bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Approach to Predicting Improvements in Perforation Cluster Treatment Efficiency
Authors: Mientka Matthew , Romberg Eric , Scott Ellen 
Published: October 2018

Abstract
In horizontal-well, plug-and-perforate completions, various studies have shown that not all perforation clusters are stimulated equally. To increase perforation cluster treatment efficiency, engineers attempt to move the perforations of each stage to similarly-stressed rock. Most of these efforts have not included predictions quantifying efficiency improvements. This paper outlines a methodology for predicting improvements of perforation cluster treatment efficiency and includes a case study verifying the results of the model using pre-treatment diagnostics.
In four Western Anadarko Basin wells, the operator measured mechanical rock properties using drill bit geomechanics. These properties were used to calculate the changes in minimum horizontal stress along each ~5,000-ft horizontal well. Within each treatment stage, the engineers chose perforation locations to minimize the difference in minimum horizontal stress. Using offset vertical logs and the geosteering interpretations, the engineers built a high-resolution fracture simulation model for each well. The model included the measured mechanical properties along the wellbore path. Comparing results from a geometric perforation model and the stress-balanced perforation model, the engineers predicted increased perforation cluster efficiencies between 10 and 20%.
The four wells were completed using the stress-balanced perforation designs. Like all previous wells in the area, the operator performed step-down rate tests on these wells before each stimulation treatment. The step-down rate test is a common hydraulic fracturing diagnostic to quantify the number of open perforations taking treatment fluid. Compared to the operator's previous geometrically-perforated wells, the wells with the stress-balanced perforation designs showed more open perforations. A higher number of open perforations suggests a greater perforation cluster treatment efficiency. The increase in efficiency measured by the step-down rate tests was consistent with the model predictions.
By understanding how stress-balancing perforation clusters will affect perforation cluster treatment efficiency, operators can optimize stimulations. The industry has not widely adopted stress-balanced perforation designs or other ‘engineered’ completion strategies. The results of ‘engineered’ completion studies have often been inconclusive, likely due to small sample sizes and reliance on production results. By combining affordable measurement of rock properties, modeled perforation cluster efficiency, and an affordable measurement of perforation efficiency, this paper provides a methodology for economically optimizing multi-stage stimulations in horizontal wells.
Early Identification of a Potential Unconsolidated Reservoir and the Prevention of Sand Flowback by Incorporating a Liquid-Consolidation Agent with a Fracturing Treatment in Saudi Arabia
Authors: Hamid Saad , Almulhim Abdulrahman , Alabbad Emad Abbad , Palanivel Maharaja 
Published: October 2018

Abstract
An engineering approach is discussed for identifying a potentially unconsolidated reservoir in an exploratory area and controlling sand flowback by fracturing using a liquid-consolidation additive as the binding agent.
A vertical gas well targeting an exploratory reservoir was completed and hydraulically fractured to help enhance productivity. A petrophysical evaluation was performed with openhole logs, and results showed a potentially unconsolidated pay zone that posed the risk of producing formation sand.
After identifying the issue, precautionary measures were taken to help prevent sand production. An engineered solution to hydraulically fracture the reservoir using a liquid-consolidating additive as a binding agent, opposed to the conventional resin-precoated proppant, was successfully performed.
The fracturing technique enhanced well productivity and allowed sand-free high production rate of hydrocarbons. Orienting the perforations toward the maximum horizontal stress direction helped reduce tortuosity and placement of the fracturing treatment.
This paper presents petrophysical analysis, treatment design, and application, including production analysis to evaluate the effectiveness of the treatment.
Evaluation of the openhole logs and understanding the criteria for potential sand-producing formations can help identify sand flowback in the early stages of well completion to promote the application of solutions that will substantially reduce/eliminate problems associated with sand flowback during the life of the well. This technique helped achieve sand control without using screens, simplifying wellbore equipment while enhancing reservoir production. Early identification of the problem minimized production losses and non-productive time (days) for the operator and potential formation sanding problems.
Influence of Regional Tectonics and Pore-Pressure Depletion on Tight-Gas Recovery in the Sanga Sanga PSC
Authors: Rylance M.. 
Published: October 2018

Abstract
The Sanga-Sanga PSC fields are located onshore Mahakam delta, East Kalimantan, Indonesia. Since the 1970s, they have produced over 80% of originally estimated gas in place with the remaining gas locked up in low permeability sands. A prize of at least 0.75 Tcf would be achievable, if these sub milli-Darcy resources could be developed. However, previous attempts at hydraulic fracturing, over three decades, have been spectacularly ineffective and rarely enjoyed any improvement or uplift at all.
During late 2006, a detailed review of the regional stress-state and prior unsuccessful frac operations was performed. This review unearthed significant evidence of a reverse stress-ordering in the deep low permeability sands, resulting in horizontal fractures being created. While this provided some logic behind the widespread failure rate, it did not in itself offer a direct solution. However, there was also sufficient evidence from previous frac history, to indicate that the solution may lie with a pore-pressure reduction. A pilot program, with meticulous candidate selection was planned to investigate this.
Further investigation determined the presence of a strong poro-elastic relationship and it was assessed that when combined with longevity of production (30 years), that the stress-state would be substantially affected. During 2008, a suite of well candidates were carefully selected with a range of reduced pore- pressures, aligned with the poro-elastic understanding, hydraulic frac treatments were performed and the wells flowed and produced for two years to confirm productivity. The subsequent production behaviour, confirmed a very positive response and the treated wells netted substantial gas/condensate sales. Production behaviour confirmed the poro-elastic relationships and a set of absolute guidelines on candidate selection and fracture execution were created. Subsequent operations that have adhered to these strict guidelines have been extremely successful. The ability of the new approach to reverse a 30- year trend of hydraulic fracturing failure will now lead to the development of the remaining resource within the fields. An extensive treatment campaign will now be possible to perform with between 50 - 100 candidates well opportunities likely to be available in the field.
A careful assessment of the regional stress-state indicated a reverse ordering of the principal stresses as being the root cause of the poor hydraulic fracturing behaviour. However, careful consideration of the rock mechanics and a coherent pilot programme demonstrated the ability, under effective depletion conditions, to place economic and successful hydraulic fracturing treatments.
Seed Distribution and Invertebrate Seed Predation in No‐Till and Minimum‐Till Maize Systems
Authors: Law Jeffrey J. , Gallagher Robert S. 
Published: October 2018

Core Ideas
Minimum tillage was not detrimental to the granivorous invertebrate community.
Seed predation was not weed species specific.
Minimum tillage could obscure seeds from invertebrate seed predators.
The use of low‐intensity tillage is becoming more widespread throughout the United States, and the effects of these tillage methods on invertebrate seed predator activity and weed seed removal is unknown. We investigated the effects of a minimum tillage system (min‐till) (i.e., vertical coulter + rotary harrow + high residue cultivation) that disturbs the first 2 to 5 cm of soil on invertebrate seed predators and invertebrate seed predation in maize (Zea mays L.) fields in the northeastern United States. Pitfall trapping was conducted and weed seed removal was assessed with seed cards in min‐till and no‐till plots. The depth of seed burial by min‐till implements was examined. Overall granivorous invertebrate activity‐densities were higher in min‐till plots when compared with no‐till, with three ground beetle species (Bembidion quadrimaculatum oppositum Say, Pterostichus melanarius Illiger, Chlaenius tricolor Dejean) and field crickets (Gryllus spp.), having increased activity densities and only one ground beetle species (Harpalus pensylvanicus DeGeer), having a decreased activity‐density. Surface seed predation in min‐till and no‐till was not significantly different. Seed burial was found to be significantly higher in min‐till vs. no‐till. We conclude that min‐till is a promising weed management option for the future, but seed burial may hinder the ecosystem service of weed seed predation and bears further examination.
Grazing Crop Residues Has Less Impact in the Short‐Term on Soil Properties than Baling in the Central Great Plains
Authors: Rakkar Manbir K. , Blanco‐Canqui Humberto , Rasby Rick J. , Ulmer Kristen , Cox‐O’Neill Jordan , Drewnoski Mary E. , Drijber Rhae A. , Jenkins Karla , MacDonald James C. 
Published: October 2018

Core Ideas
Corn residue grazing had little to no impact on soil health indicators.
Residue baling increased wind erosion risks by 22 to 56%.
Baling reduced near‐surface soil water content by 8 to 32%.
Soil type or precipitation amount did not influence residue removal impacts on soil properties.
Residue grazing can be a more sustainable practice than baling
Cattle grazing and baling of corn (Zea mays L.) residues are common practices in integrated crop–livestock systems, but their impacts on soil properties are not well understood on a regional scale. We conducted a 3‐yr study across a precipitation gradient (ranging from 400 to 804 mm) in the central Great Plains to evaluate soil compaction, structural quality, water content, fertility, sorptivity, and microbial biomass in response to corn residue grazing and baling. Six on‐farm sites varying in soil texture, organic matter, crop rotation, and irrigation practices were established with three residue treatments: control, grazing, and baling. Sites were predominantly under conservation tillage management. Residue baling reduced residue cover by 57% and residue grazing by 17% relative to the control. At most sites, residue baling reduced near‐surface soil water content by 8 to 32% and increased wind erodible fraction by 22 to 56% compared with the control but grazing generally had no effect. Residue grazing and baling had small or no negative effects on other measured soil properties regardless of soil type or precipitation amount. When changes in soil properties did occur, they were due to differences in grazing duration or agronomic management. For example, grazing during spring at one of the sites increased soil bulk density by 7% (1.17 vs. 1.26 Mg m−3) relative to the control. This short‐term study indicates that residue grazing, in general, does not impact soil properties, but residue baling at high rates (>50%) could increase wind erosion risks and reduce surface soil water content in this region.
Fertilizer Application Effects on Grain and Storage Root Nutrient Concentration
Authors: Wortmann Charles S. , Dicko Mohammed K. , Maman Nouri , Senkoro Catherine J. , Tarfa Bitrus Dawi 
Published: October 2018

Grain nutrient concentrations can be affected by crop management.
Grain nutrient concentrations were often increased for cereal crops by N–P–K application.
Grain N, K, S, Cu, Mn, and B were reduced by Mg–S–Zn–B application for bean, maize, and rice.
Nutrient concentrations were not much affected by nutrient application for other crop nutrients.

Fertilizer application can affect nutrient concentrations of edible plant products. Data from 70 crop‐nutrient response trials conducted in Mali, Niger, Nigeria, and Tanzania were used to evaluate nutrient application effects on nutrient concentrations for grain of five pulse and five cereal crops and for storage roots of cassava (Manihot esculenta L.). Treatments per trial were ≥12, but this study was limited to: no fertilizer applied; macronutrients applied (NPK or PK); and the macronutrient treatment plus Mg, S, Zn, and B applied (MgSZnB). Dried grain or cassava flour samples were analyzed for concentrations of all essential soil nutrients, except for Ni and Cl. Concentrations of N and K were positively correlated with concentrations of most other nutrients. The concentrations were relatively low overall for cowpea (Vigna unguiculata L.) and pigeonpea (Cajanus cajan L.) compared with other pulse crops and for maize (Zea mays L.) compared with other cereal crops. Application of NPK or PK had little effect on nutrient concentrations, except for increased mean cereal grain concentrations for N, Ca, Mg, S, Zn, Cu, and B. Bean (Phaseolus vulgaris L.), maize and rice (Oryza sativa L.) grain concentrations were reduced by MgSZnB for N, K, S, Cu, Mn, and B. There were no or inconsistent effects of MgSZnB on other crop‐nutrient concentrations. Nutrient concentrations are not reduced by NPK for non‐legumes or PK for pulses, but MgSZnB often reduced bean and cereal nutrient concentrations with greater reductions for immobile compared with mobile nutrients.
Soil Nitrogen Leaching in Logged Beetle‐Killed Forests and Implications for Riparian Fuel Reduction
Authors: Rhoades Charles C. 
Published: October 2018

Recent extensive forest mortality and subsequent salvage logging may threaten the water supply from headwater catchments in western North America. Land managers confronting current insect outbreaks and projected increases in forest disturbance require information about the potential water quality consequences of these changes. This study is a hillslope‐scale evaluation of soil N and C leaching in lodgepole pine forests that have experienced 80% overstory tree mortality. I measured extractable inorganic and ion resin exchangeable‐N forms, in situ net mineralization and nitrification, and leaching in upland and riparian forests with the following treatment combinations: (i) uncut upland with uncut riparian, (ii) harvested upland with uncut riparian buffer, and (iii) harvested upland with harvested riparian. This design permitted comparison of N cycling and leaching in 30‐m‐wide riparian buffers and a riparian fuel break designed to remove canopy fuels and reduce wildfire concerns in areas with extensive bark beetle infestation. Harvesting increased NO3–N, total dissolved N, and dissolved organic C leachate concentrations in upland landscapes but had little effect on net N transformations. Leachate N and C concentrations were 1.5 times higher in riparian buffers downslope of harvested uplands than those in riparian zones downslope of uncut uplands. Riparian forest harvest increased N leaching relative to uncut buffers, although postharvest concentrations remained well below regional water quality standards. Thus, while this study provides evidence that N leaching from dead buffers is low, it also suggests that riparian fuel reduction may complement wildfire mitigation objectives without compromising watershed protection.Core Ideas
Nitrogen leaching was low in riparian buffers even though most trees were dead.
Harvest of dead riparian forest increased N losses, but concentration remained low.
Novel riparian management may achieve both wildfire mitigation and watershed protection.
Slow and Fast‐Release Boron Sources in Potash Fertilizers: Spatial Variability, Nutrient Dissolution and Plant Uptake
Authors: da Silva Rodrigo C. , Baird Roslyn , Degryse Fien , McLaughlin Michael J. 
Published: October 2018

Core Ideas
A dual‐release boron (B) fertilizer can reduce the risks of seedling toxicity and leaching.
Muriate of potash (MOP) was co‐compacted with slow‐ and fast‐release B sources.
MOP+B resulted in a more uniform B spatial distribution compared to traditional bulk‐blends.
Incorporation of colemanite in the formulation slowed the release of B from the MOP+B fertilizers.
This novel B fertilizer may improve the synchrony between nutrient availability and crop demand.
Boron (B) supply to crops is a challenging fertilization practice, due to its high mobility in soil, its narrow window between deficiency and toxicity and the necessity to evenly apply this micronutrient to the soil. We aimed to increase B fertilizer efficacy through the use of slow‐ and fast‐release borate compounds in a macronutrient carrier fertilizer. Borax, ulexite, and colemanite (alone or combined) were compacted with muriate of potash (MOP) to produce B‐enriched fertilizers varying in proportion of water‐soluble B. One such fertilizer was assessed for spatial B distribution compared with a bulk blend equivalent in a soil tray, while others were assessed for nutrient release in a soil column, and canola (Brassica napus L.) growth in a leached and non‐leached pot trial. The compacted MOP+B fertilizer improved B distribution in soil compared to a simulated bulk blend. The release of B was fastest for borax (>93% released within 2.5 pore volumes [PV]) and slowest for colemanite (<20% released after 20 PV). The combination of slow‐ and fast‐release B sources resulted in initial fast‐release of B followed by a constant slower B release. In leached soil, the higher B losses (up to 80% of applied B) resulted in lower canola B uptake with increasing borax and decreasing colemanite in the formulation. In non‐leached soils, there was no difference in B uptake among fertilizer treatments. The use of dual release B sources in MOP+B fertilizer formulations effectively addresses the risk of B loss, and better matches crop B demands during growth.
Gastric mucosa structure in patients with different serum pepsinogen levels and ratios
Authors: Tsukanov V. V. , Tonkikh Yu. L. , Vasyutin A. V. , Peretyatko O. V. , Pulikov A. S. , Baron I. I. 
Published: October 2018

Purpose of the study. Determine the gastric mucosa Structure in patients with different serum pepsinogen levels and ratios.Material and methods. 801 people (387 men, 414 women) underwent clinical examination and determination of pepsinogen-1, pepsinogen-2 and serum anti-Helicobacter pylori antibodies using GastroPanel (Biokhit, Finland). 161 patients with different levels of atrophy determined by serological screening method underwent a fibroesophagogastroduodenoscopy (Olimpus-10) with biopsy and subsequent morphological examination of the gastric mucosa performed using a visual analogue scale according to the Sydney Staging System. 107 patients had morphometry of the gastric mucosa with the determination of the number of central, parietal and mucoid cells.Results. The prevalence of severe atrophic gastritis in the stomach accounted for 10.9%. H. pylori was detected in 90.0% of the subjects. The morphological study showed atrophy in 94.4–95.8% of subjects with atrophic gastritis of the corpus mucosa of the stomach as defined by serological testing.Conclusions. Atrophy of the stomach mucous membrane as determined by morphological examination was prevalent in patients with severe atrophic gastritis of the corpus mucosa of the stomach, diagnosed using the method for determining serum pepsinogen levels.
Treatment with a minoinvasive method of the major duodenal papilla
Authors: Levchenko N. V. , Khrachkov V. V. , Shavaliev R. R. , Kislitsyn D. P. 
Published: October 2018

In this article there are data of comparative analysis of the results of minimally invasive treatment of benign stenosis of the major duodenal papilla through the use of endoscopic retrograde papillosphincterotomy and antegrade laser papillotomy carried out by means of high-energy holmium (YAG:Ho) laser.Resolution of stenosis of the major duodenal papilla was performed in the patients of the control group (n = 102) through the use of endoscopic papillosphincterotomy before and after laparoscopic cholecystectomy.Antegrade laser papillotomy (invention patent №2449757 from 09.11.2010) and cholecystectomy were performed in the patients of core group (n = 35) in the presence of evidence.Antegrade laser papillotomy was successfully performed in all cases. It allows to less traumatic resolve the stenosis of the major duodenal papilla, even in its intradiverticular location and with the combination of choledoholitiasis. It minimizes the possibility of complications such as bleeding, perforation, pancreatitis in comparison with retrograde techniques.
Therapy for erosive esophagitis induced by mixed reflux in patients with CAD
Authors: Minushkin O. N. , Shuleshova A. G. , Bondarev K. A. , Danilov D. V. 
Published: October 2018

The article presents the results of using a combination of PPI (pantoprazole) and UDCA for the treatment of erosive esophagitis induced by mixed reflux in patients with coronary artery disease.A total of 62 patients with EGDS-proven erosive esophagitis were enrolled in the study. The patients were divided into two groups: the active treatment group (ATG) which included 34 patients with erosive reflux esophagitis and control group (CG), which included 28 patients with erosive reflux esophagitis without CAD. The patients of both groups received IPP (pantoprazole) 80 mg/day and UDCA at a dosage of 15 mg/kg/day for 12 weeks. (84 days).The study showed that complete epithelialization of esophageal mucosa defects was detected in 100% of ATG patients by Day 84 of therapy, the same was achieved in CG patients by Day 56 of the basic course of therapy.The treatment of EE induced by mixed reflux with a combination of PPI (pantoprazole) at a dose of 80 mg/day and UDCA at a dosage of 15 mg/kg/day was efficient in patients with GERD and CAD as a basic course of therapy for not less than 84 days. An effective dose of UDCA for maintenance therapy is 5 mg/kg/day in combination with PPI at a daily dose of 40 mg for not less than 2 months.
A economia da Rússia no século 21: as dinâmicas da ascensão econômica e da relativa estagnação após a crise global de 2008
Authors: Manzi Rafael Henrique Dias 
Published: October 2018

O desempenho da economia da Rússia na primeira década após o esfacelamento político da União Soviética foi marcado por instabilidades macroeconômicas e por uma profunda recessão econômica. Esse cenário reverteu-se a partir do início do século 21 quando o país entrou em um novo ciclo de expansão econômica marcada por uma expressiva aceleração das taxas de crescimento do PIB. Contudo, a partir da década de 2010, a economia russa perdeu dinamismo e o processo de convergência de renda com os países desenvolvidos estagnou-se novamente. O principal objetivo do artigo é fazer uma análise do processo deascensão econômica da Rússia e do atual quadro de relativa estagnação a partir da eclosão da crise global de 2008. Os resultados apontam que o quadro de relativa estagnação da economia da Rússia não está ligado somente a fatores conjunturais, como a queda dos preços das commodities energéticas nos mercados internacionais e o acirramento das tensões geopolíticas com o mundo ocidental, mas refletem também, em grande medida, fragilidades domésticas da economia russa.