bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computed Tomography Use Among Children Presenting to Emergency Departments With Abdominal Pain
Authors: Fahimi Jahan , Herring Andrew , Harries Aaron , Gonzales Ralph , Alter Harrison 
Published: October 2012

OBJECTIVE:
To evaluate trends in and factors associated with computed tomography (CT) use among children presenting to the emergency department (ED) with abdominal pain.

METHODS:
This study was a cross-sectional, secondary analysis of the National Hospital Ambulatory Medical Care Survey data from 1998 to 2008. We identified ED patients aged &lt;19 years with abdominal pain and collected patient demographic and hospital characteristics, and outcomes related to imaging, hospital admission, and diagnosis of appendicitis. Trend analysis was performed over the study period for the outcomes of interest, and a multivariate regression model was used to identify factors associated with CT use.

RESULTS:
Of all pediatric ED visits, 6.0% were for abdominal pain. We noted a rise in the proportion of these patients with CT use, from 0.9% in 1998 to 15.4% in 2008 (P &lt; .001), with no change in ultrasound/radiograph use, diagnosis of appendicitis, or hospital admission. Older and male patients were more likely to have a CT scan, whereas black children were one-half as likely to undergo a CT scan compared with white children (odds ratio: 0.50 [95% confidence interval: 0.31–0.81]). Admitted children had much higher odds of undergoing a CT scan (odds ratio: 4.11 [95% confidence interval: 2.66–6.35]). There was a plateau in CT use in 2006 to 2008.

CONCLUSIONS:
There was a dramatic increase in the utilization of CT imaging in the ED evaluation of pediatric patients with abdominal pain. Some groups of children may have a differential likelihood of receiving CT scans.
Occurrence and Family Impact of Elopement in Children With Autism Spectrum Disorders
Authors: Anderson Connie , Law J. Kiely , Daniels Amy , Rice Catherine , Mandell David S. , Hagopian Louis , Law Paul A. 
Published: October 2012

OBJECTIVES:Anecdotal reports suggest that elopement behavior in children with autism spectrum disorders (ASDs) increases risk of injury or death and places a major burden on families. This study assessed parent-reported elopement occurrence and associated factors among children with ASDs.METHODS:Information on elopement frequency, associated characteristics, and consequences was collected via an online questionnaire. The study sample included 1218 children with ASD and 1076 of their siblings without ASD. The association among family sociodemographic and child clinical characteristics and time to first elopement was estimated by using a Cox proportional hazards model.RESULTS:Forty-nine percent (n = 598) of survey respondents reported their child with an ASD had attempted to elope at least once after age 4 years; 26% (n = 316) were missing long enough to cause concern. Of those who went missing, 24% were in danger of drowning and 65% were in danger of traffic injury. Elopement risk was associated with autism severity, increasing, on average, 9% for every 10-point increase in Social Responsiveness Scale T score (relative risk 1.09, 95% confidence interval: 1.02, 1.16). Unaffected siblings had significantly lower rates of elopement across all ages compared with children with ASD.CONCLUSIONS:Nearly half of children with ASD were reported to engage in elopement behavior, with a substantial number at risk for bodily harm. These results highlight the urgent need to develop interventions to reduce the risk of elopement, to support families coping with this issue, and to train child care professionals, educators, and first responders who are often involved when elopements occur.
Reducing Fracture Propagation During the Drilling Process by Altering Wettability
Authors: Quintero Lirio , Brege Jonathan J. , Christian Chad F. , Clark David E. 
Published: October 2012

Abstract
While drilling through pressure-depleted formations, drilling-induced fracturing often occurs. Fracturing results when the drilling fluid overburden pressure exceeds the fracture pressure of the rock, initiating fractures that may further propagate as overburden pressure is increased. The growth in the aperture of these fractures results in lost circulation incidents. The consequences pose a major economic and safety risk when drilling. Numerous papers have been published on the concept of maximizing the fracture width to preserve the resulting hoop stress around the wellbore and effectively decrease drilling fluid losses. Using these techniques to control lost circulation with bridging materials can be extremely difficult when drilling with non-aqueous, oil-based fluid. The reduced permeability of an oil-wet filter cake prevents carrier fluid leak-off and necessary solids concentration. The resulting lower-strength plug in the fracture prevents effective support. The fracture then closes, preventing maximum hoop compression of the wellbore.
Altering the oil-wet solids in the fracture to water-wet conditions increases the ability for pressure to leak-off in fractures when placing bridging agents. This capability is paramount to improving bridging agent placement and increasing the effective strength of the wellbore. A lost circulation pill system has been developed that alters the wettability of the fracture from oil-wet to water-wet. This pill system penetrates and water-wets oil-containing fractures and enables fast pressure leak-off and fracture support, effectively increasing pressure required for fracture growth. Laboratory and chemical methods are presented that show the system is effective over a broad range of temperatures and differential pressures.
Subsea Processing in Remote Marginal Fields
Authors: Vichitrananda Vatanyoo , Simms Nigel , Sumner Joy 
Published: October 2012

Abstract
With ever increasing energy demands and the depletion of hydrocarbon resources, marginal fields play an important role in oil and gas exploitation. Flow assurance issues, including wax and hydrate formation, can be found in long distance tiebacks. Subsea processing, where processing equipment is installed on the seabed, can be used to solve these flow assurance issues in remote marginal fields. Subsea processing is the leading edge technology for unlocking production from reservoir under complex conditions. This paper demonstrates the opportunities in marginal field development, and analyses the implication of applying subsea processing in remote marginal fields.
The marginal field case study concerns a development with an 80 km tieback, having reserves of 120 million barrels of oil and in water 3,000 m deep in the Gulf of Mexico. The technical and economic aspects of two field development options, one employing subsea separation and boosting, and the other, an electric trace heated pipe-in-pipe flowline and subsea boosting, are compared. Hydraulic analysis of three phase flow (oil, gas, and water) using state of the art simulation software (OLGA) is performed to demonstrate production fluid behavior inside the flowline. Life cycle cost, combining both economic (CAPEX and OPEX) and risk factors (RAM), are used as the selection criterion.
Subsea separation with continuous hydrate inhibitor injection can prevent flowline blockage over the field life, while the electric trace heated pipe-in-pipe option may require subsea boosting to override the large pressure drop in late field life. In the analysis, subsea separation shows potential life cycle cost savings of up to 13% compared to electric trace heated pipe-in-pipe, indicating it may be the appropriate option when developing fields with these specific conditions. Improvement of subsea processing requires more compact designs for deepwater applications, which will help reduce both capital investment and intervention cost.
Cement Failure Probability under HPHT Conditions Supported by Long Term Lab Studies and Field Cases
Authors: Yuan Zhaoguang , Al-Yami Abdullah S. , Schubert Jerome , Teodoriu Catalin 
Published: October 2012

Abstract
Cement durability is very important to maintain proper well isolation and stability under HPHT conditions. In the process of well completion and production, pressure decline and temperature variation with time can contribute to cement failure and wellbore stability issues. However, there is no available investigation in the durability and comparison of different types of cement at higher temperature and at different operational scenarios.
Three different types of cement (72 pcf, 101 pcf and 118 pcf) commonly used in the Middle East were cured and tested at 300°F in the study. The tests included one year mechanical properties measurement such as compressive strength development, Young's modulus and Poisson's ratio.
Finite element method was used to analyze the failure probability of HPHT wells over with time. At the variation of bottom hole pressure and temperature, the casing, cement, and formation system failure probability was studied for these types of cement. The results show that the pressure variation has more effect on the wellbore stability than the temperature variation for HPHT wells. Low density cement can improve the wellbore stability issues due to the cement elastic behavior.
This paper introduces the operational envelope for every type of cement investigated in order to achieve successful operations based on field conditions. Field cases were discussed to validate the results of this investigation.
Prediction of Liquid Loading in Gas wells
Authors: Nallaparaju Yashaswini Devi 
Published: October 2012

Abstract
It is a well known fact that the hydrocarbon demand increases by the day. Now, in order to meet this ever increasing demand it is essential for us to produce at the required rate over a specified period of time. The most prominent problem affecting production in gas wells is Liquid Loading. It is basically the inability of gas to remove liquids being produced in the wellbore. This occurs when the velocity of gas being produced falls down a particular value known as "critical velocity". The produced liquid will accumulate in the well creating a static column of liquid, therefore creating a back pressure against formation pressure and reducing production until the well ceases production. This problem should be predicted early and dealt properly to prevent economic losses and produce efficiently.
Some notable correlations that exist for predicting the critical rate required for liquid unloading in gas wells include Turner et al., (1969), Coleman et al., (1991), Nosseir et al. (1997) and Li et al. (2001). However, these correlations offer divergent views on the critical rates needed for liquid unloading and for some correlations in particular, at low wellhead pressures below 500 psia. In this paper, we compared the critical velocity graphs obtained from different models for four different wells and concluded that Turner model gives the most conservative value of critical velocity of all the methods for any value of pressure. The turner model is most widely used and accepted in oil and gas industries and moreover all the theories are based on the Turners model.
Using Nodal Analysis we integrated IPR and TPR curves to find out the operating point of the wells. Then by intersecting turner model curve with the future IPR curves we predicted the year in which the problem of liquid loading may occur. This will help us in taking necessary precautions beforehand.
After liquid loading has occurred, there are different deliquification techniques to deload the well. They have been presented in this paper, which help in reinitiating gas production.
Responsible Oil Well Tests on Artificial Islands Close to Offshore Waters
Authors: Dhufairi Mubarak , Arukhe James , Mutairi Saleh , Ghamdi Saleh , Aborshaid AbdulHameed 
Published: October 2012

Abstract
Safeguarding and restoring the normal ecosystems and environment of the Arabian Gulf in an active hydrocarbon province undergoing field development is a tough challenge. Nevertheless, a multidisciplinary team involved in this field development has maintained a profound commitment in stewarding natural resources of the major carbonate field in Saudi Arabia.
As part of the Kingdom's strategy to maintain crude oil production targets, production tests were needed to confirm potential of the wells in the Southern part of the field's structure prior to commissioning. The wells are located on drill sites in some artificial islands that were reclaimed from the sea. The six-well deliverability testing campaign should greatly enhance offshore field development, help to obtain reservoir characterization parameters, evaluate stimulation needs for producers, and assess comingling concept for selected wells. A total of 27 artificial Islands and a major transportation causeway were constructed by land reclamation from offshore waters of the Arabian Gulf. These facilitate onshore access to drill sites thus eliminating relatively more expensive fixed steel jacket rigs or platforms.
Due to land space limitation and well spacing constraints on the drill sites, a compact well test facility layout was specifically designed to achieve smokeless flaring, full combustion, and minimize environmental impact. The design consists of two heat exchangers, three-phase separators, i-loop systems for effective H2S scavenging and chemical mix with crude, surge tanks and air compressors. When deployed, this system helped to meet the test objectives and addressed space limitation challenges, mitigated risk to sea pollution in a sensitive marine environment, and forestalled uncontrolled release of hydrocarbons to the environment.
The completion of the cleanup and flow back operation on these wells with no single safety incident, uncontrolled release of hydrocarbons, or spill to nearby offshore waters was a major demonstration of leadership and a key contribution to well testing in similar environments.
Integrated Dynamic Flow Analysis to Characterize an Unconventional Reservoir in Argentina: The Loma La Lata Case
Authors: Badessich Matías Fernandez , Berrios Vicente 
Published: October 2012

Abstract
In November 2010 YPF brought online the very first shale oil well in Argentina in the northern area of Loma La Lata field after successfully fracturing the Vaca Muerta formation, the main source rock in the Neuquen basin. Initial choked productivity exceeded 250 bopd of high quality oil from an average depth of 9,500 ft. Since then, YPF has pioneered a new era of production from unconventional reservoirs in Argentina with many more wells coming onstream.
As it is well known, production forecasting and reserves estimation in this kind of reservoirs is fraught with challenges and pitfalls. Many methods have been applied so far; these range from very simple decline curve analysis to highly elaborate reservoir simulation models.
In order to understand and monitor the production behaviour of the YPF wells, several reservoir and production analysis techniques have been applied such as pressure transient analysis, rate transient analysis, interpretation of available DFITs and time-lapsed production logging measurements.
In this paper we present what YPF has implemented as a robust workflow for analyzing dynamic data that captures the physics of the flow process, explains the observed data and provides a method for forecasting reserves for a range of assumed in-place volumes.
Optimization of Gravel Pack Techniques in Baram South Using a Statistical Tool
Authors: Hatta Siti Aishah , Jadid Maharon , Saaid Ismail M 
Published: October 2012

Abstract
Baram field is a mature oil field in Sarawak, Malaysia and it is the largest and most structurally complex field in the Baram Delta Province. The reservoirs are thinly stacked and predominantly friable and unconsolidated requiring active sand control by gravel packing techniques being the most reliable sand control method available. Sand production in Baram wells resulted in several wells being shut-in, low oil production and costly surface maintenance to remove the sand. The drawbacks of gravel packing techniques were its high wellbore skins due to gravel carrier fluids, intermixing of gravel and fine sands, and blockage of gravel filter bed from fines migration over time resulting in lower well PIs and flow efficiencies through the gravel pack (GP) completions.
This paper reviews the gravel packing techniques applied in 47 completions in Baram South with the aim of identifying the most optimum method for gravel packing in future Baram South wells. A statistical tool called Taguchi Method for Design of Experiment and Analysis of Variance (ANOVA) were employed to analyze impact of the well deviations, gravel packing techniques and permeability variation on skin factor. It is a simple and reliable tool to analyze extensive amount of data and introduces the signal-to-noise ratio as an indication of effect each variable has on the output (skin). The statistical study concluded that the most suitable gravel packing technique for Baram South is High Rate Water Frac (HRWF). The GP technique adopted appears to be the dominant factor contributing to the skin while the type of reservoir and the deviation of the well have minimal effect.
Coiled Tubing Long Perforation CIRP with Live Correlation GR/CCL Application via Optical Telemetry: A Success Story at Angsi Field, Malaysia
Authors: A. Jalil M. Izwan , Ooi Zhon Wei , Kasim M. Heikal , Ishak M. Fakhrurazi 
Published: October 2012

Abstract
Angsi is one of the major fields in PETRONAS Carigali Sendirian Berhad. Located at offshore Terengganu in the Malay basin area, Angsi has become the top priority in terms of oil and gas production. A33L was producing intermittently through low-pressure system. Due to its rapid production decline, decision was made to restore its potential by adding perforations via Coiled Tubing.
Since adding perforations could be challenging due to the complexities such as on-depth perforation, depth accuracy of Coiled Tubing and uncertainty of depth correlation prior to detonation, fibre optic-enabled Coiled Tubing was chosen to convey the perforating guns. The job, planned to perforate I-95 and I-100 sand would require 120-ft of future perforations interval; was performed with an under pressure deployment system namely Completion Insertion and Retrieval under Pressure (CIRP). CIRP enables long perforating guns to be deployed in a single run and the combination of live correlation Gamma Ray and Casing Collar Locator via fibre optic-enabled Coiled Tubing; multiple perforating runs were avoided specifically for this well.
As a result, the well is currently producing 50 MMscf/day and with the success of this operation, it is anticipated that by combining several key technologies for this kind of job will not only ensure high level of perforating accuracy but also economically acceptable considering the value creation by the job.
This paper will discuss in detail the complexity of the overall operation, well challenges and the extended jacking frame built to accommodate the operation. Futhermore, the gun insertion, deployment and retrieval as well as live correlation via optical telemetry through coiled tubing will also be elaborated. The decision making process and well intervention equipment selection throughout the overall job operations will also be highlighted.
An Innovative Processing Method for High Resolution LWD Density Images in Water and Oil Based Mud
Authors: Li Jing , Kennedy David , Dawber Mike , Lee Rick , Boonen Paul , Hollmann Joseph 
Published: October 2012

Abstract
With the rapid growth of horizontal drilling, azimuthal LWD bulk-density images (and also photo-electric effect images) have proven to be indispensable tools for the identification of bed boundaries, estimating bed dips, and determining the steering direction of the drilling assembly. The inherent low resolution of the density measurement has, however, typically limited the interpretation of these images to the analysis of structural scale features. The ability to image finer scale detail is governed to a large extent by sampling density.
Sampling density depends upon the sampling frequency of the instrument, the rate of penetration of the drilling assembly and the rotary speed of the drillstring. Conventional downhole image processing schemes average raw measurements either in time or depth before sectoring them into relatively large circumferential sectors. This averaging process conserves tool memory and smooths noisy data but inevitably results in the loss of high spatial frequency instrument responses associated with fine scale geological features. Instead of compressing data, we present a method that preserves all the raw measurements stored in the tool memory and maps them to a grid around and along the borehole. Statistical noise is mitigated and a specially designed interpolation scheme is used to fill empty grid locations before analyzing the data and smoothing the results. This methodology allows the creation of high resolution images with up to 256 circumferential sectors and a depth increment as small as 0.6 inches.
The technique is equally applicable to borehole image data acquired by any type of logging tool providing that the raw measurements are frequently sampled and stored in the tool memory. For example, high resolution borehole caliper images have also been created from ultrasonic transducer measurements of the same tool used to acquire the data presented in this paper. Azimuthal bulk-density data acquired in this manner allows for the opportunity to produce optimized images in oil-based mud and overcomes the limitations of LWD micro-resistivity imaging tools in non-conductive borehole fluids. This technique has been successfully applied to wells drilled in both the UK North Sea and US land. Field examples presented in this paper illustrate the benefits of the application in imaging thin beds, sedimentary bedding structures, coal seam bedding internal structure, faults and fractures.