bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ccr4 Alters Cell Size in Yeast by Modulating the Timing of CLN1 and CLN2 Expression
Authors: Manukyan Arkadi , Zhang Jian , Thippeswamy Uma , Yang Jingye , Zavala Noelle , Mudannayake Malkanthi P , Asmussen Mark , Schneider Colette , Schneider Brandt L 
Published: May 2008

Abstract
Large, multisubunit Ccr4-Not complexes are evolutionarily conserved global regulators of gene expression. Deletion of CCR4 or several components of Ccr4-Not complexes results in abnormally large cells. Since yeast must attain a critical cell size at Start to commit to division, the large size of ccr4Δ cells implies that they may have a size-specific proliferation defect. Overexpression of CLN1, CLN2, CLN3, and SWI4 reduces the size of ccr4Δ cells, suggesting that ccr4Δ cells have a G1-phase cyclin deficiency. In support of this, we find that CLN1 and CLN2 expression and budding are delayed in ccr4Δ cells. Moreover, overexpression of CCR4 advances the timing of CLN1 expression, promotes premature budding, and reduces cell size. Genetic analyses suggest that Ccr4 functions independently of Cln3 and downstream of Bck2. Thus, like cln3Δbck2Δ double deletions, cln3Δccr4Δ cells are also inviable. However, deletion of Whi5, a transcriptional repressor of CLN1 and CLN2, restores viability. We find that Ccr4 negatively regulates the half-life of WHI5 mRNAs, and we conclude that, by modulating the stability of WHI5 mRNAs, Ccr4 influences the size-dependent timing of G1-phase cyclin transcription.
Caenorhabditis elegans num-1Negatively Regulates Endocytic Recycling
Authors: Nilsson Lars , Conradt Barbara , Ruaud Anne-Françoise , Chen Carlos Chih-Hsiung , Hatzold Julia , Bessereau Jean-Louis , Grant Barth D , Tuck Simon 
Published: May 2008

AbstractMuch of the material taken into cells by endocytosis is rapidly returned to the plasma membrane by the endocytic recycling pathway. Although recycling is vital for the correct localization of cell membrane receptors and lipids, the molecular mechanisms that regulate recycling are only partially understood. Here we show that in Caenorhabditis elegans endocytic recycling is inhibited by NUM-1A, the nematode Numb homolog. NUM-1A∷GFP fusion protein is localized to the baso-lateral surfaces of many polarized epithelial cells, including the hypodermis and the intestine. We show that increased NUM-1A levels cause morphological defects in these cells similar to those caused by loss-of-function mutations in rme-1, a positive regulator of recycling in both C. elegans and mammals. We describe the isolation of worms lacking num-1A activity and show that, consistent with a model in which NUM-1A negatively regulates recycling in the intestine, loss of num-1A function bypasses the requirement for RME-1. Genetic epistasis analysis with rab-10, which is required at an early part of the recycling pathway, suggests that loss of num-1A function does not affect the uptake of material by endocytosis but rather inhibits baso-lateral recycling downstream of rab-10.
The Small Ubiquitin-Like Modifier (SUMO) and SUMO-Conjugating System ofChlamydomonas reinhardtii
Authors: Wang Ying , Ladunga Istvan , Miller Amy R , Horken Kempton M , Plucinak Thomas , Weeks Donald P , Bailey Cheryl P 
Published: May 2008

AbstractThe availability of the complete DNA sequence of the Chlamydomonas reinhardtii genome and advanced computational biology tools has allowed elucidation and study of the small ubiquitin-like modifier (SUMO) system in this unicellular photosynthetic alga and model eukaryotic cell system. SUMO is a member of a ubiquitin-like protein superfamily that is covalently attached to target proteins as a post-translational modification to alter the localization, stability, and/or function of the target protein in response to changes in the cellular environment. Three SUMO homologs (CrSUMO96, CrSUMO97, and CrSUMO148) and three novel SUMO-related proteins (CrSUMO-like89A, CrSUMO-like89B, and CrSUMO-like90) were found by diverse gene predictions, hidden Markov models, and database search tools inferring from Homo sapiens, Saccharomyces cerevisiae, and Arabidopsis thaliana SUMOs. Among them, CrSUMO96, which can be recognized by the A. thaliana anti-SUMO1 antibody, was studied in detail. Free CrSUMO96 was purified by immunoprecipitation and identified by mass spectrometry analysis. A SUMO-conjugating enzyme (SCE) (E2, Ubc9) in C. reinhardtii was shown to be functional in an Escherichia coli-based in vivo chimeric SUMOylation system. Antibodies to CrSUMO96 recognized free and conjugated forms of CrSUMO96 in Western blot analysis of whole-cell extracts and nuclear localized SUMOylated proteins with in situ immunofluorescence. Western blot analysis showed a marked increase in SUMO conjugated proteins when the cells were subjected to environmental stresses, such as heat shock and osmotic stress. Related analyses revealed multiple potential ubiquitin genes along with two Rub1 genes and one Ufm1 gene in the C. reinhardtii genome.
The Relative Importance of Wellbore Pressure Drop and Formation Damage in Horizontal Wells
Authors: Hill A. D. , Zhu D. 
Published: May 2008

Summary
Numerous studies have examined the roles of wellbore pressure drop and near-wellbore formation damage on the production performance of horizontal wells. These studies identified particular conditions for which these effects are important, but no quantitative general guidelines have been developed. In this paper, we present simple, analytical expressions that can be used to determine the relative effects of wellbore pressure drop and formation damage on horizontal well inflow. The equations developed are used to show how horizontal wells or laterals can be designed so that neither of these effects causes significant flow restrictions.
The relative importance of the pressure drop in a horizontal wellbore is shown to be a simple function of two dimensionless numbers: the Reynold's Number for the flow in the wellbore and a new dimensionless number called the Horizontal Well Number. With this relationship, we illustrate how the wellbore diameter and length can be designed to ensure that the wellbore pressure drop is not restricting production.
In this paper, we also illustrate a technique for identifying the most critical part of the well flow system (far-field reservoir flow, near-well convergent flow, or flow through the completion) from the relative sizes of different terms in the inflow equations. This analysis method shows that the importance of formation damage and the efficiency of well stimulation depend on formation thickness, well length, and reservoir extent in the horizontal plane. Guidelines are presented to show how much damage can be tolerated while still maintaining productivity within a prescribed fraction of the undamaged productivity.
Inhibitor Performance on Corrosion and Erosion/Corrosion Under Turbulent Flow With Sand and CO2—An AC Impedance Study
Authors: Wang C. , Neville A. 
Published: May 2008

Summary
Erosion/corrosion is a severe problem in oil and gas producing wells because of high flow velocity and sand particles entrained in the system. Using corrosion inhibitors to reduce erosion/corrosion has recently been proposed as an economically viable solution for carbon-steel piping systems (Smart 1991). In the literature, most studies using inhibitors to mitigate corrosion have been conducted under stagnant or low flow rate (&lt;1 m/s) conditions. However, severe erosion/corrosion may occur when inhibitor films are removed from the steel by high liquid shear forces under actual oil and gas production conditions.
The inhibiting effect of a commercial inhibitor [named Inhibitor A (Wang et al. 2005)] on the behavior of carbon steel in CO2-saturated media has been examined under high flow velocity with sand by electrochemical and gravimetric measurements. Experiments were performed using a Rotating Cylinder Electrode (RCE). The alternate current (AC) impedance technique was used to study the effect of inhibitor adsorption onto the metal surface. The study clearly reveals that the addition of the inhibitor moves the corrosion potential toward positive values and reduces the corrosion rate. Changes in impedance parameters (Rct and Cdl) are indicative of adsorption of inhibitor on the metal surface leading to the formation of protective films.
A Rigorous Composite-Inflow-Performance Relationship Model for Multilateral Wells
Authors: Guo Boyun , Zhou Jinkui , Ling Kegang , Ghalambor Ali 
Published: May 2008

Summary
Use of multilateral wells for oil and gas production has gained strong momentum in the past 5 years. However, most of the multilateral wells do not deliver hydrocarbon fluids at expected production rates. One of the reasons for this is that the well planners overestimate the productivity of wells by using inaccurate methods for predicting composite-inflow-performance relationship (IPR) of well laterals. A more-accurate method for predicting composite IPR of multilateral wells is highly desirable. This paper fills the gap.
Starting from terms familiar to petroleum engineers, a general well model was developed with consideration of reservoir-wellbore crossflow for lateral IPR and coupling of fluid flow from individual laterals to the main wellbore. The model allows different IPRs of laterals and permits crossflow between laterals. Pressure losses in the vertical-, curvic- and horizontal-hole sections are rigorously considered. Oil and gas wells are treated differently. The modified Hagedorn-Brown correlation is used for modeling the flow in the vertical sections, and the Beggs and Brill correlation is used for the curvic and horizontal sections for oil wells. The Cullender and Smith method was used for modeling the flow in gas wells. A computer simulator was developed based on the model for predicting multilateral-well production rate. Case studies have indicated excellent accuracy of the computer model. This work provides petroleum engineers a reliable and user-friendly tool for designing and evaluating multilateral wells.
Quantification of Uncertainties for Drilling-Induced Formation Damage
Authors: Ding Y. , Renard G. , Herzhaft B. 
Published: May 2008

Summary
It has been widely recognized that formation damage caused by drilling fluid has a huge impact on well productivities. The degree of formation damage can be studied using a numerical model. However, uncertainties in the prediction of productivity loss need to be investigated. To quantify these uncertainties, experimental designs combined with the Response Surface Methodology (RSM) are used to assess the impact of uncertain parameters on formation damage. This approach allows to identify the most influential parameters on well productivity loss and to estimate the risks of formation damage. A good control of the most sensitive parameters can limit productivity loss. This approach provides key recommendations for the selection of drilling fluid to maximize well performance.
Comparative Study of Flowback Analysis Using Polymer Concentrations and Fracturing-Fluid Tracer Methods: A Field Study
Authors: Asadi Mahmoud , Woodroof Robert A. , Himes Ronald E. 
Published: May 2008

Summary
This paper compares flowback efficiencies using polymer concentration and frac fluid tracer methods. Results are presented for the flowback efficiency of each frac fluid segment using nonradioactive chemical frac tracers injected in a well, along with the results for the total flowback efficiencies using polymer concentration and frac fluid tracer analysis methods. Two wells were fraced and traced with various chemical frac tracers. Upon commencing flowback, samples of produced aqueous fluid solution were collected according to a pre-designed sampling schedule that lasted for 72 hours. Samples were analyzed for tracer, polymer, calcium, potassium, sodium, and chloride concentrations. With the use of the mass balance technique, the total flowback volume and flowback efficiency for each fluid segment were calculated by use of the tracer method. In addition, total flowback and flowback efficiency were calculated by use of both polymer concentration and tracer methods. To better evaluate and compare the results of polymer concentration and frac fluid tracer analyses, dynamic fluid leakoff tests were conducted in a laboratory environment by use of both low and high permeability core samples. Detailed laboratory and field results are presented along with a comparison of flowback results from both polymer concentration and frac fluid tracer methods.
Well Integrity Operations at Prudhoe Bay, Alaska
Authors: Anders Joe , Rossberg Steve , Dube Anna , Engel Harry , Andrews David 
Published: May 2008

Summary
This paper discusses the well-integrity-management system used at the Prudhoe Bay field located in Alaska. The focus is on systems and processes implemented to manage the well operations and interventions phase of a well's life. Well integrity is a multifaceted discipline, spanning a well's life from design to abandonment. The engineering aspects of well integrity have received increasing attention in recent years as public scrutiny and resultant regulatory requirements have evolved. The issue of sustained casing pressure (SCP) on the annulus of a well has also shaped current well-integrity practices. There have been several recent applied-technology workshops focused on well integrity, demonstrating its increasing importance. However, there is notably little well-integrity-related literature in the SPE paper library (see Michel 1995; Attard 1991; Soter et al. 2003; and Bourgoyne et al. 1999 for a listing of relevant papers).
The well-integrity-management system used at Prudhoe Bay has been evolving since field startup in 1977. Extensive experience has resulted in the design and management of systems to ensure safe operations; compliance with industry standards, regulatory-agency requirements, and internal company policies; and incorporating "lessons learned" from local incidents. This paper focuses on the operational and well intervention phases of a well's life and discusses evolution of the well-integrity-management system. Current operating practices are reviewed using BP's "7 Elements of Well Integrity" categorization. Finally, the data-management system used to monitor the well-integrity-system status is reviewed.
Performance Appraisals of Gas/Oil Separation Plants
Authors: Kokal Sunil , Al-Ghamdi Abdullah 
Published: May 2008

Summary
Produced crude oil typically is processed at a wet-crude-handling facility (WCHF) or a gas/oil separation plant (GOSP). Most of the crude is commingled with water and produced in the form of emulsions that are separated at the GOSP using demulsifiers. In general, the emulsions at the inlet of Saudi Aramco GOSPs are tight, and no free water is observed in the feed stream.
This paper describes the performance appraisal of several Saudi Aramco GOSPs. It also discusses the evaluation of these facilities and the efforts undertaken to reduce and optimize the costs of oil/water separation. The most important effort was the characterization of emulsions from various fields. It shows the relative tightness of emulsions and the associated causes of tightness. It has become a diagnostic tool in the quest to understand the causes and treatment of emulsions. The inlet emulsions were characterized by conducting field tests at each of the GOSPs using fresh emulsion samples. The factors associated with the tightness of emulsions include the amount of fine solids such as asphaltenes and scales in the crude, water cuts, temperature, brine chemistry, and shear. Another aspect of oil-water separation investigated was the effect of processing equipment and vessel retrofitting. These included the conversion of two-phase (gas/liquid) separators into three-phase (gas/oil/water) separators, installation of coalescer packs, demulsifier injection strategies, and use of online analyzers. An innovative approach to optimizing oil/water separation is described. The paper provides operational data including demulsifier-treatment costs per barrel of oil, invaluable experience, and many "lessons learned" that are applicable to other crude-oil-treating facilities.
Consideration for Future Stimulation Options Is Vital in Deciding Horizontal Well Drilling and Completion Schemes for Production Optimization
Authors: Surjaatmadja Jim B. , McDaniel Billy W. , Case Leonard R. , East Loyd E. , Pyecroft James F. 
Published: May 2008

Summary
Many horizontal wells have been completed without plans for stimulation. Often, horizontal wells were not planned for stimulation, because the belief at the time of completion was that horizontal wellbores eliminate the need for hydraulic fracturing stimulation. This presumption has turned out to be false. Often, by the time it is discovered that a horizontal well needs to be stimulated, it cannot be stimulated effectively because of mechanical or reservoir limitations. This regrettable outcome may have been avoided if extensive preplanning had included consideration for future stimulation. Such preplanning may be limited—not only to the already extensive plans for prospective stimulation activities and selection of the most promising stimulation methods—but for all activities required during the life of the well.
PPDM - A Basis for Integration
Authors: Huszti Mel 
Published: May 2008

Abstract
The Public Petroleum Data Model (PPDM) is a non-proprietary data model that is designed for the oil industry to store, retrieve and process computer information more efficiently through standardization. By using a common model, data bases avoid duplicating information and improve the versatility of relating one item to any other item. It also allows compliant software to simply "plug in" to existing databases. With a common model, adding data or upgrading software becomes very easy and inexpensive. This will allow industry to better keep pace with new technology.
Workovers in Sour Environments: How Do We Avoid Coiled Tubing (CT) Failures?
Authors: Nasr-El-Din Hisham A. , Metcalf Arthur S. 
Published: May 2008

Summary
Workover of wells contaminated with hydrogen sulfide (H2S) is a difficult task. Coiled tubing (CT) has become one of the mainstays in treating this type of well, but failures do occur, such as tubing recovered with leaks or catastrophic parting, which can leave several thousand feet of tubing, including bottomhole assemblies (BHAs), to be fished.
Corrosion control is essential to protect production equipment, and to avoid CT failures during acid treatments. Also essential for the safe use of CT are the proper selection of metallurgy for the downhole environment, appropriate use of H2S inhibitors, nondestructive testing of the coil before usage, and periodic sampling of the coil for physical examination. Other precautionary measures are still in the development stages.
In this paper, we discuss two case histories of CT failure during workover in sour environments. The analyses performed to determine causes and recommended practices to avoid the reoccurrence of these failures are included along with a set of guidelines for the safe use of CT in sour-well workovers.
Eliminating Multiple Interventions Using a Single Rig-Up Coiled-Tubing Solution
Authors: Kumar P. Santhana , Gisbergen Stan Van , Harris Jeremy , Ferdiansyah Erik , Brady Mark , Al Harthy Salah , Pandey Arun 
Published: May 2008

Summary
This paper describes new methods to economically improve production levels in one of the mature fields of Petroleum Development Oman. This field had been developed by infill drilling programs, which were suspended in early 2001 to review the development strategy. A reservoir management team set a challenge to effectively conduct logging operations and quickly use the data collected to identify and avail of optimization opportunities. The ensuing campaign resulted in maximizing the production of the wells whilst lowering overall costs. The optimization activity consisted of clean-out, saturation logging, perforation, and stimulation. These activities were initially carried out in two ways: 1) with coiled tubing using only conventional coiled tubing and e-line coiled tubing or 2) with the combination of coiled tubing and a hoist. Both methods involved multiple well entries. Both of these methods were successful in that they resulted in incremental net oil production but at relatively high costs.
This paper presents an enhanced methodology which enables clean-out, logging, stimulation, and perforation with one coiled-tubing intervention, which includes a plastic-coated "e-line" coiled tubing, coiled-tubing perforating head, and new perforation technology. All systems are in complete compliance with the most stringent safety criteria. The new method has a considerable time and cost savings impact. These results are fully illustrated in this paper with field trial case histories, in which a multi-disciplinary team effectively targeted the most suitable zones for perforation and stimulation by use of a state of the art self-diverting, non-damaging, acid system. Technical and economic comparisons are made with conventional practices. The new methodology is currently being used in this field and is potentially applicable to other fields.
Low Sulfate Seawater Injection for Barium Sulfate Scale Control: A Life-of-Field Solution to a Complex Challenge
Authors: Jordan Myles M. , Collins Ian R. , Mackay Eric J. 
Published: May 2008

Summary
The injection of seawater into oil-bearing reservoirs to maintain reservoir pressure and improve secondary recovery is a well-established, mature operation. Moreover, the degree of risk posed by deposition of mineral scales to the injection and production wells during such operations has been much studied. The current deepwater subsea developments offshore West Africa and Brazil have brought into focus the need to manage scale in an effective way. To this end, the challenge of scale control during the lifecycle of water injection, production, and produced-water reinjection (PWRI) has been reviewed for a number of fields by the authors.
This paper outlines the risk assessment process that should be undertaken to select the most economical and effective scale control methodology (which for sulfate-based scale could be seawater injection with scale inhibitor squeeze treatments to maintain production, or sulfate reduction of the injection water with or without the need to scale inhibitor squeeze). In the case of sulfate reduction, parameters to be investigated include the degree of desulfation required to minimize the scale risk of downhole scale formation, the impact the degree of fluid mixing will have on the resulting brine (from injection to production), and the impact the desulfated brine will have on scale control during PWRI.
The paper draws on a wide range of technical inputs to make scale management decisions including: computer modeling techniques (e.g., deposition models that incorporate the kinetics of sulfate scale formation at low supersaturation ratios), reservoir simulation of fluid mixing and reaction; the resulting produced brine chemistry, laboratory-generated coreflood data to assess chemical selection for scale inhibitor squeeze and produced water application; and field results that will demonstrate the impact of the type of injection water source on the long-term manageability of such deepwater projects. Finally, the paper outlines in detail the particular issues associated with the full economic assessment of low-sulfate water injection vs. full sulfate seawater injection.