellbore azimuth on well performance in the Marcellus shale. Results showed that, for each degree a well was suboptimal to minimum horizontal stress, the estimated ultimate recovery decreased by 7.25 Mscf per foot of effective lateral length.
Unified-fracture-design methodology indicates the hydraulic- fracturing treatment design that maximizes well productivity for any set of reservoir and proppant properties and a given injected-proppant mass. This methodology introduces the concept of proppant number, which describes the weighted ratio of propped-fracture volume to a square reservoir volume.
This study applies and further extends the unified-fracture-design approach to show that, for any given set of reservoir and proppant properties along with a given proppant mass, as long as the created fractures define the same stimulated rock volume, there exists a well direction resulting in maximized well productivity that is not parallel to the minimum-stress direction. First, a correlation is established between the proppant number and the optimum drainage-area aspect ratio. Then, this correlation is used to express what the optimum fracture angle is for a specific proppant number.
Technology Focus: Production Monitoring/Surveillance
Authors: Kuck Marc 
Published: February 2016

Technology Focus
As we take a look over the last year, the industry has seen further advancements in the areas of production monitoring, surveillance, analysis, and optimization. We continue to find new ways of data gathering, processing, and interpretation. We are optimizing our operations and even predicting future production behavior in a new manner. Innovative intervention methods have also followed with creative methods of addressing a variety of performance issues. We have become more efficient at using existing technology to improve performance in mature fields and in full-field management strategies for new developments. Technology is improving continuously to help us with production optimization through new approaches, including downhole multiphase-flow measurement, wireless data gathering, wireless power-transfer methods, and new fluids technology. We have seen enhancement in predictive analysis with regard to determination of production performance as well as equipment failure for multiple types of artificial-lift methods. The last year witnessed further studies and improvements in the understanding of heavy-oil and unconventional reservoirs.
While production optimization is improving continuously, growing environmental concerns are also being addressed with better understanding and technology. The contributions allowing these steps forward are being generated from large fields, offshore developments, smaller land-based operations, and all sectors of our business. New ideas and methods are being shared from all regions of the globe, demonstrating the diversity and strength of the industry as well as the people making these contributions. This efficiency and innovation should help us continue on a path of success as global markets change in the future.
The articles selected for review are intended to show some examples of implementing multiple concepts and methodologies for production evaluation while applying the data to achieve better performance. While demonstrating the full system overview, also included is an insight into the enabling technology allowing these improvements and possibly a glimpse into what may lie ahead as we continue down the path toward further understanding of our reservoirs. JPT
Recommended additional reading at OnePetro: www.onepetro.org.
SPE 171101 An Integrated Approach Using Commercial Monitoring and Surveillance Tools Coupled With Statistical Analysis Techniques To Optimize Oil, Heavy-Oil, and Extraheavy- Oil Reservoirs by D. Lee, DL Petroleum Engineering and Consulting, et al.
SPE 170864 Mature Fractured Reservoir Meets the Era of Young Minds and the New Age of Technology Digital Oil Field by Mariam Abdul-Raheem Jamal, KOC, et al.
SPE 164854 Downhole Multiphase-Flow Measurement in Horizontal Wellbores by o. Haldun unalmis, Weatherford, et al.
Seismic-Frequency- vs. Seismic-Interval- Velocity-Based Pore-Pressure Prediction
Authors: Carpenter Chris 
Published: February 2016

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 167915, “Seismic-Frequency- vs. Seismic-Interval-Velocity-Based Pore- Pressure-Prediction Methodologies for a Near-Salt Field in Mississippi Canyon, Gulf of Mexico: Accuracy Analysis and Implications,” by T. Mannon, Stone Energy and University of Louisiana at Lafayette; S. Salehi, University of Louisiana at Lafayette; and R. Young, eSeis, prepared for the 2014 SPE Drilling Conference and Exhibition, Fort Worth, Texas, USA, 4–6 March. The paper has not been peer reviewed.
The process of risk and uncertainty reduction in unconventional-drilling operations starts with improving techniques for pore-pressure modeling. A study conducted in a near-salt field in deepwater Gulf of Mexico (GOM) that compared the accuracy of seismic-frequency- and seismic-interval-velocity-based methodologies showed significantly higher accuracy for the seismic-frequency- based approach in wells that were in near- or subsalt environments and higher overall accuracy for all wells.
Introduction
The current standard practice for modern pore-pressure prediction relies on interval velocities obtained through seismic surveys. The methodology has seen many changes, but transforms used for interval-velocity-based pore-pressure prediction are for the most part still heavily reliant on the assumption that the porosity trend is directly related to pore pressure. Also, rock velocities are highly dependent on factors such as lithology and porosity, which may have nothing to do with effective stress, the key factor that all pore- pressure models are designed to predict. A seismic application for formation-pressure prediction has been explored that avoids any and all assumed relationships between porosity and effective stress: seismic-frequency-based pore-pressure prediction.
Seismic-Frequency-Based Pore-Pressure Prediction
To grasp the idea of pore-pressure prediction through seismic frequencies, the concept of attenuation and quality factor (Q) must be understood first. Attenuation can be defined in regard to seismic applications as the progressive loss of energy of an acoustic wave traveling through a medium. Attenuation will cause a drop in average frequency for a given seismic signal. Q defines the “quality” of the rock, or any medium through which an acoustic wave is passed. A signal that shows a higher average frequency will be associated with a higher Q value than a signal of lower frequency; thus, attenuation is inversely related to Q.
Impact of Weather on Sigatoka Leaf Spot of Banana (<i>Musa</i> spp. L.) and its Ecofriendly Management
Authors: Khan M A H , Hossain I , Ahmad M U 
Published: February 2016

A study was carried out during July 2010 to April 2012 to understand the effect of weather prevalence on sigatoka disease of banana suckers in different areas of Bangladesh and to develop an environment friendly disease management practice. Four locations viz. Dinajpur, Bogra, Rangpur and Madhupur were surveyed. To find out suitable and ecofriendly management practices for controlling sigatoka disease of banana, seven treatments were used viz. i) Soil drenching with BAU- Biofungicide (2%), ii) BAU-Biofungicide as foliar spray (2%), iii) Soil drenching with BAU-Biofungicide (2%) plus foliar spray (2%), iv) Bavistin (carbendazim) spray (0.2%), v) Dithane M-45 (mancozeb) spray (0.2%), vi) Soil drenching with BAU-Biofungicide (2%) plus Bavistin spray (0.2%); and vii) control. The average highest incidence (26.42%) and severity (22.84%) of sigatoka disease of banana suckers were recorded during October at Bogra, while the lowest incidence (9.75 %) and severity (8.51%) were recorded during January at Dinajpur. Out of the control measures employed, BAU-Biofungicide (2%) either alone or in combination with Bavistin (0.2%) was found as an excellent biocontrol means for controlling sigatoka disease of banana suckers.DOI: http://dx.doi.org/10.3329/agric.v13i2.26587The Agriculturists 2015; 13(2) 44-53
Genetic Diversity Analysis in Exotic Hybrid Rice Genotypes Grown During Wet Season in Bangladesh
Authors: Ahmed A , Shaon S G , Islam M S , Saha P S , Momin M A 
Published: February 2016

Two experiments were conducted with 43 IRRI developed F1 hybrid rice genotypes (HRDC) for ten agronomic characters in a randomized complete block design to study the genetic diversity through multivariate analysis in Gazipur and Pabna districts, respectively during wet season 2013. On the basis of D2 values, the genotypes were grouped into five different clusters. During wet season, cluster III comprised maximum number of genotypes (15). The data obtained across locations showed that there are significant differences among HRDC genotypes for all growth parameters, yield and yield components. The highest yield (5.65 t ha-1) was observed in HRDC 1341 because of produced heaviest panicle (4.28 g) and the lowest (2.48 t ha-1) in HRDC 1311 because of obtained lowest fertility (49.9 %) and 1000-grain wt. (12.9 g), respectively. The maximum inter-cluster distances were observed between cluster I and V (11.63) and the minimum between cluster III and IV (2.35). The highest intra-cluster distance (1.73) was observed in cluster III and minimum in cluster I (0.00), since it consisted with one genotype. Difference in cluster means existed for almost all the characters studied. Among the characters, growth duration, spikelet panicle-1, fertility (%) and 1000-grain wt contributed the most for divergence in the genotypes. The highest mean values for fertility percentage, panicle weight and 1000 grain wt. but early flowering and short maturing genotypes were grouped into Cluster II followed by Cluster III and IV indicating that the genotypes have genetic potentiality to contribute better for yield maximization of hybrid rice.The Agriculturists 2015; 13(2) 89-96
Yield Potential of Twelve Potato (<i>Solanum tuberosum</i>) Varieties Grown from Different Generations of Seed
Authors: Hossain Shafayet , Rasul Golam , Mian M A Khaleque , Haque M Moynul , Akanda Abdul Mannan 
Published: February 2016

An experiment was conducted at the research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur to determine the yield potential of twelve potato varieties for consecutive years during 2009-2011. The mean performance of varieties, generations and their interactions varied significantly. Field performance revealed that the plant height decreased in all the varieties Raja, Arinda, Patrones, Multa, Asterix, Granola, Felsina, Diamant, Cardinal, Provento, Ailsa and BARI TPS1 in the 4th generation compared to 2nd generation (Breeders Seed) except Raja and Arinda and it decreased compared to 3nd generation in Patrones and Felsina. The highest plant vigor was observed in Felsina and Asterix in the 1st generation, Patrones, Multa and Asterix in the 2nd generation and Raja and Granola in the 3rd generation. The highest number of stems per hill was produced by Patrones in all the three generations and the lowest was in Arinda in the 3rd generation. The highest number of hills per plot was recorded in Asterix and Granola and the lowest were in Ailsa and Raja. Higher tuber yield per hill was obtained from Ailsa, followed by Raja, Arinda and Felsina. Patrones produced higher number of tubers per plot in all the three generations while Ailsa produced the minimum which were followed by Felsina, Diamant, Raja and Arinda in all the generations. The yield of different varieties in the 2nd generation ranged from 11.94 t/ha (Ailsa) to 26.18 t/ha (Asterix) with an average yield of 19.06 t/ha. However, the highest yield was observed by Asterix followed by Granola, Arinda, Provento and Diamant in the 2nd generation.The Agriculturists 2015; 13(2) 120-132
First Report of Laribacter hongkongensis Peritonitis in Continuous Ambulatory Peritoneal Dialysis
Authors: Woo Patrick C.Y. , Poon Rosana W.S. , Foo Chuen-Hing , To Kelvin K.W. , Lau Susanna K.P. 
Published: February 2016

The most common pathogens associated with peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD) are gram-positive bacteria, which constitute 60 – 80% of all isolates. With the advancement of molecular technologies for bacterial identification, cases of CAPD-related peritonitis caused by bacteria previously not known to be associated with this clinical condition have been reported. Here we report the first case of CAPD-related peritonitis due to Laribacter hongkongensis.
THE CATERPILLAR PROJECT: A LARGE SUITE OF MILKY WAY SIZED HALOS
Authors: Griffen Brendan F. , Ji Alexander P. , Dooley Gregory A. , Gómez Facundo A. , Vogelsberger Mark , O’Shea Brian W. , Frebel Anna 
Published: February 2016

ABSTRACT
We present the largest number of Milky Way sized dark matter halos simulated at very high mass (∼104

/particle) and temporal resolution (5 Myr/snapshot) done to date, quadrupling what is currently available in the literature. This initial suite consists of the first 24 halos of the Caterpillar Project whose project goal of 60–70 halos will be made public when complete. We do not bias our halo selection by the size of the Lagrangian volume. We resolve ∼20,000 gravitationally bound subhalos within the virial radius of each host halo. Improvements were made upon current state-of-the-art halo finders to better identify substructure at such high resolutions, and on average we recover ∼4 subhalos in each host halo above 108

which would have otherwise not been found. The density profiles of relaxed host halos are reasonably fit by Einasto profiles (α = 0.169 ± 0.023) with dependence on the assembly history of a given halo. Averaging over all halos, the substructure mass fraction is

, and mass function slope is dN/d

. We find concentration-dependent scatter in the normalizations at fixed halo mass. Our detailed contamination study of 264 low-resolution halos has resulted in unprecedentedly large high-resolution regions around our host halos for our fiducial resolution (sphere of radius

Mpc). This suite will allow detailed studies of low mass dwarf galaxies out to large galactocentric radii and the very first stellar systems at high redshift (z

15).
COLLISIONS OF CO2 ICE GRAINS IN PLANET FORMATION
Authors: Musiolik Grzegorz , Teiser Jens , Jankowski Tim , Wurm Gerhard 
Published: February 2016

ABSTRACT
In protoplanetary disks, CO2 is solid ice beyond its snow line at

. Due to its high abundance, it contributes heavily to the collisional evolution in this region of the disk. For the first time, we carried out laboratory collision experiments with CO2 ice particles and a CO2-covered wall at a temperature of 80 K. Collision velocities varied between 0 and 2.5 m s−1. Particle sizes were on the order of ∼ 100 μm. We find a threshold velocity between the sticking and the bouncing regime at 0.04 m s−1. Particles with greater velocities, but below 1 m s−1, bounce off the wall. For yet greater velocities, fragmentation occurs. We give analytical models for the coefficients of restitution and fragmentation strength consistent with the experimental data. Set in context, our data show that CO2 ice and silicate dust resemble each other in the collisional behavior. Compared to water ice, the sticking velocity is an order of magnitude smaller. One immediate consequence as an example is that water-ice particles mantled by CO2 ice lose any “sticking advantage.” In this case, preferential planetesimal growth attributed to the sticking properties of water ice will be limited to the region between the H2O ice line and the CO2 ice line.
DUST AND POLYCYCLIC AROMATIC HYDROCARBON IN THE PRE-TRANSITIONAL DISK AROUND HD 169142
Authors: Seok Ji Yeon , Li Aigen 
Published: February 2016

ABSTRACT
The pre-transitional disk around the Herbig Ae star HD 169142 shows a complex structure of possible ongoing planet formation in dust thermal emission from the near-infrared (IR) to millimeter wavelength range. Also, a distinct set of broad emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and

, commonly attributed to polycyclic aromatic hydrocarbons (PAHs), is detected prominently in the HD 169142 disk. We model the spectral energy distribution (SED) as well as the PAH emission features of the HD 169142 disk simultaneously with porous dust and astronomical-PAHs, taking into account the spatially resolved disk structure. Our porous dust model, consisting of three distinct components that are primarily concentrated in the inner ring, middle ring, and outer disk, provides an excellent fit to the entire SED, and the PAH model closely reproduces the observed PAH features. The accretion of ice mantles onto porous dust aggregates occurs between ∼16 and

, which overlaps with the spatial extent (∼

) of the observed PAH emission features. Finally, we discuss the role of PAHs in the formation of planets possibly taking place in the HD 169142 system.
ARE TIDAL EFFECTS RESPONSIBLE FOR EXOPLANETARY SPIN–ORBIT ALIGNMENT?
Authors: Li Gongjie , Winn Joshua N. 
Published: February 2016

ABSTRACT
The obliquities of planet-hosting stars are clues about the formation of planetary systems. Previous observations led to the hypothesis that for close-in giant planets, spin–orbit alignment is enforced by tidal interactions. Here, we examine two problems with this hypothesis. First, Mazeh and coworkers recently used a new technique—based on the amplitude of starspot-induced photometric variability—to conclude that spin–orbit alignment is common even for relatively long-period planets, which would not be expected if tides were responsible. We re-examine the data and find a statistically significant correlation between photometric variability and planetary orbital period that is qualitatively consistent with tidal interactions. However it is still difficult to explain quantitatively, as it would require tides to be effective for periods as long as tens of days. Second, Rogers and Lin argued against a particular theory for tidal re-alignment by showing that initially retrograde systems would fail to be re-aligned, in contradiction with the observed prevalence of prograde systems. We investigate a simple model that overcomes this problem by taking into account the dissipation of inertial waves and the equilibrium tide, as well as magnetic braking. We identify a region of parameter space where re-alignment can be achieved, but it only works for close-in giant planets, and requires some fine tuning. Thus, while we find both problems to be more nuanced than they first appeared, the tidal model still has serious shortcomings.