bluuebunny/crossref_metadata_2025 huggingface dataset:
Análise das curvas de torque isocinético em movimentos do ombro
Authors: Sonza Anelise , Andrade Mário Cesar de
Published: June 2012

A curva de torque de uma avaliação isocinética fornece ao avaliador indicativos da performance muscular, podendo detectar déficits no sujeito apreciado. No entanto, relatórios automáticos produzidos pelos equipamentos podem gerar dados e interpretações equivocados. Este estudo objetivou determinar a curva de torque isocinética, identificando em qual ponto a velocidade passa a ser constante dentro dos parâmetros do teste. Procurou, ainda, verificar se o pico de torque máximo (PTM) encontrava-se na fase de estabilização do protocolo. Atletas de natação (n = 10) foram avaliados através do dinamômetro isocinético Kin-Com® AP-125. Solicitou-se a contração máxima concêntrica-excêntrica nos movimentos: rotação interna (RI) e externa (RE), flexão (FL) e extensão (EX), abdução (AB) e adução (AD) horizontal do ombro, em 120º/seg, na posição de decúbito dorsal. Os softwares Matlab 6.0 e Origin 6.0 foram utilizados no processamento das curvas. Nos movimentos de RI e RE, ação concêntrica e excêntrica, em movimentos mais estáveis e de menor braço de alavanca, a velocidade manteve-se constante no intervalo de 5 a 98% das curvas. Para a FL-EX e AB-AD, considerados mais instáveis e com maiores braços de alavanca, a velocidade foi constante no intervalo de 10 a 98% das curvas. Nos movimentos de RI e EX concêntrico e FL e AB-AD horizontal concêntrico e excêntrico, os PTM centraram-se no terço inicial das curvas, exigindo maiores cuidados no processamento. No movimento de FL excêntrica, 80% dos PTM estavam fora da velocidade preestabelecida, necessitando reprocessamento, o que não ocorreria no fornecimento de laudo automático. Sugeriu-se o descarte dos 5% iniciais e finais da curva de torque nos movimentos de rotação do ombro e 10% para FL-EX e AB-AD horizontal para interpretações mais fidedignas dos picos de torque e obtenção da real condição muscular do avaliado.
Integrated management of childhood illness (IMCI): an innovative vision for child health care
Authors: Benguigui Yehuda
Published: June 2012

The Integrated Management of Childhood Illness (IMCI) strategy developed by the World Health Organization (WHO), Panamerican Health Organization (PAHO) and the United Nation Children's Fund (UNICEF), joint experiences of previous frequent diseases programs in children, with prevention and health promotion activities. In this new approach the family, the community and health workers have a leading role in health condition of the child. The strategy aims a reduction in Infant Mortality Rate, specially in those regions and countries in which it is high. Pneumonia, diarrhea, malnutrition and other preventable diseases are the main causes of deaths in this settings. Health workers can early recognized danger signs of severe diseases, as well as they can evaluate and treat the most frequent health problems. By enhancing prevention and health promotion activities, as better conditions of life, giving an holistic vision of the child and his family, and not only looking for the symptom that motivate the consultation.
Risk factors for maternal death in patients with severe preeclampsia and eclampsia
Authors: Amorim Melania Maria Ramos de , Santos Luiz Carlos , Porto Ana Maria Feitosa , Martins Leila Katz Dias
Published: June 2012

OBJECTIVES: to determine the principal death causes in patients with severe preeclampsia/eclampsia and identify related risk factors. METHODS: a case-control study was performed comprising all cases of maternal death (n = 20) in patients with severe preeclampsia or eclampsia (n = 2.541). 80 controls (survivors) were randomly selected. The odds ratio and an estimate of maternal death relative risk were determined, and a multiple logistic regression analysis performed to determine the adjusted odds ratio. RESULTS: the basic causes for death were: acute pulmonary edema, disseminated intravascular coagulopathy, hemorrhagic shock, pulmonary embolism, acute renal failure, sepsis and three cases of undetermined causes of death. The principal risk factors were: age > 25 years old, multiparity, gestational age < 32 weeks, lack of prenatal care, diastolic pressure > 110mmHg, convulsions, chronic systemic arterial hypertension, HELLP syndrome, pulmonary edema, normally inserted abruptio placenta, disseminated intravascular coagulation, acute renal failure. Variables persistently related to maternal death were: HELLP syndrome, eclampsia, acute pulmonary edema, eclampsia, chronic hypertension and lack of prenatal care. CONCLUSIONS: the principal risk factors for death in women with preeclampsia/eclampsia are the lack of prenatal care, associated to chronic hypertension, HELLP syndrome, eclampsia and acute pulmonary edema.
Tratamento não-cirúrgico de abscessos intra-cavitários pós-apendicectomia
Authors: Falbo Neto Giliatt Hanois , Vilela Paulo Carvalho , Arnold Marianne Weber , Grangeiro David Negrão , Araujo Claudia Corrêa de
Published: June 2012

OBJETIVOS: avaliar a eficácia do tratamento não cirúrgico em crianças que desenvolveram abscessos intra-cavitários pós-apendicectomia, no Instituto Materno Infantil de Pernambuco, Recife, Brasil, e comparar os resultados obtidos com dois esquemas antimicrobianos (Cefoxitina versus Amicacina com Metronidazol) utilizados. MÉTODOS: o estudo corresponde ao período de janeiro de 1997 a janeiro de 2000 no qual 427 crianças foram apendicectomizadas; 41 delas desenvolveram abscessos intra-cavitários sendo 39 incluídas no estudo. O diagnóstico dos abscessos intra-cavitários baseou-se em sinais clínicos e exames complementares. RESULTADOS: A incidência de abscessos intra-cavitários pós-apendicectomias foi de 9,6%. 89,7% dos pacientes obtiveram sucesso com o tratamento. Não houve diferença entre os percentuais de cura obtidos com os dois esquemas antimicrobianos. CONCLUSÕES: o tratamento não cirúrgico de abscessos intra-cavitários pós-apendicectomias, baseado na antibioticoterapia endovenosa é uma opção segura e eficaz. Os esquemas antimicrobianos com Cefo-xitina e associação de Amicacina com Metronidazol têm eficácia semelhantes. A associação Amicacina com Metronidazol é recomenda pelo seu menor custo.
Epidemiology of preterm deliveries in Southeast Brazil: a hospital-based study
Authors: Nascimento Luiz Fernando Costa
Published: June 2012

OBJECTIVES: to evaluate the role of some factors in the genesis of preterm deliveries in Southeast Brazil. METHODS: a cohort hospital-based study of 589 mothers who delivered in Taubaté, a middle-size city in the state of São Paulo, Brazil, between May 1, and October 31, 1999. The statistical approach was Risk Ratio with statistical significance established at alpha: 5%. RESULTS: 70 preterm newborns were identified representing 11,9% of the total birth rate. The variables holding statistical significance were: previous history of stillbirth delivery, smoking during pregnancy, poor weight gain, arterial hypertension, vaginal bleeding, genitourinary tract infection and five or less medical visits for prenatal care. CONCLUSIONS: this study indicates that good quality prenatal care has a great value in preventing preterm births, for poor weight gain, arterial hypertension, vaginal bleeding, genitourinary tract infection and smoking are conditions that can be controlled in the course of pregnancy.
Potential for carfree development in the UK
Authors: Melia Steven , Barton Hugh , Parkhurst Graham
Published: June 2012

Carfree residential areas have been developed in a number of cities in Europe, with clear social and environmental benefits, but the concept has not been widely adopted in the UK. This paper aims to assess the potential consumer demand for housing in carfree developments in the UK and the circumstances under which it might be feasible. Two surveys of possible target groups were conducted: an online national survey aimed at members of environmental and cycling groups and a postal survey in Camden, London, followed by qualitative telephone interviews with a subset from both surveys. The findings revealed that potential demand for carfree housing is concentrated among ‘carfree choosers’ – people who currently live without cars by choice. These are mainly found in the inner areas of larger cities, where the greatest potential for carfree development exists. A substantial minority of carfree choosers would like to move to less urban locations; in these circumstances proximity to good rail services is a key requirement.
Advances in Drilling and Evaluation Technology Create New Opportunities for Deepwater High-Pressure Wells
Authors: Edwards Hal , Rask James , Maehs Juergen , Wandstrat Matthew , Donadieu Brian
Published: June 2012

With well depths more commonly surpassing 30,000 ft below the mudline and ever-increasing water depths, exceedingly high-pressure environments present a new and challenging frontier for both operators and service companies. These new environments demand advances to existing technology to endure such pressure extremes while also accurately positioning the wellbore in the reservoir and obtaining critical geological information as the well is drilled.

A recent example in this pressure regime in the deepwater Gulf of Mexico will be reviewed. Pressure limits of the currently available technology are extended while successfully meeting drilling and evaluation goals. The drilling and evaluation technologies delivered real-time formation pressure and geological information, along with continuous directional control, enabling the operator to make vital decisions while drilling and for sidetrack evaluation. This real-time decision-making capability reduced the time required to execute casing point selection and subsequent sidetrack plans. Emphasis is placed on the need for operators and service companies alike to focus on thorough pre-job planning while paying close attention to complete system requirements high-pressure evaluation tools and detailed reviews.

Newer drilling opportunities, particularly in the deepwater arena, involve operating in extreme environments such as ultrahigh pressures, and demand different approaches to ensure flawless execution. This paper presents the variety of challenges, critical success factors, and lessons learned when drilling these ultra-high pressure wells in the demanding waters of the Gulf of Mexico. With downhole pressures approaching 30,000 psi and ever-increasing rig costs, the need for dependable drilling systems and integrated advanced formation evaluation technology is needed now more than ever.

The case results showcase the ability to set a new performance standard, extend the conventional operating envelop farther, and deliver answers while drilling.
Frac-Packing: Best Practices and Lessons Learned from over 600 Operations
Authors: Weirich John , Li Jeff , Abdelfattah Tarik , Pedroso Carlos
Published: June 2012

Frac-packing is a completion technique that merges two distinct processes: Hydraulic fracturing and gravel packing. The main challenge of a frac-pack completion is the successful creation of high conductivity fractures using the tip-screen out technique and placement of proppant within those fractures and the annulus between the screen and wellbore. This is further compounded by having to do so in an ultra high permeability environment, where high fluid leak-off rates are evident.

Since 1997, job data from more than 600 frac-packing operations worldwide have been compiled into a database. This paper reviews well information and key frac-packing parameters. Also summarized are engineering implementations and challenges, best practices, and lessons learned. Essential frac-pack design parameters attained from the step-rate-test (SRT) and mini-frac test are evaluated. These include bottom hole pressure, rock closure time and fracturing fluid efficiency. Down hole pressure and temperature are also discussed because of their importance to the post completion efficiency evaluation and fracturing fluid optimization phase.

Worldwide case histories are provided demonstrating how to deploy different frac-packing systems and pack the wellbore under extreme conditions with improved packing efficiency and a higher chance of success.
Advancement in Acid-Precursor Chemistry for Removal of Drill-in Fluid Filter Cake
Authors: Wang Xiaolan , Smith Kern , Cutler Jennifer , Beall Brian
Published: June 2012

It is challenging to remove filter cake uniformly and thoroughly from the production interval in horizontal and multi-lateral wells with heterogeneous formation characteristics. The inability to obtain complete filter cake removal is a common occurrence with the currently available reactive fluid systems. Another instance where conventional reactive systems are not adequate is when it’s desirable to spot the treatment fluid prior to running final completion. In some instances, this kind of operation can take several days.

Conventional practice to remove filter cake formed by water-based drill-in fluid usually includes strong mineral acids, buffered organic acids, oxidizers, enzymes, and chelating agents. These systems all have limitations that can result in non-uniform clean-up of the filter cake. Certain esters of organic acid have been investigated and used for filter cake removal to achieve better zonal coverage by delaying acid release. However, esters of formic acid generally hydrolyze too quickly, while acetic and lactic acid precursors hydrolyze more slowly but are not strong enough to effectively remove filter cake.

This paper presents a new delayed-release acid system that can generate an organic acid in situ. The system hydrolyzes more slowly than formates and lactates in the medium-to-high temperature ranges, and the generated organic acid is stronger than formic, lactic and acetic acid. Laboratory studies with a static HT/HP filter press demonstrated this new system can clean up filter cake effectively. Laboratory evaluation also demonstrated that polymer-specific enzymes can be added to the system to enhance clean-up efficiency because of its long delay time. Compared to conventional chemical methods of filter cake removal, this new delayed-release acid system provides a more efficient alternative, especially when the completion activity requires a long system delay time before the clean-up acid will be released across the entire production interval.
Innovative Whipstock Technology / Procedures Successfully Complete Challenging Low-Side, Uncemented Casing Exits: UK North Sea
Authors: Finlay Andrew , Sea Apache North , Bain James , Fairweather Alan , Ford James
Published: June 2012

Maximizing profitability in mature fields is dependent on reducing drilling and operational expenses to maintain optimized hydrocarbon production. As Forties field UK North Sea matures, drilling challenges are becoming increasingly more difficult and complex. Wellbore instability caused by the loss of reservoir pressure and anisotropic properties of overburden shale is a major issue as targets are pushed further away from the platform.

To continue successful development of Forties field, the operator is required to drill high-inclination deviated wellbores sidetracked from existing boreholes. The unstable shale outside of the sidetrack window requires a low-side casing exit. To optimize operations the sidetrack must be completed on the first attempt. When a first sidetrack fails, a second is often initiated approximately 10m (or interval thereof) further up in the wellbore with a higher mud weight. Unable to get more than a few feet away from the original wellbore within such a short distance, the new sidetrack can frequently re-enter the zone already damaged by the previous attempt and again runs into trouble. This broken formation becomes even more destabilized with increased mud weight.

To solve the operational / economic challenges, a unique wellbore departure system was developed to deliver fast, high-quality windows and sidetracks tailored specifically to meet operator’s low-side application objectives without compromising performance. The low-side exit requires a unique set of pre-job equipment modifications which is performed in the service provider’s workshop prior to shipping equipment to the well-site. The modification allows an upward force to be exerted at the tip of the whip face on setting the permanent packer / anchor thereby overcoming the natural gravitational forces. This upward force does not come into effect until the packer is energized, thus ensuring the whipstock assembly remains flexible enough to mitigate wellbore tortuosity encountered whilst running in the hole.

The system was successfully applied initially on three challenging uncemented whipstock sidetracks with single-trip window success (up to 77° inclination / 180° orientation). On all three jobs the anchoring and milling technology worked flawlessly with no issues when subsequently tripping directional BHA or liners through the window. Application engineers performed pre / post-job briefings with service provider’s rig site / offshore supervisors to ensure specific low-side exit guidelines were followed and that lessons learned or suggestions for improvement were captured and documented for prosperity.

The authors will present Forties field case studies that document procedural repeatability and how the tools and techniques could be used for any challenging low-side uncemented casing exits.
Review of Methods for Uniaxial Compressive Rock Strength Estimation in Deepwater Formation With Uncertainty Quantification in Wellbore Stability Analysis in Absence of Core Measurements
Authors: Kumar Rajeev Ranjan , Rao Dhiresh Govind
Published: June 2012

With the increase in deepwater exploration and unconventional tight gas exploration, wellbore stability analysis has emerged as a pivotal part of finalizing drilling programs. It becomes more important when inclined wellbores are drilled where stable mud weight windows are narrow. Wellbore stability analysis is conducted to validate calculated stress and rock properties against drilling observations. Uniaxial compressive rock strength (UCS) is an integral part of geomechanics studies involving mechanical earth modeling. Absence of direct core measurement brings uncertainty in the model. Presently, the industry uses different empirical relationships for estimation of UCS depending on formation type. It is critical to use appropriate relationship with minimum error and known quantification effects on final mud weight recommendation. Depositional sequence brings formation under different compaction regime of grains with interstitial pore fluid. Sandstone and shale are two common lithology found in India deepwater exploration field with intermediate siltstone. Validation of different models depends on porosity, volume of clay, saturation and sonic slowness response of formation. The present paper reviews these methods with four case studies from India and discusses how different models respond in deepwater formation sequences. Best method depending on range of volume of clay and porosity has been discussed in term of fuzzy logic. Mathematical model is build for uncertainty quantification of effect on mud weight optimization using different methods for UCS estimation is also discussed.
Horizontal Openhole Gravel Packing in Wells with Long Blank Pipe and Screen Sections
Authors: Costamte Y. R. , Trondsen A.. , Bergkvam R.. , Hodne H.. , Saasen A..
Published: June 2012

For offshore developments it is anticipated that several wells will be completed using gravel packed sand screens divided by long blank pipe sections. Open-hole gravel packing has routinely been used as a sand control method in long horizontal wells. However handling long blank pipe sections represents a challenge. The length of blank pipe section could be 600 meters or longer. In such cases, the chart of the surface pump pressure versus the pumping time is different when compared with a typical profile from a horizontal gravel pack in a section without blank pipe. Typically, gravel pack sand moves in from heel to toe of a well for roughly half of the cross section area (alpha wave) followed by a final placement of the remaining part of the annulus from toe to heel (beta wave).

Since there is no flow through the pipe in the blank pipe section, the beta wave does not exist here, and its absence complicates the gravel placement in the heel region of the reservoir. On the upstream side of the blank pipe, the slurry is dehydrated through the screen. This slows down the rate in the area adjacent to the blank pipe where in turn a new alpha wave adjacent to the blank pipe starts. This process appears to continue until the majority of the area open to flow above the alpha wave adjacent to the blank pipe has been filled in. The beta wave adjacent to the screen on the upstream side of the blank pipe then continues normally.

The paper describes in detail a mechanistic model based on experiments which predicts the phenomena discussed above. This model for gravel placement has been validated both qualitatively and quantitatively with both laboratory and the North Sea field Heidrun data.
First Application of EC-Drill in Ultra Deepwater: Proven Subsea Managed Pressure Drilling Method
Authors: Rajabi M. Mir , Toftevåg K.. , Stave R. S. , Ziegler R..
Published: June 2012

A previous attempt to drill an exploration well in ultra-deepwater in the Gulf of Mexico (GoM) did not reach its objective due to an inability to maintain a Water Based Mud (WBM) system light enough to maintain circulation. For the next round of exploration drilling, a system was sought that allows dynamic management of Equivalent Circulation Density (ECD). Conventional Rotating Control Device (RCD) based Constant Bottom Hole Pressure (CBHP) management systems were not suitable, as no drilling fluid light enough to manage ECD via backpressure could be applied for this campaign.

AGR has developed a pumped riser Managed Pressure Drilling (MPD) system named EC-Drill that facilitates an automated control of mud level inside the riser to a specific BHP set point to mitigate the problems of tight drilling margins in deep waters and low pressure reservoir. This allowed drilling from a semisubmersible with an adjustable mud level, effectively reducing BHP and managing ECD without using any types of backpressure devices. Fluid level inside the riser is adjusted by a field proven subsea pump system.

EC-Drill detects influxes and fluid losses quickly, allowing the driller to respond before significant problem occurs.

In this paper we will discuss how EC-Drill is planned to pave the way for the operator to access a previously unattainable ultra deepwater target. EC-Drill principles, well design, equipment, and planning will be covered.
Design and Qualification of an Ultra-High Pressure Perforating System
Authors: Mhaskar Nauman , Sloan Mark , Myers William , Harvey William
Published: June 2012

With the steadily increasing demand for oil and gas, operators have been forced to explore deeper and hotter areas to find the most prolific reservoirs. This paper hightlights the design and qualification steps performed during development of a 7.0-in. O.D. 16 shots per foot (SPF) 30,000 psi perforating gun system. Finite-element modeling was used to optimize the gun design for 30,000 psi external pressure, and 400° F. As part of the qualification requirements, ballistic survival testing was conducted using low-debris gravel pack shaped charges.

Comprehensive knowledge of the post-perforated condition of the gun body is required, as its failure may lead to an expensive fishing operation and possible damage of the oil well casing. Survival testing was conducted under two different conditions, no load on the gun body and the second contion with a tensile load equivalent to the weight of 1,500 ft of perforating guns.

The methodology of finite-element modeling is discussed along with experimental data obtained by collapse testing of perforating hollow carriers (HC) of different diameters and shot densities. Data from computer simulations and physical testing in the lab are presented to provide better insight into the behavior of perforating guns under external pressure. The data from the survival tests showed virtually no change in the swell of the HC when subjected to a high tensile load as compared to the no-load condtion. This testing method provides insight into the behavior of perforating systems under different loading parameters.

The results described in this paper highlight the need to apply rigorous methods for design and qualification of ultra-high pressure gun systems when exploring new oilfield frontiers characterized by extremely harsh environmental conditions.
A Solution to the Problems Associated with Tight-Clearance Boreholes: the Close Tolerance Press-Fit Stop Collar
Authors: Wimberg J. A. , Tkach S. A. , Marque J. M. , Domingue K.. , Buytaert J.. , Harless K..
Published: June 2012

With the continual development of offshore drilling operations comes new ways to approach old challenges. For any operator in a mature field, it is commonplace to enhance value by sidetracking existing wellbores to unswept areas within the reservoir where using a new drill would not be economically feasible. However, this approach often involves inherent risk. By using an existing wellbore, hole size and casing combinations are limited to the largest outer diameter (OD) casing string the operator can exit from and still safely case and cement the objective with a high probability of success. A bicenter drilled or under-reamed hole in combination with the use of noncoupled tubular connections (flush connections) is often required to construct a wellbore of sufficient size that does not constrict eventual production rates. Tight annular clearances and subsequent enlarged holes create standoff problems for subsequent cementing operations. In addition, sidetracks commonly drilled with only limited casing strings require efficient use of the minimal amount of casing sizes available. This often requires washing, rotating, or reaming casing to bottom when borehole conditions deteriorate. This paper describes a creative solution to the challenge of achieving casing standoff in an enlarged borehole while being robust enough to ream lengthy distances and retain the flexibility to properly centralize a tubular string for a quality cement job.
Improvement of Hole Cleaning Through Fiber Sweeps
Authors: Cheung Erik , Takach Nicholas , Ozbayoglu Evren , Majidi Reza , Bloys Ben
Published: June 2012

Hole cleaning is often more difficult during drilling of inclined wells. The resulting poor removal of cuttings can lead to problems such as borehole pack-off and excessive ECD, which are both difficult and expensive to resolve. Fluid sweeps are commonly implemented when normal circulation cannot adequately remove cuttings from the borehole. Field reports have indicated that specialized fibrous-type materials enhance cleaning performance when added to fluid sweeps. Yet, understanding of the behavior of this improvement remains inexact.

This paper presents a comparative experimental investigation of the hole cleaning performances of fiber sweeps, conducted with different drill pipe rotation speeds and fiber concentrations. Experiments were carried out in an inclined flow loop apparatus with an inner rotating drill pipe. The hole cleaning performance of fiber-containing sweep fluids using different fiber concentrations (0%, 0.05%, 0.1%, and 0.2%, by weight) and varying drill pipe rotation speeds (0 to 90 rpm) was evaluated. Sweep efficiencies were compared in terms of the measurement of cuttings bed heights before and after circulating the sweep fluid.

The results indicate that significant improvement associated with higher fiber content requires a commensurate increase in drill pipe rotation speed. With lower or no pipe rotation speed, increasing fiber concentration yields less dramatic returns. Pairing high fiber content with rapid pipe rotation resulted in enhanced performance over the control sweep, which contained no fiber, but relatively low concentrations did not surpass the control.

With the increasing need in the industry to drill extended reach or otherwise inclined wells, there is greater potential to develop problems stemming from inadequate hole cleaning. This research gives insight into the specific interaction of sweep fiber and pipe rotation with the cuttings bed, and with each other. Deeper understanding of fiber sweeps would inform in-field decisions when dealing with poor hole cleaning.
Multidisciplinary Approach and Engineered Solution Sets New North Sea Performance Benchmarks
Authors: Cockram Mark , Ritchie Allan , Norge BG , O’Keefe John , van der Laan Rene , Sundfør Erik , Larsen Olav , Kleimeer Peter , Rapp Tom , Shotton Peter , Gjertsen Ole Jacob
Published: June 2012

To efficiently develop reserves in the Norwegian North Sea, the operator must drill a challenging 12¼" directional borehole through a Chalk formation with high stick-slip potential. In Gaupe North, a negative vertical section was required in the initial kickoff to properly line up the well path before entering the reservoir target. The reservoir is comprised of channel/sheet sandstones interbedded with shale sequences with different pressure regimes and nearby reservoir depletion issues. The 8½" wellbore must penetrate an unstable organic shale just above the reservoir, infamous for causing hole stability problems and stuck pipe events. The regulatory agency requires this shale to be drilled in an 8½" section, requiring long exposure time, which increases risk for hole problems when running the production liner. The objective was to efficiently drill these trouble-zones and deliver two horizontal producers in a cost effective manner using an integrated engineering solution.

To achieve the objective, a sophisticated multidisciplinary approach was employed including: bit/BHA offset analysis to reduce stick-slip in the chalk; BHA/RSS and drilling fluids modeling/planning; and drilling parameter plots to identify optimum RPM/WOB. Also, a real-time parameter analysis system was deployed to optimize ROP without compromising hole cleaning or well integrity.

The synergy provided by a fully integrated service provider increased drilling performance and was a major contributor to the success of the Gaupe wells performance. Well 6/3-A-1H broke the previous Rushmore index for subsea development wells in the region and set a Norwegian record for wells in this class. Both wells (15/12-E-1H & 6/3-A-1H) achieved positive P10 curves and saved a total of 18 days vs AFE. Compared to an analogous UK North Sea field, significant increases in ROP were achieved resulting in the wells being drilled 20+ days faster than benchmark. The average increases in ROP for the two Gaupe wells were approximately 146%, 47% and 148% in the 17½", 12¼" and 8½" sections respectively.
Challenges in Setting Cement Plugs in Deep-water Operations
Authors: Bogaerts M.. , Kanahuati A.. , Khalilova P.. , Moretti F.. , Voon E.. , Dighe S..
Published: June 2012

Offshore cementing poses many challenges across the world as drilling operations move towards deep-water and ultra-deep-water. As a new initiative of continuous improvement, a deep-water cementing peer review process was started early 2011. To this date, this team has reviewed more than 1200 deep-water cementing jobs in more than 30 countries worldwide.

Plug cementing makes up nearly 53% of all the deep-water jobs reviewed. The majority of the cement plugs placed are for plug and abandonment purposes; however a significant part is for loss circulation, kick-off, or squeeze. Although plug cementing comprises a big portion of deep-water cementing, it often does not get the same level of attention as primary cementing.

Specialized plug cementing software is used to design all cement plugs set in deep-water operations. The software simulates fluid interfaces, contamination during placement (both when the fluid is travelling down the pipe and when it is being placed in the annulus) and while pulling out of hole. As a final result, it provides the top of uncontaminated cement. Aside from proper job placement, good slurry design is very important. Cement slurries used for plug cementing need to be designed according to the objectives of the job. Several case histories will show lessons learned from the analysis of plug cementing operations in deep-water operations.

As the industry and local regulations gets more stringent on the evaluation and acceptance of the barrier for well integrity, the success of setting a cement plug the first time is becoming ever more critical. Getting it right the first time easily saves several days of NPT resulting in savings of millions of dollars, especially in this deep-water environment. Appropriate focus on sound engineering practices and the use of the specialized software has improved reliability of setting cement plugs in deep-water and helps operators avoid costly remedial operations.
A Novel Tubing Movement Workflow Increases Efficiency and Planning for Deepwater Frac-Pack Operation
Authors: Boisvert Ian , Strobel Marshal , Szatny Michael
Published: June 2012

The frac-pack completion has become one of the prominent completion types for deepwater formations throughout the world. The vast majority of frac-pack stimulation treatments are pumped through complex sand control tools in wells with large gravel pack assemblies. The forces created by these stimulation treatments have increased as treatment size, water depth, and total depth have increased offshore. To plan appropriately for these deepwater completions, engineers expend a significant amount of effort to ensure that the tools are robust enough to accommodate the treatment demands. This planning and simulation can be a very time consuming process; moreover, it may evaluate only a limited range of potential frac-pack scenarios.

To reduce time and limit uncertainty, a novel tubing movement workflow has been developed. A commercially available workflow software suite was used to connect a commercially available fracture design component and a commercially available casing and tubing simulator. This workflow uses formation parameters and a wellbore input file to process hundreds or thousands of stimulation injection schedules to determine tubing movement, pipe forces, and weight transmitted downhole. The entire process is completed within a significantly shortened time span, depending on the computer speed and the number of iterations desired. The results of the workflow enable the determination of optimal workstring and service tool characteristics. A sample case study is included.
Transformational Reduction in Non-productive Time through Implementation of Broadband Networked Drill-string and Modified Drilling Practices in an Extended Reach Drilling Campaign
Authors: Veeningen Daan , Fear Martyn , Energy Husky , Willson Stephen
Published: June 2012

Historically, extended reach offshore wells in Trinidad & Tobago were characterized by wellbore instability and hole cleaning challenges. These phenomena had become almost impossible to manage effectively in the highest angle wellbores, leading to levels of non-productive time (NPT) that threatened the economic viability of the latest development.

Wellbore instability exacerbated the hole cleaning challenge, fueled by a new instability mechanism at highest wellbore inclinations. This led to pack-offs and stuck pipe incidents. Additionally, poorly understood and generally insufficient hole cleaning practices increased stuck pipe risk, and also caused the equivalent circulating density (ECD) to rise, resulting in mud losses due to the narrow window between mud density required for wellbore stability, and formation fracture gradient.

The solution to these problems was found through advanced downhole measurements of borehole stability and hole cleaning, transmission of those data back to surface via a high frequency medium ("networked or wired" drill-pipe), deployment of subject matter experts into the rig team for critical phases of the operation, and introduction of unconventional drilling and decision-making practices to mitigate the problem phenomena.

This paper describes the transformational efficiency improvement that was achieved by this combination of new technology, improved workflows, and multidisciplinary expertise deployed to the rigsite. The methodology was implemented on the third well, resulting in a reduction of NPT from 47% and 48% on the first two wells, to 10% on the third, clearly expressing the enhanced control of these drilling phenomena on the third well.

Recommendations offered are relevant to many extended reach drilling campaigns, and may be critical to the success of ultra-ERD wells.
Application of Mechanical Specific Energy Techniques in Reducing Drilling Cost in Deepwater Development
Authors: Amadi Kingsley , Iyalla Ibiye
Published: June 2012

This paper examines the application of mechanical specific energy optimisation techniques in cost reduction through prediction of optimum ROP using real-time drilling parameters data and intrinsic formation data acquired during the actual drilling process. In fields where offset well data exist accurate field penetration rate benchmark can be established aiding cost Optimisation. In recent times, the global number of deep water wells drilled has risen with the oil price, however growth is patchy and the actual spending on wells is rising rapidly. Spending surge on drilling cost impacts on the bottom line performance and sustainability of E&P business. Therefore the need for drilling performance improvement as operational cost reduction initiatives has become a critical industry goal. This study show that in most cases, drilling progress could be raised by 30 – 60% compared to best offset well performance. It also highlights drilling flounder (point at which the penetration rate stops responding linearly with increasing weight on bit) during the drilling process enabling informed decisions towards improving the drilling process with the overall goal of achieving lowest cost per foot drilled.
A Numerical Model for Predicting the Rate of Sand Production in Injector Wells
Authors: Azadbakht S.. , Jafarpour M.. , Rahmati H.. , Nouri A.. , Vaziri H.. , Chan D..
Published: June 2012

In this paper, a numerical model for volumetric prediction of sand production in injector wells is presented. Sanding in injector wells is mainly associated with the back-flow and cross-flow generated during shut-in in addition to the waterhammer pressure pulsing in the wellbore due to fast flow rate changes. Emphasis is given to the geomechanical aspects of sanding such as rock fatigue due to cyclic pressure changes and the concomitant degradation of bonding between the sand grains. This model is robust in capturing the key parameters in the sandstone behavior such as stress-dependent elasticity, hardening, softening and dilatancy. Rock degradation is considered to be the necessary condition for sand production which is assumed to obey the erosion mechanics. The model is calibrated and validated using physical model tests carried out under various stresses and fluid flow conditions. The numerical model has been utilized to analyze sanding potential in a cased and perforated injector which will be presented to demonstrate the field application of the proposed concepts.
Marine Well Containment Company Progress
Authors: Massey Marty
Published: June 2012

Following the Deepwater Horizon incident, ExxonMobil, Chevron, ConocoPhillips and Shell recognized the need to improve containment capability for a potential deepwater well control incident in the U.S. Gulf of Mexico.

This led to the formation of a not-for-profit, independent company, Marine Well Containment Company, which would develop, maintain and advance well containment systems for the deepwater U.S. Gulf. Following formation, MWCC gained six additional members (for a total of ten member companies): BP, Apache, Anadarko, BHP Billiton, Statoil and Hess. This coming together signified unprecedented industry collaboration and is a key reason that drilling has resumed in the U.S. Gulf of Mexico.

As the leader in deepwater well containment in the U.S. Gulf of Mexico, the company is committed to being continuously ready to respond to a well control incident in the Gulf and is committed to advancing its capabilities to keep pace with its members’ needs. Membership is open to all oil and gas operators in the U.S. Gulf of Mexico.
Assessment of waterborne protozoan passage through conventional drinking water treatment process in Venezuela
Authors: Betancourt Walter Q. , Mena Kristina D.
Published: June 2012

Three drinking water treatment plants (DWTPs) differing in source water and treatment capacity were investigated for the potential passage of waterborne protozoan (oo)cysts through conventional processing. DWTP I (15,000 L/s), DWTP II (7,500 L/s) and DWTP III (4,300 L/s) provide drinking water for approximately 2.7 million inhabitants of the Metropolitan District of Caracas (Venezuela). The US Environmental Protection Agency Method 1623 for detection of Cryptosporidium and Giardia was used to analyze raw water and finished drinking water samples collected from the three plants. (Oo)cyst recovery efficiencies varied between 23 and 84%. The concentration of confirmed (oo)cysts detected in raw water samples ranged between 1 and 100 per 100 L. (Oo)cyst levels in finished water samples ranged from 2 to 25 per 100 L. These data indicated that the conventional treatment process to produce finished water at two filtration plants was not effective in preventing the passage of protozoan (oo)cysts. Monitoring strategies that include multiple microbial indicators and waterborne pathogens are strongly recommended for accurate source water characterization and for verification of the effectiveness of treatment process barriers to microbial breakthrough in the finished water.
Identifying host sources, human health risk and indicators of Cryptosporidium and Giardia in a Canadian watershed influenced by urban and rural activities
Authors: Van Dyke Michele I. , Ong Corinne S. L. , Prystajecky Natalie A. , Isaac-Renton Judith L. , Huck Peter M.
Published: June 2012

Cryptosporidium and Giardia were characterized in a watershed in southern Ontario, Canada, over a 2½ year period. River samples were collected every two weeks, primarily near a municipal drinking water treatment plant intake. Cryptosporidium and Giardia were frequently detected with an overall occurrence rate of 88 and 97%, respectively. Giardia concentrations were higher than Cryptosporidium, with median values of 80 cysts 100 L−1 and 12 oocysts 100 L−1, respectively. Although pathogens rarely show a significant relationship with fecal or water quality indicators, this study determined that Cryptosporidium, but not Giardia, was significantly correlated with Escherichia coli, turbidity and river flow. There was no correlation between the two types of protozoa, and only Giardia showed a seasonal trend with higher concentrations at cold water temperatures. Cryptosporidium genotyping of all samples found that farm animals and wildlife were an important contributor of oocysts in the watershed, and that Cryptosporidium strains/genotypes of medium to high risk for human infection (C. hominis, C. parvum and C. ubiquitum) were detected in 16% of samples. This study was able to identify Cryptosporidium host sources and human health risk, and to identify differences between Cryptosporidium and Giardia occurrence in the watershed.
Methods for assessing long-term mean pathogen count in drinking water and risk management implications
Authors: Englehardt James D. , Ashbolt Nicholas J. , Loewenstine Chad , Gadzinski Erik R. , Ayenu-Prah Albert Y.
Published: June 2012

Recently pathogen counts in drinking and source waters were shown theoretically to have the discrete Weibull (DW) or closely related discrete growth distribution (DGD). The result was demonstrated versus nine short-term and three simulated long-term water quality datasets. These distributions are highly skewed such that available datasets seldom represent the rare but important high-count events, making estimation of the long-term mean difficult. In the current work the methods, and data record length, required to assess long-term mean microbial count were evaluated by simulation of representative DW and DGD waterborne pathogen count distributions. Also, microbial count data were analyzed spectrally for correlation and cycles. In general, longer data records were required for more highly skewed distributions, conceptually associated with more highly treated water. In particular, 500–1,000 random samples were required for reliable assessment of the population mean ±10%, though 50–100 samples produced an estimate within one log (45%) below. A simple correlated first order model was shown to produce count series with 1/f signal, and such periodicity over many scales was shown in empirical microbial count data, for consideration in sampling. A tiered management strategy is recommended, including a plan for rapid response to unusual levels of routinely-monitored water quality indicators.
Traditional copper water storage vessels and sub-lethal injury of Salmonella enterica serovar Typhi and Vibrio cholerae
Authors: Sharan Riti , Chhibber Sanjay , Reed Robert H.
Published: June 2012

Recent studies on Escherichia coli have demonstrated sub-lethal injury–sensitivity to oxygen and selective agents prior to irreversible inactivation when kept in water in a brass vessel. The present study was carried out to investigate whether equivalent responses occur in copper vessels using the pathogens Salmonella enterica serovar Typhi and Vibrio cholerae. Bacterial suspensions were stored in water in a traditional copper vessel for up to 24 h at 30 °C. Samples were withdrawn and plated on selective and non-selective media, then incubated under (a) aerobic conditions and (b) conditions where reactive oxygen species were neutralized to enumerate injured bacteria. Short-term incubation in water kept in a copper vessel caused a greater decrease in counts for both pathogens on selective media, compared to non-selective media with greater differences between aerobic and reactive oxygen species-neutralized counts using selective media compared to non-selective nutrient agar. These findings have practical implications for the short-term storage of water samples in copper storage vessel as the possibility of bacterial injury is high, hence enumeration under conventional aerobic conditions may not be sufficient to give a count of all viable bacteria.
A post-implementation evaluation of ceramic water filters distributed to tsunami-affected communities in Sri Lanka
Authors: Casanova Lisa M. , Walters Adam , Naghawatte Ajith , Sobsey Mark D.
Published: June 2012

Sri Lanka was devastated by the 2004 Indian Ocean tsunami. During recovery, the Red Cross distributed approximately 12,000 free ceramic water filters. This cross-sectional study was an independent post-implementation assessment of 452 households that received filters, to determine the proportion still using filters, household characteristics associated with use, and quality of household drinking water. The proportion of continued users was high (76%). The most common household water sources were taps or shallow wells. The majority (82%) of users used filtered water for drinking only. Mean filter flow rate was 1.12 L/hr (0.80 L/hr for households with taps and 0.71 for those with wells). Water quality varied by source; households using tap water had source water of high microbial quality. Filters improved water quality, reducing Escherichia coli for households (largely well users) with high levels in their source water. Households were satisfied with filters and are potentially long-term users. To promote sustained use, recovery filter distribution efforts should try to identify households at greatest long-term risk, particularly those who have not moved to safer water sources during recovery. They should be joined with long-term commitment to building supply chains and local production capacity to ensure safe water access.