bluuebunny/crossref_metadata_2025 huggingface dataset:
The Other Side of the Radar: PATCO and the Airlines
Authors: Orenic Liesl
Published: December 2012

This issue's Bookmark section focuses on Joseph A. McCartin's Collision Course: Ronald Reagan, the Air Traffic Controllers, and the Strike that Changed America. While drawing raves for the power of its narrative and depth of research, McCartin's work also attracts questions and criticism from a range of well-informed commentators. Liesl Orenic wonders about the connections, real or fatefully missed, between the controllers and other workers and unions in the airline industry. Former controller David Sapadin emphasizes the impact of new automation systems on the controllers' work process as an underacknowledged factor in the 1981 strike defeat. Jack Metzgar gratefully leans on McCartin's careful storytelling to tease out a counterfactual narrative — i.e., a victory that would truly have “changed America” — but as the PATCO strike unfolded, Metzgar doubts it had much impact on the strikebreaking paradigms of the 1980s. Rosemary Feurer, in turn, seeks to rescue the creative and even heroic strains of resistance in the controllers' initiative, challenging the message that McCartin's readers may derive that impetuous union leaders led their members over a cliff. McCartin, of course, has the last word.
“The End of Collaboration”: Industrial Relations' Re-Engagement of the Labor Question and Progressive Labor Policy Activism
Authors: Hillard Michael
Published: December 2012

This roundtable is a frank state-of-the-field discussion by leading scholars of industrial relations. Whereas the decline of organized labor has likely helped push labor history into new arenas of inquiry, the near-collapse of collective bargaining represents a more existential threat to the discipline of industrial relations. In the event, as four experts attest, the “mother field” or industrial relations – labor economics is now looking to its labor history offspring as one source of re-inspiration. Following Michael Hillard's introductory overview, Thomas A. Kochan, Rosemary Batt, and Richard McIntyre set the current crisis in the context of the dispersion of both the institutional economics of the long New Deal era as well as the class-collaborative “Japanese” or “Saturn Motors” models of workplace efficiency that (briefly) succeeded them. A more combative policy agenda together with a Marxist-inspired theoretical critique—both looking to connect with labor history scholarship—has most recently come to the fore.
From the Editors—Brainstorming, Multiplicative Utilities, Partial Information on Probabilities or Outcomes, and Regulatory Focus
Authors: Keller L. Robin , Abbas Ali , Bickel J. Eric , Bier Vicki M. , Budescu David V. , Butler John C. , Diecidue Enrico , Dillon-Merrill Robin L. , Hämäläinen Raimo P. , Lichtendahl Kenneth C. , Merrick Jason R. W. , Simon Jay R. , Wu George
Published: December 2012

This is the final issue under this Editor-in-Chief, so this column is fittingly coauthored with the associate editors, whose terms also end with this issue, to emphasize their major role in the leadership of the journal. We first introduce incoming Editor-in-Chief Rakesh K. Sarin, briefly review this year's operations, and thank our editorial board and referees. Then we move on to this issue's five research articles. In our first article, Ralph L. Keeney presents “Value-Focused Brainstorming.” Next, Kenneth C. Lichtendahl Jr. and Samuel E. Bodily develop models for “Multiplicative Utilities for Health and Consumption.” Then, Luis V. Montiel and J. Eric Bickel present “A Simulation-Based Approach to Decision Making with Partial Information.” Our fourth article, by Kash Barker and Kaycee J. Wilson, is “Decision Trees with Single and Multiple Interval-Valued Objectives.” Our final article, by Anton Kühberger and Christian Wiener, is on “Explaining Risk Attitude in Framing Tasks by Regulatory Focus: A Verbal Protocol Analysis and a Simulation Using Fuzzy Logic.”
Crucible of California Capitalism
Authors: Lynch Timothy G.
Published: December 2012

The Pacific Mail Steamship Company’s shipyard in Benicia, California, established in 1850, represents a very early case of hi-tech, vertically integrated industry on the West Coast. The Benicia works made an important impact on skilled labor, shipping, and economic development in the region.
Benevolent Desires and Dark Dominations
Authors: Greenfield Mary C.
Published: December 2012

The career of the Pacific Mail Steamship Company’s SS City of Peking, 1874–1910, both outlined and undermined the currents of American cultural identity, national policy, industrial development, and immigration and labor history. Most significantly, the roles it played in the establishment of an American Pacific challenged the moral foundations on which the American political system was founded.
Interactions of NADP-Reducing Enzymes Across Varying Environmental Conditions: A Model of Biological Complexity
Authors: Rzezniczak Teresa Z , Merritt Thomas J S
Published: December 2012

Interactions across biological networks are often quantified under a single set of conditions; however, cellular behaviors are dynamic and interactions can be expected to change in response to molecular context and environment. To determine the consistency of network interactions, we examined the enzyme network responsible for the reduction of nicotinamide adenine dinucleotide phosphate (NADP) to NADPH across three different conditions: oxidative stress, starvation, and desiccation. Synthetic, activity-variant alleles were used in Drosophila melanogaster for glucose-6-phosphate dehydrogenase (G6pd), cytosolic isocitrate dehydrogenase (Idh), and cytosolic malic enzyme (Men) along with seven different genetic backgrounds to lend biological relevance to the data. The responses of the NADP-reducing enzymes and two downstream phenotypes (lipid and glycogen concentration) were compared between the control and stress conditions. In general, responses in NADP-reducing enzymes were greater under conditions of oxidative stress, likely due to an increased demand for NADPH. Interactions between the enzymes were altered by environmental stress in directions and magnitudes that are consistent with differential contributions of the different enzymes to the NADPH pool: the contributions of G6PD and IDH seem to be accentuated by oxidative stress, and MEN by starvation. Overall, we find that biological network interactions are strongly influenced by environmental conditions, underscoring the importance of examining networks as dynamic entities.
A TargetedIn VivoRNAi Screen Reveals Deubiquitinases as New Regulators of Notch Signaling
Authors: Zhang Junzheng , Liu Min , Su Ying , Du Juan , Zhu Alan Jian
Published: December 2012

Notch signaling is highly conserved in all metazoan animals and plays critical roles in cell fate specification, cell proliferation, apoptosis, and stem cell maintenance. Although core components of the Notch signaling cascade have been identified, many gaps in the understanding of the Notch signaling pathway remain to be filled. One form of posttranslational regulation, which is controlled by the ubiquitin-proteasome system, is known to modulate Notch signaling. The ubiquitination pathway is a highly coordinated process in which the ubiquitin moiety is either conjugated to or removed from target proteins by opposing E3 ubiquitin ligases and deubiquitinases (DUBs). Several E3 ubiquitin ligases have been implicated in ubiquitin conjugation to the receptors and the ligands of the Notch signaling cascade. In contrast, little is known about a direct role of DUBs in Notch signaling in vivo. Here, we report an in vivo RNA interference screen in Drosophila melanogaster targeting all 45 DUBs that we annotated in the fly genome. We show that at least four DUBs function specifically in the formation of the fly wing margin and/or the specification of the scutellar sensory organ precursors, two processes that are strictly dependent on the balanced Notch signaling activity. Furthermore, we provide genetic evidence suggesting that these DUBs are necessary to positively modulate Notch signaling activity. Our study reveals a conserved molecular mechanism by which protein deubiquitination process contributes to the complex posttranslational regulation of Notch signaling in vivo.
Multiple Mechanisms Contribute to Lateral Transfer of an Organophosphate Degradation (opd) Island in Sphingobium fuliginis ATCC 27551
Authors: Pandeeti Emmanuel Vijay Paul , Longkumer Toshisangba , Chakka Deviprasanna , Muthyala Venkateswar Reddy , Parthasarathy Sunil , Madugundu Anil Kumar , Ghanta Sujana , Medipally Srikanth Reddy , Pantula Surat Chameli , Yekkala Harshita , Siddavattam Dayananda
Published: December 2012

The complete sequence of pPDL2 (37,317 bp), an indigenous plasmid of Sphingobium fuliginis ATCC 27551 that encodes genes for organophosphate degradation (opd), revealed the existence of a site-specific integrase (int) gene with an attachment site attP, typically seen in integrative mobilizable elements (IME). In agreement with this sequence information, site-specific recombination was observed between pPDL2 and an artificial plasmid having a temperature-sensitive replicon and a cloned attB site at the 3′ end of the seryl tRNA gene of Sphingobium japonicum. The opd gene cluster on pPDL2 was found to be part of an active catabolic transposon with mobile elements y4qE and Tn3 at its flanking ends. Besides the previously reported opd cluster, this transposon contains genes coding for protocatechuate dioxygenase and for two transport proteins from the major facilitator family that are predicted to be involved in transport and metabolism of aromatic compounds. A pPDL2 derivative, pPDL2-K, was horizontally transferred into Escherichia coli and Acinetobacter strains, suggesting that the oriT identified in pPDL2 is functional. A well-defined replicative origin (oriV), repA was identified along with a plasmid addiction module relB/relE that would support stable maintenance of pPDL2 in Sphingobium fuliginis ATCC 27551. However, if pPDL2 is laterally transferred into hosts that do not support its replication, the opd cluster appears to integrate into the host chromosome, either through transposition or through site-specific integration. The data presented in this study help to explain the existence of identical opd genes among soil bacteria.
In VivoRegulation of E2F1 by Polycomb Group Genes inDrosophila
Authors: Ji Jun-Yuan , Miles Wayne O , Korenjak Michael , Zheng Yani , Dyson Nicholas J
Published: December 2012

The E2F transcription factors are important regulators of the cell cycle whose function is commonly misregulated in cancer. To identify novel regulators of E2F1 activity in vivo, we used Drosophila to conduct genetic screens. For this, we generated transgenic lines that allow the tissue-specific depletion of dE2F1 by RNAi. Expression of these transgenes using Gal4 drivers in the eyes and wings generated reliable and modifiable phenotypes. We then conducted genetic screens testing the capacity of Exelixis deficiencies to modify these E2F1-RNAi phenotypes. From these screens, we identified mutant alleles of Suppressor of zeste 2 [Su(z)2] and multiple Polycomb group genes as strong suppressors of the E2F1-RNA interference phenotypes. In validation of our genetic data, we find that depleting Su(z)2 in cultured Drosophila cells restores the cell-proliferation defects caused by reduction of dE2F1 by elevating the level of dE2f1. Furthermore, analyses of methylation status of histone H3 lysine 27 (H3K27me) from the published modENCODE data sets suggest that the genomic regions harboring dE2f1 gene and certain dE2f1 target genes display H3K27me during development and in several Drosophila cell lines. These in vivo observations suggest that the Polycomb group may regulate cell proliferation by repressing the transcription of dE2f1 and certain dE2F1 target genes. This mechanism may play an important role in coordinating cellular differentiation and proliferation during Drosophila development.
Evidence for Population-Specific Positive Selection on Immune Genes ofAnopheles gambiae
Authors: Crawford Jacob E , Bischoff Emmanuel , Garnier Thierry , Gneme Awa , Eiglmeier Karin , Holm Inge , Riehle Michelle M , Guelbeogo Wamdaogo M , Sagnon N’Fale , Lazzaro Brian P , Vernick Kenneth D
Published: December 2012

Host-pathogen interactions can be powerful drivers of adaptive evolution, shaping the patterns of molecular variation at the genes involved. In this study, we sequenced alleles from 28 immune-related loci in wild samples of multiple genetic subpopulations of the African malaria mosquito Anopheles gambiae, obtaining unprecedented sample sizes and providing the first opportunity to contrast patterns of molecular evolution at immune-related loci in the recently discovered GOUNDRY population to those of the indoor-resting M and S molecular forms. In contrast to previous studies that focused on immune genes identified in laboratory studies, we centered our analysis on genes that fall within a quantitative trait locus associated with resistance to Plasmodium falciparum in natural populations of A. gambiae. Analyses of haplotypic and genetic diversity at these 28 loci revealed striking differences among populations in levels of genetic diversity and allele frequencies in coding sequence. Putative signals of positive selection were identified at 11 loci, but only one was shared by two subgroups of A. gambiae. Striking patterns of linkage disequilibrium were observed at several loci. We discuss these results with respect to ecological differences among these strata as well as potential implications for disease transmission.
Molecular and genetic background of sudden cardiac death
Authors: Simkó József , Szabó Zoltán , Barta Kitti , Újvárosi Dóra , Nánási Péter , Lőrincz István
Published: December 2012

Despite recent findings on the functional, structural and genetic background of sudden cardiac death, the incidence is still relatively high in the entire population. A thorough knowledge on susceptibility, as well as pathophysiology behind the development of malignant arrhythmias will help us to identify individuals at risk and prevent sudden cardiac death. This article presents a review of the current literature on the role of altered intracellular Ca2+ handling, acute myocardial ischaemia, cardiac autonomic innervation, renin-angiotensin-aldosterone system, monogenic and complex heritability in the pathogenesis of sudden cardiac death. Orv. Hetil., 2012, 153, 1967–1983.
Novel quality assurance method in oncology: the two-level, multi-disciplinary and oncotherapy oncology team system
Authors: Mangel László , Kövér Erika , Szilágyi István , Varga Zsuzsanna , Bércesi Éva , Nagy Zsuzsanna , Holcz Tibor , Karádi Oszkár , Farkas Róbert , Csák Szilvia , Csere Tibor , Kásler Miklós
Published: December 2012

By now therapy decision taken by a multi-disciplinary oncology team in cancer care has become a routine method in worldwide. However, multi-disciplinary oncology team has to face more and more difficulties in keeping abreast with the fast development in oncology science, increasing expectations, and financial considerations. Naturally the not properly controlled decision mechanisms, the permanent lack of time and shortage of professionals are also hindering factors. Perhaps it would be a way out if the staff meetings and discussions of physicians in the oncology departments were transformed and provided with administrative, legal and decision credentials corresponding to those of multi-disciplinary oncology team. The new form of the oncotherapy oncoteam might be able to decide the optimal and particular treatment after previous consultation with the patient. The oncotherapy oncoteam is also suitable to carry out training and tasks of a cancer centre and by diminishing the psychological burden of the doctors it contributes to an improved patient care. This study presents the two-level multi-disciplinary and oncotherapy oncology team system at the University of Pécs including the detailed analysis of the considerations above. Orv. Hetil., 2012, 153, 1984–1991.
A Pilot Study of the Impact of Housing First–Supported Housing for Intensive Users of Medical Hospitalization and Sobering Services
Authors: Srebnik Debra , Connor Tara , Sylla Laurie
Published: December 2012

Objectives. We examined changes in service use in a Housing First (HF) pilot program for adults who were homeless with medical illnesses and high prior acute-care use relative to a similar comparison group.

Methods. We used a 1-year pre–post comparison group design. The 29 participants and 31 comparison group members were adults who were homeless with inpatient claims of at least $10 000 or at least 60 sobering “sleep off” center contacts in the prior year.

Results. Participants showed a significantly greater reduction in emergency department and sobering center use relative to the comparison group. At a trend level, participants had greater reductions in hospital admissions and jail bookings. Reductions in estimated costs for participants and comparison group members were $62 504 and $25 925 per person per year—a difference of $36 579, far outweighing program costs of $18 600 per person per year.

Conclusions. HF participants showed striking reductions in acute-care use relative to the comparison group, demonstrating that HF can be a successful model for people with complex medical conditions and high prior acute-care use. Despite notable methodological limitations, these findings could be used to inform a larger multisite study that would establish greater generalizability.
Effects of Socioeconomic Status and Health Care Access on Low Levels of Human Papillomavirus Vaccination Among Spanish-Speaking Hispanics in California
Authors: Chando Shingisai , Tiro Jasmin A. , Harris T. Robert , Kobrin Sarah , Breen Nancy
Published: December 2012

Little is known about the effect of language preference, socioeconomic status, and health care access on human papillomavirus (HPV) vaccination. We examined these factors in Hispanic parents of daughters aged 11 to 17 years in California (n = 1090). Spanish-speaking parents were less likely to have their daughters vaccinated than were English speakers (odds ratio [OR] = 0.55; 95% confidence interval [CI] = 0.31, 0.98). Adding income and access to multivariate analyses made language nonsignificant (OR = 0.68; 95% CI = 0.35, 1.29). This confirms that health care use is associated with language via income and access. Low-income Hispanics, who lack access, need information about free HPV vaccination programs.
One-Dimensional Inversion of Full Waveforms using a Genetic Algorithm
Authors: Tran Khiem T. , Hiltunen Dennis R.
Published: December 2012

A technique is presented to invert full waveforms using a genetic algorithm. The inversion scheme is based on a finite-difference solution of the 2-D elastic wave equation in the time-distance domain. The strength of this approach is the ability to generate all possible wave types (body waves and surface waves, etc.) and thus to simulate complex seismic wavefields that are then compared with observed data to infer subsurface properties. The capability of this inversion technique is tested with both synthetic and real experimental data sets. The inversion results from synthetic data show the ability of characterizing both low- and high-velocity layers, and the inversion results from real data are generally consistent with crosshole, SPT N-value, and material log results, including the identification of a buried low-velocity layer. Based upon the cases presented, coupling of global optimization with full waveforms is computationally practical, as the results presented herein were all achieved in about two hours of computer time on a standard laptop computer.
Laboratory Investigation of Dynamic Growth of Asphaltene Deposition and Formation Damage on Sandstone Cores
Authors: Ali Mohammad A. , Kholosy S. M. , Al-Haddad A. A
Published: December 2012

A live oil sample was subjected to a solid detection system (SDS) to measure asphaltene onset point (AOP) at 3850 psi, and asphaltene content of 1.3%. A high-resolution digital camera was used to measure asphaltene particle size distribution. The result showed that asphaltene particles were not uniform in size, but has a normal distribution of 100–120 μm. Asphaltene reversibility to dissolved back into the oil with increasing pressure was only 35% of the original deposition. Two core samples were examined for formation damage due to asphaltene deposition. A Low permeability core showed significant permeability reduction exceeding 50% of its baseline permeability, and the higher permeability core showed less permeability decline, even with the same asphaltene precipitation.
Laboratory Challenges of Sand Production in Unconsolidated Cores
Authors: Ali Mohammad A. , Al-Hamad K.. , Al-Haddad A.. , AlKholosy S.. , Sennah H. Abu , Sanyal T.. , Aniel J..
Published: December 2012

Improved oil recovery for heavy oil reservoirs is becoming a new research study for Kuwaiti reservoirs. There are two mechanisms for improved oil recovery by thermal methods. The first method is to heat the oil to higher temperatures, and thereby, decrease its viscosity for improved mobility. The second mechanism is similar to water flooding, in which oil is displaced to the production wells. While more steam is needed for this method than for the cyclic method, it is typically more effective at recovering a larger portion of the oil.

Steam injection heats up the oil and reduce its viscosity for better mobility and higher sweep efficiency. During this process, the velocity of the moving oil increases with lower viscosity oil; and thus, the heated zone around the injection well will have high velocity. The increase of velocity in an unconsolidated formation is usually accompanied with sand movement in the reservoir creating a potential problem.

The objective of this study was to understand the effect of flowrate and viscosity on sand production in heavy oil reservoir that is subjected for thermal recovery process. The results would be useful for designing completion under steam injection where the viscosity of the oil is expected to change due to thermal operations.

A total of 21 representative core samples were selected from different wells in Kuwait. A reservoir condition core flooding system was used to flow oil into the core plugs and to examine sand production. Initially, the baseline liquid permeability was measured with low viscosity oil and low flowrate. Then, the flowrate was increased gradually and monitored to establish the value for sand movement for each plug sample. At the end of the test, the produced oil containing sand was filtered for sand content.

The result showed that sand production increased with higher viscosity oil and high flowrate. However, sand compaction at the injection face of the cores was more significant than sand production. In addition, high confining pressure contributes to additional sand production. The average critical velocity was estimated ranged from 18 to 257 ft/day for the 0.74 cp oil, 2 to 121 ft/day for the 16 cp oil, and 1 to 26 ft/day for the 684 cp oil.
Laboratory Evaluation of Organically Crosslinked Polymer for Water Shutoff in High-Temperature Well Applications
Authors: Salgaonkar Lalit , Das Prasanta
Published: December 2012

Excessive water production from unwanted zones in oil producing wells is one of the major challenges faced by the oil industry. The applicability of organically crosslinked polymer (OCP) systems as sealants for water shutoff treatments in temperatures up to 350°F is well documented. However, their effectiveness at temperatures above 350°F has not been evaluated. This paper presents experimental data from using an OCP system for water shutoff treatments at 400°F.

At temperatures around 400°F, crosslinking is expected to happen faster and can lead to premature gelation of the recipe before the entire treatment is in place. Thus, controlling the gelation time at such temperatures is extremely crucial. Optimizing the amount of retarder is essential to provide adequate time for placement of the treatment fluid. This paper provides gelation time data at temperatures between 350 and 400°F with different amounts of retarder. With an optimum amount of retarder, the OCP showed a gelation time of 1 hr 20 min.

This paper also describes the experimental setup used to study and determine the long-term stability of the OCP system at 400°F. Sand packs measuring 1-ft long were used for the test to simulate formation conditions. Once the optimized OCP recipe was gelled inside the sand pack, measurements were taken by gradually applying incremental differential pressure (ΔP) to evaluate the sealant at temperature, as well as the threshold ΔP the system could withstand. Even after one month at 400°F, the OCP recipe was able to sustain a AP of 950 psi over the sand pack.

The data indicates the applicability of this system as an effective conformance product to shut off water-producing zones over an extended period of time at 400°F.
Optimization of Polymer Flood Performance by Preflush Injection - Numerical Investigation
Authors: Abedi M.. , Algharaib M..
Published: December 2012

Currently, many reservoirs in the region approach the end of primary recovery phase where new techniques are needed to enhance recovery. Therefore, the need to optimize oil recovery from the current resources is very well understood by regional oil companies. To enhance oil recovery from current oil resources, field operators need to overcome the forces responsible for oil entrapment. Enhanced Oil Recovery techniques (EOR) introduce new energy into oil reservoirs to reduce the influence of these forces. Most of these resources contain light oil and are considered suitable candidates for either miscible or chemical EOR techniques. The first technique is challenged by the availability of suitable miscible gas. While, chemical EOR techniques are challenges by the high salt concentrations in the maturing oil reservoirs. The high salinity conditions encourage deficiencies in the performance of chemical EOR processes. Therefore, minimizing the effect of in situ salt on the injected chemical would impose tremendous improvement that leads to higher oil recovery. One way to diminish salt effect is to condition the oil reservoirs by injecting a slug of preflush water prior to chemical injection.

In this paper, the performance of polymer flooding, after preflush slug, in high salinity reservoir is investigated by numerical simulation means. The injected slugs, both preflush and polymer, are driven by water. The objective is to identify the relationship between preflush, polymer, and drive water characteristics and oil recovery. Seven parameters were considered: preflush slug size, preflush salinity, polymer slug size, polymer concentration, polymer slug salinity, and drive water salinity. The results show that these parameters have various degree of influence on oil recovery. For example, increasing the preflush slug size would results in more oil recovery especially during the early time. Detailed findings will be presented in the paper.
Efficient Polynomial Chaos Proxy-based History Matching and Uncertainty Quantification for Complex Geological Structures
Authors: Bazargan Hamid , Christie Mike
Published: December 2012

The purpose of history matching is to achieve geological realizations calibrated to the historical performance of the reservoir. For complex geological structures it is usually intractable to run tens of thousands of full reservoir simulation to trace the most probable geological model. Hence the inadequacy of the history-matching results frequently leads to poor estimation of the true model and high uncertainty in production forecasting. Reduced-order modeling procedures, which have been applied in many application areas including reservoir simulation, represent a promising means for constructing efficient surrogate models. Nonlinear dimensionality reduction techniques allow for encapsulating the high-resolution complex geological description of reservoir into a low-dimensional subspace, which significantly reduces number of unknowns and provides an efficient way to construct a proxy model based on the the reduced-dimension parameters.

Polynomial Chaos Expansions (PCE) is a powerful tool to quantify uncertainty in dynamical system when there is probabilistic uncertainty in the system parameters. In reservoir simulation it has been shown to be more accurate and efficient compared to traditional experimental design (ED). PCEs have a significant advantage over other response surfaces as the convergence to the true probability distribution is proved when the order of the PCE is increased. Accordingly PCE proxy can be used as the pseudo-simulator to represent the surface responses of the uncertain variables. When the objective and constraints of a reservoir model is described by multivariate polynomial functions, there are very efficient algorithms to compute the global solutions. We have developed a workflow at which incorporates PCE to find the global minimum of the misfit surface and assess the uncertainty associated with. The accuracy of the PCE proxy increases with the additional trial runs of the reservoir simulator.

We conduct a two dimensional synthetic case study of a fluvial channel as well as a real field example to demonstrate the effectiveness of this approach. Kernel Principal Component Analysis (KPCA) is used to parameterize the complex geological structure. The study has revealed useful reservoir information and delivered more reliable production forecasts. PCE-based history match enhances the quality and efficiency of the estimation of the most probable geological model and improve the confidence interval of production forecasts.
Utilising Process Safety Management to Reduce Risks in E&P Operations - Long Term Commitment Required.
Authors: Gopaul G. A. , Al-Kandari H.. , Al Qallaf H..
Published: December 2012

In April 2010 we were reminded that Drilling operations are amongst the most hazardous in the world, having the potential for Major Incidents, with the Deepwater Horizon rig fire and explosion. This incident resulted in 11 lives being lost, almost 5,000,000 million barrels of oil being spilt into the Gulf of Mexico over an 87 day period and significant financial loss for bp. This Major Incident also served to remind us that while traditional "Personal Safety" programs are important to achieve safe drilling operations, these alone cannot effectively manage Major Incident Hazards. E&P Operations can learn valuable lessons from the Process Industry in this regard.

This paper looks at how "Process Safety Management" implementation, aimed at reducing the potential for Major Incidents, has commenced at an onshore E&P operation. It also discusses the challenges of integrating the culture of Process Safety into existing company culture for operations involving over 60 land rigs comprising both local and international Drilling Contractors and Service Companies.

Process Safety Management system is used to describe those parts of an organisation’s management system intended to prevent major incidents arising out of the production, storage and handling of dangerous substances (UK HSE, 2012). It addresses the potential release of these substances caused by: Mechanical FailuresProcess UpsetsProcedures/Human Error.
Third Generation Glass Barrier Technology: Improving Well Completion Integrity and Reliability
Authors: Gimre Rune , Maitre Shawn Le
Published: December 2012

In recent times the topic of well barrier integrity has become increasingly salient. Within the well completion arena, there have traditionally been two main alternatives for barrier plugs used for packer setting or temporary well abandonment; these are the metallic flapper or ball type isolation plugs. This paper describes the evolution of an innovative glass type barrier plug from its first appearance in the oilfield in 2004, to the deployment of third generation prototype systems into wells in the North Sea today.

Traditional ball or flapper type plug systems need to operate in two states: open and closed. This functionality typically necessitates the use of dynamic seals, which also have to compensate for the pressure differential applied across the plug. Plugs built in this manner can be prone to malfunctions in the dynamic seals and have limitations as to the pressure differentials that can be applied to them when opening. Additionally as the balls or flappers themselves are traditionally manufactured using metallic alloys, in the event that a plug fails to open the only alternative is milling, which if successful, will still leave a restriction in the well limiting options for future well interventions.

Glass barrier plugs have to operate in two slightly different states, solid or shattered. When the plug is run in hole the glass is in a solid state with pressure integrity maintained using static elastomeric seals. Once well operations have progressed to the stage when the plug needs to be opened, a preinstalled trip saver can be activated which would shatter the glass and open well communication. Operating in this manner avoids the use of dynamic seals thereby increasing plug reliability. Other major advantages are that the differential pressure applied across the plug when opening has no effect on the plugs functionality and since the plug is made out of glass, in the event of a trip saver malfunction the plug can be opened using a shoot down tool, a spear, or milled within approximately 10 minutes using a wireline tractor (Welltec, 2011) leaving a full bore ID for future well interventions.

This paper describes how BP Norway and TCO used the lessons learned from two generations of Glass Barrier Plugs (GBPs) to develop a system with increased debris tolerance, improved redundancy and a larger inner diameter.
Heavy Oil and Tar Mat Characterization Within a Single Oil Column Utilizing Novel Asphaltene Science
Authors: Seifert Douglas J. , Qureshi Ahmed , Zeybek Murat , Pomerantz Andrew E. , Zuo Julian Y. , Mullins Oliver C.
Published: December 2012

A Jurassic oil field in Saudi Arabia is characterized by black oil in the crest, with heavy oil underneath and all underlain by a tar mat at the oil-water contact (OWC). The viscosities in the black oil section of the column are similar throughout the field and are quite manageable from a production standpoint. In contrast, the mobile heavy oil section of the column contains a large, continuous increase in asphaltene content with increasing depth extending to the tar mat. Both the excessive viscosity of the heavy oil and the existence of the tar mat represent major, distinct challenges in oil production. A simple new formalism, the Flory-Huggins-Zuo (FHZ) Equation of State (EoS) incorporating the Yen-Mullins model of asphaltene nanoscience, is shown to account for the asphaltene content variation in the mobile heavy oil section. Detailed analysis of the tar mat shows significant nonmonotonic content of asphaltenes with depth, differing from that of the heavy oil. While the general concept of asphaltene gravitational accumulation to form the tar mat does apply, other complexities preclude simple monotonic behavior. Indeed, within small vertical distances (5 ft) the asphaltene content can decrease by 20% absolute with depth. These complexities likely involve a phase transition when the asphaltene concentration exceeds 35%. Traditional thermodynamic models of heavy oils and asphaltene gradients are known to fail dramatically. Many have ascribed this failure to some sort of chemical variation of asphaltenes with depth; the idea being that if the models fail it must be due to the asphaltenes. Our new simple formalism shows that thermodynamic modeling of heavy oil and asphaltene gradients can be successful. Our simple model demands that the asphaltenes are the same, top to bottom. The analysis of the sulfur chemistry of these asphaltenes by X-ray spectroscopy at the synchrotron at the Argonne National Laboratory shows that there is almost no variation of the sulfur through the hydrocarbon column. Sulfur is one of the most sensitive elements in asphaltenes to demark variation. Likewise, saturates, araomatics, resins and asphaltenes (SARA); measurements also support the application of this new asphaltene formalism. Consequently, the asphaltenes are very similar, and our new FHZ EoS with the Yen-Mullins formalism properly accounts for heavy oil and asphaltene gradients.
Impact of Facies Modeling on Reservoir Performance Forecasting: a Comparison between Discrete Modeling and Mixed Lithology Approaches
Authors: Alqassab Hisham , Vaughan Lee
Published: December 2012

Facies modeling forms an integral part of geological numerical modeling. Over the last two decades, different facies modeling methods have been developed using geostatistical algorithms. Most of these methods rely on the assumption of discrete or binary modeling during which each model cell is assigned a single facies. In this study, the size of the cells is on average 100 meters by 100 meters laterally by one meter thick. Based on comparisons to outcrops and subsurface data, such cells should, in fact, include a mixture of facies.

The discrete-facies approach assumes a single facies per cell. The distribution of the facies between wells is described using classical categorical geostatistical algorithms. Reservoir properties are then populated by facies within mapped environments of deposition. This process is well-established and straightforward, especially with regard to tying well data, handling property trends, and applying net rock cut-offs.

A mixed-facies approach can be performed using effective property modeling in which multiple small, fine-scale models are built for each environment of deposition. These models are re-sampled to the full-field cell volume using static and flow-based upscaling methods. The resulting statistics are then used with geostatistics, conditioned to the proportion of each facies present, to populate the full-field model. Such models allow the incorporation of core-scale heterogeneity potentially important in improved oil recovery projects, and may reduce modeling cycle times, especially when multiple iterations are required, such as during history-matching or uncertainty analysis.

This paper compares the impact on simulated fluid flow of modeling facies using discrete modeling versus a mix of facies per cell. Shoreface and subordinate fluvial environments of deposition facies, and five reservoir lithofacies, were modeled.

Fluid-flow simulation of the mixed-facies model, under both primary depletion and pressure maintenance conditions, was smooth and uniform, with a highly conformable flood front. The discrete model was more stratified, with faster and less conformable water movement.

The assignment of discrete facies to large model cells (few hundred meters laterally & few meters vertically) takes less time than a mixed-facies approach and does a better job of preserving organized extremes of permeability important at the production timescale. In the early stages of field development, when there is much uncertainty and a rapid, scenario-based modeling approach is desirable, the discrete approach can be used to flag heterogeneity-related risks more quickly and confidently than the mixed-facies technique. Inaccuracies in performance parameters resulting from the assignment of unscaled discrete values can be corrected using fine-scale sector models tailored to the highest risk cases.
Rock Typing and Characterization of Carbonate Reservoirs: A Case Study from South East Kuwait
Authors: Turkey S.. , Al-Kanderi J.. , Kumar P.. , Al-Alawi G.. , Al-Hashmi S.. , Al-Harthy A.. , Al-Raisi M..
Published: December 2012

This paper presents the main steps of rock-typing workflow and the technique applied to estimate permeability.

Reservoir rock typing (RRT) is a process of up-scaling detailed geological and petrophysical information to provide more accurate input for 3D geological and flow simulation models. The reservoir rocks that correspond to a particular rock type should have similar rock fabric, pore types and pore throat size distribution. The study integrated multi-scale data types to develop a robust and predictable rock type scheme. This consists of detailed sedimentological description of depositional environment and associated sedimentary features, detailed numerical petrographic analysis of rock texture, grain types, porosity types and rock mineralogy and petrophysical data grouping using openhole log and core plugs porosity-permeability relationship and pore throat size distribution (MICP).

The main objective was to develop a reliable reservoir rock type scheme that captures the heterogeneity in Jurassic carbonate reservoir for the Middle Marrat Formation in South East Kuwait area and implementation of the RRT to the permeability prediction within the field. Integration of the thin sections, porosity-permeability, pore throat size and distribution has resulted in the identification of reservoir rock types. A total of 14 different rock types were identified within the reservoir interval in the cored wells, which is subsequently grouped into eight due to modelling limitation. The RRT up-scaling was done in a way to minimize the impact of grouping on permeability and saturation computations. The prediction success between the cored RRT and the predicted RRT using openhole data is more than 85%. As a result, the permeability computation success between core plugs and computed permeability using the RRT is more than 80%.
Lower Your Crude Oil Dehydration OPEX using Enhanced Electrostatic Fields
Authors: Sellman Erik L. , Sams Gary , Mandewalkar S. Pavan Kumar
Published: December 2012

Abstract

Heavy crude oils and diluted Bitumen ( DilBit ) continue to be a challenge to dehydrate and desalt for the Oil & Gas Industry. These challenges include reduced crude oil / formation water density difference, higher crude oil viscosity and often smaller water droplets due the production techniques used for heavy crude oil production.

The traditional remedy to the above challenges often leads to high operating temperatures, large dosages of demulsifier chemicals, equipment fouling, production upsets and use of very large treaters. This leads to both higher operating expenditure ( OPEX ) as well as higher capital expenditure ( CAPEX ).

Other challenges include higher crude oil conductivity and increased crude oil emulsion viscosity formed by higher water cuts. Typically crude oil dehydration vessels use heat, retention time and AC type electrostatic dehydration technology. The AC technology produces limited voltage gradients and is not efficient for treating conductive crude oils, leading to the use of very large vessels and power units. For AC technology, the use of lower voltage gradient may be preferred.

The use of combined AC / DC electrostatic technologies provides high bulk water removal efficicency in the weaker AC field combined with higher removal efficiency of small water droplets in the stronger DC field. Further improvements include amplitude modulated electrostatic fields, high frequency AC fields, improved electrode configurations as well as improved fluid distribution inside the electrostatic treaters.

More efficient dehydration and desalting processes provide potential for operating the treaters and desalters at lower operating temperatures and reduced dosage of demulsifier chemicals, in addition to the potential for using smaller treaters.

This paper describes potential lowered OPEX for crude oil dehydration and desalting processes, using advanced electrostatic dehydration technologies, efficient test methods for optimized use of production chemicals and selection of electrostatic technologies, including case studies.
A Unique Emulsified Acid System with Three Intensifiers for Stimulation of Very High Temperature Carbonate Reservoirs
Authors: Pandya Nisha , Wadekar Sushant , Cassidy Juanita
Published: December 2012

The demand for hydrocarbons is expected to grow worldwide. As a result, deeper reservoirs are being explored. Emulsified acid systems are preferred for the stimulation of high-temperature carbonate reservoirs with bottomhole temperatures (BHTs) of 275°F and above. The retarded nature of an emulsified acid system decreases both the acid reaction rate and the rate of corrosion. However, the lack of emulsion stability of these systems is a major problem associated with high-temperature applications (at 300°F and above).

Corrosion inhibitors and intensifiers can interfere with the stability of an emulsified acid system, which consequently leads to higher corrosion losses. At the same time, there is a need for better inhibition systems to counteract the effects of corrosion at higher temperatures. In this paper, a combination of three intensifiers was used, based on the differences in their mechanisms for inhibitor intensification action. The study includes the effect of varying the concentration of each component, hydrochloric (HCl) acid strength (20 to 28%), and temperature (275 to 325°F) on the stability and corrosion rate using P-110/N-80 coupons. The unique combination of the corrosion inhibitor and three intensifiers with proper optimization created a system capable of passing a corrosion test at 300°F using 28% HCl acid. The temperature limit of the system can be extended up to 325°F using an additional intensifier with 25% acid strength.

The present system can be used for acid stimulation of carbonate reservoirs with BHTs up to 325°F. This study revealed a better understanding of the effect of the intensifiers in an emulsified acid system and the synergism amongst them. This enabled the use of an emulsified acid stimulation on carbonate reservoirs having BHTs up to 325°F while reducing the corrosion rate to a level that meets the current market demand for acidizing operations. This work shows that emulsified acid systems can be used with HCl acid strengths ranging from 20 to 28% at high temperatures. The resultant better wormholing at high temperatures should also lead to enhanced oil production.
Integrated Evaluation of Formation Damage/Remediation Potential of Low Permeability Reservoirs
Authors: Elkewidy Tarek Ibrahim
Published: December 2012

Oil or gas effective and relative permeabilities can be reduced to a great extent due to the invading liquid phase of the drill-in or completion fluid, contrary to the misconception that formation damage is less of a concern in lower permeability reservoirs (e.g., less than 5 md). Many laboratory, well logging, and formation tester data proved that mud filtrate (both from water- and oil-based muds) can deeply invade the formation enhanced by capillary forces. This will result in reduction of the oil or gas effective permeability, especially if the formation exhibits fluid emulsion blocks and phase trapping. Unfavorable interaction of the filtrate with the reservoir fluids and rock minerals can generate emulsions and precipitates. The same scenario may occur in hydraulically fractured formations.

An integrated multidisciplinary approach is pursued in this study to evaluate formation damage/remediation potential of low permeability reservoirs. The techniques involve different formation evaluation methods including core analysis, well logging, and well testing along with various cleanup scenarios. Furthermore, results from petrographic analysis and laboratory experiments (Micro and Macroscopic scales) are related and correlated with the larger Mesoscopic and Megascopic scales of well logs and well testing, respectively.

Results of these efforts lead to the following technical contributions; a) Delineation of the low permeability heterogeneous reservoirs, e.g. the Leduce carbonates, into their hydraulic units. b) Determination of the undamaged formation absolute and relative permeabilities along with the diameter of filtrate invasion. c) A rule of thumb is to minimize or prevent damage from taking place by selecting a drilling fluid that quickly forms an easily removable mudcake. d) Cleaning up damage due to water filtrate may be accomplished by just flowing the well and can be accelerated using solvents or surfactants. However, once the formation reaches its irreducible water saturation, remediating water saturation below the irreducible value may not significantly improve its permeability.