bluuebunny/crossref_metadata_2025 huggingface dataset:
Up-to-Date Haemophilus influenzae Type b Vaccination Coverage During a Vaccine Shortage
Authors: White Karen E. , Pabst Laura J. , Cullen Karen A.
Published: February 2011

OBJECTIVES:

We sought to assess Haemophilus influenzae type b (Hib) vaccination coverage in diverse areas of the United States during the 2008–2009 Hib vaccine shortage. Interim recommendations for Hib vaccination during the shortage called for deferral of the booster dose only among children not at high risk for disease; the primary series given during the first year of life continued to be recommended for all children.

METHODS:

Vaccination data on ∼123 000 children were collected from 8 Immunization Information System (IIS) sentinel sites. Completion of the primary Hib series (with 2 or 3 doses depending on vaccine type) by 9 months old during the vaccine shortage was compared with coverage of 2 vaccines given at similar ages (7-valent pneumococcal conjugate vaccine and diphtheria, tetanus acellular pertussis vaccine) in children born between November 1, 2007, and March 31, 2008.

RESULTS:

During the shortage period, Hib vaccination coverage for the primary series was 7.8 to 10.3 percentage points lower than diphtheria, tetanus acellular pertussis vaccine and 7-valent pneumococcal conjugate vaccine coverage for children by the age of 9 months in 7 of 8 sentinel sites.

CONCLUSIONS:

A significant decrease in Hib vaccination coverage for the primary series was observed and was consistent across several US localities. Close collaboration between the public health community and vaccine providers is essential during vaccine shortages to ensure that interim vaccination recommendations are clear, widely disseminated, and closely followed, and that access to available vaccine supplies is maintained.
Statewide NICU Central-Line-Associated Bloodstream Infection Rates Decline After Bundles and Checklists
Authors: Schulman Joseph , Stricof Rachel , Stevens Timothy P. , Horgan Michael , Gase Kathleen , Holzman Ian R. , Koppel Robert I. , Nafday Suhas , Gibbs Kathleen , Angert Robert , Simmonds Aryeh , Furdon Susan A. , Saiman Lisa ,   the New York State Regional Perinatal Care Centers
Published: February 2011

OBJECTIVE:

In 2008, all 18 regional referral NICUs in New York state adopted central-line insertion and maintenance bundles and agreed to use checklists to monitor maintenance-bundle adherence and report checklist use. We sought to confirm whether adopting standardized bundles and using central-line maintenance checklists reduced central-line–associated bloodstream infections (CLABSI).

METHODS:

This was a prospective cohort study that enrolled all neonates with a central line who were hospitalized in any of 18 NICUs. Each NICU reported CLABSI and central-line utilization data and checklist use. We used χ2 to compare CLABSI rates in the preintervention (January to December 2007) versus the postintervention (March to December 2009) periods and Poisson regression to model adjusted CLABSI rates.

RESULTS:

Each study period included more than 55 000 central-line days and more than 200 000 patient-days. CLABSI rates decreased 67% statewide (risk ratio: 0.33 [95% confidence interval: 0.27–0.41]; P < .0005); after adjusting for the altered central-line–associated bloodstream infection definition in 2008, by 40% (risk ratio: 0.60 [95% confidence interval: 0.48–0.75]; P < .0005). A total of 13 of 18 NICUs reported using maintenance checklists for 10% to 100% of central-line days. The checklist-use rate was associated with the CLABSI rate (coefficient: −0.57, P = .04). A total of 10 of 18 NICUs were independent CLABSI rate predictors, ranging from 1 site with greatly reduced risk (incidence rate ratio: 0.04, P < .0005) to 1 site with greatly increased risk (incidence rate ratio: 2.87, P < .0005).

CONCLUSIONS:

Although standardizing central-line care elements led to a significant statewide decline in NICU CLABSIs, site of care remains an independent risk factor. Using maintenance checklists reduced CLABSIs.
From Dalits to Bene Ephraim
Authors: Egorova Yulia
Published: February 2011

The community of Bene Ephraim was established in the late 1980s in Andhra Pradesh by a group of Christianized Madiga who declared that they belonged to one of the Lost Tribes of Israel. The paper explores the extent to which Bene Ephraim narratives of origin have been and are being shaped by the responses of others on the level of national and international politics. It is demonstrated that while in the beginning the leaders of the community were keen to stress their affinity to the scheduled castes of India and portrayed their social and economic problems in terms of the upper and lower caste dichotomy, later on they modified their story of origin to dissociate the community from the untouchables. Their self-representation as victims of caste domination gave way to expressions of concern about the possibility of becoming victims of anti-Jewish terrorist attacks. The paper argues that this change in the way the Bene Ephraim chose to frame the socio-political problems that the community is facing was linked to their attempts to be recognized as a Jewish group and be accepted in the State of Israel. At the same time, it is also suggested that this tactic provides yet another example of a Dalit group attempting to attract the attention of the international community to their condition of discrimination by reinterpreting their plight in the terms that foreign audiences would be more familiar with and could relate to more easily.
Jaiminiya Asvamedhika Parva in the Mahabharata. Shekhar Sen (trans.) and Pradip Bhattacharya (ed.)
Authors: Brodbeck Simon
Published: February 2011

Jaiminiya Asvamedhika Parva in the Mahabharata. Shekhar Sen (trans.) and Pradip Bhattacharya (ed.). Calcutta: Writers Workshop, 2008. 488 pp. Rs 800 (hardback), Rs 500 (flexiback). ISBN 978-81-8157-849-5 (hardback), 978-81-8157-850-1 (flexiback).
Castration-Resistant Prostate Cancer: Targeted Therapies and Individualized Treatment
Authors: Aggarwal Rahul , Ryan Charles J.
Published: February 2011

Various molecular mechanisms have been implicated in the progression from hormone-sensitive to castration-resistant prostate cancer (CRPC). Novel targeted agents to treat CRPC have been developed that inhibit either androgen receptor (AR)-mediated signaling (AR antagonists and inhibitors of androgen synthesis) or non–AR-mediated signaling (inhibitors of Src, mammalian target of rapamycin, chaperone proteins, insulin-like growth factor-1 receptor, vascular endothelial growth factor, and endothelin-A receptor) pathways. However, variable efficacy has been observed in clinical trials, most likely because of the biologic heterogeneity of CRPC. To account for potential differences in disease biology, a more individualized approach to treatment, based on genomic and/or proteomic analyses of individual tumors, is being investigated. By identifying tumors with a characteristic molecular subtype and assigning treatment accordingly, it is hoped that a higher proportion of patients will benefit from targeted therapy. Additionally, lessons learned through the application of these technologies to prostate cancer may subsequently influence therapeutic development in other solid tumors.
Role of 18F-Fluorodeoxyglucose Positron Emission Tomography in Predicting Epidermal Growth Factor Receptor Mutations in Non-Small Cell Lung Cancer
Authors: Mak Raymond H. , Digumarthy Subba R. , Muzikansky Alona , Engelman Jeffrey A. , Shepard Jo-Anne O. , Choi Noah C. , Sequist Lecia V.
Published: February 2011

Purpose.

To compare 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and computed tomography (CT) imaging characteristics in non-small cell lung cancer (NSCLC) with or without epidermal growth factor receptor (EGFR) mutations.

Methods.

We retrospectively identified NSCLC patients who underwent EGFR mutation testing and pretreatment FDG-PET and CT scans. The maximum standard uptake value (SUVmax) of the primary tumor and any metastases was measured and normalized to the SUV of blood in the pulmonary artery. We compared normalized SUVmax values between EGFR-mutant and wild-type patients and modeled radiographic and clinical predictors of EGFR mutation status. Receiver operator characteristic (ROC) curves were used to identify potential SUV cutoffs predictive of genotype.

Results.

We included 100 patients (24 EGFR-mutant and 76 wild-type). There was a trend for higher normalized SUVmax in the primary tumors among patients with EGFR-wild-type versus mutant (median, 3.4; range, 0.6–12.8; versus median, 2.9; range, 0.4–5.0; p = .09). Normalized SUVmax of nodal and distant metastases, and CT characteristics were not associated with genotype. On multivariate analysis, low normalized SUVmax of the primary tumor was predictive for EGFR mutation (odds ratio, 0.72; 95% confidence interval, 0.53–0.98; p = .034). ROC curve analyses yielded an area under the curve of 0.62, and identified a potential cutoff of ≥5.0 to distinguish wild-type from mutant tumors.

Conclusions.

In this retrospective study, high FDG avidity (normalized SUVmax ≥5) correlated with EGFR-wild-type genotype. Although genotyping remains the gold standard, further work to validate FDG-PET as a surrogate for tumor genotype may provide useful information in patients without available tumor tissue.
A Review of an Unfavorable Subset of Breast Cancer: Estrogen Receptor Positive Progesterone Receptor Negative
Authors: Thakkar Jigisha P. , Mehta Divyesh G.
Published: February 2011

Estrogen receptor (ER)+ progesterone receptor (PR)− tumors are a distinct subset of breast cancers characterized by aggressive behavior and tamoxifen resistance in spite of being ER+. They are categorized as luminal B tumors and have greater genomic instability and a higher proliferation rate. High growth factor (GF) signaling and membranous ER activity contribute to the aggressive behavior of these tumors. The absence of PR is attributable to low serum estrogen, low levels of nuclear ER, and features of molecular crosstalk between GFs and membranous ER. PR expression is also downregulated by expression of mutated epidermal growth factor receptor (EGFRvIII). This subset of patients has greater expression of human epidermal growth factor receptor (HER)-1 and HER-2 and active GF signaling mediated by the phosphoinositide 3-kinase–Akt–mammalian target of rapamycin pathway. Currently, aromatase inhibitors, fulvestrant, and chemotherapy may be the favored treatment approaches for this subset of patients. Overcoming tamoxifen resistance with targeted therapies such as gefitinib is being evaluated and strategies involving short courses of tamoxifen have been postulated for prevention of recurrence of this subtype. Understanding the interplay between molecular endocrinology and tumor biology has provided experimental therapeutic insights, and continued work in this area holds the promise of future advances in prognosis.
Progression of Periodontitis in a Sample of Regular and Irregular Compliers Under Maintenance Therapy: A 3‐Year Follow‐Up Study
Authors: Oliveira Costa Fernando , Miranda Cota Luís Otávio , Pereira Lages Eugênio José , Medeiros Lorentz Telma Campos , Soares Dutra Oliveira Alcione Maria , Dutra Oliveira Peterson Antônio , Costa José Eustáquio
Published: February 2011

Background: To our knowledge, prospective studies (matched for sex, smoking, and diabetes) that investigated the influence of compliance in the progression of periodontitis and tooth loss in periodontal maintenance therapy (PMT) programs were not previously reported.

Methods: A total of 58 regular complier (RC) and 58 erratic complier (EC) individuals were recruited from a prospective cohort with 238 patients under PMT and matched by sex, diabetes, and smoking habits. A full‐mouth periodontal examination that included bleeding on probing (BOP), probing depths (PDs), clinical attachment levels, and number of teeth were determined at all PMT visits during a 3‐year interval. The influence of variables of interest was tested through multivariate logistic regression.

Results: The progression of periodontitis and tooth loss was significantly lower among RC compared to EC patients. A higher progression of periodontitis was observed among EC patients who smoked. The final logistic model for the progression of periodontitis in the RC group included smoking (odds ratio [OR]: 4.2) and >30% of sites with BOP (OR: 2.8), and the final logistic model for the progression of periodontitis in the EC group included smoking (OR: 7.3), >30% of sites with BOP (OR: 3.2), PDs of 4 to 6 mm in 10% of sites (OR: 3.5), diabetes (OR: 1.9), and number of lost teeth (OR: 3.1).

Conclusions: RC patients presented a lower progression of periodontitis and tooth loss compared to EC patients. This result highlighted the influence of the pattern of compliance in maintaining a good periodontal status. Moreover, important risk variables such as smoking and diabetes influenced the periodontal status and should be considered when determining the risk profile and interval time for PMT visits.
Challenges, Uncertainties, and Issues Facing Gas Production From Gas-Hydrate Deposits
Authors: Moridis G.J.. J. , Collett T.S.. S. , Pooladi-Darvish M.. , Hancock S.. , Santamarina C.. , Boswell R.. , Kneafsey T.. , Rutqvist J.. , Kowalsky M.B.. B. , Reagan M.T.. T. , Sloan E.D.. D. , Sum A.K.. K. , Koh C.A.. A.
Published: February 2011

The current paper complements the Moridis et al. (2009) review of the status of the effort toward commercial gas production from hydrates. We aim to describe the concept of the gas-hydrate (GH) petroleum system; to discuss advances, requirements, and suggested practices in GH prospecting and GH deposit characterization; and to review the associated technical, economic, and environmental challenges and uncertainties, which include the following: accurate assessment of producible fractions of the GH resource; development of methods for identifying suitable production targets; sampling of hydrate-bearing sediments (HBS) and sample analysis; analysis and interpretation of geophysical surveys of GH reservoirs; well-testing methods; interpretation of well-testing results; geomechanical and reservoir/well stability concerns; well design, operation, and installation; field operations and extending production beyond sand-dominated GH reservoirs; monitoring production and geomechanical stability; laboratory investigations; fundamental knowledge of hydrate behavior; the economics of commercial gas production from hydrates; and associated environmental concerns.
Prediction of Salinity of Salty Crude Oil Using Arrhenius-Type Asymptotic Exponential Function and Vandermonde Matrix
Authors: Bahadori Alireza
Published: February 2011

Production of wet crude because of a rise in the oil/water contact in many oil fields has been a growing field problem, and it has affected the quality of crudes. In almost all cases, salt is dissolved in the water that is dispersed in the crude oil and its separation is not simple because desalting is a critical operation because of the importance of meeting the specifications of acceptable quantities of salt and water in the treated oil. For these reasons, measurements of salt and water content in crude oils are very important in all oil-industry operations, including crude-oil production, processing, and transportation and refining. In this paper, we attempt to formulate a method that is easier than existing approaches, that is less complicated and requires fewer computations for accurate and rapid estimation of crude-oil salinity as a function of the quantity of brine that remains in the oil, its salinity (in vol% of sodium chloride concentration), and temperature, using an Arrhenius- type asymptotic exponential function and Vandermonde matrix. The proposed method predicts the salinity of salty crude oil for temperatures up to 373 K and sodium chloride concentrations up to 250,000 ppm (25% by volume). Estimations from the proposed correlation are found to be in excellent agreement with the reported data in the literature, with average absolute deviation being 0.3%. The proposed method is superior owing to its accuracy and clear numerical background based on the Vandermonde matrix, wherein the relevant coefficients can be retuned quickly for various cases. The tool developed in this study can be of immense practical value for engineers, providing a quick check on the salt content in the crude oil at various conditions without the necessity of any experimental measurements. In particular, petroleum and field engineers would find the proposed approach to be user friendly, with transparent calculations involving no complex expressions.
Integrity in Drilling and Wireline Operations in Offshore Assets: A Case on the Potential Error Causation Paradigms
Authors: Vignes Birgit , Liyanage Jayantha P.
Published: February 2011

The Petroleum Safety Authority, Norway, has performed projects and audits related to human factors and the work situation of drillers and wireline operators. The drillers and the wireline operators actively engage in the control of the well barrier status and the management of well integrity, which are considered critical in terms of limiting integrity incidents, leaks and well control situations. Updated and relevant information on the well barrier status enables the companies to manage operational integrity in a proactive manner and thereby to ensure "healthy" & safe wells, and prevent or reduce potential risks and economic losses.

The purpose of this paper is to present the potential error causation paradigms in drilling and wireline operations based on the experience from projects and audits. The error causation paradigms are classified into four paradigms: the engineering-, organizational-, cognitive- and the individual-error paradigm. The different paradigms look at the challenges in drilling and wireline operations from different points of view. The paper presents specific challenges that have a large potential to pose some serious threats to the health, safety integrity, and work performance efficiency. The drillers have challenges due to the design of the working environment and because they have to handle, analyze and respond to a large amount of information. The wireline operator has challenges due to the design of the wireline cabin, communication and the number of procedures.

The drilling and wireline operators' work performance has to be understood in a Human-Technology-Organization (HTO) context, to reduce system vulnerability and to improve performance from a safety, environmental, and economical point of view. The HTO context in drilling and wireline operations is seen as an interesting complex work settings which includes a number of interactive elements in a dynamic work setting, where there is close inter-connection between technical and managerial aspects to ensure safe and productive operations.
Reducing Safety Incidents by Lifting Single Joints of Drill Pipe with a New Design of Elevator
Authors: Law Alan , Turnbull Jon , Redlinger Thomas , Frilot Melissa , Brady Gary
Published: February 2011

The traditional methods, equipment and safety measures currently in use have failed to eliminate incidents, injuries and near misses which occur while picking up single joints of drill pipe. Operations in the North Sea and elsewhere have recorded a significant number of serious incidents with the "variable" type of single joint elevators that are commonly used which have resulted in dropped objects, lost time incidents with attendant injuries and near misses. The root causes of the lifting incidents include a variety of both operational and equipment failures such as incomplete latching, safety pin problems, incorrect selection of blocks to suit the pipe size and hinge pin failures.

A recent joint effort between a major oil company and a service company has led to the development of tools and methods that incorporate several key features and provide a means to enhance safety and operational efficiency while lifting single joints of drill pipe. The authors will discuss the problem as it existed, review the new methods and handling tools which evolved and provide current data on their implementation.
Produced Water Treatment Using Wetlands - Reducing The Environmental Impact Of Oilfield Operations
Authors: Breuer Roman , Grissemann Ernst
Published: February 2011

In order to reduce the environmental impact of produced water management a wetland system is being installed in the Sultanate of Oman. The facility will reduce the disposal of hydrocarbon polluted produced water into deep aquifers, recover hydrocarbons by means of an additional oil/water separation step and decrease the overall power consumption of the oil field operation by using a gravity flow system. During construction measures have been taken to reduce the impact by using only local materials for the installation of a sealing layer.

The project is currently in the commissioning phase and first result have shown that up to 60 bbl/d of crude oil were recovered, an overall a reduction of the power consumption between 1.2 and 1.8 Mio MWh can possibly achieved in the 20 years of operation and due to the installation of a mineral sealing layer the impact during construction could be reduced by 80 % for this element compared to the installation of an artificial sealing.
How to Design and Implement a Cardiovascular Disease Prevention Program in an Oil and Gas Company - Revision
Authors: Vasile Catalin , Frano Mika , Giorgi Eristavi
Published: February 2011

Cardio Vascular Diseases represent the first cause of premature death and disability all over the world. As different premises assert that employees working in oil and gas industry are exposed to a higher risk than general population, Saipem has developed and started to implement a comprehensive Cardiovascular Disease Prevention Program (CVDPP). The scope of CVDPP is to identify, assess and reduce controllable Cardio Vascular Disease Risk Factors (CVDRF) of employees, this program being focused on prevention and health promotion (life style modification). The program addresses to all employees, at risk or not; their participation is strongly recommended but not mandatory. People at risk are advised to enroll further in Risk Factor Follow-up Program in order to decrease or at least to maintain their individual Cardio Vascular Disease Risk (CVDR) to the lowest possible value, according to European cardiovascular guidelines recommendations. The Heart SCORE, developed by European Society of Cardiology is the method used to select people at risk. The development of CVDPP runs properly and the full assessment of its effectiveness would be after 5 years of correct implementation. This paper intends to present CVDPP and Saipem experience during its development and implementatation, taking in consideration specific realties encountered in oil and gas industry. Current paper is a revision of that presented one year ago (SPE Europena HSE Vienna, Austria 22-24 February) which includes up to date information to the end of 2011.
Investigation of Process Safety Incidents & Implementing Effective Corrective & Preventive Actions
Authors: Martland Roland
Published: February 2011

This paper sets out the author's recent experiences with offshore oil and gas exploration and production companies to improve the identification and investigation of Process Safety Incidents, PSIs. The paper will describe the difficulties that companies experience when dealing with relatively simple issues, such as agreeing what a PSI is and how to link the underlying and root causes of incidents to weaknesses in the process safety risk controls. The paper will also demonstrate that the actions identified after an investigation do not always correct the causation factors - examples will be provided to illustrate common pitfalls in selecting effective actions after a PSI. The prevention of process safety has significant business benefits and several industry initiatives currently in place or proposed will be presented.
Integrated Analysis of Fire Exposed Structures Introducing Probabilistic Analysis into Fire Modeling and Structural Analysis
Authors: Huse Jan Reier
Published: February 2011

Integrated fire modeling and structural integrity analyses of offshore modules during accidental fires has become customary during the last two decades. Normal input to the analysis are design accidental fires, and the need for passive fire protection (PFP) on the load carrying members are assessed for the given heat loads and fire durations.

A new approach is to include advanced probabilistic methods and tools into the integrated analysis loop. Changes in process layout can be suggested and the need for PFP can be reevaluated. Such an approach requires that the analysis is carried out on an early stage in the project.
Mirror of E&P Safety Performance 2005-2009
Authors: Dijkhuizen Bart C. , Henriquez Leopoldo R.
Published: February 2011

Incidents are a source of information about management and control, and a good basis for further improvements. Operating companies can and should learn from incidents. However, most information that can be obtained from incidents is hardly used as a result of time constraints. Proper incident analyses according to proven and detailed methodologies are only conducted for incidents with severe impacts, or the potential of severe impacts. Luckely incident rates are low in the E&P sector, but that also means that detailed incident analyses are rare. The E&P sector as a whole could therefore benefit from sharing incident data, enlarging the learning database. Although there is some sharing, and benchmarking against lagging KPI's like LTI frequencies, there is no sharing of consistently classified data about root causes, direct causes and failing control measures. It is this information operating companies would benefit most from, since it directly indicates where action is required.

In this paper the results are presented and discussed of a review, analyses and classification of 478 fatal accidents in the period 2005 – 2009, as reported bij members of the International Association of Oil & Gas Producers (OGP). Information about incidents of OGP members is publicly available on the OGP website. The information from the incidents have resulted in statistics of direct causes, root causes and lacking or failing control measures, including some trends. This paper has the intent to initiate a step change in the thinking about, and in taking action with respect to analyzing and sharing available incident data in industry on a common analysis and classification approach, in order to enlarge the learning database and enable real risk-based management.

Since this review has been based on publicly available information, it is considered a mirror of E&P safety performance from an independent, third-party perspective. All information was already available. The strength of this study is the consistent analyses on the basis of a single analysis model, independent of the source of information. The outcomes presentated provide a good basis to focus management and control, and even to focus regulatory inspections by government bodies.
Using Partial Separability of the Objective Function for Gradient-based Optimizations in History Matching
Authors: Ding D. Y. , McKee F.
Published: February 2011

Assisted history matching is widely used to constrain reservoir models by integrating well production data and/or 4D seismic data. However, history matching is a complex inverse problem, and the computational effort increases with the increasing of the number of matching parameters. It is always a big challenge to history match large fields with a large number of parameters.

In history matching, the objective function can be separated into local components referred to the wells and/or the seismic zones, and a local component generally depends on a smaller number of principal parameters. This partial separability of the objective function helps to compute derivatives with a smaller number of reservoir simulations for the gradient-based optimization methods. In this paper, we present a new technique for the derivative computation and discuss how to generate an "optimal" perturbation design for a partially separable objective function. The proposed method can decrease the objective function with much fewer simulations in history matching.
A Biodegradable Chelating Agent Designed to be an Environmentally Friendly Filter-Cake Breaker
Authors: Collins Natalia , Nzeadibe Kingsley , Almond Stephen W
Published: February 2011

A new biodegradable member of the chelating family of breaker fluids has been developed for treating oil and gas wells over a wide temperature range in environmentally sensitive locations. The enhanced filter-cake breaker is engineered to achieve improved bio-degradation with reduced toxicity and environmental footprint, while offering less corrosion potential than hydrochloric acid (HC1). Meanwhile, it maintains the high reaction rate with metal ions that is critical for efficient filter-cake removal.

Chelating agents are chemicals that are used to control undesirable reactions of metal ions. Treatment with chelate-based fluids has been successfully applied in the past for numerous well stimulations, for iron control during acidizing and for filter-cake breaker fluids in a variety of formations. A novel polyacidic chelate (NPC) breaker has been developed. The chelate-based fluid effectively dissolves calcium carbonate (CaCO3), yet has a low corrosion potential and is easy to apply.

From an environmental standpoint, NPC is readily biodegradable and is a renewable raw material. NPC has low animal and aquatic toxicity. As a replacement for live mineral acids, NPC is significantly safer to the environment and humans and is less corrosive.

This paper describes laboratory studies comparing the effectiveness of NPC in removing the acid soluble content of the filter cake versus conventional breaker systems that contain formic, lactic and acetic acid precursors. Additionally, application challenges in terms of corrosion potential, usage volumes, fluid preparation, and conformance to discharge regulations in various locations are reviewed.
1.500m3 LNAPL Remediation Project – Antwerp/Belgium
Authors: van den Brand Marco
Published: February 2011

At many refining and distributing sites soil and groundwater pollution occurs, often resulting in free floating product or LNAPL (Light Non-Aqueous Phase Liquids). Often costly remediation measures have to be undertaken. A practical, robust and (cost) effective remediation program is therefore key important. For a major oil spill in Antwerp Harbor HMVT has successfully designed and implemented the remedial works for a major NAPL of 1.500m3 (!) free floating product of volatile hydrocarbons, diesel and naphtha. The case, design, results and cost of the project will be presented.

The site is located in the Antwerp Harbor. On the site a pumping station of a petrochemical pipeline is present, pumping Naphtha from Antwerp, Belgium to the south of The Netherlands. The Naphtha pollution was caused by a leakage at the pumping station. On the site also petrochemical products are stored. The diesel pollution was caused by a leaking above ground storage tank.

On the site ca. 23.000m2 of soil was polluted with LNAPL with a maximum thickness of 1–1,5m. In total 1.000m3 of product was expected, but during the project ca. 1.500m3 of LNAPL is been removed. On the picture on the right it can be seen that most of the product was present underneath the pumping station and the ‵contractor's village2.

For port construction reasons the ground level has been raised with sandy material up to 4-5 meters in the past. Underneath this fine sandy upper layer the original, clayey soil is present. The water table is found at ca. 2 m-bgl, but this water table fluctuates ca. 1m between summer and winter.
Development of an Electronic Safety Case for Offshore Operations - From a Paper Version to an Operational Tool
Authors: Durbac Monica
Published: February 2011

Starting from the idea that every activity can be improved in order to facilitated the safest working places, an effective risk management process requires a structured and systematic analysis method involving the Identification, Assessment and Control of hazards. In the same way the Recovery from potential events should be investigated and recovery measures analysed and prepared.

The Petromar offshore operations in the Black Sea of Romania are a significant part of Petrom E&P. There is no legal requirement in Romania to provide a HSE Case for offshore installation. According to OMV group (the owner of Petrom) standards the preparation and implementation of a HSE Case is necessary.

A key deliverable of this HSE Case was the purpose to make it electronically available for all the platforms and operational people to facilitate consistent use in the ongoing operations.

OMV Petrom is committed to on-going improvement in HSE management; therefore HSE-MS in Petromar is effectively implemented with a continuous improvement in the management of all HSE hazards and effects that could occur in the workplaces.

According to the HSE Case standard used in OMV/Petrom, the scope of the HSE Case is to: Deliver an integrated HSE Case to modern standards as seen in the international oil and gas industryProvide a comprehensive qualitative assessment of the hazards and current risk levels;Identify where improvements in control measures are required and areas where additional control measures (risk reduction measures) could be practicably implemented;Provide a reference document that defines the current position with regard to hazard management against which improvement can be demonstrated; andTo bring the common offshore and onshore Petromar HSE issues together in one document.

The implementation of all these aspects is facilitated through the use of an electronic tool. This tool shows all the important aspects of the HSE Case; it has a user friendly interface and is easy to use. The tool provide a comprehensive qualitative assessment of the hazards and current risk levels; it identified where improvements in control measures are required and areas where additional control measures (risk reduction measures) could be practicably implemented and bring common offshore and onshore HSE issues together in one tool.
Managing Environmental Risks from Shale Gas Exploration - Applying Lessons Learned in the US to New Ventures in Poland
Authors: Jones F. V. , Zimmerman M. D. , Heinz W..
Published: February 2011

Outside of the United States (US), unconventional gas resources like shale gas have not been intensively studied or explored until recently. This paper describes the specific environmental risks and potential social impacts of shale gas exploration and how lessons learned from the US shale gas programs can be transferred to new ventures in Poland and other European countries.

Compared to conventional gas resources, the extraction of natural gas from tight shales is more difficult and therefore requires additional efforts. These are mostly related to the need for long-reach horizontal drilling into shale formations of variable thickness and the need for fracturing these formations by high pressure water with additives (e.g. sand, friction reduction agents, and other chemicals).

Environmental risks are associated with greater surface disturbance to perform more extensive seismic studies, more traffic and well pad activities, the need for large volumes of water, the application of water additives, and specialized wastewater handling. Aspects that need to be considered in the development of Polish (European) assets are more densely populated areas, land divided in smaller parcels, a relatively large number of protected areas, as well as the typical issues associated with gas development such as stormwater management, air emissions, spill management, social aspects, and stakeholder engagement.

This paper discusses these potential issues and provides a review in tabular form along with potential mitigation and management programs, which have been successfully applied by operators in US shale gas programs.

The ability to identify the potential impacts and then develop focused mitigation programs is a key factor in developing a well rounded SHE program and facilitate acceptance of shale gas exploration in Poland and Europe.
Aquifers Vulnerability: A New Mapping Method Based on Hydrogeological and Seismic Data – Case Study: Mio-Pliocene Aquifer in Hassi Messaoud - Algeria
Authors: Bensenane F. K. , Dhina O.. , Abdallahelhadj M. A. , Boukraba M.. , Cherfaoui A..
Published: February 2011

Non renewable groundwater resources in some arid regions are the unique source of water and constitute strategic reserves for more than ever with the expected water shortage in the near future. Thus, contamination due to the infiltration of pollutants coming from oil and gas industries is one of the major risks that are jeopardizing these valuable resources.

The main purpose of this paper is to present the widespread aquifers vulnerability evaluation methods prior to introduce and discuss the new mapping method we propose for oil and gas upstream activities.

The rationale for this mapping method is linked to time of travel and the quantity of contaminants that move from the surface to the aquifer. Three key parameters are considered: ■Depth to water table (D);■Consolidation of the upper geologic layers in the unsaturated zone (C);■Aquifer Media (A).

Therefore, hydrogeological Data from almost a hundred water wells in Hassi Messaoud field in Algeria have been used to determine the hydraulic head, the static level and the local underground flow of the mio-pliocene water table. Seismic data have been used to measure the consolidation rate of the unsaturated (vadose) zone, as well.

Thus, processed data were used for the purpose of drawing the vulnerability maps allowing a better understanding and assessment of the aquifer sensitivity to potential pollution. This simple yet useful method is developed to be used as a decision making tool when dealing with groundwater protection in oil and gas activities.
Addressing MAH (Major Accident Hazards) – From Assessment to Actions
Authors: Peball Ulrich , Dragan Sorin
Published: February 2011

An international Oil and Gas Company took over a state owned oil company in 2005 with about 22.000 employees, operating in more than 300 fields all over the country with significant offshore operations in the black Sea. The Original Company had been in operation for 150 years with 50 years under communist management and had become available for buy out after several restructuring efforts by the state.

In the early years after take over the focus was very much on inventorying the existing infrastructure and an assessment of technical safety aspects.
Multilateral-Complex Well Optimization
Authors: Crumpton P. I. , Habiballah W. A. , Wardell-Yerburgh P. G. , Nasser K. A. , Faleh A. A.
Published: February 2011

Reservoir simulation is used to optimize the design of multilateral wells, where the parameters include the well path, well position, the completions design (e.g. ICD configuration), the production constraints and uncertainty from multiple realizations of a geological model.

The target application is the design of new multi-lateral complex wells within an established large study. The optimized well is included in the prediction scenario of a history matched model. The target full field models are very large (millions of cells) and have large amounts of wells (hundreds).

The parameterization of the well path and position is performed by constraining the well path to surfaces, and geometric translation. Laterals are independently parameterized allowing the tie-in depth, angle and length to be parameterized. Completion design is parameterized by compartment length, number of valves per compartment and valve inflow diameter. The complex completion design relies on advanced well modeling features of the reservoir simulator. Production constraints, such as target oil rates and water limits are considered within the optimization. Finally, the uncertainty from multiple geological realizations is accounted for; this is achieved by introduction of a risk aversion factor which penalizes the objective function by a scaled standard deviation.

Examples of optimization demonstrate long multi-lateral wells being optimized within a Full field study. The sensitivity of each parameter is studied, i.e. the effect of oil production on the well position, effect of modifying ICD inflow area, the ICD compartment length, the water handling limits, and the geological uncertainty.

The major significance of this work is the provision of a system to enable engineers to produce an optimal well configuration given geological, production, well placement and completion (ICD) uncertainties in a timely fashion. The use of optimization assists the engineer in designing an optimal solution given many variables.
Modeling Multi-tubing Wells in Reservoir Simulation
Authors: Browning David J. , Morton Alison
Published: February 2011

This paper describes the modeling of single and dual tubing wells in a full-field reservoir simulator. The tubings associated with each well are modeled in terms of one primary and one or more secondary wells. The multi-segment well modeling techniques incorporated in the simulator have been extended to model multi-tubing systems thereby avoiding the requirement to model special grid blocks representing a wellbore. Wells with two or more tubings present a significant challenge to reservoir simulation where traditionally the coupling of the well with the reservoir, however complex, is solved in terms of a single surface inlet or outlet.

The case studies have been selected to demonstrate that injectors and producers can both be modeled in terms of primary and secondary wells both with targets and constraints. Comparisons are presented showing the differences between single and dual tubing injection and production schemes. An example of a multi-tubing production schemes is also included. These demonstrate that modeling wells with two or more tubings using the multi-segment well approach is practicable for the simulation of hydrocarbon recovery processes.
Application of Operator Splitting Technique in Numerical Simulation of Gas Hydrate Reservoirs
Authors: Shahbazi A. , Pooladi-Darvish M.
Published: February 2011

Modeling of hydrate reservoirs has revealed large timescale discrepancies between the involved mechanisms. Compared to the fluid and heat flow terms, the timescale of the kinetics term is orders of magnitude smaller, especially when the intrinsic reaction rate is large. Previous studies have shown that simulation of hydrates may require very small time steps, due to a convergence problem. Further investigations have shown that, for sharp decomposition cases where dissociation occurs in a narrow region, non-physical oscillation becomes a simulation issue, unless very small time steps are chosen. A three-dimensional numerical model incorporating heat/fluid flow, with kinetics of decomposition and (re)formation of hydrates has been developed. In this paper, a methodology for the use of larger time steps is proposed without loss of accuracy. The focus of this work is on the decoupling of the reaction and flow operators. The decoupling, or so-called operator splitting, helps to select different time steps for different mechanisms. The success of the splitting methodology in saving computational time is demonstrated for two cases. The first case shows oscillatory solutions, and the application of operator splitting allows for an oscillation free solution at a smaller run time. In the second case, a problem with a range of reaction constants is studied. Obtaining a stable solution requires adjusting the overall time step, such that the problem with the larger reaction rate requires very small time steps. The application of operator splitting in this case allows for a stable solution with much larger time steps. The contribution of this work is the computational timesaving in large-scale simulations of gas hydrate reservoirs without losing accuracy. Furthermore, using the splitting technique does not require a change of physically determined parameters, including the reaction constants.
Exploiting Capabilities of Many Core Platforms in Reservoir Simulation
Authors: Klie Hector , Sudan Hari , Li Ruipeng , Saad Yousef
Published: February 2011

The forthcoming generation of many-core architectures suggests a strong paradigm shift in the way algorithms have been designed to achieve maximum performance in reservoir simulations. In this work, we propose a novel poly-algorithmic solver approach to develop hybrid CPU multicore and GPU computations for solving large sparse linear systems arising in realistic black oil and compositional flow scenarios. The GPU implementation exploits data parallelism through the simultaneous deployment of thousands of threads while reducing memory overhead per floating point operations involved in most BLAS kernels and in a suite of preconditioner options such as BILU(k), BILUT and multicoloring SSOR. On the other hand, multicore CPU computations are used to exploit functional parallelism to perform system partitioning and reordering, algebraic multigrid preconditioning, sparsification and model reduction operations in order to accelerate and reduce the number of GCR iterations. The efficient orchestration of these operations relies on carefully designing the heuristics depending on the timestep evolution, degree of nonlinearity and current system properties. Hence, we also propose several criteria to automatically decide the type of solver configuration to be employed at every time step of the simulation. To illustrate the potentials of the proposed solver approach, we perform numerical computations on state-of-the-art multicore CPU and GPU platforms. Computational experiments on a wide range of highly complex reservoir cases reveal that the solver approach yields significant speedups with respect to conventional CPU multicore solver implementations. The solver performance gain is of the order of 3x which impacts in about 2x the overall compositional simulation turnaround time. These results demonstrate the potential that many core solvers have to offer in improving the performance of near future reservoir simulations.
Mixed Multiscale Finite Volume Method for Reservoir Simulation in Porous Media with Non Local Features
Authors: Mishev Ilya , Jiang Lijian
Published: February 2011

Multiscale finite volume (MsFV) methods have been successfully applied to solving reservoir simulation problems with localized high heterogeneity (i.e., separable scales), but the accuracy decreases when this is not possible (non-separable scales and long-range features). We develop a mixed multiscale finite volume method (MMsFV) on a uniform mesh that can use global information in order to improve the accuracy and the robustness of the multiscale simulations of fluid flows in porous media with non-local features.

Our development starts with the observation that multi-point flux approximation (MPFA) methods implicitly approximate the velocity and therefore any multiscale generalization also has to do the same. MsFV uses multiscale approximation of the pressure and piecewise constant approximation of the velocity. The novelty of the mixed MsFV method is the explicit approximation of the velocity. We construct a new multiscale basis for the velocity and approximate the pressure with piecewise constants. The velocity basis functions can be calculated with either local information (local mixed MsFV) or global information (global mixed MsFV). We demonstrate the improved accuracy of the global mixed MsFV compared to the local version on several problems including the SPE 10 comparative solution problem. The error of the global mixed MsFV is usually much smaller than the error of the local method when porous media exhibit non-local features.

Using the same framework and the extra flexibility of the two approximation spaces other mixed multiscale finite volume methods can be derived including extensions to unstructured meshes.