bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Detection of Downward Flow of Water Behind Casing Using Oxygen Activation Technique in Inverted Mode
Authors: Akram Naveed , Ali Shahzad , Shaukat Bilal , Mughal Muhammad Haroon , Khidri Muzammil Ahmed , Rana Muhammad Shafique 
Published: January 2012

Abstract
It has been long recognized that using the conventional production logging tool in combination with the electrical probes measurement for water holdup can resolve the source identification of water inside the borehole. The source of water for single layer reservoir can be identified easily and can be complex for borehole involving multilayers and multiphase. The current limitations with the conventional production logging tool is that it covers the quantitative measurements inside borehole and to some extent qualitative measurement behind casing e.g. temperature profile.
The conditions get complex in the absence of cement behind casing and multiple pay zones behind the production casing and thus mixture profile tends to complicate the identification of phases within borehole. An alternative way to identify the hydraulic isolation between layers is to detect fluid movement directly behind the casing. Using a novel approach of Oxygen activation of water, the axial movements of water can be identified and quantified.
A Solid state neutron source in a stationary logging tool is first turned on activating the oxygen in the region near the wellbore, and then turned off. If the oxygen in stationary, decay is exponential and predictable. However, if flow is present, axial fluid movement transports some of the temporarily activated atomic oxygen in the water past three detectors where gamma ray count rate transient responses are recorded. Analysis of transients allows direct detection of water flow in annular space, a velocity measurement, and an estimate of the flow magnitude.
The case study presents oil producing well with two reservoirs started producing excessive amount of water. Where top reservoir was cement squeezed. The water producing zones across bottom reservoir was to be identified and to investigate if top reservoir contributing this water behind the liner. First time in Pakistan Oxygen activation technique with detectors at bottom (inverted mode) was utilized along with conventional production logging tool to resolve the source of water flowing downward behind casing.
Role of EWT in Declaration of Commerciality & Field Development
Authors: Rehman Zaghum Ur , Jozsef Tomics , Ahmed Nadeem 
Published: January 2012

Abstract
Every hydrocarbon discovery is not of commercial scale. Once a reservoir is discovered by drilling an exploration well with encouraging results with presence of hydrocarbons, an extended testing period starts to authenticate the in-place hydrocarbon volumes and deliverable rates and gain more knowledge on reservoir driving mechanism, heterogeneity, geometry, etc. which helps to make field development plan and hence the declaration of commerciality.
OMV Pakistan GmbH. has two discoveries in year 2007, Tajjal and Latif. Tajjal reservoir was discovered in May 2007 in Gambat Exploration License, whereas Latif was discovered in February 2007 in Latif Exploration License. Tajjal is located in south-east of Sawan gas field and Latif is in south-east of Miano gas field, operated by OMV GmbH. Both Tajjal and Latif wells were suspended for almost a year and half until gas pipelines laid from Tajjal and Latif to Sawan CPP and Kandwari CPP respectively for processing the raw gas. Couple of wells drilled in each discovery based on G&G input before start of EWT period as a part of field appraisal plan. In January 2009, extended well test (EWT), an extended testing period started to confirm the in-place volumes and instigate the field development plan for both the discoveries.
EWT is planned to acquire dynamic data for Tajjal & Latif, on average after every 3 months of production a flow after flow test & build-up data have been acquired for estimating reservoir pressure, permeability, type of aquifer & skin factors. Acquired reservoir pressure have substantially used for estimating Gas Initially In Place (GIIP).
Gas in-place estimates are made using EWT data by different techniques; P/Z plots, flowing material balance, analytical model, numerical model and well test evaluations. Results from these methods are reasonably comparable. A resolution will be drawn at the end of EWT phase regarding declaration of commerciality and hence full field development.
Hydraulic Fracturing in Gas Condensate Reservoirs: Successes, Setbacks and Lessons Learnt
Authors: Khan M. Noman , Siddiqui Fareed I. , Mansur Sheharyar , Ali Syed Dost 
Published: January 2012

Abstract
Hydraulic fracturing is being widely employed to augment wells’ productivity, thus facilitating proper depletion of the reservoir fluids and adding to the recoverable hydrocarbon reserves. The benefits of hydraulic fracturing are particularly pronounced in reservoirs exhibiting low permeability, high skin and, in case of gas condensate reservoirs, near wellbore condensate banking.
A gas condensate field, code name ‘Delta’, has been producing from sandstone reservoirs for the last two decades. Most of the wells have been suffering from low productivity primarily due to a relatively low reservoir permeability (0.5 to 10mD) and high drilling induced skin. The problem has become more pronounced with the depletion of reservoir pressure resulting in condensate drop out around the wellbore.
This paper details the envisioned economic incentives and the post-frac deliverability results from the recent hydraulic fracturing campaign carried out in a gas condensate field. The paper highlights the operational challenges encountered and the evolution of the hydraulic fracturing treatment design, execution and post-frac completion / flow-back strategy based on our experiences that contributed towards a successful and challenging campaign.
A Process for Safety and Environmental Excellence
Authors: Admire J. D. , Bradford R. A. 
Published: January 2012

Abstract
For a company to realize the highest levels of success, consistent performance must be maintained in the many elements that define "operating excellence". Employees and contractors involved in Alaska's oil and gas businesses will easily recognize that safety and environmental protection are core values in operating excellence and critical to a company's success.
Process oriented approaches, often used to guide a business toward continuous improvement in the elements of operating excellence, also have great potential to provide for improvements in safety and environmental programs. This paper outlines the Phillips Petroleum Company Process for Safety and Environmental Excellence (PSEE), which is used to guide the Company in its quest for continuous improvement in safety and environmental programs.
PSEE serves as a management tool to achieve the objectives of being the safest company in the industry, protecting the health of employees and the environment, and being recognized as a valued member of the community. The process establishes a foundation based on people, assets, and systems. Seventeen elements are defined to provide the framework which the Company's operating locations use to improve safety and environmental programs based on the risks at each location.
It is generally recognized that one key to a successful safety and environmental program is focussing on behaviors which lead to accidents, injuries, releases, and other unplanned incidents. The seventeen PSEE elements guide each operating location toward this focus and provide a planning process for continuous improvement.
Glucose Mass Transfer Under Substrate Inhibition Conditions in a Stationary Basket Bioreactor with Immobilized Yeast Cells
Authors: Galaction Anca Irina , Rotaru Roxana , Cascaval Dan 
Published: January 2012

The work is dedicated to the study on the external and internal mass transfers of glucose for alcoholic fermentation under glucose inhibition limitation using a bioreactor with stationary basket beds of immobilized Saccharomyces cerevisiae cells. By means of the substrate mass balance for a single particle of biocatalysts, considering the kinetic model adapted for the inhibitory effect of glucose, specific mathematical models have been developed for describing the profiles of the substrate concentration in the outer and inner regions of biocatalysts and, implicitly, for estimating its mass flows in the liquid boundary layer surrounding the particle and inside the particle. The values of the mass flows are significantly influenced by the internal diffusion velocity of substrate and rate of the biochemical reaction of substrate consumption, but also by the position inside the basket bed. These influences cumulated led to the appearance of biological inactive region near the particle centre, its magnitude varying from 0.34 to 31% from the overall volume of particles.
The presented results are the first unitary approach of the aspects of substrate mass transfer in a basket bed of immobilized biocatalysts, the proposed models being original and complex.
Comparison of surgical site infection rates in clean and clean-contaminated wounds in dogs and cats after minimally invasive versus open surgery: 179 cases (2007–2008)
Authors: Mayhew Philipp D. , Freeman Lynetta , Kwan Toni , Brown Dorothy C. 
Published: January 2012

Abstract
Objective—To report and compare the surgical site infection (SSI) rates for clean and clean-contaminated procedures performed by either a minimally invasive surgical or open surgical approach in a large population of dogs and cats.
Design—Prospective case series.
Animals—179 patients (dogs and cats) undergoing minimally invasive abdominal or thoracic surgery.
Procedures—Case information from all animals that underwent minimally invasive abdominal or thoracic surgery was prospectively collected and compared with an existing database of the same information collected from 379 patients undergoing laparotomy or thoracotomy via an open surgical approach. For both groups, an SSI was defined as any surgical wound in which purulent discharge was observed within 14 days after the procedure. Follow-up for all patients was obtained by direct examination or telephone interviews.
Results—Overall SSI rate in the minimally invasive surgery (MIS) group was 1.7% and in the open surgery (OS) group was 5.5%. On univariate analysis, there was a significantly lower SSI rate in the MIS group, compared with the SSI rate for the OS group. On multivariable logistic regression analysis, this difference appeared to be a result of the fact that surgery times were longer (median, 105 vs 75 minutes) and hair was clipped ≥ 4 hours prior to surgery for more animals (23% vs 11 %) in the OS group, compared with the MIS group.
Conclusions and Clinical Relevance—MIS may be associated with a lower SSI rate, compared with OS, but confounding factors such as differences in surgery time and preoperative preparation contributed in part to this finding. As such, surgical approach cannot be categorized as an independent risk factor for SSIs in small animals until further studies are performed.
The use of air-bottoming cycle as a heat source for the carbon dioxide capture installation of a coal-fired power unit
Authors: Chmielniak Tadeusz , Lepszy Sebastian , Czaja Daniel 
Published: January 2012

The use of air-bottoming cycle as a heat source for the carbon dioxide capture installation of a coal-fired power unitThe installations of CO2capture from flue gases using chemical absorption require a supply of large amounts of heat into the system. The most common heating medium is steam extracted from the cycle, which results in a decrease in the power unit efficiency. The use of heat needed for the desorption process from another source could be an option for this configuration. The paper presents an application of gas-air systems for the generation of extra amounts of energy and heat. Gas-air systems, referred to as the air bottoming cycle (ABC), are composed of a gas turbine powered by natural gas, air compressor and air turbine coupled to the system by means of a heat exchanger. Example configurations of gas-air systems are presented. The efficiency and power values, as well as heat fluxes of the systems under consideration are determined. For comparison purposes, the results of modelling a system consisting of a gas turbine and a regenerative exchanger are presented.
Feasibility study of forced cooling of a supercritical steam turbine after a shut down of a power generating unit
Authors: Kosman Wojciech 
Published: January 2012

Feasibility study of forced cooling of a supercritical steam turbine after a shut down of a power generating unitTemperature related decrease of steam turbine components is one of the main transient processes that occur during a typical long-term operation. With a natural cooling (no user interference) it takes more than 14 days before the temperature of components reaches the level that allows to open and repair a turbine. It is then reasonable to apply a forced cooling in order to decrease the time between a shut-down of a power generating unit and a beginning of a repair. This paper presents the analysis of application of a forced cooling process to supercritical steam turbines. The main problems under the investigation are the safety issues of the process and the optimization of cooling conditions. The paper describes the safety restrictions and the optimization criteria. The process is analyzed in numerical simulations conducted for various cooling conditions.
Application of the entropy information for the optimization of an additional measurements location in thermal systems
Authors: Szega Marcin 
Published: January 2012

Application of the entropy information for the optimization of an additional measurements location in thermal systemsFor the optimal location of an additional surplus measurements in the design of redundant measurements system, from data reconciliation point of view, of thermal processes, an information entropy has been applied. The relative entropy - Kullback-Leibler divergence, has been used. As a criterion of the optimal location of an additional surplus measurements in a system of measurements data, the minimum of the entropy information of reconciled measurements data has been assumed. Hence, the objective function in the described optimization task is maximum of the relative entropy - Kullback-Leibler divergence concerning sets of raw and reconciled measurements data. Simulation calculation with application of data reconciliation algorithm and Monte Carlo method concerning the influence of installation of the additional surplus measurements on decrease of entropy information of measurements after data validation have been carried out. The example calculations concerned the cross high-pressure heat regeneration system with cascade flow of condensate installed in 153 MW power unit equipped with cooler of steam are presented. Calculations for all variants of configurations of an additional surplus measurements in the analyzed thermal system have been done. Usefulness of the proposed Kullback-Leibler divergence as a objective function has been demonstrated.
Thermodynamic and economic analysis of a 900 MW ultra-supercritical power unit
Authors: łukowicz Henryk , Dykas Sławomir , Rulik Sebastian , Stępczyńska Katarzyna 
Published: January 2012

Thermodynamic and economic analysis of a 900 MW ultra-supercritical power unit
The paper presents a thermal-economic analysis of different variants of a hard coal-fired 900 MW ultra-supercritical power unit. The aim of the study was to determine the effect of the parameters of live and reheated steam on the basic thermodynamic and economic indices of the thermal cycle. The subject of the study was the cycle configuration proposed as the "initial thermal cycle structure" during the completion of the project "Advanced Technologies for Energy Generation" with the live and reheated steam parameters of 650/670 °C. At the same time, a new concept of a thermal cycle for ultra-supercritical parameters with live and reheated steam temperature of 700/720 °C was suggested. The analysis of the ultra-supercritical unit concerned a variant with a single and double steam reheat. All solutions presented in the paper were subject to a detailed thermodynamic analysis, as well as an economic one which also included CO2emissions charges. The conducted economic analysis made it possible to determine the maximum value of investment expenditures at which given solutions are profitable.
Influence of Bicarbonate/Low-GDP Peritoneal Dialysis Fluid (Bicavera) on in Vitro and Ex Vivo Epithelial-to-Mesenchymal Transition of Mesothelial Cells
Authors: Fernández–Perpén Antonio , Pérez–Lozano María Luisa , Bajo María–Auxiliadora , Albar–Vizcaino Patricia , Correa Pilar Sandoval , Del Peso Gloria , Castro María–José , Aguilera Abelardo , Ossorio Marta , Peter Mirjam E. , Passlick–Deetjen Jutta , Aroeira Luiz S. , Selgas Rafael , López–Cabrera Manuel , Sánchez–Tomero J. Antonio 
Published: January 2012

Background Peritoneal membrane damage induced by peritoneal dialysis (PD) is largely associated with epithelial-to-mesenchymal transition (EMT) of mesothelial cells (MCs), which is believed to be a result mainly of the glucose degradation products (GDPs) present in PD solutions. Objectives This study investigated the impact of bicarbonate-buffered, low-GDP PD solution (BicaVera: Fresenius Medical Care, Bad Homburg, Germany) on EMT of MCs in vitro and ex vivo. Methods: studies Omentum-derived MCs were incubated with lactate-buffered standard PD fluid or Bica-Vera fluid diluted 1:1 with culture medium. Ex vivo studies: From 31 patients randomly distributed to either standard or BicaVera solution and followed for 24 months, effluents were collected every 6 months for determination of EMT markers in effluent MCs. Results Culturing of MCs with standard fluid in vitro resulted in morphology change to a non-epithelioid shape, with downregulation of E-cadherin (indicative of EMT) and strong induction of vascular endothelial growth factor (VEGF) expression. By contrast, in vitro exposure of MCs to bicarbonate/low-GDP solution had less impact on both EMT parameters. Ex vivo studies partially confirmed the foregoing results. The BicaVera group, with a higher prevalence of the non-epithelioid MC phenotype at baseline (for unknown reasons), showed a clear and significant trend to gain and maintain an epithelioid phenotype at medium- and longer-term and to show fewer fibrogenic characteristics. By contrast, the standard solution group demonstrated a progressive and significantly higher presence of the non-epithelioid phenotype. Compared with effluent MCs having an epithelioid phenotype, MCs with non-epithelioid morphology showed significantly lower levels of E-cadherin and greater levels of fibronectin and VEGF. In comparing the BicaVera and standard solution groups, MCs from the standard solution group showed significantly higher secretion of interleukin 8 and lower secretion of collagen I, but no differences in the levels of other EMT-associated molecules, including fibronectin, VEGF, E-cadherin, and transforming growth factor β1. Peritonitis incidence was similar in both groups. Functionally, the use of BicaVera fluid was associated with higher transport of small molecules and lower ultrafiltration capacity. Conclusions Effluent MCs grown ex vivo from patients treated with bicarbonate/low-GDP BicaVera fluid showed a trend to acquire an epithelial phenotype, with lower production of proinflammatory cytokines and chemokines (such as interleukin 8) than was seen with MCs from patients treated with a lactate-buffered standard PD solution.
Effluent Free Radicals Are Associated with Residual Renal Function and Predict Technique Failure in Peritoneal Dialysis Patients
Authors: Morinaga Hiroshi , Sugiyama Hitoshi , Inoue Tatsuyuki , Takiue Keiichi , Kikumoto Yoko , Kitagawa Masashi , Akagi Shigeru , Nakao Kazushi , Maeshima Yohei , Miyazaki Ikuko , Asanuma Masato , Hiramatsu Makoto , Makino Hirofumi 
Published: January 2012

Objective Residual renal function (RRF) is associated with low oxidative stress in peritoneal dialysis (PD). In the present study, we investigated the relationship between the impact of oxidative stress on RRF and patient outcomes during PD. Methods Levels of free radicals (FRs) in effluent from the overnight dwell in 45 outpatients were determined by electron spin resonance spectrometry. The FR levels, clinical parameters, and the level of 8-hydroxy-2′-deoxyguanosine were evaluated at study start. The effects of effluent FR level on technique and patient survival were analyzed in a prospective cohort followed for 24 months. Results Levels of effluent FRs showed significant negative correlations with daily urine volume and residual renal Kt/V, and positive correlations with plasma β2-microglobulin and effluent 8-hydroxy-2′-deoxyguanosine. A highly significant difference in technique survival ( p < 0.05), but not patient survival, was observed for patients grouped by effluent FR quartile. The effluent FR level was independently associated with technique failure after adjusting for patient age, history of cardiovascular disease, and presence of diabetes mellitus ( p < 0.001). The level of effluent FRs was associated with death-censored technique failure in both univariate ( p < 0.001) and multivariate ( p < 0.01) hazard models. Compared with patients remaining on PD, those withdrawn from the modality had significantly higher levels of effluent FRs ( p < 0.005). Conclusions Elevated effluent FRs are associated with RRF and technique failure in stable PD patients. These findings highlight the importance of oxidative stress as an unfavorable prognostic factor in PD and emphasize that steps should be taken to minimize oxidative stress in these patients.
Microbiology of Peritonitis in Peritoneal Dialysis Patients with Multiple Episodes
Authors: Nessim Sharon J. , Nisenbaum Rosane , Bargman Joanne M. , Jassal Sarbjit V. 
Published: January 2012

Background Peritoneal dialysis (PD)–associated peritonitis clusters within patients. Patient factors contribute to peritonitis risk, but there is also entrapment of organisms within the biofilm that forms on PD catheters. It is hypothesized that this biofilm may prevent complete eradication of organisms, predisposing to multiple infections with the same organism. Methods Using data collected in the Canadian multi-center Baxter POET (Peritonitis, Organism, Exit sites, Tunnel infections) database from 1996 to 2005, we studied incident PD patients with 2 or more peritonitis episodes. We determined the proportion of patients with 2 or more episodes caused by the same organism. In addition, using a multivariate logistic regression model, we tested whether prior peritonitis with a given organism predicted the occurrence of a subsequent episode with the same organism. Results During their time on PD, 558 patients experienced 2 or more peritonitis episodes. Of those 558 patients, 181 (32%) had at least 2 episodes with the same organism. The organism most commonly causing repeat infection was coagulase-negative Staphylococcus (CNS), accounting for 65.7% of cases. Compared with peritonitis caused by other organisms, a first CNS peritonitis episode was associated with an increased risk of subsequent CNS peritonitis within 1 year (odds ratio: 2.1; 95% confidence interval: 1.5 to 2.8; p < 0.001). Among patients with repeat CNS peritonitis, 48% of repeat episodes occurred within 6 months of the earlier episode. Conclusions In contrast to previous data, we did not find a high proportion of patients with multiple peritonitis episodes caused by the same organism. Coagulase-negative Staphylococcus was the organism most likely to cause peritonitis more than once in a given patient, and a prior CNS peritonitis was associated with an increased risk of CNS peritonitis within the subsequent year.