bluuebunny/crossref_metadata_2025 huggingface dataset:
MOV10L1 in piRNA processing and gene silencing of retrotransposons during spermatogenesis
Authors: Zhu Xiaobin , Zhi Erlei , Li Zheng
Published: February 2015

Piwi-interacting RNAs (piRNAs) are a broad group of non-coding small RNAs with important biological functions in germline cells. It is well known that piRNAs can maintain genome integrity via silencing retrotransposons. Previous studies on the animal models harboring gene deletions have shown that the genes involved in piRNA biogenesis and their defective expression can result in the spermatogenic dysfunction. In the past decade, significant progress has been achieved for piRNAs and their roles in male germ cells. This review addresses the advances on piRNAs and piRNA biogenesis-associated genes, with a particular focus on the Moloney leukemia virus 10-like 1 (MOV10L1) gene, whose role in primary piRNA processing and in the ‘ping–pong’ cycle during secondary piRNA processing has been illustrated. The biological characteristics of piRNA has been summarized, and emphasis was laid on the roles ofMOV10L1in the mediation of piRNA biogenesis and retrotransposons silencing by DNA methylation. Furthermore, the association betweenMOV10L1gene polymorphisms and complete maturation arrest in men has been discussed. Hence, thorough literature review was conducted in order to obtain a greater understanding of the function ofMOV10L1and its mechanisms underlying spermatogenesis in mice and humans.

Free Chinese abstract: A Chinese translation of this abstract is freely available athttp://www.reproduction-online.org/content/149/5/R229/suppl/DC1.
Noninvasive Ventilation Strategies for Early Treatment of RDS in Preterm Infants: An RCT
Authors: Salvo Vincenzo , Lista Gianluca , Lupo Enrica , Ricotti Alberto , Zimmermann Luc J.I. , Gavilanes Antonio W.D. , Barberi Ignazio , Colivicchi Micaela , Temporini Francesca , Gazzolo Diego
Published: February 2015

BACKGROUND AND OBJECTIVES:

There is evidence that new methods of noninvasive ventilation (NIV) support have significantly changed respiratory distress syndrome (RDS) management in preterm infants. Further perspectives for neonatologists involve the assessment of different NIV strategies in terms of availability, effectiveness, and failure. This study evaluates the efficacy of 2 different NIV strategies for RDS treatment in very low birth weight (VLBW) infants: nasal synchronized intermittent positive pressure ventilation (NSIPPV), which is a modality of conventional ventilation with intermittent peak inspiratory pressure, and bilevel continuous positive airway pressure (BiPAP), not synchronized, with 2 alternate levels of continuous positive airway pressure.

METHODS:

We conducted a 2-center randomized control study in 124 VLBW infants (<1500 g and <32 weeks of gestational age) with RDS who received NIV support (NSIPPV, n = 62; BiPAP, n = 62) within 2 hours of birth. We evaluated the performance of NIV strategies by selected primary outcomes (failure rate and duration of ventilation) and secondary outcomes.

RESULTS:

The number of failures and duration of ventilation support did not differ between NSIPPV and BiPAP strategies (P > .05 for both). Moreover, no differences between groups were found regarding secondary outcomes (P > .05 for all).

CONCLUSIONS:

The present data show no statistically significant differences between NSIPPV and BiPAP strategies in terms of duration of ventilation and failures, suggesting that both NIV techniques are effective in the early treatment of RDS in VLBW infants. Further randomized investigations on wider populations are needed to evaluate the effect of NIV techniques on long-term outcomes.
Amphibia, Anura, Hylidae, Cruziohyla craspedopus (Funkhouser, 1957): distribution extension and first record from the state of Pará, Brazil
Authors: Bitar Youszef Oliveira da Cunha , Silva Kleiton Rodolfo Alves , Filho Heriberto Figueira da Silva , Pinheiro Leandra Cardoso
Published: February 2015

Here we report the first record of Cruziohyla craspedopus from Pará, Brazil, showing the presence of this species also in eastern Amazon. The new record is based on a juvenile specimen collected in the left side margin of the Tapajós River, in a well-preserved upland forest area.
Determination of the Optimum Torque to Tighten the Smartpegs of Magnetic Resonance Frequency Analyses Devices: An Ex Vivo Study
Authors: Geckili Onur , Cilingir Altug , Bural Canan , Bilmenoglu Caglar , Bilhan Hakan
Published: February 2015

The aim of this study was to find an optimal value for tightening the Smartpegs for magnetic radiofrequency analysis devices (RFAs) devices. Thirty implants were placed in 3 cow ribs. The RFA value of each implant was measured in buccal and mesial directions after tightening the Smartpegs with 1, 3, 4, 8, 9, 10, and 11 Ncm. Additionally, 4 different examiners measured the RFA after hand tightening the Smartpegs, and the results were compared. The buccal implant stability quotient (ISQ) values when the Smartpegs were tightened to 1Ncm were significantly lower than the ISQ values when the Smartpegs were tightened to 3, 4, 8, 9, 10, and 11 Ncm (P < .05). The mesial ISQ values when the Smartpegs were tightened to 1, 3, and 4 Ncm were significantly lower than the ISQ values when the Smartpegs were tightened with higher torque values (P < .05). The buccal measurements made by 1 examiner was significantly lower than 3 Ncm (P < .05), and the buccal measurements made by 1 examiner was significantly lower than 4 Ncm (P < .05). The mesial ISQ values measured by 2 examiners were significantly lower than 3 Ncm (P < .05), and the mesial ISQ values measured by the other 2 examiners were significantly lower than 8 Ncm (P < .05). The tightening of the Smartpegs should be standardized by the manufacturer to a range of 5-8 Ncm in order to gain reliable objective RFA values, instead of leaving it to subjective finger pressure.
Żandarmeria Wojskowa – oddziały służące zapewnianiu bezpieczeństwa i porządku publicznego w Polsce i Unii Europejskiej
Authors: Karwoth-Zielińska Dominika
Published: February 2015

There are many threats to national security today. Some of them are the negative aspects of globalisation. Increasing crime in many areas (as the results of social, economic and political consequences of terrorist acts, the excessive influx of illegal immigrants – often from other cultures and civilisations), as well as threats to personal safety have forced governments to search for new methods and tools to combat and prevent various types of threats – within the area of a single country and the entirety of the EU. Given its geographical position in Europe, Poland participates naturally in a number of supranational economic, political and military structures. Preventing threats has forced institutions today to become involved in securing safety across many fields of cooperation. The inability to accurately identify security threats requires advance planning, flexibility, responsiveness and a comprehensive approach to security and defense. This includes taking various initiatives using allied and multinational militaries and non-military solutions in response to contemporary threats. Both the Polish and European Gendarmerie Forces belong to a branch of special police constituted only by elements of police forces with military status in order to perform all police tasks within the scope of crisis management operations.
Wizja państwa polskiego w programach politycznych Samoobrony RP
Authors: Lisiakiewicz Rafał
Published: February 2015

The Self-Defense Party of the Republic of Poland was for many years a phenomenon on the Polish political scene. Its hayday was in the first years of the twenty-first century. However, the party suffered electoral defeat in the 2007 elections and lost representation in parliament. Up to that point it had been able to attract significant public support, and even contributed to the make-up of the government. The article presents the vision of the Polish state propagated by the Self-Defense Party. It was that vision that helped it to a period of political successes. The populist nature of the Self-Defense programme was at the same time one of the reasons for the party’s collapse.
Koncepcja regulacji sharia zones w wybranych krajach Unii Europejskiej
Authors: Frańczuk Magdalena
Published: February 2015

The study presents issues related to the possibility of introducing into traditional urban areas of the European Union (to western culture) special zones regulated by Shariah law (sharia zones). It draws on recent statistics and forecasts on the number of the Muslim population living in the European Union. These are widely reported in the media. The author also provides examples of proposed regulations of sharia zones in selected European cities. This is a current issue in the largest countries in the European Union and interesting from the point of view of both sociology and law.
Imazapic Effects on Competition Dynamics Between Native Perennial Grasses and Downy Brome (Bromus tectorum)
Authors: Burnett Shayla A. , Mealor Brian A.
Published: February 2015

Downy brome inhibits revegetation efforts following ecosystem disturbance. Imazapic is a commonly used herbicide for downy brome management, but more information is needed regarding effective application timing for restoration efforts. We wished to determine (1) if native species establishment exhibited a tradeoff between downy brome competition and injury from herbicide and (2) if this differed between pre- and postemergent applications of imazapic. We used a standard replacement series design and overlaid herbicide treatments. Nine weeks after planting, aboveground biomass was harvested and relative yield (RY) indices calculated. Both imazapic applications reduced downy brome biomass by 91% or more (P < 0.05). Imazapic caused drastic reductions in native biomass but less than what was caused by downy brome competition (P < 0.05). Natives were less injured by a pre- than postemergent application (P < 0.05). In situations where downy brome may impact restoration efforts, pre-emergent applications of imazapic at 70 g ai ha−1 (0.06 lb ai ac−1) may reduce downy brome with less negative impacts on newly-seeded native grasses than post-emergent applications. Ensuring sufficient proportions of native species seeds on restoration sites may reduce downy brome.
EPSPS Gene Amplification is Present in the Majority of Glyphosate-Resistant Illinois Waterhemp (Amaranthus tuberculatus) Populations
Authors: Chatham Laura A. , Wu Chenxi , Riggins Chance W. , Hager Aaron G. , Young Bryan G. , Roskamp Gordon K. , Tranel Patrick J.
Published: February 2015

With the frequency of glyphosate-resistant waterhemp increasing throughout the Midwest, the identification of resistant populations has become important for managing this species. However, high-throughput screening for glyphosate resistance in the greenhouse is tedious and inefficient. Research was conducted to document the occurrence of glyphosate-resistant waterhemp throughout the state of Illinois, and to determine whether a molecular assay for 5-enolypyruvyl-shikimate-3-phosphate synthase (EPSPS) gene amplification can be used as an alternative means to detect resistant populations. Populations throughout the state of Illinois were collected in 2010 and screened for glyphosate resistance using a whole-plant assay in a greenhouse, and survivors were examined for EPSPS gene amplification. Of 80 populations investigated, 22 were glyphosate resistant based on the greenhouse screen, and gene amplification was identified in 20 (91%) of the resistant populations. Although there are multiple mechanisms for glyphosate resistance in waterhemp, a molecular test for EPSPS gene amplification provides a rapid alternative for identification of glyphosate resistance in most populations.
Geographic information system modelling of freight transport and logistics in Saint Petersburg, Russia
Authors: Kotikov Jurij
Published: February 2015

Saint Petersburg in Russia is a vital hub in the Eurasian transport system. Its 4300 ha Baltic ‘Big Port' is one of the busiest in the world, handling around 70 Mt of bulk and containerised cargo a year. It is Russia's leading container port, with liner routes to Rotterdam, Hamburg, Lübeck, Bremerhaven and Antwerp, and the refrigeration area is one of the largest in Europe. The total annual value of goods shipped is nearly £40 billion. A complex and continually developing road and rail network is needed to serve the fast-expanding port area. This paper describes how geographic information systems are being used to model and improve the city's transport and logistics infrastructure, helping to ensure it meets both social and economic needs and form an intergral part of the European transport network.
Raising the roof on design in Russia: Pulkovo airport
Authors: Mills Shonn , Hares Kevin
Published: February 2015

Pulkovo International airport near St Petersburg is nearing completion of a €1 billion redevelopment as a vital new gateway into Russia. Its new main terminal opened in December 2013 and by the end of 2015 the airport will have a capacity of 17 million passengers per year. It is also one of the first public–private partnership projects of its kind in Russia. Use of conventional construction techniques in innovative ways was a key factor in successful on-time completion of the new terminal building. Developing a flexible concrete frame allowed the contractor to work productively and continuously through the harsh Russian winters. In addition, early geometric studies developed a diagonal spanning roof truss system to realise the competition-winning architectural design. The Russian market has its own unique set of challenges and this paper outlines the techniques utilised to strike the right balance between local compliance and innovation to deliver a major international transport facility.
Los vínculos que brindan mayor satisfacción en la red de apoyo social de los adultos
Authors: Polizzi Luciana , Arias Claudia Josefina
Published: February 2015

Las redes de apoyo social constituyen un tema de gran interés en relación con los adultos mayores. Su efecto sobre el bienestar integral ha sido extensamente comprobado y por ello se ha incluido entre los principales objetivos, estrategias, planes y recomendaciones internacionales dirigidos a la población mayor. Este estudio se propuso tanto identificar y caracterizar los vínculos de la red de apoyo social que brindan mayor satisfacción en esta etapa de la vida, como evaluar las funciones de apoyo que estos cumplían según la conformación del grupo conviviente. Se implementó un diseño no experimental transversal. El estudio fue descriptivo-correlacional. Se seleccionó una muestra no probabilística-intencional de 120 adultos mayores (de 60 a 85 años), de ambos sexos y de tres tipos de grupo conviviente: los que vivían solos, los que vivían únicamente con su pareja y los que vivían con otros familiares. A la muestra se le administró el cuestionario de datos sociodemográficos y la Entrevista Estructurada de Fuentes de Apoyo Social (Vaux y Harrison, 1985). Los resultados evidencian el papel central que ocupan los hijos, la pareja y los amigos en la vejez. Además, se observaron diferencias estadísticamente significativas según género y grupo conviviente en la elección del vínculo que brinda mayor satisfacción.
Aspectos críticos de la concepción de Piaget sobre los números
Authors: Navarro José I.
Published: February 2015

De acuerdo con las teorías constructivistas de Piaget, para que los niños pequeños aprendan matemáticas, es necesario enseñarles primero los procesos lógicos y su organización, puesto que estos serían “prerrequisitos” para la adquisición del concepto de número. De acuerdo con la reciente investigación científica contrastada sobre aprendizaje de las matemáticas, esta concepción piagetiana de la adquisición del número en el niño no está suficientemente justificada. Es claro que los escolares tienen mucho que aprender sobre aritmética y su comprensión del número mejora con la edad y con el aprendizaje, pero eso no significa que carezcan de nociones numéricas acertadas antes de llegar a la educación infantil, incluso desde el nacimiento. Piaget diseñó ingeniosos procedimientos para estudiar la adquisición de los prerrequisitos del número (seriación, conservación, correspondencia), pero lo que nos dice la investigación empírica al respecto es que cuando a los niños de 3 a 6 años se les presentan situaciones análogas a las ideadas por Piaget, de características no verbales, sus habilidades con los números progresan vertiginosamente. En este trabajo, a partir del experimento clásico de Piaget sobre la conservación del número, se analiza la teoría piagetiana de manera crítica desde los resultados encontrados en experimentos paralelos.
La discapacidad en el contexto puertorriqueño: Conceptos, legislaciones y normativas para las personas con discapacidad desde el quehacer psicológico
Authors: Velásquez-González Héctor José , Uribe-Rodríguez Ana Fernanda , Martínez-Rozo Ana Milena
Published: February 2015

Alrededor del mundo se estima que 600 millones de personas tiene algún diagnóstico que puede clasificarse como discapacidad. Puerto Rico se posiciona entre los primeros territorios de Estados Unidos con mayor incidencia de discapacidades. Desde la educación hasta los sistemas de prestación de servicios sociales están regulados por distintas legislaciones que pretenden, como fin último, la inclusión de las personas con discapacidad en la participación activa en la sociedad. Este trabajo busca comprender la transformación de la significación del concepto de discapacidad tanto en el contexto legal y de las representaciones sociales que se le atribuye, como en las legislaciones que promueven y protegen los derechos de las personas con discapacidad. Los psicólogos y las psicólogas deben desarrollar competencias y conocimientos en torno a la discapacidad y la legislación para que intercedan por la población de personas con discapacidad, desarrollar autonomía en estos y promover una mejor calidad de vida y participación activa en la sociedad con base en el respeto y la tolerancia hacia la diversidad.
Reflexiones sobre la interpretación del concepto de locus de control en investigación social
Authors: De Grande Pablo
Published: February 2015

Este artículo se propone revisar el concepto de locus de control como herramienta de interés dentro del campo de la investigación de la percepción de control y sus efectos en la acción. El locus de control ha sido una medida ampliamente utilizada dentro y fuera de la psicología para vincular las creencias con la acción individual, demostrando su capacidad para condicionar ámbitos tan diversos como la educación, la salud, la movilidad laboral y los consumos culturales. Sin embargo, el éxito en su nivel empírico ha conducido en algunos casos –según su creador, Julian Rotter– a imprecisiones conceptuales en lo referido a su definición y a la interpretación de sus resultados. ¿Es equivalente el locus de control a la medida de autoeficacia? ¿Debe considerarse la internalidad del locus de control como algo positivo y la externalidad como algo negativo? ¿Es posible predecir conductas individuales con la medida generalizada de locus de control? Como ejes centrales de su desarrollo, el artículo contextualiza la medida de locus de control en su espacio teórico de origen –la teoría del aprendizaje social– señalando algunas claves interpretativas relevantes para su análisis y utilización.
Evaluación de procesos comunitarios y análisis de redes inter-organizativas: elementos para mejorar la efectividad de las intervenciones comunitarias
Authors: Ramos-Vidal Ignacio , Holgado Daniel , Maya-Jariego Isidro , Palacio Jorge E.
Published: February 2015

El propósito de este artículo es investigar la conexión existente entre el Sentido Psicológico de Comunidad, la Participación Comunitaria y el análisis de redes organizativas, examinando la influencia que dichos enfoques ejercen en los niveles de análisis individual, organizativo y comunitario. Para alcanzar este objetivo, ofrecemos una revisión de la literatura en las tres perspectivas y, a continuación, se analiza el modo en que quedan articulados con los distintos niveles de análisis. Finalmente, exponemos algunas aportaciones que la aplicación de un enfoque ecológico multinivel puede tener para mejorar la efectividad de las intervenciones comunitarias.
Les réseaux de l’émigration clandestine portugaise vers la France entre 1957 et 1974
Authors: Pereira Victor
Published: February 2015

The Portuguese Migration Networks regarding France between 1957 and 1974

This article draws a comparison of different types of networks of illegal emigration which have allowed the illegal departure of more than 500.000 Portuguese to France between 1957 and 1974. It illuminates the different resources (social, reputation) used in that process. Finally, it describes how this process took the shape of a game with three players (migrants, smugglers and State officers), who followed both antagonistic and convergent interests.
Periodontal Soft Tissue Root Coverage Procedures: Practical Applications From the AAP Regeneration Workshop
Authors: Richardson Christopher R. , Allen Edward P. , Chambrone Leandro , Langer Burton , McGuire Michael K. , Zabalegui Ion , Zadeh Homayoun H. , Tatakis Dimitris N.
Published: February 2015

Focused Clinical Question: How should gingival recession (GR) defects be managed based on current evidence?

Summary: The purpose of this practical application is to illustrate the management of GR defects with a primary outcome goal of complete root coverage. The consensus in dental literature and among expert clinicians is that root coverage may be attained through the application of different procedures and that outcomes are generally measured by reduced defect depth, gain in clinical attachment, and an increase in keratinized tissue (KT). These procedures may include the use of: 1) subepithelial connective tissue graft (SCTG); 2) coronally advanced flap; 3) free gingival graft; and 4) soft tissue graft substitutes (acellular dermal matrix and xenogeneic collagen matrix materials) and biologics (recombinant human platelet‐derived growth factor and enamel matrix derivative). The variability in these techniques revolves around the inclusion or avoidance of a palatal donor graft. The decision as to how to approach a specific clinical GR‐type defect should be a combination of considerations relative to the clinician's surgical goals and the patient's understanding of the anticipated outcome. The associated systematic review (Chambrone and Tatakis, J Periodontol 2015;86(Suppl.):S8‐S51) provides clear evidence that SCTG‐based procedures provide the best outcome for mean and complete root coverage, as well as an increase in KT. Patient‐reported outcomes, a topic that needs additional research, should be considered in the decision‐making process.

Conclusion: Based on the available evidence and the illustrated cases included in this practical application, root coverage can be predictably achieved and a successful clinical outcome can be maintained long term.
Energy 360: Invited Perspective: E&P Portfolio Modeling 2.0
Authors: Haldorsen Helge Hove , Howell John I.
Published: February 2015

President's column

The three Ps that successful companies get right are: people, portfolio, and performance. And you cannot have one without the other. Great people select great portfolios and great portfolios deliver great performance. The exploration and production (E&P) industry is made up of thousands of companies exploring for and producing oil and gas worldwide. Common to all companies, whether listed on the stock exchange or not, is the need to have a vision, a mission, core values, a differentiating DNA or corporate culture and unique competitive advantages to avoid delivering below average performance results.

Also, every company develops an ambition and goals to achieve. They can be volume goals such as a certain production rate in 2020 or value goals such as growing net income by 30% in year X+1 over year X. The ambition, goals, and the strategy are communicated internally and externally and then it is time to roll up one’s sleeves and deliver. Most companies have a portfolio of assets, all along the E&P value chain from exploration to abandonment, some onshore, some offshore, all with their individual uncertainties, good risks (grisks) when you do better than the expected case and bad risks (brisks) when you deliver below the expected case. The forecasted production, reserves, schedule and costs are uncertain for each individual asset and for the aggregate, as is the forecasted oil and gas prices/price differentials.

In this column, I would like to discern how companies in 2015 arrive at ambitions, goals, strategies, downsides/ upsides, and the aggregate or composite probability of goal delivery. This is a very important theme because not delivering on a company’s communicated goals has consequences in the marketplace. In a volatile, uncertain, complex, and ambiguous (VUCA) world, perhaps portfolio modeling is the key goal and strategy setting tool in 2015?

John I. Howell III, CEO and president of Portfolio Decisions, has been involved with E&P portfolio modeling for more than 25 years. He has advised hundreds of companies worldwide in the science and practice of portfolio modeling and has seen this forecasting tool and its use evolve. He answers my questions below.
Upfront Reservoir Monitoring Investment Promises Long-Term Rewards
Authors: Bostick Tad
Published: February 2015

Guest Editorial

The industry’s continued migration into deeper, hotter, and more unconventional oil and gas reservoirs carries the potential for significant financial rewards and major economic risks. Because the development of unconventional reservoirs often requires some form of stimulation—thermal stimulation for heavy oil formations and hydraulic fracturing for shale plays—well construction costs are reaching new highs. Rather than developing these wells in a trial-and-error or even blind fashion, more operators realize that the only way to maximize the value of these assets is through real-time monitoring at the reservoir level.

Permanent reservoir monitoring calls for the deployment of one or more downhole sensors to monitor and record a number of reservoir properties, such as temperature, pressure, and flow rates at various locations in and around the wellbore. By monitoring these properties in real time and over time, operators can gauge the progress of reservoir development at each stage of the well’s life cycle.

Full-Asset Life Cycle Benefits

During fracture stimulation of shale wells, for example, a permanent monitoring solution can reliably report information on the fracture network being created, including data on both the quantity and quality of fractures being created in different zones. In steam-assisted gravity drainage (SAGD) wells, downhole temperature sensors can track the propagation of steam moving into the formation, and then the progress of heated oil moving into the producing well.

Once the well is brought onto production, these same monitoring tools can accurately measure the pressures, temperatures, and flow rates of fluids at different points in the wellbore and from different producing zones. Such insight informs when the operator may need to implement some form of remediation or artificial lift in the well to boost dwindling production rates. Once artificial lift has begun, the real-time reservoir data can help optimize the pumping rates of various lift technologies to maintain production at desired rates.

The benefits of permanent reservoir monitoring extend past a single well to encompass production optimization at a field level. For example, by installing permanent sensors in producing, injection, and monitor wells as part of an enhanced oil recovery (EOR) campaign, the operator can feed these data into simulation models to track production across the reservoir. Such information can then be used to aid development decisions—an expansion of EOR or the drilling of additional wells—to boost the long-term production of an entire field.

Weighing Monitoring Options

The past 2 decades have brought an impressive pace of development for different permanent downhole monitoring options. For operators, the choice of a system is a function of several interrelated factors.
Technology Update: Managed-Pressure Drilling Advances Expand Options of Onshore Drillers
Authors: Hannegan Don
Published: February 2015

Technology Update

This is an update on several managed-pressure drilling (MPD) technologies and downhole drilling performance-enhancing tools in use onshore and is the first of a two-part series. The second article on offshore MPD technologies will appear in the February issue of JPT.

Numerous recent advances in managed-pressure drilling (MPD) technology have led to the increased use of MPD and an expanded repertoire of solutions for a variety of drilling challenges.

This article will focus on several such advances in onshore drilling, including new rotating control devices (RCDs), additional MPD applications, new downhole tools activated by radio frequency identification (RFID), and a rate-of-turn gyroscope, which is based on a microelectromechanical system (MEMS) and uses smart algorithms to alert drillers when harmful rotational dynamics are occurring in the drillstring.

Conventional Systems vs. MPD

The hydraulics of conventional drilling was founded in the Spindletop field in Beaumont, Texas, circa 1901. After the initial gushers, the celebration of such quickly waned, and the industry learned to drill with a weighted fluid—literally mud from a cattle pond at the time—to enable drilling into the reservoir without inviting a blowout. The rig pumps returned mud and cuttings to an open-to- atmosphere drilling nipple beneath the rig floor.

Thus, the hydrostatic head pressure of the annulus returns column became the primary well-control barrier. A precipitous fall of the returns compromises that barrier and an overflow signals a potential well-control situation.

For more than a century, this system has served the land drilling industry well. However, most of the “easy” prospects that can be drilled that way have already been drilled. An inherent weakness of the system has become more troublesome, and a growing number of otherwise promising prospects have proved undrillable with the conventional approach. The only way to adjust the pressure on the exposed formation without interrupting drilling is to change the circulating rate, which slightly increases or decreases the equivalent mud weight (EMW).

The closed-loop system of MPD adds an important component to the equation, enabling more precise management of the wellbore pressure profile, whether circulating or not. EMW may be managed with mud pumps on the front side or with discrete applications of backpressure on the back side. Specialized enabling tools include a fitfor- purpose RCD, nonreturn valves in the drillstring, and a dedicated drilling choke manifold. The choke may be manual, semiautomatic (a typical hydraulic or more precise electric set-point choke) or automatic (controlled by programmable logic). EMW complements the primary well-control barrier.
Tengiz Field Sector Model for IOR/EOR Process Evaluation
Authors: Wilson Adam
Published: February 2015

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 170605, ’A Sector Model for IOR/EOR Process Evaluation,’ by Shie-Way Wang, Batima Yeskaiyr, SPE, and Chuck Walker, Tengizchevroil, prepared for the 2014 SPE Annual Technical Conference and Exhibition, Amsterdam, 27-29 October. The paper has not been peer reviewed.

This work presents a methodology to construct a sector model for the Tengiz field that covers one-sixth of the field area to evaluate improved-/ enhanced-oil-recovery (IOR/EOR) processes to increase oil recovery through the life of the field. The method takes into account boundary flux, edge wells, and compositional effects to replicate full-field-model performance and subsequently generate alternative predictions. This model matches production/injection data of existing wells and the anticipated performance of future wells in the full-field model.

Introduction

The Tengiz field is a giant carbonate oil field onshore western Kazakhstan at the northern end of the Caspian Sea’s eastern shoreline. Tengiz is a stratigraphic trap consisting of a carbonate buildup with a large central platform area (10×15 km) with a raised rim area (up to 2 km wide). The Tengiz reservoir has mesa-like geometry overall—flat topped and steep sided. The top of the platform has a slight regional tilt (less than 1° to the south). The sides of the platform generally dip approximately 25° on all flanks.

Production has been mainly from primary pressure depletion through oil expansion. Sour-gas injection was implemented in 2007 to address pressure decline and improve recovery efficiency. In general, the platform lacks fractures and is best suited for gas injection, whereas the slope is suitable for depletion drive because of high fracture density. Because gas injection is limited to the platform region, the main objective of this study is to investigate the best pressure-maintenance or IOR/EOR method to apply to the fractured slope region.

Sector Model

The area of the field modeled with the sector model was selected to include geological regions, material-balance regions, and displacement processes that are representative of Tengiz as a whole. The model incorporates 15.2% of the field surface area and has platform and slope regions within its boundary. Fig. 1 shows that the sector model includes (a) two five-spot existing sour-gas-injection patterns (green-line-pattern area) and (b) seven future-growth-project and sour-gas-injection patterns in the central platform region (black-line-pattern area). This sector model has 127 wells divided into two groups. The first group has 62 future and existing producers and eight injectors associated with base business operations. The second group has 57 potential future infill wells for long-term IOR/EOR development plans.
CO2 Low-Salinity Water Alternating Gas: A Promising New Approach for EOR
Authors: Wilson Adam
Published: February 2015

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 169071, ’CO2 Low-Salinity Water Alternating Gas: A New Promising Approach for Enhanced Oil Recovery,’ by Cuong T.Q. Dang, SPE, University of Calgary; Long X. Nghiem, SPE, Computer Modelling Group; Zhangxin Chen and Ngoc T.B. Nguyen, SPE, University of Calgary; and Quoc P. Nguyen, SPE, The University of Texas at Austin, prepared for the 2014 SPE Improved Oil Recovery Symposium, Tulsa, 12-16 April. The paper has not been peer reviewed.

Significant advantages have been seen from combining low-salinity waterflooding (LSW) with other enhanced-oil-recovery (EOR) techniques. This paper proposes a novel concept of low-salinity-water-alternating- gas (LSWAG) injection with CO2 under CO2-miscible-displacement conditions. While LSW is an emerging EOR method based on alteration of wettability from oil-wet to water-wet conditions, water-alternating-gas (WAG) injection is a proven method for improving gas-flooding performance by controlling gas mobility. Therefore, LSWAG injection promotes a synergy of the mechanisms underlying these methods that enhances oil recovery further.

Introduction

LSW is receiving increasing attention in the oil industry and is currently identified as an important EOR technique because it shows more advantages than conventional chemical EOR methods in terms of chemical costs, environmental impact, and field process implementation.

Although the benefits of LSW have been realized, the mechanism for incremental oil recovery by LSW is still a topic that is open for discussion. Among the proposed hypotheses, wettability alteration toward increased water-wetness during LSW is accepted widely as the cause for the EOR. It has been found experimentally that low-salinity brine has a significant effect on the shape and the endpoints of the relative permeability curves, resulting in a lower water relative permeability and higher oil relative permeability. The mechanisms of wettability alteration because of ion exchange and geochemical reactions have been implemented successfully in a compositional simulator for modeling LSW. Excellent agreements between simulation results and important measurements from coreflood experiments and pilot observations were obtained with this modeling approach.
Technology Focus: Mature Fields and Well Revitalization (January 2015)
Authors: Lee Jesse
Published: February 2015

Technology Focus

In last year’s editorial for mature fields, I talked about achieving sustainable growth by employing a combination of new technology and improved production methodology. It is always exciting to see that there are continuous advances on both fronts; however, I would like to take this opportunity to draw your attention to safety (risk to personnel and environment) while the industry is implementing these new ideas. It is not only logical but also prudent to balance safety and project economics, especially while dealing with aging infrastructures. That is, safety should not be considered a cost element. When implemented properly, it is a positive contributor to the economic life cycle.

One of the key aspects of safety in mature fields is to maintain well integrity, which is associated directly with maximizing well productivity and minimizing risks to personnel and environment. It is essential for the operators to construct, implement, and follow through with their own version of well-integrity surveillance and maintenance programs. The value of such programs goes beyond detecting problems early to avoid costly remedial treatments, because the lesson learned can become tremendously useful in the development of game-changing technology. For instance, the industry most certainly will benefit from having a zonal-isolation technology that is superior to what is available today. It is also evident that environmentally friendly chemistry is another way to improve safety.

Speaking of game changing, I am sure most JPT readers have become more productive since the introduction of smartphones and tablets. That is how technology advances fundamentally change the way we live and work. Our industry has embraced the digital age, and the footprint can be seen in many different aspects of producing from mature fields. The integration of digital inventions into the suites of existing technology presents an additional resource for the industry to improve safety and well integrity further in terms of optimizing the production from mature fields.

In this editorial, I have written about safety, well integrity, and digital technology. Therefore, I have selected several papers on these topics to share with you. For 2015, I wish all readers a safe and productive year. JPT

Recommended additional reading at OnePetro: www.onepetro.org.

SPE 167424 Real-Time Optimization of a Maturing North Sea Gas Asset With Production Constraints by Ruud van der Linden, TNO, et al.

SPE 167023 Post-Shutdown Recovery Behavior of Horizontal Coalbed-Methane Wells in the Bowen Basin by Tonna Gilbert, Arrow Energy, et al.

SPE 171568 Hyperbolic Decline Parameters During and After Linear Flow: Field Example From the Barnett Shale Using Public Data by H. Pratikno, ConocoPhillips, et al.
Effective Well-Integrity Management in a Mature Sour-Oil Field
Authors: Carpenter Chris
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 16767, ’Effective Well-Integrity Management in a Mature Sour-Oil Field,’ by Abdulaziz A. Al-Mukhaitah and Surajit Haldar, SPE, Saudi Aramco, prepared for the 2013 International Petroleum Technology Conference, Beijing, 26-28 March. The paper has not been peer reviewed. Reproduced by permission.

A large mature onshore Saudi Arabian oil field is producing sour crude oil that multiplies well-integrity challenges. A stringent well-integrity-surveillance and maintenance program is followed for this field. Under this program, any well-integrity-related problem can be predicted through a structured preventive-diagnosis and maintenance schedule for both wellhead and downhole integrity.

Introduction

The Ghawar oil field has moderate-to-high hydrogen sulfide (H2S) and carbon dioxide (CO2) content that is dissolved in crude oil, which demands a very stringent well-integrity program. The well-integrity-surveillance program is a mechanism that is applied to the wells in this onshore oil field to ensure the quality and soundness of all completion components. The developed program not only ensures the identification of well problems at a very early stage but also maintains the soundness and upkeep of all the assets in the field. Data obtained from the monitoring program are used for integrity evaluation that in turn leads to deciding the type of well work required for integrity control and repair and when to perform it. The majority of the well work is cost-intensive, and a sound integrity evaluation is key to its success.

The Program Approach

In small fields, manual tracking and monitoring of well-integrity-related issues are reasonable, but in large oil fields this approach can invite human errors. Automation of this important activity can reduce human errors, and a systematic process is established that can enhance the efficiency of tracking the problematic wells with a definite action plan to fix the issues in a timely manner. The well-integrity- monitoring program starts with the following six primary well-integrity inspections or surveys, carried out periodically for each well:

Integrity testing and maintenance (greasing) of wellhead valves

System-functionality and -integrity testing for surface and subsurface safety valves (SSVs and SSSVs, respectively) and emergency-shutdown (ESD) systems

Annuli pressure and sample survey

Landing-base inspection

Downhole-temperature-profile survey

Corrosion logging

The well-surveillance program has a manifold approach that consists of the following steps:

Maintain a survey-frequency-tracking system.

Analyze, validate, and approve the primary surveys to identify problem wells.

Maintain a problem-well-tracking system.

Repair the problems through minor maintenance; if this is not possible, tag the well for workover operations.
Digital Core Analysis and Pore-Network Modeling in a Mature-Field Project
Authors: Carpenter Chris
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 24772, ’Application of Digital Core Analysis and Pore-Network Modeling on the Basis of 3D Micro-CT Images for an Enhanced-Oil-Recovery Project in a Mature Oil Field in East Malaysia,’ by W. Nur Safawati, Bt. W.M. Zainudin, Zahidah M. Zain, and Lutz Riepe, Petronas, prepared for the 2014 Offshore Technology Conference Asia, Kuala Lumpur, 25-28 March. The paper has not been peer reviewed. Reproduced by permission.

For the planning of an enhanced-oil- recovery (EOR) project in a major mature oil field in east Malaysia, an extensive routine-core-analysis (RCA) and special-core-analysis (SCAL) program has been performed on unconsolidated clastic reservoir rocks. In view of the limited availability of homogeneous core plugs of suitable size for coreflooding experiments and for “conventional” SCAL laboratory investigations, a complementary analysis of petrophysical properties was performed on the basis of the acquisition of high-resolution 3D microcomputed-tomography (MCT) images.

Introduction

As part of an extensive core study for this field, the “conventional” core-analysis program was complemented by acquiring 3D images and applying digital-core-analysis (DCA) and pore-network- modeling (PNM) methods at different scales with the following main objectives:

Visualize the status and monitor potential changes of pore morphology, fluid distributions, and wettability during the handling and execution of laboratory experiments on unconsolidated-friable-rock samples.

Evaluate and model the impact of sample heterogeneity and wettability changes on petrophysical properties.

Provide petrophysical properties for individual distinct rock types at pore scale for heterogeneous or irregularly shaped samples that are not suitable or available for RCA/SCAL and flooding experiments.

Scale up drainage and imbibition predictions of subplugs from heterolithic/laminated plugs to full-plug scale and, potentially, further to reservoir scale.

However, because of the lack of preserved core material from earlier wells, and the relatively poor recovery of new conventional cores from recent infill wells in this field, alternative data-acquisition options were investigated in this pilot test on the basis of the significant improvements in, and encouraging results from, DCA and PNM technologies in recent years.

Procedures

Sample Selection. Approximately 22 m of core was recovered from the shallower reservoir sections of two wells (three cores from Well A from a depth interval between 700 and 800 m and three cores from Well B from a depth interval between 1100 and 1300 m), but only 8 m was suitable for plugging. The low-resolution medical computed-tomography images from the whole core indicated a high extent of rubble and broken and highly fractured unconsolidated sections.
Abandonment of Subsea Wells in the Jabiru and Challis Fields
Authors: Carpenter Chris
Published: February 2015

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 170523, ’Abandonment of 19 Subsea Wells in the Jabiru and Challis Fields,’ by Iain Clyne and Neil Jackson, PTTEP, prepared for the 2014 IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition, Bangkok, Thailand, 25-27 August. The paper has not been peer reviewed.

This paper describes the preplanning and execution of Australia’s largest subsea well-abandonment campaign to date. The Jabiru and Challis fields are located in the Timor Sea, 640 km from Darwin, Australia. The fields consist of 13 subsea producers and six suspended or partially abandoned wells. The paper describes actual experience in a relatively uncommon operation in the industry and includes learnings that can be applied to future development planning.

Introduction

The Jabiru field was discovered in July 1983, with a total of 17 wells drilled to appraise and develop the structure. The field was developed with five subsea production wells tied back to a floating production, storage, and offtake (FPSO) facility. Water depth is approximately 120 m. In addition to the five subsea producers, there were three suspended or partially abandoned wells in the field.

The Challis and Cassini fields were discovered in October 1984 and June 1988, respectively. Cassini is a single-well satellite field, but for the purposes of this paper has been classified as part of the Challis field. In total, 18 wells were drilled to appraise and develop the structure. Production commenced in December 1989 and ceased in September 2010. The field was developed with eight subsea production wells tied back to an FPSO facility. Water depth is approximately 110 m. In addition to the eight subsea producers, there were three suspended or partially abandoned wells in the field.

It was originally intended to carry out the entire abandonment in one continuous program. However, time pressures required two phases. The four simplest wells were moved forward into a Phase 1 program and carried out at the beginning of the rig campaign. The remaining wells were abandoned in Phase 2 following the drilling of three exploration wells. A semisubmersible rig was deemed best for the project.

Preplanning

There were four wells that were already abandoned subsurface to the extent that only wellhead removal was required. To assist in planning, the remaining wells that all required re-entry and subsurface abandonment were divided into abandonment types.