bluuebunny/crossref_metadata_2025 huggingface dataset:
UN PERSONAJ CONTROVERSAT PE SCENA ISTORIEI RELIGIILOR: ZALMOXIS
Authors: Olaru Ioana Iulia
Published: March 2017

Pe teritoriul României, perioada geto-dacică nu poate fi socotită ca una carac- terizată prin existenţa unei filosofii autohtone, gândirea fiind raportată la mitologie şi apoi la re- ligie. Cu toate acestea, înţelepciunea geţilor era recunoscută de autorii timpului, iar „filosofia” lui Zalmoxis – asociat uneori cu Pitagora – încă se încearcă a fi reconstituită, cum, de altfel, se în- tâmplă şi cu panteonul local. După transformarea Daciei în provincie romană, divinităţile popu- lare au supravieţuit, prin interpretatio romana transformându-se, asimilate sincretic de cele ro- mane. Iar morala zalmoxiană, susţin unii istorici, a înlesnit introducerea la noi a creştinismului.
POEZIJA SILVIJE PLAT U OKVIRIMA DRUGOG TALASA FEMINIZMA
Authors: Novkinić Sandra
Published: March 2017

U relativno kratkoj ali plodnoj karijeri Silvija Plat stvorila je, a po njoj osta- la i zapamćena, kompleksnu, gotovo mističnu poeziju koja je dobila notu univerzalnosti među čitaocima savremenog doba. Njene pjesme, koje su pisane strastvenim, bogatim i pomalo haotič- nim stilom, govore o smrti, usamljenosti, strasti, majčinstvu, samoobnavljanju, sebičnosti i bolu. Platova se bavila pisanjem u jednoj kulturi koja je pružala manje mogućnosti za žene pisce nego za muškarce. Žene su morale dosegnuti bar izvjestan stepen jednakosti s muškarcima da bi uopće mogle isticati sopstvenu različitost u odnosu na njih, kao nešto pozitivno. Silvija Plat je, prema mišljenju kritike, došla u fokus drugog talasa feminizma, koji je insistirao na preobražaju patrijarhalne i andocentrične socijalne hijerarhije u zajednicu ravno- pravnih individua. Ova pesnikinja je svojim poetskim stvaralaštvom predstavljala avangardu i paradigmu američkim ženama jer je nastojala da sebe kao takozvani „drugi pol“ upiše u stranice književne istorije, koja je oduvijek bila privilegija muškaraca. Kada se govori o njenom stvaralaštvu, govo- ri se zapravo o neprikosnovenosti „ženske kreativnosti“ izražene „ženskim pismom“, želji za samoobnavljanjem, odbijanjem žene da predstavlja žrtvu, objekat i neizbježni „dodatak“ patrijar- halnoj shemi. Upravo zato kad u svojoj poeziji Silvija Plat govori o položaju žene u muškom svijetu, o identitetu žene, o različitosti svog pola, o pravu na svoj jezik, o andocentričnoj osnovi književnosti, ona želi i traži promjenu.
POSTMODERNI PEJZAŽI U KLANICI PET
Authors: Kačavendić Marija
Published: March 2017

Klanica pet je vrlo složen postmoderni roman, koji, na površini, ima cilj da ispriča priču o bombardovanju Drezdena; međutim, ovaj roman treba posmatrati kao nešto mnogo više od običnog istorijskog romana. Tvrditi da je istorija i samim tim stvarnost, dok istovremeno go- voriti da to nije u potpunosti tako jeste ono što Linda Hačion naziva istoriografskom metafikcijom. Prezentacija i ideja stvarnosti i metafikcije verovatno su najznačajniji pojmovi ovog romana. Rat je haos, i naracija je haotična; Vonegat pravi paralele između Drugog svetskog rata i Vijetnamskog rata uz pomoć putovanja kroz vreme tako što skače iz jednog vremenskog okvira u drugi, iz jednog rata u drugi, čime stvara nelinearnu priču. Umesto da pokuša da odgonetne smisao haosa, Vonegat ga prihvata i njime oslikava izlomljenost sveta. Dok dekonstruiše ustaljene pojmove tradicionalnog pripovedanja, on uspeva da pronađe „američki glas“, koji je sposoban da ispriča priču o američkom društvu.
CONTEXTUL MULTIETNIC AL ANTROPONIMIEI ÎN SATUL SELEUŞ
Authors: Dărăbuş Carmen , Popović Virginia
Published: March 2017

În context multietnic, onomastica (în acest caz, antroponimia) are impor- tante valori sociolingvistice. Numele indică apartenenţa la o comunitate etnică, purtând în sine istoria colectivă, mai degrabă decât cea individuală, transferând numele de la periferia lingvisti- că în domeniul mai generos al antropologiei. Satul Seleuş, situat în Banatul sârbesc, a conservat pentru o lungă perioadă de timp o structură predominant românească, care se reflectă, de aseme- nea, la nivel onomastic. Perioada contemporană, prin diverse contaminări cauzate de mobilitatea populaţiei, formază inserţii spontane sau artificiale, care influenţează procesul de transformare în structura populaţiei.
ЖЕНСКИ ДОМЕН МОЋИ У ДЕЛУ „ПЛАЧ РАХИЛИ“ КОНСТАНТИНА МАРИНКОВИЋА
Authors: Дракулић Наташа С.
Published: March 2017

У фокусу овог рада јесу женски ликови у религиозном епу Плач Рахили Константина Маринковића са циљем да се испита њихов положај са аспекта моћи. При томe се ослањамо на релевантну литературу претходних проучаваоца овог предромантичарског спева. Уочава се приличан број јунакиња чији је утицај различито дистрибуиран. Основа подела подразумева позитивне и негативне хероине. Међутим, такво рашчлањивање додатно се усложњава увођењем параметра њиховог деловања, па оне даље могу бити разликоване као активне и пасивне. Посебна пажња посвећена је односу ових двају становишта.
PROBLÉM “ANJELSKÝCH KRAJÍN” V SLOVENSKEJ PRÓZE ŠTYRIDSIATYCH ROKOV 20. STOROČIA
Authors: Valentová Anna Margaréta V.
Published: March 2017

V predkladanom príspevku sa zameriavame na Polemiku o „anjelských krajinách“, ktorá poznačila slovenskú prózu štyridsiatych rokov 20. storočia. Polemiky boli uverejňované v niekoľkých dobových časopisoch, pričom sa kritici zmieňovali predovšetkým o lyrizačných tendenciách autorov tej doby. Príspevok je koncipovaný vo dvoch rovinách. V prvej časti sa táto práca sústreďuje na samotnú polemiku, zvlášť na jej prvý článok, ako aj na ohlasy, ktoré vzbudil. A v druhej časti analyzujeme konkrétne diela, ktoré boli terčom odsúdenia, predovšetkým s cieľom prispieť k analýze ich „únikového rázu“. Našu pozornosť venujeme dielam Hany Zelinovej, Margity Figuli, Jozefa Cígera Hronského, Františka Švantnera, Dobroslava Chrobáka a zmieňujeme sa aj o diele Dominika Tatarku.
DIE FUNKTION DES GESPENSTERMOTIVS BEI FRIEDRICH DE LA MOTTE FOUQUÉ UND HEINRICH VON KLEIST
Authors: Marinkov Ivana S.
Published: March 2017

Als besonders spannendes Kapitel in der jahrhundertelangen Geschichte der literarischen Gestaltung des Gespenstermotivs zeigt sich die Zeit um 1800, in der das Motiv durch die Herausbildung der fantastischen Literatur um die Qualität des Unheimlichen bereichert wurde, sodass die Gespensterliteratur eine Art Blütezeit im Rahmen der sog. Schwarzen Romantik erlebt hat. In der vorliegenden Arbeit wurden Friedrich de la Motte Fouqués Erzählungen Der böse Geist im Walde (1812) und Die Köhlerfamilie (1814) und Heinrich von Kleists Das Bettelweib von Locarno (1810) zur Analyse gezogen, und diese wird auf dem Gespenstermotiv zugeteilten Funktionen im Text ausgerichtet, woraufhin die einzelnen Werke hinsichtlich der jeweiligen Funktionen des Motivs miteinander verglichen werden. Ein solches komparatives Verfahren hat zunächst zum Ziel, Gemeinsamkeiten und Unterschiede in der Bearbeitungsweise des Gespenstermotivs in den erwähnten Werken beider bedeutender Autoren von Gespenstergeschichten festzustellen, an dessen Beispiel ein Einblick in die variantenreichen Möglichkeiten des Einsatzes vom Gespenstermotiv in der fantastischen Literatur um 1800 gegeben werden soll, und zwar insbesondere im Hinblick auf die literarische Funktion des Motivs.
Imaginarios rurales. El modelo de afincamiento en la Planificación Rural del Uruguay de Gómez Gavazzo
Authors: Souza Lucio de
Published: March 2017

Entre 1934 y 1952 el Arquitecto Carlos Gómez Gavazzo desarrolla un enfoque de las problemáticas rurales de Latinoamérica y en particular de nuestro país. Ampliando la escala de las preocupaciones, pasa de problematizar la unidad de hábitat familiar del campo a una completa teoría sobre el modo de ordenar la totalidad del territorio productivo rural. Este decurso va acompañado de una formulación precisa de un imaginario radicalmente alternativo al habitual de los trabajadores rurales. Esta tesis busca probar que las condiciones del hábitat propuestas para el ámbito conformarían una red de localizaciones de pequeña escala, de alta densidad y equipada con buen nivel de servicios, es decir, un imaginario netamente urbano para la vida en el campo. Para ello se analizará el proceso de construcción de la problemática rural y se tomará por caso el proyecto para el centro colónico de Chapicuy de 1953.
A porosidade no Largo da Batata, em São Paulo [SP]: cultura como patrimônio imaterial na cidade contemporânea
Authors: Blümer Mariana Piovan , Victal Jane
Published: March 2017

O Largo da Batata torna-se objeto de estudo na busca pela compreensão da Porosidade na cidade como condicionante de ocupação e uso dos espaços públicos pelo ser humano, assim como este próprio se construindo a partir de experiências possíveis por imersão nessa esfera. O espaço público identificado como um espaço de significações, constituído por camadas que denotam as transformações do sentido de lugar.  Nesse contexto, os poros são indiretamente percebidos, pois não são possíveis de serem interpretados apenas pelas formas físicas (visuais). Trata-se de uma análise fenomenológica das formas de ocupação atuais somadas às dinâmicas de uso e identidade desse lugar ao longo do tempo, as quais são entendidas aqui como membranas. Investiga-se, portanto, quais são os parâmetros que definem a porosidade? Há relação entre as condicionantes de porosidade física e de porosidade social? Como elas qualificam os espaços urbanos públicos no cotidiano citadino (espaço existencial)? É possível construir porosidade?
Editorial L&E 10 (3): Selección VIII SIIU y las paisajes culturales
Authors: Argollo Ferrão André Munhoz de , Sabaté Bel Joaquín
Published: March 2017

Un año más, nuestro querido amigo y compadre, André Argollo nos solicita que seleccionemos de entre las ponencias presentadas al Seminario Internacional de Investigación en Urbanismo, las más interesantes dentro de la temática de Paisajes Culturales, con la intención de publicarlas en la revista Labor & Engenho.
Machiavellism in William Shakespeare’s Macbeth: A Critical Study
Authors: SEGUEDEME Hergie Alexis , TOWA-SELLO Kossi Joiny
Published: March 2017

The aim of this article is to showcase and discuss Machiavellism in William Shakespeare’s play portraying by the tragedy attitudes on Macbeth and the challenge around Scotland kingdom power in British society during the Elizabethan period. This study has carried out a great desire of William Shakespeare’s Macbeth characters and their double dealing to get the Scotland kingdom great power or get-up-and-go throughout strong or a longing through unnatural power act of ambitious characters. In the process, this article has highlighted some cogent impacts of a great glory and the side effect of a foolish ambition throughout unethical practice. Indeed in order to meet up its objective, this article has carried out its criticism against the backdrop of literary theories of Psychoanalysis, New Historicism and Womanism. The findings of this study reveal that Macbeth is a royal entertainment, for all those of us who enjoy the suspense and excitement of a murder story. It could be interpreted Shakespeare’s play as a moral lesson. Throughout this scientific work, Macbeth teaches us, in a new way, the old lesson that crime does not pay. All in all Macbeth is a sinister, violent drama, full of fear, evil and death. The language of the play creates this dark drama.
Physical Activity Participation and Nutrition and Physical Activity Knowledge in University Dance Students
Authors: Hanna Katherine , Hanley Anne , Huddy Avril , McDonald Michael , Willer Fiona
Published: March 2017

OBJECTIVE: To assess participation in physical activity and knowledge of general nutrition and current public health messages about the health benefits of physical activity in university dance students, and to investigate differences between first-year and later-year students and between
students in dance and dance performance course groups. METHODS: This cross-sectional study recruited 67 participants from dance undergraduate degrees in a university in Australia. Nutrition knowledge was assessed using the General Nutrition Knowledge Questionnaire. Physical activity participation
and awareness of its benefits were assessed using the Active Australia Survey. RESULTS: Results indicate low nutrition knowledge among dance students, with 47% and 52% of responses correct in dance and dance performance students, respectively. Nutrition knowledge did not vary between students
in first or later years. Self-reported participation in moderate and vigorous physical activity varied substantially and met or exceeded recommendations based upon duration and frequency for 98% of participants. However, awareness of physical activity messages varied, with dance students more
likely to disagree about the level of activity needed for health benefits. CONCLUSIONS: Dance students report varying levels of physical activity that usually met or exceeded recommendations; however, knowledge of general nutrition and physical activity benefits was low. Improved knowledge
could contribute to changes in behavior that improve health status in this population.
Case Study of Section Milling Run in Abrasive Salt Dome Formation and Technological Development for Multi-String Section Milling
Authors: Smalley Michael T. , Hay Christopher , Teale David W. , Haq Mohammed A.
Published: March 2017

The Stratton Ridge salt dome located in Brazoria County, Texas, has been used extensively by industry for brining operations and for the storage of liquid hydrocarbons, refined products, and natural gas. The shape of the dome has been defined by several hundred oil and gas wells drilled over the top of this highly anomalous geologic diapir structure. Cavern operations at Stratton Ridge historically are known to have experienced a number of problems. These difficulties and "off-normal events" include severe lost circulation while drilling through cap-rock, sheared well casings, corrosion, shifting, and encountering hydrocarbon products that appear to have escaped from the storage cavern.

This paper describes a case study of section milling in the gas storage cavern of this highly abrasive salt dome, the challenges faced, and how the challenges were detected and overcome. The unique aspect of this case study is the introduction of new section milling technology. New technologies in multiple-string section milling plays an important role to improve operational performance, reduce costs, and eliminate NPT—especially in the current global environment of low oil prices. This paper also touches the R&D development for multi-string section milling in various settings.
Improved Bottomhole Pressure Control with Wired Drillpipe and Physics-Based Models
Authors: Park Junho , Webber Thomas , Shishavan Reza Asgharzadeh , Hedengren John D.
Published: March 2017

Wired Drillpipe (WDP) technology provides two-way and high speed measurements from bottom hole and along-string sensors. The data offered by WDP technology has maximum benefit when applied in an automation system or as a real-time advisory tool. Improved control is demonstrated for Managed Pressure Drilling (MPD) with the use of high-speed telemetry and physics-based models. Stabilizing and minimizing pressure within an acceptable bound leads to higher and more consistent Rate of Penetration (ROP).

MPD control is challenging due to tight pressure windows and the nonlinearity of the choke and pump response on Bottom Hole Pressure (BHP). This work demonstrates a new Hammerstein-Wiener nonlinear model predictive controller for BHP regulation in drilling. Hammerstein-Wiener models employ input and output static nonlinear blocks before and after linear dynamics blocks and thereby simplify the controller design. The control performance is evaluated in scenarios such as drilling, pipe connections, and kick attenuation. A physics-based drilling simulator, WeMod, is used for model identification and control performance evaluation.

The control performance of the new nonlinear controller is compared to conventional controllers in various scenarios. Because of the interconnected multivariable and nonlinear nature of the drilling operation, conventional controllers show severe limitations. In a first scenario, the performance of set point tracking during normal drilling operation is compared. By changing the set point of the BHP, the conventional controller manipulates only the choke valve opening while the nonlinear controller moves choke valve opening, mud pump, and back pressure pump simultaneously. In a second scenario, a pipe connection of a typical drillpipe stand is demonstrated. The conventional controller is not able to regulate the BHP by adjusting the choke valve only. Although a linear version of the controller is able to exploit multivariable relationships, absence of the nonlinear relationships results in severe oscillation when the operational range is shifted outside of the training region. The nonlinear controller maintains a BHP within ±1 bar of the requested set point. A third scenario investigates the kick attenuation performance of conventional and nonlinear control algorithms. The nonlinear controller attenuates the kick within well control conditions, without requiring a well shut-in procedure.

Recent advances in drilling simulators and the reliability of the WDP data highway have enabled tighter BHP control. This study presents a robust method to control BHP by applying Hammerstein-Wiener models in an efficient model predictive controller. The proposed methods have been validated in the downstream industry, but are applied for the first time to drilling with nonlinear control functionality. The multivariable control adjusts three main manipulated variables in MPD simultaneously.
A Case History of the First Drilling with Liner Application in Romania
Authors: Qureshi Ali M. , Rosenberg Steven M. , McGrath Martyn , Tan Ming Zo
Published: March 2017

Drilling a creeping salt formation at a depth of more than 4,200 mMD can be a challenging task, especially when the mud weight cannot be increased enough because of losses in zones above. A stuck pipe can often be released by pumping water pills; however, after drilling through salt while running casing, the hole can close in (time-dependent creep), making it impossible to run casing across this interval. In such situations, innovative ideas to drill and isolate such an interval can help save the day.

One such idea was implemented in a deep well in Romania. While drilling at a depth of 4,237 mMD, the bit encountered an aggressive salt layer, causing stuck pipe that could not be released with water pills and eventually resulted in three sidetracks. On the third attempt, the well was drilled to the top of salt layer, and then the 7-in. liner, a casing bit, and a hydraulic set, rotating liner hanger system were run together on drill pipe. The bit drilled through the 17-m salt layer and died out immediately after achieving its objective. The liner was cemented in place, and the salt layer was successfully isolated. Drilling then continued through the reservoir section below.

This was OMV Petrom's first application of drilling with liner (DwL) and proved to be successful in terms of meeting its objective (i.e., isolating the salt layer). Because the DwL operation was not in the original well design, the DwL system and operating procedures were designed, planned, and delivered on short notice. Considered instrumental to the success of the operation, the collaboration between OMV Petrom and the integrated service provider enabled the engineering and subsequent execution of the DwL operation to move forward in a seamless manner, which contributed greatly to the success of the DwL operation.

The operation proved that DwL can be implemented to case off problematic zones, which increases the likelihood of meeting well objectives. Had this technology not been implemented, the available alternate solution could have resulted in additional time and cost with a low probability of success. This paper will present the experience of the first ever application of drilling with liner in Romania and the associated lessons learned, as well as a discussion of the circumstances under which it became the foremost technology on the way to reaching the target reservoir.
Case History: A Decade of Experience Using Intelligent Completions for Production Optimization and Water Shut-Off in Multilateral Wells in the World's Largest Oilfield
Authors: Dulaijan Auda , Shenqiti Mohammad , Ufondu Kenechukwu , Zahrani Bader , Abouelnaaj Khaled , Shafiq Muhammad
Published: March 2017

Following the success of the first installed intelligent completion system in Saudi Arabia in 2004, over 260 Intelligent Completion systems have been installed in a majority of Maximum Reservoir Contact (MRC) Multilateral (ML) wells. These intelligent completion systems have been successfully installed in openhole, expandable liners, expandable sand screen, Extended Reach Drilling (ERD) wells and also integrated with Electric Submersible Pumps (ESP). This technology has led enhanced oil recovery while reducing water production to surface. Water handling cost at surface is reduced by producing less water to surface and also shutting off downhole water production completely.

This paper covers some of the case histories of over ten (10) years of design, planning, installation, testing and optimization of intelligent completion systems in Multilateral (ML) Maximum Reservoir Contact (MRC) wells within Saudi Arabia. Production optimization practices and enhancement of production life in carbonate multilateral wells in the world's largest oilfield are also documented. Case histories highlighting how water production was remotely choked back, shut-off and production optimized from identified lateral without any intervention in the well are reviewed.

Advantages of intelligent completion technology for multilateral wells and the review of the downhole choke customization process that included design flow area after modelling well data for different flow rates and differential pressures are detailed. This is in addition to the integration of the surface control system to the production supervisory control and data acquisition (SCADA) system which provided real-time downhole pressure and temperature data and remote control of downhole flow control valves during the life cycle of the well. This paper also discusses a closed-loop approach which led to efficient real time production optimization. Performance review of how intelligent completion systems provide selective lateral control, delay water breakthrough, control water production, shut off wet lateral, reduce opex, optimize production, enhance recovery and reduce safety risks thereby minimizing future interventions are documented.
Coiled Tubing Cementing Operation Using MPD Technique in a HP/HT Well
Authors: Mammadov Elvin , Osayande Nadine , Sadat Ali Yousefi , Murtaza Muhammad
Published: March 2017

In the continual search for Oil and Gas, more and more exploration wells are being drilled in High Pressure-High Temperature (HPHT) environments. Pore and Fracture pressure prediction and understanding the true drilling window in HPHT exploration wells poses significant challenges. Once the pressure profile is ascertained, then the next challenge is to drill and cement the well within those limits to avoid kicks, losses and maintain the integrity of the well.

There are special challenges in cementing HPHT wells. These wells typically have a narrow drilling window which could make it very difficult to manage the bottom hole pressure correctly while cementing the open hole section. In any stage of cementing in this type of wells, hydrostatic, dynamic and circulating effects should be considered. These tight windows in HPHT wells, combined with the effect of temperature and pressure on mud density possess significant risks for cementing operation. Also physical and chemical behavior of cement changes in high pressure and temperature. This paper details the advantages of applying advanced Managed Pressure Drilling (MPD) technology during coiled tubing cementing operations in a case study HPHT well. This advanced technique not only allows for maintaining a Constant Bottom Hole Pressure (CBHP) but also reduces the additional costs associated with cement weight and additives. Furthermore, real time flow monitoring eliminates the down hole fluid losses which in conjunction with CBHP reduce formation damage.

A precise managed pressure coiled tubing cementing program was analyzed and planned inclusive of operational procedures and risks management. The well was displaced to a lighter drilling fluid through coiled tubing, while keeping bottom hole pressure (BHP) constant slightly over the formation pressure by applying surface back pressure (SBP). Four different densities of cement slurries were pumped in the hole through coiled tubing and held bottom hole pressure constant during the entire cementing operation within 30 kg/m3 (0.25 ppg) pore pressure and fracture pressure window. Held annular pressure constant with the help of SBP during the eight hours of cement setting time to ensure that hydrostatic pressure would remain in place.

This document demonstrates the successful application of managed pressure coiled tubing cementing operation. It also elaborates the recommended operational procedures, integrated MPD and Coiled tubing equipment setup, along with real-time graphs and data from the case study well.
Overcoming Marginal Load Limits in Small Diameter Tubing Operations by Using Strain Gauge Measurements
Authors: Mehta Atul , Marland Chris , Maharaj Navin , Riise Henrik
Published: March 2017

Because wells are becoming increasingly longer and more complex in trajectory and construction, safe operating limits for running pipe are becoming increasingly smaller. Because of narrow buckling margins in small diameter drillpipe and tubing, an accurate measurement of pipe tension is critical to ensure success when running this pipe. Severe buckling could result in tubing damage or failure, generating potentially significant non-productive time (NPT) or loss of the wellbore. Unreliable surface measurements for hookload and the need to measure minor changes in weights have created a need for the means to measure them. A fully validated and applicable solution is available to overcome these challenges. When run in conjunction with a measurement-while-drilling (MWD) toolstring, including a pressure-while-drilling (PWD) sensor, directional sensor, a controller module and pulser, the tool containing strain gauges provides real-time updates and stores data in memory, with tension readings at the sensor depth, to represent the weight of the string below that point.

This paper presents two cases in which this solution was successfully applied, using strain gauges to measure tension below a point of interest in a string of pipe or tubing in non-drilling applications.

Accurate torque and drag modeling with tripping-in weights and buckling limits plotted against real-time updates from the strain gauge tool provided continuous updates on the load regime downhole. This enabled the tension to be maintained above the buckling limits. Where the tension fell below the limits, remedial actions were taken or operations were carefully continued with extra vigilance for any signs of a deteriorating situation or of string lockup.

The benefits of using strain gauges have been found in yet another non-drilling application described in this paper. Technology to measure tension that has been traditionally used in the improvement of drilling performance can also be applied to improve the performance in activities that pose the challenges of overcoming low operational margins.
Introduction of New Drilling Technology Provides Continuous High Build Rate Capability in Complex Corkscrew Well Trajectory, Accessing Unswept Reserves in the North Sea
Authors: Krueger Stefan , Sharpe Robert , Attridge William , Ruszka Jon
Published: March 2017

In areas of the United Kingdom Continental Shelf (UKCS) operators are progressively seeking to drill increasingly complex well profiles to access un-swept reserves. Wells of such complexity require the introduction of new drilling technology to meet the challenge. In a recent UKCS operation, operator objectives for a wellbore required continuously high rates of curvature and tight dogleg severity control in a soft formation with unconfined compressive strengths (UCS) of 5 to 10 kpsi.

A new, integrated high build-up rate rotary steerable system (RSS), capable of delivering up to 12°/100ft in an 8½-in. hole, was implemented as a solution to achieve and optimize the wellbore placement, thus accessing untapped reserves beneath the offshore platform. In this mature field, collision avoidance with existing wells presented an additional challenge. Focusing on a total system approach, new polycrystalline diamond compact (PDC) drill bit technology was designed to integrate with the high build-up rate (BUR) drilling system. The PDC bit includes features for a smooth torque response, enhanced rate of penetration (ROP), improved durability, and precise steering control. Proprietary software provided confidence in the planning phase that the bit responses, in combination with the deployed steering system and the overall BHA set-up, would deliver the demanding well profile.

This paper presents the details of the integrated drilling technology, as well as the background of pre-drill planning and setup processes necessary for the successful application where no offset experience was available. In addition, this paper details the process management and implementation steps during the service introduction of the new drilling technology. The final performance of the integrated system that drilled the ‘corkscrew’ profile in one drilling run, providing the required well placement and hole quality will be shown. The overall new approach enables the industry to utilize previously inaccessible reserves and drive field economics further.
Successful Application of a New Inertial Steering Mode of Point-the-Bit RSS in Middle East Oilfield
Authors: Li F. , Balka M. , Al-Ghazzawi A.
Published: March 2017

In the past two decades, the point-the-bit rotary steerable system (RSS) has been widely used for high-profile directional drilling jobs in challenging environments, which require accurate directional control. A new inertial steering mode of the point-the-bit RSS was developed by using accelerometers and a rate gyroscope sensor to achieve toolface control in environments, where magnetometers cannot be used for steering. This inertial steering mode effectively expands the operational envelope of point-the-bit RSS by improving its steering ability when magnetic interference, such as drilling out of whipstock window and close to offset wells or ferrous formations, is present or within a Zone of Exclusion (ZOE). Furthermore, the new steering mode can be used as a redundancy scheme in circumstance during magnetometer failures.

Through close collaboration between Research and Development (R&D) and field operation, the inertial steering mode of the point-the-bit RSS has been successfully applied in four wells in Middle East oilfield. In the first well, the new steering mode was used to kick off two 8 3/8" hole sections after setting whipstocks in near vertical wells and it completed the kick-offs in desired directions with accurate toolface control in a high magnetic noise environment. In the second well, the new steering mode was used to exit the casing and drill to TD by using a whipstock. In the third and fourth wells, 12 ¼" hole sections passing through the ZOE were successfully drilled according to the well plan. The application of the new steering mode in these wells saved extra BHA trips, which would have been required if without this new steering mode.

The successful application of the new steering mode in the Middle East oilfield has proven its technical advantages and business benefits.
Blowout Control Challenges of Pad Drilling and Production: A Case History with Lessons Learned
Authors: Haghshenas A. , Cuthbert A. , Portillo L.
Published: March 2017

Efforts to help reduce environmental footprint, infrastructure, and development costs have led to an increased use of pad drilling. However, the close proximity of wells in pad drilling increases the risk of more severe consequences during well control incidents. In the case of a burning well, both radiant and direct heat can potentially ignite adjacent wells, possibly threatening both human life and equipment and detrimentally affecting the immediate environment. This paper describes challenges and lessons learned from controlling a multiwell pad blowout.

A series of six wells with 15 ft spacing was drilled on a pad. Each well was completed with multistage hydraulic fractures; however, during flowback operations, a well developed a leak through a flowback line connection. The gas exiting the well eventually ignited, and the heat from the fire damaged the seals and wellhead equipment on neighboring wells, causing all of the wells on the pad to develop leaks, which consequently caught fire. Successful well kill operations using surface well intervention subsequently secured all of the wells. This paper provides unique insight into the challenges of containing a blowout on closely spaced well pad configurations and highlights lessons learned.
Challenges and Solutions to the Correct Interpretation of Drilling Friction Tests
Authors: Cayeux Eric , Skadsem Hans Joakim , Daireaux Benoît , Holand Remi
Published: March 2017

During drilling operations, it is important to monitor carefully that cuttings are transported out of the hole and that the open hole formations do not collapse. A friction test is a simple procedure involving measurement of pickup weight (PUW), slack off weight (SOW) and free rotating torque (FRT) that provides information about possible changes in mechanical friction between the drill-string and the borehole while drilling deviated wells. It is not uncommon to observe very large variations in measured values between consecutive tests, even if there are no obvious reasons why the downhole conditions should have changed.

The inherent problem with the interpretation of friction tests is that many factors influence the observations. First, the drilling fluid circulation conditions have an impact on the forces applied to the drill-string. If friction tests are performed with different flowrates, the results are necessarily dissimilar. Second, as the drill-string is elastic, the transitions from pure rotation, to upward axial movement and then to lowering are transient and require some time before reaching steady state movement. Since the elasticity of the drill-string changes with the bit depth, the minimum distance that is necessary to attain stable measurements varies throughout the drilling operation.

A dynamic drill-string mechanical model coupled with a transient hydraulic model has been used to analyze a series of high quality real-time measurements taken during the drilling of a medium complexity well in the North Sea. Half of the friction tests were taken with a totally automated procedure while the other half were performed manually by the drillers. The automatic friction test procedure resulted in greatly improved consistency in test measurements compared to the manually executed tests. The results of this investigation show that many of the variations observed in measurements of the PUW, SOW and FRT were in fact related to slight dissimilarities in the way the manual friction tests were executed by the drillers.

This study clearly demonstrates the value of using transient mechanical and hydraulic models to interpret friction tests. Especially in cases where the friction tests are performed manually, these models enable much more reliable indications of whether the downhole conditions are changing or not. Furthermore, the new method has shown that it is possible to even further improve the automatic test procedure by reducing execution time without sacrificing the result quality.
A Comparison of Stick-Slip Mitigation Tools
Authors: Kyllingstad Aage
Published: March 2017

The most effective way to mitigate torsional stick-slip oscillations is to apply smart control of the top drive so that it effectively absorbs energy from vibration components near the stick-slip frequency. This paper is a comparative study of several smart control systems available in the market.

The comparison is based mainly on analysis of the top drive mobility over a wide range of frequencies. Torsional mobility is defined as the complex ratio of speed to torque variations at the top drive output shaft and it carries information on both amplitude and phase relations between the two variables. The real part of normalized mobility, defined as the non-dimensional product of this mobility and the characteristic impedance for the upper drill string section, has proved to be a very useful tool for analyzing damping characteristics and for calculating the risk of instabilities.

Four different variants of smart control methods have been analyzed, both with perfect tuning and no signal delays and when signal delays are present. The systems have not been rated against each other, but they all show a relatively high sensitivity to signal delays, even small delays in the order of 50 milliseconds.
Improved Wellbore Stability in Tor/Ekofisk Wells through Shale-Fluid Compatibility Optimization
Authors: Oort Eric van , Pasturel Christian , Bryla Jedrzej , Ditlevsen Frederik
Published: March 2017

Tor/Ekofisk wells drilled in the Danish sector of the North Sea have historically suffered from borehole instability problems when intersecting the Upper/Lower Lark and Horda shale formations using either water-based mud (WBM) or oil-based mud (OBM). An extensive wellbore stability investigation was carried out, focused primarily on improving shale-fluid compatibility. It was augmented by a lookback analysis of historical drilling operations in order to identify practical solutions to the borehole instability problems.

A state-of-the-art experimental rock mechanics and shale-fluids compatibility investigation was carried out featuring X-ray diffraction and cation exchange capacity characterizations, shale accretion, cuttings dispersion, mud pressure transmission and a new type of borehole collapse test for 11 different mud systems (WBM, OBM and high-performance WBM). The results of this investigation were then combined with the results of a comprehensive well lookback study. The integrated study clearly identified the root cause(s) of the Tor/Ekofisk well problems and highlighted comprehensive practical solutions, which were subsequently implemented in the field.

The borehole instability problems at Tor/Ekofisk in the Lark/Horda shales have a characteristic time-dependency, with wellbore cavings occurring after 3-5 days of open-hole time. The problems were not related to mud weight selection, but were instead caused by mud pressure invasion into the shales, which destabilizes them over time. An extensive experimental testing program revealed that this effect occurs in both WBM and OBM to equal extent, which explains why non-optimum field performance has historically been obtained with both types of mud systems. New high-performance WBM (HP-WBM) formulations were identified that significantly improve upon the mud pressure invasion and borehole collapse behavior of conventional OBM and WBM systems, yielding extended open hole time that would allow the hole sections in the Lark/Horda shales to be drilled, cased and cemented without triggering large-scale instability. Lookback review also indicated that secondary causes of wellbore instability, such as barite sag, extensive backreaming and associate drillstring vibrations should be minimized for optimum drilling performance. A new HPWBM system, together with improved operational guidelines, was successfully implemented in the field.
New Gas-Tight V0 Packoff Stage-Cementing Equipment Provides Reliable Solution for Wellbore Integrity and Significant Reduction in Rig Time
Authors: Abdel Al Aziz Mahmoud , Khallaf Ahmed , Urdaneta Nava Luis , Jacob Jobby , Farley Doug , Shaker Sherif
Published: March 2017

Selective cementing is required in challenging wellbores with tight mud-weight windows between low-and high-pressure formations around the Arabian Gulf. It is typical to cover the Thamama 5,6 high-pressure formation and the Mishrif low-pressure formation in the Satah Al Razboot (SARB) field and the Salabikh formation in the Zakum and Umm Shaif fields in a single 12.25-in. hole section. This paper will discuss the reliability and cost impact of using new packoff stage-cementing equipment for cementing and zonal isolation in this situation.

Operators have a history of compromised casing integrity requiring intervention of wells because of the short lifetime of stage-cementing equipment. They have been forced to select other, more costly and more time-consuming methods (requiring four to six trips), such as installing a liner hanger and a tieback to surface. Although these methods are reliable and field proven, they have added considerable upfront investment in rig days and greater expense to the operation.

The evolution of reliable, gas-tight stage cementers (two-trip systems) rated at up to 10,000 psi at 350°F reduces the required number of operating days and total well costs and expands the technology limit for more challenging well conditions.

Rigorous testing and equipment qualification to International Organization for Standardization (ISO) 14998 V0 and ISO 14310 V0 have established confidence in stage-cementing tools with integral packer and slip systems. Based on this validation, wells in the Arabian Gulf Region can now be constructed using a single long string of casing, thereby eliminating the added expense of a liner hanger and liner tieback system. In addition to equipment savings, these stage-cementing tools reduce by as many as to 6 to 7 days the total number of operating days required to construct the well. The tools also reduce approximately US $1 to $1.5 million in direct cost and subsequent costs of intervention over the life of the asset.

This paper will provide insight into equipment installation methods and comparative time and cost for the use of pack-off, two-stage cementing tools in the United Arab Emirates. Technology innovation was achieved by combining completion accessories and downhole products that meet international standards set forth by ISO/API. This maximizes the reliability and validates the extended limitations of the technology to apply alternative well construction techniques that will retain wellbore integrity and reduce cost over the life of the well.
A Study of the Dynamics of Lateral Fastline Vibrations
Authors: Kyllingstad Aage
Published: March 2017

The transversal vibrations of the fastline have been studied. The fastline, which is the part of the drill line running between the drawworks drum and the fast sheave, is put into vibrations by spooling induced motion at the drum and by variations of the line tension. Both excitation mechanisms are described in some detail and the transversal line response is studied with and without fastline stabilizers applied to reduce the vibration amplitudes.

Two type of models have been used in the study, a simplified linear model suitable for frequency analysis and another more advanced simulation model which can also handle non-linear stabilizer damping. Both models show that the vibration amplitude can be severe if the excitation is cyclic with a frequency component matching one of the natural resonance frequencies of the fastline. Both models also show that the effect of a stabilizer is highly dependent on its damping characteristics and on its vertical location.

The study has resulted in the design of a new and patent applied type of stabilizer placed more close to the fast sheave than a conventional stabilizer commonly used today. One of its main advantages is that it provides equal damping to both transversal directions.
RED: Revolutionary Drilling Technology for Hard Rock Formations
Authors: Wiercigroch Marian , Vaziri Vahid , Kapitaniak Marcin
Published: March 2017

Large Rates of Penetration (ROPs) with a good borehole stability in hard rock formations is still one of the major challenges in downhole drilling. In this regard, the Resonance Enhanced Drilling (RED), a new downhole drilling technology being developed by the University of Aberdeen, could offer a radically new way of drilling for oil and gas wells at a reduced cost and a lower environmental footprint. Market research estimated that the RED technology could result in an annual savings of $1.05 billion for operators [1].

The RED technology applies a controllable high frequency dynamic stress on the drilled formation, which is induced by axial oscillations of a drill-bit at the resonance conditions. The resonance conditions between the drill-bit and the formation are maintained for varying drilling conditions by adjusting the frequency and amplitude of the dynamic load to produce a steadily propagating fracture zone. The RED technology is particularly well suited for hard rocks.

Through an extensive physical and mathematical modelling, and experimental studies on the developed full scale experimental rigs, it has been proved that RED can significantly reduce wellbore creation time and deliver the capability to drill with one bit through in various rock formations and drilling conditions. RED also allows to drill efficiently even with a smaller Weight-On-Bit (WOB).

The University of Aberdeen is just about to complete a large multi-million pounds research and development programme funded by the Scottish Enterprise aimed to scale up the laboratory findings and bring the RED technology closer to the commercial world. The paper introduces this technology and discusses its potential impact on the industry.
Changing the Chalk Drilling Paradigm in the Netherlands
Authors: Brands S. , Bocquet R. , Matviykiv T. , van der Pouw Kraan A.
Published: March 2017

In the Dutch sector of the North Sea the Ommelanden Chalk formation commonly contains large amounts of chert, a very hard nodular rock. High friction exacerbates the harsh drilling conditions leading to mechanical dysfunction of the drilling process: severe downhole shocks, large torsional vibrations, bit and bottom hole assembly (BHA) wear and loss of directional steerability. Acceptance of these drilling conditions have long prevented drilling teams in the Netherlands to make significant drilling performance improvements.

This case study shows a step-by-step optimization approach, where we evaluated various drilling systems and their interdependence at each step. Separately optimizing the individual drilling sub-systems: bit, BHA, fluids and the rig led to little overall improvements. The initial focus was on the bit and drive system, but their successful utilization was limited by the harsh drilling environment. Close examination and various attempts proved that a combination of non-aqueous based mud (NABM), lubricant and a rotary drive control system could deliver a stable drilling environment. This allowed us to select different bits and drive systems. After multiple attempts with new technology PDC bits we proved drilling the entire chalk interval in one run was possible. In addition, rotary steerable systems (RSS) enabled directional steering in any part of the 12 ¼-in section.

The improvements led to fewer bit runs. The average progress rate through this section has been increased from 100 m/day to 300 m/day, with estimated savings of 10 to 15 rig days per well. In addition, the downside risk of equipment damage, inability to maintain trajectory control and related cost has been reduced significantly.

Pursuing drilling optimization can take considerable time and effort. It is often not a single-step process, but requires a multidisciplinary approach. This case study demonstrates important process improvements and technology applications, which reduced operating risk and cost.