bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physical Concept Validation Testing Performed for a Pore and Fracture Pressure Margin Prediction System During Offshore MPD Operations
Authors: Piccolo B. , Leuchtenberg C. 
Published: April 2015

Abstract
A pressure determination system (PDS) was field tested to progress Managed Pressure Drilling (MPD) from a reactive system to one that prevents well control events from initiating. Physical testing performed on an offshore drilling operation successfully demonstrated the capability of the PDS to detect a simulated, unsafe change in fracture margin without incurring significant losses in August 2014. The test methods and results will be discussed in detail this report.
The PDS is designed to oscillate the position size of a dedicated pressure control valve (PCV) in a repeatable and gradual fashion and analyze the resultant behavior of Applied Surface Back Pressure (ASBP), Bottom Hole Pressure (BHP), and Flow Out indicators over time. In the event that average BHP begins to near a margin, the behavior of the above indicators at the crest or trough of a wave cycle will momentarily deform indicating a pending well control event. Since, average BHP has continuously remained within drilling margins during this process, any resultant gain or loss is negligible. Once the threat of a well control event is detected, a dedicated MPD PCV will adjust average wellbore pressure to a safer value to prevent the occurrence of a well control event.
During field testing, the PDS concept was verified with two assessments, signal transmission reliability and simulated fracture detection. The signal transmission reliability test validated that the PDS can oscillate PCV position in a controlled and consistent fashion as well as create highly repeatable behaviors in ASBP, BHP, and flow rate waves over time. The simulated fracture margin test demonstrated that the PDS has the sensitivity to detect a fracture margin at 20 psi above the driller's intended wellbore pressure with a negligible volume of losses while the PDS PCV oscillated wellbore pressure as described above.
Both tests were performed in an open hole section of a medium depth well with a rotating and reciprocating drill string.
Prior to field testing, a SIT (System Integrity Test) was performed on the PDS equipment installed on MPO's MPD Pressure Control Manifold (PCM) to ensure the system was prepared for concept testing. The SIT was performed with the MPD PCM isolated from well bore riser returns in August 2014.
The field tests described above were previously performed as an initial test, at the MPO Dubai Training Center Flow Loop where the PDS concept was also successfully validated in a laboratory environment. During those tests, the sensitivity of the PDS system was also demonstrated by validating that a 4 inch Coriolis Coriolis meter in a small, closed loop system was able to detect less than a 1 gallon difference in flow.
Early Detection and Localization of Downhole Incidents in Managed Pressure Drilling
Authors: Willersrud Anders , Imsland Lars , Blanke Mogens , Pavlov Alexey 
Published: April 2015

Abstract
Downhole incidents such as kick, lost circulation, pack-off, and hole cleaning issues are important contributors to downtime in drilling. In managed pressure drilling (MPD), operations margins are typically narrow, implying a risk of more frequent incidents and more severe consequences than during conventional drilling. Detection and handling of symptoms of downhole drilling contingencies at an early stage are therefore crucial for the reliability and safety of MPD operations.
This paper describes a method for early detection and localization of incidents, based on a fit-for-purpose model of the downhole pressure hydraulics, distributed pressure measurements from wired pipe, and statistical change detection methods. Using statistical change detection methods, it is possible to detect the incidents and their location at a very early stage when small changes in process data are covered in measurement noise, which may be very hard to observe for a human operator.
The method has successfully been tested on experimental data from a medium-scale horizontal flow loop in Stavanger, Norway. The flow loop represents a 700 m borehole with emulation of the following downhole contingencies: drillstring washout, drill bit nozzle plugging, gas influx and fluid loss. In the tests, these incidents were successfully detected at an early stage. The developed detection and localization method could be included as a diagnosis tool in a drilling system with MPD or conventional drilling.
Offshore Implementation Factors for Managed Pressure Drilling
Authors: Patel Harish , Bruton Jay 
Published: April 2015

Abstract
Managed pressure drilling (MPD) has been used for more than a decade onshore to drill an increasing number of challenging wells. However, the offshore drilling industry has only recently begun to adopt this innovative drilling technique. This paper will address some of the reasons delaying the application of this proven drilling method to drill offshore. It will describe offshore implementation and risk factors to consider for MPD.
MPD methods deliver advantages in drilling operations and risk reduction compared to conventional drilling methods. Benefits such as drilling previously unreachable targets, better kick control, smaller kick size and increased safety have led offshore operators to deploy MPD for offshore wells. For this reason, MPD technology is moving offshore from land-based application, where operational practices and environmental conditions are different. Applying MPD offshore requires consideration of additional design, operational, maintenance and safety issues. This paper will discuss some of these high-level issues and mitigations based on ABS experience gained working on various MPD projects for high-specification offshore floating rigs. Issues are identified based on offshore drilling practices, rig configuration, integration, offshore environments, limited space, training and regulatory requirements.
Based on various project experiences, ABS determined that additional improvements are needed to most effectively operate MPD systems offshore. This paper summarizes major concerns to be addressed and provides necessary mitigation measures. Heightened awareness of drilling conditions during MPD will often eliminate unscheduled events, or lessen their duration, and help minimize drilling risk. The result is reduced time on location, a safer drilling operation and lower total well costs.
Field Trial of Well Control Solutions with a Dual Gradient Drilling System
Authors: Cohen John H. , Stave Roger , Hauge Espen , Molde Dag Ove 
Published: April 2015

Abstract
Well control has been a major obstacle for introducing dual gradient systems for deep water drilling, involving both new and more complex procedures and equipment. Here test results using a new dual gradient drilling (DGD) system to control simulated well control events are presented. After successfully drilling a Statoil well with Enhanced Drilling's dual gradient solution (EC-Drill) at the Troll (Kjøsnes et al. 2014) field on the Norwegian continental shelf, the well was plugged and made ready for 48 hours of controlled testing. Several tests were run, each designed to determine the functionality of the system; to detect and handle liquid loss, gas and liquid influx, gas migration in the riser, and circulation of gas through the subsea pump module. The detection tests were carried out with a reduced riser level and an open annular, to quantify the capability of the system to detect volume imbalances while drilling. Three circulation tests with increasing amount of gas injected through the drillstring were performed. After the influx was detected, the annular was closed, and the flow was routed from the well through a bypass line to the subsea pump module. A topside choke in the mud return line was actively used to apply backpressure with the objective to control bottom-hole pressure, while circulating the gas from the well. In the last test gas was allowed to migrate into the marine drilling riser with a reduced riser level and open annular.
The paper will present the planning and preparations as well as the results.
Retrofitting Conventional Drilling Rigs With MPD: A Profitable Challenge Between Available Technologies
Authors: Carini Nicola , Allara Paolo 
Published: April 2015

Abstract
The integration of an MPD system during a new drilling floater design phase is today a common practice. While working on a brand new project, different MPD technologies could be evaluated choosing the one that suit best next well campaign properties of each drilling contractor. At the design phase, technically speaking, almost everything can be arranged and integrated. Now, given the high appeal that MPD systems are reaching today within Oil Companies, and considering the best possible delivery time for a new floater, are we sure we will be granted all this time to wait? The idea of limiting MPD chances to new builds seems not to be wise, thus, the profitability of retrofitting this new philosophy on an existing drilling rig should be properly evaluated. Developing this assessment, it is easy to notice how the implementation of an MPD set up on a conventional drilling plant impose the designer a different approach. Limitations in space on decks, integration between new and existing equipment and need for crew training are just some of the criticalities the drilling contractor will face choosing the best solution for them within the increasing number of potential providers. Let's say “constrains” will drive the choice.
The two major technologies available in the MPD market - and relevant set up - have been analysed on a “retrofitting point of view”, highlighting benefits and deficiencies of each in a critical trade-off between drilling development and operative constrains.
Managed Pressure Drilling System Provided Value to Offshore Drilling Operation
Authors: Onifade James , Patel Bhavin , Ertas Engin , Sammat Essam , Sahin Benhur 
Published: April 2015

Abstract
The pore and fracture pressure provides the boundaries during drilling operation. Nominal disparities between pore pressure and fracture pressure gradients cause the drilling window to be narrow, hence the term, “narrow margin wells.” Using conventional drilling methods, the drilling of narrow margin wells can be very challenging, hence the industry has begun exploring various methods of drilling through the narrow windows in a safe and effective manner. Managed Pressure Drilling MPD has evolved as a drilling method, which if properly engineered and implemented, could enable drilling through narrow margins in a safe and effective manner with significant reduction in drilling problems.
MPD utilizes the application of Surface Back Pressure (SBP) in order to manipulate the bottomhole pressure (BHP) within the confines of the pore and fracture pressure and enables precise navigation while drilling through the narrow margins. According to Fredericks et al, the effective control provided by MPD allows a more precise and better management of the annular pressure profile, allows accurate management of bottomhole pressure while drilling, during connections and even during well control operations.
The Weatherford MPD system was installed on an offshore Jack-Up rig to fulfill various requirements of the drilling operation. With the proven capability of the MPD system to “walk the line” between the pore and fracture pressure limits, the MPD system provided immense value to the entire drilling operation and enabled the operator to drill to the target depth.
This paper will detail a case study of this MPD operation and also describe significant values provided by the MPD system to the overall drilling objective. The MPD system enabled early kick and loss detection, ability to maintain constant bottomhole pressure during drilling and during pumps - off events and ability to utilize the Annular Pressure Control mode (APC) to automatically displace heavy mud cap at specific depths in order to maintain the static overbalance when the drill string is out of hole. The MPD system was incorporated into the existing rig system with minimal disruptions to rig operations and equipment. Drilling process safety and operational efficiencies were greatly improved with the adoption of MPD.
Internet Access at Home and its Relationship to Well-being in Deprived Areas of London
Authors: Boniwell Ilona , Osin Evgeny N. , Renton Adrian 
Published: April 2015

Purpose:
The existing studies of the association between Internet usage and well-being have produced contradictory
results. This study explores the associations between Internet access at home and well-being, as well as other lifestyle
variables.

Design/methodology/approach:
The study was done in a probability sample of 800 community-dwelling
adults aged 16 and over in six most deprived areas of the Redbridge borough of London. Using face-to-face interviews,
information on the demographics, lifestyle, Internet access at home, happiness, trait hope, and subjective health was obtained.
Path analysis and structural equation modelling were used to investigate the associations between Internet access
and well-being, controlling for demographic variables.

Findings:
Respondents with home Internet access had stronger social
ties with friends and relatives, engaged in a wider repertoire of community creative activities and cultural events, and
reported having higher social support. Controlling for demographic variables, Internet access at home was a weak but statistically
significant predictor of happiness, agency, and absence of mental health problems. The effect of home Internet
access on happiness was partially mediated by social ties.

Research limitations/implications:
The correlational nature of
the study forbids making causal inferences. The data suggest that people with low socioeconomic status may derive wellbeing
benefits from having access to information technology which can serve as an instrument for social integration.

Originality/value:
The data provide a demographic snapshot of the digital divide in one of the most deprived areas of London.
Genetic Predisposition to Central Obesity and Risk of Type 2 Diabetes: Two Independent Cohort Studies
Authors: Huang Tao , Qi Qibin , Zheng Yan , Ley Sylvia H. , Manson JoAnn E. , Hu Frank B. , Qi Lu 
Published: April 2015

OBJECTIVE
Abdominal obesity is a major risk factor for type 2 diabetes (T2D). We aimed to examine the association between the genetic predisposition to central obesity, assessed by the waist-to-hip ratio (WHR) genetic score, and T2D risk.

RESEARCH DESIGN AND METHODS
The current study included 2,591 participants with T2D and 3,052 participants without T2D of European ancestry from the Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). Genetic predisposition to central obesity was estimated using a genetic score based on 14 established loci for the WHR.

RESULTS
We found that the central obesity genetic score was linearly related to higher T2D risk. Results were similar in the NHS (women) and HPFS (men). In combined results, each point of the central obesity genetic score was associated with an odds ratio (OR) of 1.04 (95% CI 1.01–1.07) for developing T2D, and the OR was 1.24 (1.03–1.45) when comparing extreme quartiles of the genetic score after multivariate adjustment.

CONCLUSIONS
The data indicate that genetic predisposition to central obesity is associated with higher T2D risk. This association is mediated by central obesity.
Prevalence of and Racial Disparities in Risk Factor Control in Older Adults With Diabetes: The Atherosclerosis Risk in Communities Study
Authors: Parrinello Christina M. , Rastegar Ina , Godino Job G. , Miedema Michael D. , Matsushita Kunihiro , Selvin Elizabeth 
Published: April 2015

OBJECTIVE
Controversy surrounds appropriate risk factor targets in older adults with diabetes. We evaluated the proportion of older adults with diabetes meeting different targets, focusing on possible differences by race, and assessed whether demographic and clinical characteristics explained disparities.

RESEARCH DESIGN AND METHODS
We conducted a cross-sectional study of 5,018 participants aged 67–90 years (1,574 with and 3,444 without diagnosed diabetes) who attended visit 5 of the Atherosclerosis Risk in Communities (ARIC) study (2011–2013). Risk factor targets were defined using both stringent (and less stringent) goals: hemoglobin A1c (HbA1c) &lt;7%, &lt;53 mmol/mol (&lt;8%, &lt;64 mmol/mol); LDL cholesterol (LDL-c) &lt;100 mg/dL (&lt;130 mg/dL); and blood pressure (BP) &lt;140/90 mmHg (&lt;150/90 mmHg). We used Poisson regression to obtain prevalence ratios (PRs).

RESULTS
Most older adults with diabetes met stringent (and less stringent) targets: 72% (90%) for HbA1c, 63% (86%) for LDL-c, and 73% (87%) for BP; but only 35% (68%) met all three. A higher proportion of whites than blacks met targets, however defined. Among people treated for risk factors, racial disparities in prevalence of meeting stringent targets persisted even after adjustment: PRs (whites vs. blacks) were 1.03 (95% CI 0.91, 1.17) for HbA1c, 1.21 (1.09, 1.35) for LDL-c, 1.10 (1.00, 1.21) for BP, and 1.28 (0.99, 1.66) for all three. Results were similar but slightly attenuated using less stringent goals. Black women were less likely than white women to meet targets for BP and all three risk factors; this disparity was not observed in men.

CONCLUSIONS
Black-white disparities in risk factor control in older adults with diabetes were not fully explained by demographic or clinical characteristics and were greater in women than men. Further study of determinants of these disparities is important.
Polymorphism rs11465553 in the Interleukin-17F Gene in Serbian Patients with Psoriasis and Healthy Controls
Authors: Popadić Svetlana , Ramić Zorica , Medenica Ljiljana , Pravica Vera , Popadić Dušan 
Published: April 2015

Abstract
We examined single nucleotide rs11465553 polymorphism in the interleukin-17F gene causing valine to isoleucine substitution at the position 155 in the third exon of IL17F gene in Serbian patients with psoriasis and healthy blood donors. For the first time we found rs11465553 G (valine) and A (isoleucine) allele frequency in healthy Serbian population and in psoriasis patients, but without statistically significant difference between the two groups.
Spectrum of Biopsy Proven Glomerular Disease in Children at Kanti Children’s Hospital
Authors: Khatun N , Bista KP , Mahaseth C 
Published: April 2015

Introduction: Glomerular disease is one of the most common forms of renal disease and can have many different clinical presentations. However there is variation in the prevalence in the type of glomerular disease according to geographical location and race of population. The aim of the study was to find the overall distribution pattern of glomerular disease based on renal biopsies. Material and Methods: The medical records of all children who underwent kidney biopsy (n=29) between January 2012-june 2014 were analyzed. In this retrospective study we review children from Kanti Children’s Hospital, Nephrology Department. Demographic data including age, sex and indication of kidney biopsy as well as complication of the procedures were recorded. Result: A total number of thirty one biopsies were done. Two children were excluded from the study due to inadequate tissue and artifacts defects in preservative. The remaining twenty nine biopsies were included in the study and analyzed. Renal disease was found nearly equal in both male and female (51.72% vs. 48.27%).Mean age was 10.95±3.30 years. Maximum number of biopsies (75.86%) was performed between 10- 15 years. The most common indication of the kidney biopsy was nephrotic syndrome (steroid resistant nephrotic syndrome and steroid dependent nephrotic syndrome, 31.02% followed by lupus nephritis 27.58%.The most common glomerular disease were focal segmental glomerulosclerosis and lupus nephritis both contribute 27.58%. Among lupus nephritis class III was found more common (44.44%) in children. IgA nephropathy was also contribute (17.24%) in all glomerular disease. Regarding the kidney biopsy complication gross hematuria was observed in 6.89% of children which was self-limited. Conclusion: FSGS and lupus nephritis is becoming the most common glomerular disease in children attending the Kanti Children Hospital. IgA nephropathy was also contribute the glomerular disease in the children. J Nepal Paediatr Soc 2014;34(3):225-229 DOI: http://dx.doi.org/10.3126/jnps.v34i3.11162
Early Experience With Single-Stage Transanal Endorectal Pull Through For Rectosigmoid Hirschsprung’s Disease
Authors: Shrestha MK , Sherchan M , Dhoubhadel BK , Basnet RB 
Published: April 2015

On 24th August 2015, the spelling of the third author's name was changed from Dhaubhadel TO Dhoubhadel - Editor.Introduction: Recent trends in surgery for Hirschsprung’s disease (HD) have been towards earlier operation and fewer surgical stages. A single-stage transanal endorectal pull through (TEPT) is the latest development and minimally invasive technique for HD. This observational prospective study was designed to evaluate the safety and efficacy of single-stage TEPT technique in the management of rectosigmoid HD.Materials and Methods: Infants and children with biopsy-proved aganglionosis and barium enema (BE) documented rectosigmoid HD were included for single stage TEPT. Twenty children aged 22 days to 7 years (17 boys and 3 girls) underwent one stage TEPT over 5 year period. Median follow up was 18 months (range 6-36 months). These patients were evaluated with regard to age, sex, intraoperative details, postoperative functional outcome and complications and need for secondary surgical procedure.Results: The operating time was 105-180 minutes (mean 120 minutes). The length of resected bowel was 18-30 cm (mean 25 cm). Intraoperative blood loss was 5-40 ml, less in infants compared to older children. Blood transfusion was needed in none out of 12 infants and 2 out of 8 older children. Transient perianal excoriation occurred in 16 patients. Postoperative enterocolitis occurred in one patient. One patient developed constipation with encopresis following anastomotic stricture. None had adhesive obstruction and prolapse of pulled through colon, one required colostomy for anastomotic leakage and peritonitis while another had retained aganglionic segment and re-do pull through was required.Conclusion: Single-stage TEPT can be performed successfully in all age of children. The technique is safe, easily learned and has good clinical results.DOI: http://dx.doi.org/10.3126/jnps.v34i3.11617 J Nepal Paediatr Soc 2014;34(3):188-194