bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experiences In Introducing 3D Visualization In Petroleum Engineering Education
Authors: Gupta A. , Platt F. M. 
Published: October 2009

Abstract
This paper describes the experience obtained in introducing 3D immersive visualization exercises in petroleum engineering at Texas A&M University in Qatar. Challenges encountered in the process are discussed. An immersive visualization facility (CAVE) was recently installed at TAMUQ to support teaching and research needs. Although, similar systems are used in industry for visualizing reservoirs and making development decisions, there is no known precedent of using CAVE for petroleum engineering education. Given that petroleum engineering revolves around subsurface reservoir and well systems, there is heavy reliance on engineers' ability to use their imagination for effectively visualizing and designing such systems. Petroleum engineers do not have the luxury of seeing, touching, feeling, and in general, developing an intuitive feel for the objects and systems they are dealing with. Two types of visualization exercises have been introduced.
First experience relates to visualization of pore structure based on 3D rendering of CT-scan data obtained for core samples of sandstone and carbonate reservoirs. Time-lapse CT scans were repeated during capillary imbibition experiments to visualize and animate the displacement process in CAVE. The scanner was also used to visualize and animate frontal advances. The results are compared to animation of simulation results. The second experience relates to visualizing results of simulation of reservoir displacements. The students are able to experience various recovery mechanisms at reservoir scale.
3D visualization of subsurface reservoirs offers benefit of providing students greater insight into reservoir and well systems and mechanisms of recovery processes. It allows students to conduct virtual-walk through the reservoir pore space. It gives them insight into the nature of flow at various length scales. Students are able to view pore-level fluid-flow in reservoir rocks in "virtual-reality. Based on results of 3D visualization, students are able to "experience" recovery mechanisms at porelevel and grid-block resolution.
Composites Improve Well Construction Efficiency
Authors: Imhoff Jamie , Parmer Don , Ronck Ben , Smith Kenny , Yuan Yusheng 
Published: October 2009

Abstract
After cementing a new liner section during wellbore construction, the liner wiper plugs and landing collar must be drilled out to proceed with the next well section. Current conventional aluminum systems produce considerable resistance and wear to drilling equipment resulting in increased effort and time to drill out the components. The conventional aluminum tools are typically drilled out in 4 to 16 hours.
This paper discusses the development, laboratory testing, and field testing of composite liner wiper plug systems for two-plug and four-plug applications that dramatically reduce standard drill-out times, ease the development path for future plug designs, and open doors for other drillable products. The composite liner wiper plug systems include running tools, liner wiper plugs, pump-down plugs, and landing collars that perform multiple functions during the liner cementing process. In addition to the cost savings associated with reduced drill-out times, the systems provide wellbore fluid isolation for cementing integrity, reliable fluid displacement, high-pressure and high-temperature performance, positive bump indication, clear flow paths for setting ball compatibility, and special contingency backups.
The composite material needed excellent drillable properties without compromising performance and reliability. The lab results matched the ratings of conventional plugs and landing collars. The systems have completed many successful runs and are gaining favorable reception from our customers and operations personnel. With drill-out times of less than one hour, these initial results represent a significant reduction in rig time and operational costs, adding savings and value to the completion solution.
Significant Improvement in the Accuracy of Pressure Transient Analysis Using Total Least Squares
Authors: Dastan Aysegul , Horne Roland N. 
Published: October 2009

Abstract
In this study we show significant improvements over conventional pressure transient analysis based on nonlinear regression, by using total least squares (TLS). The TLS algorithm we have developed estimates reservoir parameters by minimizing errors in both pressure and time simultaneously. Our technique is in contrast to other approaches that also have been named TLS but which considered errors in flow rates and pressures simultaneously, rather than errors in time.
TLS regression, which is based on minimization of orthogonal distances of measured data points to the fitted curve, is not an easy problem to solve mathematically, especially for nonlinear pressure transient model functions. To our knowledge, TLS has not been applied to pressure transient analysis before in this sense. In our work, we formulated a robust approximation of the TLS solution, which can handle a variety of tests and reservoir models yet does not compromise the performance of the analysis. We used our TLS algorithm on various different reservoirs and transient tests successfully, including dual-porosity and fractured reservoirs, reservoirs with rectangular boundaries, cyclic buildup-drawdown tests, and general multirate data. We show that our technique reduces ambiguity in the estimation of parameters to a large extent, especially in the presence of noise. Using our TLS algorithm we obtained much narrower confidence intervals on the parameter estimates compared to the regular least squares approach used conventionally today.
In this paper we compare four different versions of total least squares: (1) errors in time and pressure (horizontal error and vertical error) summed in the same objective function; (2) orthogonal distance regression in linear p vs. linear t, (3) orthogonal distance regression in linear p vs. log t, (4) orthogonal distance regression in log p vs. log t. We have observed much greater robustness against noise in the estimation of reservoir parameters. In the presence of errors in pressure only, the confidence intervals were at least as good as regular least squares. However, in the presence of errors in time in addition to pressure, the performance of TLS algorithms was substantially better. On a variety of both real and synthetic data sets, we have observed much narrower confidence intervals on the estimated parameters, even for large noise. For synthetic data sets, we observed that the reservoir parameter estimates from TLS are often closer to the true values than estimates made with conventional least squares, especially for poorly determined problems. We therefore expect that our technique will provide more accurate estimation of reservoir parameters, allowing for better forecasting of reservoir performance.
Geomechanical Risk Mitigation for CO2 Sequestration in Saline Aquifers
Authors: Tran David , Shrivastava Vijay , Nghiem Long , Kohse Bruce 
Published: October 2009

Abstract
Saline aquifers are the most promising target for underground CO2 sequestration since they have the largest capacity compared to other possible locations, for example coal seams or depleted gas and oil fields. One of the major risks associated with sequestration in aquifers is the potential leakage of CO2 through cap rock and overburden leading to escape of CO2 into shallow potable aquifers or to the atmosphere. Factors responsible for rock failure need to be investigated before starting a CO2 injection program to avoid potential leakage problems.
This paper presents a novel approach for assessing and mitigating the risk of CO2 leakage caused by geomechanical effects. An equation-of-state compositional and GHG (Green-House Gas) simulator has been modified to incorporate iterative coupling with an in-house geomechanical code (geomechanics module). The coupled model is used to predict possible leakage events during an injection process. The following steps are taken to solve the problem: The reservoir simulator computes the amount of CO2 dissolution and flow in the formation, geochemical reactions, and changes in pressure, temperature and compositions.Based on the values of pressure and temperature at the end of every time step, the geomechanics module computes stress change and deformation in the formation and its surroundings to determine if and where rock failure might occur.A Barton-Bandis model is used to simulate opening and closing of fractures in the cap or country rock due to development of stresses caused by high injection pressure.
Example cases are presented to demonstrate the workflow and to show how injection scenarios may be altered to mitigate the risk of leakage. Both isothermal and non-isothermal situations are examined.
Automatic Detection of Pressure-Buildup Intervals From Permanent Downhole Pressure Data Using Filter Convolution
Authors: Suzuki Satomi , Chorneyko David 
Published: October 2009

Abstract
The availability of permanent downhole pressure data has become a rich source of information for reservoir surveillance and production optimization. Permanent downhole gauges continuously provide near real-time data without well intervention. The data can lead to timely and proactive reservoir surveillance and management decisions if effectively utilized. However, challenges lie in processing and analyzing the overwhelming volume of data. The development of tools and software for automatic data processing will facilitate interpretation and application of the data from permanent downhole gauges.
Pressure transient analysis from permanent downhole pressure data is an example of such an application. By analyzing pressure buildup behavior observed during unintentional shut-ins of wells, engineers can frequently develop insight into reservoirs without conducting scheduled buildup tests. However, manual identification and selection of each pressure buildup interval for analysis is often a time-consuming and labor intensive job as the amount of pressure data can amount to millions of sets of information. This time and effort often precludes the acquired data from being utilized. The problem has already been realized in the industry and some software offers the capability to automatically detect buildup intervals from continuous pressure data. The issue is the robustness and tolerance of detection methods to noisy data.
This paper proposes a new method to automatically detect pressure buildup intervals from permanent downhole pressure data. The buildup intervals are detected by convolving a filter with permanent gauge data. The filter is designed to detect a particular pattern of pressure response rather than merely to detect a frequency change. Also, it can be easily combined with noise-removal filters. These features of the method enhance the tolerance to noise. The method is demonstrated through the application to real data. An example of field application is also presented.
Combined Risk Allele Score of Eight Type 2 Diabetes Genes Is Associated With Reduced First-Phase Glucose-Stimulated Insulin Secretion During Hyperglycemic Clamps
Authors: ‘t Hart Leen M. , Simonis-Bik Annemarie M. , Nijpels Giel , van Haeften Timon W. , Schäfer Silke A. , Houwing-Duistermaat Jeanine J. , Boomsma Dorret I. , Groenewoud Marlous J. , Reiling Erwin , van Hove Els C. , Diamant Michaela , Kramer Mark H.H. , Heine Robert J. , Maassen J. Antonie , Kirchhoff Kerstin , Machicao Fausto , Häring Hans-Ulrich , Slagboom P. Eline , Willemsen Gonneke , Eekhoff Elisabeth M. , de Geus Eco J. , Dekker Jacqueline M. , Fritsche Andreas 
Published: October 2009

OBJECTIVE
At least 20 type 2 diabetes loci have now been identified, and several of these are associated with altered β-cell function. In this study, we have investigated the combined effects of eight known β-cell loci on insulin secretion stimulated by three different secretagogues during hyperglycemic clamps.

RESEARCH DESIGN AND METHODS
A total of 447 subjects originating from four independent studies in the Netherlands and Germany (256 with normal glucose tolerance [NGT]/191 with impaired glucose tolerance [IGT]) underwent a hyperglycemic clamp. A subset had an extended clamp with additional glucagon-like peptide (GLP)-1 and arginine (n = 224). We next genotyped single nucleotide polymorphisms in TCF7L2, KCNJ11, CDKAL1, IGF2BP2, HHEX/IDE, CDKN2A/B, SLC30A8, and MTNR1B and calculated a risk allele score by risk allele counting.

RESULTS
The risk allele score was associated with lower first-phase glucose-stimulated insulin secretion (GSIS) (P = 7.1 × 10−6). The effect size was equal in subjects with NGT and IGT. We also noted an inverse correlation with the disposition index (P = 1.6 × 10−3). When we stratified the study population according to the number of risk alleles into three groups, those with a medium- or high-risk allele score had 9 and 23% lower first-phase GSIS. Second-phase GSIS, insulin sensitivity index and GLP-1, or arginine-stimulated insulin release were not significantly different.

CONCLUSIONS
A combined risk allele score for eight known β-cell genes is associated with the rapid first-phase GSIS and the disposition index. The slower second-phase GSIS, GLP-1, and arginine-stimulated insulin secretion are not associated, suggesting that especially processes involved in rapid granule recruitment and exocytosis are affected in the majority of risk loci.
Attenuated Purinergic Receptor Function in Patients With Type 2 Diabetes
Authors: Thaning Pia , Bune Laurids T. , Hellsten Ylva , Pilegaard Henriette , Saltin Bengt , Rosenmeier Jaya B. 
Published: October 2009

OBJECTIVE
Extracellular nucleotides and nucleosides are involved in regulation of skeletal muscle blood flow. Diabetes induces cardiovascular dysregulation, but the extent to which the vasodilatatory capacity of nucleotides and nucleosides is affected in type 2 diabetes is unknown. The present study investigated 1) the vasodilatatory effect of ATP, uridine-triphosphate (UTP), and adenosine (ADO) and 2) the expression and distribution of P2Y2 and P2X1 receptors in skeletal muscles of diabetic subjects.

RESEARCH DESIGN AND METHODS
In 10 diabetic patients and 10 age-matched control subjects, leg blood flow (LBF) was measured during intrafemoral artery infusion of ATP, UTP, and ADO, eliciting a blood flow equal to knee-extensor exercise at 12 W (∼2.6 l/min).

RESULTS
The vasodilatatory effect of the purinergic system was 50% lower in the diabetic group as exemplified by an LBF increase of 274 ± 37 vs. 143 ± 26 ml/μmol ATP × kg, 494 ± 80 vs. 234 ± 39 ml/μmol UTP × kg, and 14.9 ± 2.7 vs. 7.5 ± 0.6 ml/μmol ADO × kg in control and diabetic subjects, respectively, thus making the vasodilator potency as follows: UTP control subjects (100) &gt; ATP control subjects (55) &gt; UTP diabetic subjects (47) &gt; ATP diabetic subjects (29) &gt; ADO control subjects (3) &gt; ADO diabetic subjects (1.5). The distribution and mRNA expression of receptors were similar in the two groups.

CONCLUSIONS
The vasodilatatory effect of the purinergic system is severely reduced in type 2 diabetic patients. The potency of nucleotides varies with the following rank order: UTP &gt; ATP &gt; ADO. This is not due to alterations in receptor distribution and mRNA expression, but may be due to differences in receptor sensitivity.
ATP-Sensitive K+ Channel Mediates the Zinc Switch-Off Signal for Glucagon Response During Glucose Deprivation
Authors: Slucca Michela , Harmon Jamie S. , Oseid Elizabeth A. , Bryan Joseph , Robertson R. Paul 
Published: October 2009

OBJECTIVE
The intraislet insulin hypothesis proposes that glucagon secretion during hypoglycemia is triggered by a decrease in intraislet insulin secretion. A more recent hypothesis based on in vivo data from hypoglycemic rats is that it is the decrease in zinc cosecreted with insulin from β-cells, rather than the decrease in insulin itself, that signals glucagon secretion from α-cells during hypoglycemia. These studies were designed to determine whether closure of the α-cell ATP-sensitive K+ channel (KATP channel) is the mechanism through which the zinc switch-off signal triggers glucagon secretion during glucose deprivation.

RESEARCH DESIGN AND METHODS
All studies were performed using perifused isolated islets.

RESULTS
In control experiments, the expected glucagon response to an endogenous insulin switch-off signal during glucose deprivation was observed in wild-type mouse islets. In experiments with streptozotocin-treated wild-type islets, a glucagon response to an exogenous zinc switch-off signal was observed during glucose deprivation. However, this glucagon response to the zinc switch-off signal during glucose deprivation was not seen in the presence of nifedipine, diazoxide, or tolbutamide or if KATP channel knockout mouse islets were used. All islets had intact glucagon responses to epinephrine.

CONCLUSIONS
These data demonstrate that closure of KATP channels and consequent opening of calcium channels is the mechanism through which the zinc switch-off signal triggers glucagon secretion during glucose deprivation.
Many Americans Have Pre-Diabetes and Should Be Considered for Metformin Therapy
Authors: Rhee Mary K. , Herrick Kirsten , Ziemer David C. , Vaccarino Viola , Weintraub William S. , Narayan K.M. Venkat , Kolm Paul , Twombly Jennifer G. , Phillips Lawrence S. 
Published: October 2009

OBJECTIVE
To determine the proportion of the American population who would merit metformin treatment, according to recent American Diabetes Association (ADA) consensus panel recommendations to prevent or delay the development of diabetes.

RESEARCH DESIGN AND METHODS
Risk factors were evaluated in 1,581 Screening for Impaired Glucose Tolerance (SIGT), 2,014 Third National Health and Nutrition Examination Survey (NHANES III), and 1,111 National Health and Nutrition Examination Survey 2005–2006 (NHANES 2005–2006) subjects, who were non-Hispanic white and black, without known diabetes. Criteria for consideration of metformin included the presence of both impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), with ≥1 additional diabetes risk factor: age &lt;60 years, BMI ≥35 kg/m2, family history of diabetes, elevated triglycerides, reduced HDL cholesterol, hypertension, or A1C &gt;6.0%.

RESULTS
Isolated IFG, isolated IGT, and IFG and IGT were found in 18.0, 7.2, and 8.2% of SIGT; 22.3, 6.4, and 9.4% of NHANES III; and 21.8, 5.0, and 9.0% of NHANES 2005–2006 subjects, respectively. In SIGT, NHANES III, and NHANES 2005–2006, criteria for metformin consideration were met in 99, 96, and 96% of those with IFG and IGT; 31, 29, and 28% of all those with IFG; and 53, 57, and 62% of all those with IGT (8.1, 9.1, and 8.7% of all subjects), respectively.

CONCLUSIONS
More than 96% of individuals with both IFG and IGT are likely to meet ADA consensus criteria for consideration of metformin. Because &gt;28% of all those with IFG met the criteria, providers should perform oral glucose tolerance tests to find concomitant IGT in all patients with IFG. To the extent that our findings are representative of the U.S. population, ∼1 in 12 adults has a combination of pre-diabetes and risk factors that may justify consideration of metformin treatment for diabetes prevention.
Postprandial Vascular Effects of VIAject Compared With Insulin Lispro and Regular Human Insulin in Patients With Type 2 Diabetes
Authors: Forst Thomas , Pfützner Andreas , Flacke Frank , Krasner Alan , Hohberg Cloth , Tarakci Eda , Pichotta Philip , Forst Senait , Steiner Solomon 
Published: October 2009

OBJECTIVE
Recent studies suggested an impact of prandial insulin delivery on postprandial regulation of tissue blood flow. This study compared the effect of VIAject with human regular insulin and insulin lispro on postprandial oxidative stress and endothelial function in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS
Fourteen patients (seven men; aged 61.5 ± 1.8 years; duration of diabetes 6.6 ± 4.6 years; A1C 7.2 ± 0.5% [mean ± SEM]) received a prandial injection of VIAject, human regular insulin, and insulin lispro. At baseline and after a standardized liquid meal test (Ensure Plus), the postprandial increases in asymmetric dimethylarginine (ADMA) and nitrotyrosine levels were investigated. In addition, the postprandial effects on microvascular blood flow, skin oxygenation, and vascular elasticity were measured.

RESULTS
Treatment with VIAject resulted in a significant reduction in the peak postprandial generation of ADMA compared with human insulin and insulin lispro (VIAject −27.3 ± 22.6, human insulin 97.7 ± 24.4, and insulin lispro 66.9 ± 33.9 nmol/l; P &lt; 0.05, respectively). The postprandial increases in nitrotyrosine levels were significantly less after VIAject than after human regular insulin (VIAject −0.22 ± 0.17 vs. human insulin 0.25 ± 0.15 μg/ml; P &lt; 0.05), whereas nitrotyrosine after insulin lispro was in between (insulin lispro 0.09 ± 0.07 μg/ml; NS). In parallel, earlier and more pronounced increases in microvascular blood flow and skin oxygenation were obtained after VIAject compared with those after human insulin or insulin lispro (P &lt; 0.05, respectively). All insulin formulations resulted in comparable improvements in central arterial elasticity.

CONCLUSIONS
Treatment with VIAject reduced postprandial oxidative stress and improved endothelial function compared with human regular insulin or insulin lispro.
Psychometric Findings for a Spanish Translation of the Diabetes Self-Management Profile (DSMP-Parent-Sp)
Authors: Valenzuela Jessica M. , Fernandez Michelle Castro , Hsin Olivia , Harris Michael A. , Taylor Cortney , La Greca Annette M. , Delamater Alan M. 
Published: October 2009

OBJECTIVE
Few validated measures exist to evaluate self-management of diabetes in families with limited English proficiency. The present study evaluated the psychometric properties and the factorial equivalence of a Spanish translation of the parent report version of the Diabetes Self-Management Profile (DSMP-Parent-Sp).

RESEARCH DESIGN AND METHODS
Hispanic families of youth (mean 13.7 years old) with type 1 diabetes were recruited from three clinics in South Florida and represented a wide range of nationalities and acculturation levels. A total of 127 parents reported on their child's self-management behaviors using either the original DSMP-Parent (59.8%) or the DSMP-Parent-Sp (40.2%). In addition, youth reported their self-management using the original DSMP in English, and physicians rated their perceptions of the youth's self-management. Glycemic control was indexed by A1C in the past 3 months and collected from medical chart review.

RESULTS
Item analysis confirmed that the DSMP-Parent-Sp items related to the overall composite score in expected ways, and internal consistency estimates were adequate. Paired correlations demonstrated strong parent-child concordance and a significant relationship with physician perceptions of self-management. Evidence of concurrent and convergent validity, as well as “strict factorial invariance,” was demonstrated.

CONCLUSIONS
These preliminary findings indicate that the DSMP-Parent-Sp is a reliable and valid parent report measure of the diabetes self-management behaviors of Hispanic youths. In addition, there is preliminary evidence that the translated measure may be considered equivalent to the original English measure when used to measure self-management in Hispanic youth with diabetes.