bluuebunny/crossref_metadata_2025_split huggingface dataset:
When a Good History-Matched Model Results in a Bad Forecast; Question your Petrophysical Data
Authors: Qutob Hani H. , Khlaifat Abdelaziz , Efnik Mohamed S. 
Published: September 2013

Abstract
When implementing any field development plan or an Enhanced Oil Recovery (EOR) project, it is critical to understand the key variables that influence the success of the plan such as; reservoir parameters and fluid properties. Mature Oil & Gas fields' increasing complexity of recovery mechanisms dictates an improved understanding of the fields' behaviour and the technologies that must be applied to maintain and prolong oil production plateau and achieve ultimate recovery potential.
History matching forms an integral part of the reservoir modeling workflow process. It is used to examine the field performance under different production and injection scenarios in order to select the best scenario for hydrocarbon production. However, the history-matching process can be very frustrating and time-consuming, even for fields that appear relatively small and simple in nature, because of the reservoir processes involved and the non-unique nature of the solution.
Traditionally, history matching is conducted as a deterministic process with a single realization considered representative at a single point in time. Although, the input data usually go through a data analysis process where the major uncertainties and scenarios are defined, and uncertainty ranges are created, time and budget constraints usually result in significant reductions in the number of sensitivity runs and analysis for the input data validation and quality control that results in an incomplete investigation of the uncertainty quantification. Therefore, uncertainties inherited in the Petrophysical data are carried from the static model construction throughout the entire dynamic modelling process, ultimately leading to less-than-optimal models to be used as a decision making tool.
Consequently, due to the non-uniqueness of the numerical solution, a good history-matched model might have geological and petrophysical properties quite far from those of the "Field" and therefore could lead to a bad forecast. As in any numerical model, petrophysical data quality is fundamental for model precision.
Revealing Relative Permeability Uncertainties through Integrated Experimental and Modeling Workflow
Authors: Yaslam Maged , Ghedan Shawket G. , Kalam Zubair 
Published: September 2013

Abstract
Relative permeability profile is one of the most uncertain parameters and challenging requirements in field performance models. It is a mandatory element for multi-phase flow calculations and has a significant impact on development schemes, expected hydrocarbon recovery factor and the related revenues. Moreover, it impacts the surface facilities decision based on predicted produced fluids and recycling requirements, which might affect the economics of any related projects. Accordingly, obtaining representative relative permeability profile is a historical continuous challenge in the industry through common laboratory methods of steady state and unsteady state along with other numerical modeling approaches.
Experimental relative permeability profiles using both methods of steady state and unsteady state have been obtained for one of the main reservoir rock types (RRT A) from a giant carbonate field in the Middle East. Comprehensive characterization and detailed numerical modeling for mixed wettability carbonates at full reservoir conditions has been studied covering all the details of rock properties, capillary pressure coupled with relative permeability profiles. The analysis revealed the uncertainty associated with each measurement method and surprisingly the limited data range of unsteady state method. Moreover, for the selected reservoir rock types, non-unique relative permeability profiles have been obtained using various experimental approaches and empirical correlations within the numerical modeling process in which different produced relative permeability profiles matched reasonably the laboratory reference measurements.
The resultant relative permeability profiles associated with uncertainty range presented in this paper has shown the significant influence of the measurement method selection, which impact the dynamic simulation models predictions and the eventually field development options. This work provides insight on experimental methods selection and optimum conditions to acquire representative relative permeability profiles with emphasis on possible sources of uncertainties and errors. It clearly demonstrates the relative permeability accuracy levels of various numerical modeling processes and the potential of non-unique profiles which dictate the reservoir dynamics, performance as well as economics.
Use of Digital Imaging for Improved Evaluation of Unconventional Reservoirs
Authors: Dixon Michael , Newton Barry , Schwartz Angela , Smart Erin , Hooghan Kultaransingh (Bobby) 
Published: September 2013

Abstract
Formation evaluation of rock material from unconventional reservoirs is challenging due to the rock's typically heterogeneous nature and low permeability. Measurements and descriptions of the pore network in shale/mudstone are especially difficult due to variations in mineralogy, texture and pore size. In the digital rock domain, high resolution imaging of core can be obtained from the meter to nanometer size range to create respective 3D models. Data obtained with these techniques can be integrated with other core analysis data (i.e. geochemistry, petrology, mechanical properties) to provide expanded modeling capabilities for integrated core studies of unconventional reservoirs.
This paper describes how an integrated imaging/sampling protocol serves to characterize unconventional reservoirs across a broad size range. High resolution digital imaging data derived from Helical Computed Tomography (HCT) and micro-CT captures meter- to millimeter-sized features, while Field Emission Scanning Electron Microscopy (FE-SEM), and Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) provide the means to characterize the rock fabric and pore network on a sub-micron (&lt;nm) level. For this study, a 4-inch diameter core from a proprietary well in the Middle East was submitted to Weatherford Laboratories in Houston, Texas, for analysis.
Sections of core were first imaged/analyzed using HCT. Based on observations from HCT images, samples were subsequently selected for micro-CT, FE-SEM, and FIB-SEM. Though the HCT images were also used to select data points for traditional core analysis (i.e. thin section petrography, X-ray diffraction, geochemistry, etc.), those data sets will be presented at a later date, and the focus of this paper is the use of digital imaging to characterize selected samples. The resulting images and accompanying data sets acquired in this study illustrate how digital imaging methodologies can be used to characterize the controls on reservoir quality (including depositional fabrics, structural relatioinships, diagenetic relationships, and the pore network), and ultimately lead to a better understanding of well performance in unconventional reservoirs.
NAVILAS Laser System Focal Laser Treatment for Diabetic Macular Edema - One Year Results of a Case Series
Authors: Jung Jesse J. , Gallego-Pinazo1 Roberto , Lleó-Pérez Antonio , Huz Jonathan I. , Barbazetto Irene A. 
Published: September 2013

Purpose:To report one year outcomes of focal Navigated Retina Laser Therapy (NAVILAS) for diabetic macular edema (DME).Methods:Retrospective cohort series of 7 diabetic patients treated with NAVILAS focal laser. Statistical analysis included descriptive and continuous variables (Best-corrected logMAR Visual Acuity and time-domain optical coherence tomography (OCT) parameters) which were compared using a non-parametric procedure, the Friedman tests for repeated measures. A p-value of less than 0.05 was considered to denote statistical significance.Results:diabetic patients (4 male; 3 female) with an average age of 60.8 years (range 48-85 years) were included. All treated eyes were phakic; patients had an average hemoglobin A1C of 9.1 (range 7.8-11.7) at baseline and 8.0 (range 7.4-8.4) at 12 months. Six of the 7 patients had intravitreal bevacizumab injections prior to focal laser treatment with 1 patient having had more than 1 prior injection (total 3). At 12 months, median logMAR improved from 0.695 (± interquartile range 0.574) to 0.477 (± 0.573, p <0.001). OCT median central foveal thickness decreased from 248 (± 112) to 220 µm (± 41, p <0.001); total macular volume decreased from 7.84 (± 0.8) to 7.44 mm3 (± 0.7, p = 0.117); and largest macular subfield thickness decreased from 354 (± 116) to 289 µm (± 42, p <0.001). All patients were treated without complications.Conclusions:Focal NAVILAS showed to be safe and effective in treating DME with improvement in visual acuity and macular edema on OCT over 12 months in this case series. In clinical practice, combined treatment with focal laser including NAVILAS and anti-vascular endothelial growth factor may provide long-term improvement in DME.
Modulation of Fatty Acid Metabolism by Glucagon in Man: IV. Effects of a Physiologic Hormone Infusion in Normal Man
Authors: Schade David S , Eaton R Philip 
Published: September 2013

This study was done to explore the role of physiologic elevations of glucagon concentration in plasma ketone body concentration in normal man. During the period of hormone elevation, plasma free fatty acids were pharmacologically elevated to ensure adequate free fatty acid substrate delivery to the liver to support hepatic ketogenesis.
Eighty-minute infusions of glucagon resulted in a plasma hormone concentration of ∼ 300 pg./ml. During the infusion, ketone bodies declined from their basal concentration and remained below basal for the duration of the infusion. An acute heparin-induced pharmacologic elevation of plasma free fatty acid concentration resulted in a transient rise in plasma ketone body concentration, but at no time did it attain the concentration observed during the control saline infusion. Plasma glucose concentration was not altered by glucagon infusion, but plasma insulin concentration rose by ∼ 2.5 μU./ml.
These results suggest that glucagon is not ketogenic in normal man as has been previously reported in insulin-deficient diabetics. The glucagon-induced rise in plasma insulin concentration may participate in the observed reduction in plasma ketone body concentration.
Glucose and Insulin Responses to Diet: Effect of Variations in Source and Amount of Carbohydrate
Authors: Thompson Robert G , Hayford John T , Danney Mark M 
Published: September 2013

The influence of variations in amount of carbohydrate in the diet (45 per cent or 65 per cent of total calories) and source (sucrose or corn syrup) on plasma insulin and glucose concentrations was evaluated in eight normal men. Four diets, which were alternated in a Latin square design, were consumed for 10 days. Plasma glucose and insulin concentrations were measured during an oral glucose tolerance test and over a 24-hour period while the test diets were consumed. The 24-hour study was completed with a portable, constant withdrawal pump, which allowed samples to be collected as a series of 48 consecutive, integrated, 30-minute samples. Thus, the 24-hour mean, or integrated, concentration as well as fluctuations during the day could be determined.
The 24-hour integrated concentration of glucose did not vary significantly with the dietary changes tested. In contrast, two of the three methods used, to evaluate the glucose tolerance test results indicated that high carbohydrate diets improve glucose tolerance. Glucose fluctuations were significantly greater during ingestion of diets containing corn syrup than during those containing sucrose. The percentage of dietary energy supplied as carbohydrate did not influence glucose fluctuations significantly.
Diets containing corn syrup were associated with significantly higher integrated concentrations of insulin than the sucrose diets. Insulin-integrated concentrations did not vary significantly with changes in the percentage of dietary carbohydrate. The insulin response to the glucose tolerance test did not vary with the source of carbohydrate and did not accurately reflect the 24-hour mean insulin concentrations.
We concluded that (1) a change in the percentage of energy supplied as carbohydrate does not significantly influence the concentration of either glucose or insulin in normal subjects; (2) concentrations of glucose throughout the day are more stable when the dietary carbohydrate is sucrose than when it is corn syrup; (3) sucrose-containing diets require significantly lower insulin concentrations to maintain euglycemia than do corn syrup–containing diets; (4) glucose and insulin responses to an oral glucose tolerance test do not accurately reflect the 24-hour glucose and insulin concentrations obtained during ingestion of the test diets.
Glycogen Synthase, Synthase Phosphatase, and Phosphorylase Response to Glucose in Somatostatin-Pretreated Intact Rats
Authors: Mulmed Lawrence N , Gannon Mary C , Gilboe Daniel P , Tan Agnes W H , Nuttall Frank Q 
Published: September 2013

The response of the glycogen synthase and phosphorylase systems of the liver to intravenous glucose in the presence and absence of short-term somatostatin blockade of insulin secretion was determined in fed and 20-h fasted rats. These enzyme systems regulate glycogen synthesis and degradation, respectively. In the presence of somatostatin, intravenous glucose (1.0 g/kg), promptly (5 min) increased the proportion of synthase in the I (active) form, and the increase was similar to that in animals that had not received somatostatin. In the same animals, phosphorylase a also was decreased, and the decrease was similar in all groups. When a smaller dose of glucose (250 mg/kg) was used that only modestly increased plasma glucose (139 mg/dl) and produced a less than maximal synthase response, insulin (1 U/kg) did not potentiate glucose activation of synthase either in the presence or absence of somatostatin. Phosphorylase a did not change significantly in any group.
Glucose, in both the presence and absence of somatostatin, also rapidly (2 min) converted synthase phosphatase from a form inhibited by EDTA to a form not inhibited by EDTA.
These data indicate that the synthase and phosphorylase systems in vivo respond primarily to a rise in plasma glucose and not to a simultaneous elevation in plasma insulin. Thus, glucose is regulating its own storage as glycogen in the liver. The effect of glucose on the synthase may be mediated through a conversion of the synthase phosphatase to a form that is not dependent on divalent cation for activity. This form presumably is more active in vivo.
A Different Action of Hypothermia on Insulin Release from the Isolated, Perfused Rat Pancreas, Depending on the Stimulating Agent
Authors: Loubatieres-Mariani M M , Chapal J , Puech R , Manteghetti M 
Published: September 2013

SUMMARY
Two series of experiments were performed in parallel on the isolated perfused rat pancreas. The experimental conditions differed only as pertaining to temperature. In one series the organ and the perfusion liquid were maintained at 37.5°C and in the other at 28°C. The pancreases were perfused from the start of the experiments with a perfusion medium containing 8.3 mmol/l glucose. The effects of various stimulatory agents were studied (glucose 16.6 mmol/l, tolbutamide 0.4 mmol/l, acetylcholine 0.5 μmol/l, glucagon, 2.8 nmol/l, and L-isoprenaline 0.05 μmol/l). At 37.5°C the insulin secretion induced by high glucose or tolbutamide, acetylcholine, and glucagon was biphasic and not statistically different. In all cases the hypothermia (28°C) decreased insulin secretion. However, glucoseinduced and tolbutamide-induced insulin secretion was more decreased than the secretion induced by acetylcholine and glucagon. The study of the secretion ratios obtained at 28°C relative to 37.5°C showed that the ratios for the glucose and tolbutamide groups were significantly lower than those obtained for acetylcholine and glucagon gsroups for both the first and the second phase. The ratios were not significantly different between glucose and tolbutamide on the one hand and acetylcholine and glucagon on the other hand. In all groups the ratios 28°/37.5° for the second phase were lower than those obtained during the first phase. L-isoprenaline induced only a weak increase in insulin secretion and this was not long lasting; this increase was not statistically different at both temperatures.
Measurement of Glycosylated Amino Acids and Peptides from Urine of Diabetic Patients Using Affinity Chromatography
Authors: Brownlee Michael , Vlassara Helen , Cerami Anthony 
Published: September 2013

An affinity chromatography system has been developed that retains glycosylated amino acids and peptides. Using this system, synthetic 14C-glycosylated lysine (reduced with NaB3H4) was completely separated from a mixture of reduced 14C-glycosylated lysine and unmodified 3H-lysine. Amino acid analysis of the retained peak from hydrolyzed human diabetic hemoglobin previously reduced with NaB3H4 revealed an equimolar mixture of glycosylated valine and glycosylated lysine, in agreement with previously published data obtained using other methodologies. These data demonstrate that in alkaline solution, the NaB3H4-reducible breakdown products of nonenzymatically glycosylated proteins are adsorbed to m-aminophenyl boronic acid immobilized on Bio-Gel P-6, while nonglycosylated amino acids are not. This affinity chromatography system should facilitate the rapid evaluation of nonenzymatic glycosylation in a large number of diabetic tissues.
Levels of retained compounds in urine from diabetic and normal patients were determined by measuring ninhydrin-positive material. Amino acid analysis of NaB3H4-reduced hydrolysates of these peaks showed that glycosylated lysine was the major borohydride-reducible adduct present (67%–86%). Linear regression analysis showed that the quantity of excreted compounds in normals correlated with body weight (r = 0.63). The mean level (μmol leucine-equivalent/ 24 h/kg body weight) in diabetics was over 1.5 times that found in urine from normal subjects (P &lt; 0.005).
Effects of Acute Changes in Blood Glucose on HbA1c
Authors: Goldstein David E , Peth Steven B , England Jack D , Hess Randall L , Costa Jose Da 
Published: September 2013

SUMMARY
Although hemoglobin A1c (HbA1c) is generally considered to be an accurate index of long-term blood glucose regulation, several recent studies suggest that HbA1c may be acutely responsive to changes in blood glucose. We have examined the effects of acute changes in glucose concentration in vivo and in vitro on HbA1c. HbA1c was measured by a high-performance liquid chromatography (HPLC) method. HbA1c and plasma glucose were measured in seven diabetic patients and five control subjects before and 2 h after a standard breakfast. Only diabetic patients showed increases in HbA1c and plasma glucose values 2 h after the test meal (Δ HbA1c = 0.87 ± 0.24% and Δ glucose = 210 ± 0.33 mg/dl). The increment in HbA1c correlated significantly with the increment in plasma glucose (r = 0.73, P &lt; 0.05). to examine the lability of these postmeal increments in HbA1c, erythrocytes from pre- and postmeal blood samples were incubated in 0.9% NaCl for 5 h at 37°C and HbA1c was re-measured. After saline incubations %HbA1c in pre- and postmeal blood samples decreased in both diabetics and controls, and from each subject time 0 and 2-h HbA1c values were nearly identical. HbA1c was then measured before and after incubations of erythrocytes from a larger group of diabetic patients (N = 55) and control subjects (N = 7). In both diabetic and control cells HbAlc decreased after saline incubations. Pre- and post-saline HbA1c values in diabetics were (means ± SEM) 10.07 ± 0.30% and 9.15 ± 0.27%, respectively; values in controls were 5.87 ± 0.11% and 5.46 ± 0.09%, respectively. The mean decrement in HbA1c was significantly greater in cells from diabetics than from controls (P &lt; 0.001). In diabetics the HbA1c decrement correlated with both plasma glucose (r = 0.58, P &lt; 0.001) and the preincubation HbA1c (r = 0.55, P &lt; 0.001). After dialysis of hemolysates for 5 h at 37°C or 48–72 h at 4°C, HbA1c values showed decreases comparable to those after saline incubations of intact erythrocytes. However, decreases in HbA1c after dialysis were accompanied by increases in HbA1a+b, findings that were not observed after saline incubation. The results suggest that HbA1c exists in two chromatographically indistinguishable forms: one that represents the major portion of HbA1c in normals and diabetics, is not altered by short-term changes in plasma glucose, and can be estimated by measuring HbA1c after saline incubation of erythrocytes; and a second form that is responsive to short-term fluctuations of the blood glucose level. These labile and stable fractions may be identical to the labile Schiff-base and stable ketoamine forms of HbA1c, which have been previously described. For HbA1c to be an accurate indicator of long-term glucose control, saline incubation of erythrocytes or perhaps dialysis of hemolysates before HbA1c assay may be necessary. Otherwise the assay results will reflect recent changes in blood glucose levels.
Glucose Transport Across Ocular Barriers of the Streptozotocin-Diabetic Rat
Authors: Dimattio Joseph , Altszuler Norman , Ellis Steven , Zadunaisky José A 
Published: September 2013

The transport kinetics across the plasma-aqueous and plasma-vitreous barriers were studied in normal and long-term streptozotocin-diabetic rats, using trace amounts of [14C]-L-glucose and [3H]-3-O-methyl-D-glucose. The former is passively transported while the latter uses the same transport-facilitating system as D-glucose. Transport rates of L-glucose were significantly higher in the diabetic rats, with ocular entry rates from the plasma being increased by 69% across both barriers. Thus, the data indicate that in experimental diabetes the passive permeability of the bloodocular barriers is significantly increased.
By contrast, calculated transport rate constants for 3-O-methyl-O-glucose, when adjusted for the hyperglycemia and the increased passive glucose movement, are not altered in the diabetic animal. Nevertheless, there is actually more mass D-glucose movement due to the prevailing hyperglycemia. The present study suggests that although streptozotocin diabetes alters plasma-ocular glucose transport, there is no direct impairment of glucose carrier function.
Alterations in transport occurred at both ocular barriers, suggesting that involvement is general and that both the retinal pigment epithelium and the ciliary epithelium may be affected by the diabetes. It is unknown whether the increase in passive movement is related to the prevailing hyperglycemia or to insulin deficiency or other unknown factors.