bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical Pharmacologic Aspects of Therapeutic Hypothermia After Cardiac Arrest
Authors: Arpino Paul A. , Greer David M.
Published: December 2007

Therapeutic hypothermia has emerged as an effective means of improving neurologic outcomes among cardiac arrest survivors. To achieve optimal results, clinicians must understand and anticipate potential adverse effects of cooling and provide rigorous monitoring and/or pharmacologic interventions as appropriate. Using pharmacotherapy to counter adverse effects of cooling or to treat an intrinsic process under hypothermic conditions requires understanding how hypothermia will influence the clinical effects of the drug, including the drug's pharmacokinetics and pharmacodynamics. The pharmacologic aspects of therapeutic hypothermia in relation to physiology and adverse effects are reviewed.
Benefits and Risks of Aprotinin Use During Cardiac Surgery
Authors: Kristeller Judith L. , Roslund Brian P. , Stahl Russell F.
Published: December 2007

Aprotinin is a serine protease inhibitor with antithrombotic, antifibrinolytic, and antiinflammatory effects. It is effective in reducing bleeding and the need for blood transfusions after cardiac surgery with cardiopulmonary bypass. Additional benefits, such as cerebral protection, are hypothesized but not yet thoroughly substantiated. The safety of aprotinin has been questioned based on a phase IV analysis of large data sets, including patients undergoing cardiac surgery. Potential risks including increased occurrences of stroke, myocardial infarction, renal failure, and death are implied by these analyses; however, adequate study group matching is lacking from these nonrandomized, retrospective studies. In October 2007, a large randomized controlled trial comparing antifibrinolytics in patients undergoing cardiac surgery was stopped after a preliminary analysis suggested a trend toward an increase in all‐cause 30‐day mortality associated with aprotinin. Subsequently, the manufacturer of aprotinin temporarily suspended marketing and halted all shipment of aprotinin on a worldwide basis. Pending a complete analysis of this study, the use of aprotinin could be considered as one component of a blood conservation strategy. After contemplating the benefits and risks of this controversial drug, clinicians should reserve its use for patients at high risk for postoperative blood loss.
Use of a Combination of Class III and Class Ic Antiarrhythmic Agents in Patients with Electrical Storm
Authors: Fuchs Therese , Groysman Rima , Meilichov Ilia
Published: December 2007

Study Objective. To determine the efficacy of the combination of class III and class Ic antiarrhythmic agents in suppressing an electrical storm in patients with and without a transvenous implantable cardioverter‐defibrillator (ICD).

Design. Retrospective medical record review.

Setting. Arrhythmia service of an academic medical center in Zerifin, Israel.

Patients. Ten patients who experienced an electrical storm that was not effectively treated with amiodarone or sotalol monotherapy between December 15, 1999, and June 13, 2007.

Measurements and Main Results. The medical records of 152 patients who received an ICD during the study period were reviewed. Twenty patients experienced an electrical storm, an arrhythmia defined as more than two episodes of hemodynamically unstable ventricular tachycardia during a 24‐hour period. Ten of the 20 patients responded favorably to amiodarone or sotalol monotherapy (class III antiarrhythmics), but in 10 patients, the combination of a class III and a class Ic antiarrhythmic agent was needed to effectively eliminate the electrical storm. Of the 10 patients who required both agents, two (20%) developed an electrical storm before implantation of their ICD. In another patient who had ongoing ischemia, ventricular tachycardia recurred, but the drug combination decreased the number of ventricular arrhythmia episodes. One patient with dilated cardiomyopathy had one recurrence of ventricular tachycardia, which was terminated with antitachycardia pacing. Three patients died during a mean ± SD follow‐up of 8.7 ± 9.9 months.

Conclusion. Electrical storm can be acutely treated with the combination of a class III and a class Ic antiarrhythmic agent when a class III agent alone is insufficient and when radiofrequency ablation is not an option. Patients receiving this drug combination can be discharged from the hospital only if they have an ICD.
Association of Galactose Single‐Point Test Levels and Phenytoin Metabolic Polymorphisms with Gingival Hyperplasia in Patients Receiving Long‐Term Phenytoin Therapy
Authors: Lin Chun‐Jung , Yen Ming‐Fang , Hu Oliver Yoa‐Pu , Lin Min‐Shung , Hsiong Cheng‐Huei , Hung Chin‐Chuan , Liou Horng‐Huei
Published: December 2007

Study Objective.To evaluate whether the occurrence or severity of gingival hyperplasia is associated with liver function test results or phenytoin metabolism.

Design.Prospective analysis.

Setting.University‐affiliated medical center in Taipei, Taiwan.

Patients.Sixty‐six patients (mean age 37.9 yrs) with epilepsy who were receiving phenytoin for more than 1 year.

Intervention.Four blood samples were drawn from each patient for liver function testing, concentrations of phenytoin and its metabolites R‐5‐(4′‐hydroxyphenyl)‐5‐phenylhydantoin (R‐HPPH) and S‐HPPH, and genotyping of cytochrome P450 (CYP) 2C9 and 2C19.

Measurements and Main Results.Plasma concentrations of phenytoin and its metabolites were determined by a high‐performance liquid chromatography method. The CYP2C9 and CYP2C19 genotypes were analyzed by polymerase chain reaction‐restriction fragment length polymorphism analysis. Conventional liver function assays and a quantitative liver function test—galactose single‐point (GSP) measurement—were performed. Statistical analyses were performed to evaluate the association between liver function test results as well as metabolic phenotype and the occurrence and severity of gingival hyperplasia. Among liver function tests, only GSP levels showed a significant difference between patients with and those without gingival hyperplasia. Patients with an elevated GSP level (> 280 μg/ml) had a significantly higher odds ratio (OR 4.51) for the occurrence of gingival hyperplasia. In addition, increased R‐HPPH (OR 1.02) and phenytoin (OR 1.09) concentrations were associated with an increased occurrence of gingival hyperplasia. However, only increased GSP and R‐HPPH concentrations had significantly higher ORs (2.84 and 1.02, respectively) associated with the severity of gingival hyperplasia. Although mean ± SD plasma R‐HPPH concentration was significantly lower in CYP2C19 poor metabolizers compared with CYP2C9 and CYP2C19 extensive metabolizers and CYP2C9 poor metabolizers (30.38 ± 16.73 vs 68.22 ± 44.75 and 78.95 ± 51.67 μg/ml, respectively), no significant association between genotype and gingival hyperplasia was found.

Conclusion.Increased GSP, phenytoin, and R‐HPPH concentrations were associated with increased occurrence of phenytoin‐induced gingival hyperplasia; only increased GSP and R‐HPPH concentrations were associated with increased severity of this adverse effect.
Oral Voriconazole for Empiric Antifungal Treatment in Patients with Uncomplicated Febrile Neutropenia
Authors: Przepiorka Donna , Buadi Francis K. , McClune Brian
Published: December 2007

Study Objective. To determine the success rate and toxicity profile of oral voriconazole when used as empiric antifungal therapy in patients with uncomplicated persistent neutropenic fever.

Design. Retrospective medical record review.

Setting. University hospital.

Patients. Twenty‐seven patients who received oral voriconazole as empiric antifungal treatment during 31 episodes of persistent neutropenic fever between August 1, 2003, and April 1, 2006.

Measurements and Main Results. Data were collected on patient demographics, diagnosis, cancer treatment plan, voriconazole regimen, dates of voriconazole treatment, other antibiotics administered during the episode of fever, and adverse events. Patient survival data from at least 3 months of follow‐up were also collected. Treatment success, which was defined as survival to the resolution of fever without a need to change antibiotics and without new fungal infections, was also determined. Median duration of therapy was 11 days (range 2–54 days). No patient discontinued the drug because of toxicity. The success rate was 55% (95% confidence interval [CI] 36–73%). For all patients, 90‐day survival from the start of voriconazole treatment was 81% (95% CI 63–93%). Neither treatment success nor 90‐day survival rates differed significantly when they were compared by the route used for loading doses or by the presence of a possible invasive fungal infection at the start of voriconazole therapy.

Conclusion. Oral voriconazole appears to be a safe empiric antifungal treatment with an encouraging rate of activity for patients with neutropenia and uncomplicated persistent fever. Further research, including randomized controlled trials comparing the efficacy of intravenous versus oral voriconazole, is needed.
The Stem Cell Marker Prominin-1/CD133 on Membrane Particles in Human Cerebrospinal Fluid Offers Novel Approaches for Studying Central Nervous System Disease
Authors: Huttner Hagen B. , Janich Peggy , Köhrmann Martin , Jászai József , Siebzehnrubl Florian , Blümcke Ingmar , Suttorp Meinolf , Gahr Manfred , Kuhnt Daniela , Nimsky Christopher , Krex Dietmar , Schackert Gabriele , Löwenbrück Kai , Reichmann Heinz , Jüttler Eric , Hacke Werner , Schellinger Peter D. , Schwab Stefan , Wilsch-Bräuninger Michaela , Marzesco Anne-Marie , Corbeil Denis
Published: December 2007

Cerebrospinal fluid (CSF) is routinely used for diagnosing and monitoring neurological diseases. The CSF proteins used so far for diagnostic purposes (except for those associated with whole cells) are soluble. Here, we show that human CSF contains specific membrane particles that carry prominin-1/CD133, a neural stem cell marker implicated in brain tumors, notably glioblastoma. Differential and equilibrium centrifugation and detergent solubility analyses showed that these membrane particles were similar in physical properties and microdomain organization to small membrane vesicles previously shown to be released from neural stem cells in the mouse embryo. The levels of membrane particle-associated prominin-1/CD133 declined during childhood and remained constant thereafter, with a remarkably narrow range in healthy adults. Glioblastoma patients showed elevated levels of membrane particle-associated prominin-1/CD133, which decreased dramatically in the final stage of the disease. Hence, analysis of CSF for membrane particles carrying the somatic stem cell marker prominin-1/CD133 offers a novel approach for studying human central nervous system disease.

Disclosure of potential conflicts of interest is found at the end of this article.
A new genus of ionoscopiform fish (Halecomorphi) from the Lower Cretaceous (Albian) lithographic limestones of the Tlayúa Quarry, Puebla, Mexico
Authors: Alvarado-Ortega Jesús , Espinosa-Arrubarrena Luis
Published: December 2007

Quetzalichthys perrilliataen. gen. and sp. is described based on five specimens from Lower Cretaceous (Middle-Upper Albian) limestones of the Tlayúa Quarry, near Tepexi de Rodríguez, Puebla, Mexico. This new taxon displays the diagnostic characters of Ionoscopiformes, which consequently designate it as a new member of this order of Mesozoic fishes. Additionally,Quetzalichthysn. gen. shares several derived characters withIonoscopusandOshunia, including the presence of more than 15 supraneurals, solid and well-ossified monospondylous vertebrae with two lateral longitudinal oval fossae, thin scales of the amioid type, and the ventral surface of some circumorbital bones being intensely pitted.Quetzalichthys perrilliataeis characterized by three unique characters: 26 abdominal centra, 21 principal dorsal fin rays, and two supraorbitals. Additionally, its unpaired fins and tail show conditions intermediate to those found inIonoscopusandOshunia.A cladistic analysis of Ionoscopiformes, including both taxa found in the Tlayúa Quarry (QuetzalichthysandTeoichthys), identifies two monophyletic families within the order, Ophiopsidae (includingOphiopsis, Macrepistius, Teoichthys) and Ionoscopidae (involvingIonoscopus, Oshunia, andQuetzalichthys).
Two Mississippian Caenogastropod limpets from Australia and their meaning for the ancestry of the Caenogastropoda
Authors: Cook Alex , Nützel Alexander , Frýda Jiri
Published: December 2007

Two new limpets with a caenogastropod-type larval shell are described from the Mississippian (Early Carboniferous) of Australia and assigned toAustraloscutulan. gen. of the family Pragoscutulidae. This family has previously been reported only from the Early Devonian of Europe (Czech Republic, Prague Basin). Therefore, it survived the Late Devonian biotic crisis. the fact that one of the earliest certain caenogastropods has a patelliform shell is noteworthy given most other Middle to Late Paleozoic caenogastropods are high-spired or fusiform. Pragosutulidae are interpreted as an early patelliform caenogastropod offshoot derived from coiled ancestors. the Pragoscutulidae are the oldest gastropod limpets with well-preserved larval shells. Their teleoconch is entirely limpet-shaped without helicoid coiling. However, the helicoid turbiniform larval shells suggests that this group evolved from an ancestor with turbiniform or even high-spired adult shell. Moreover, the multi-whorled dextral larval shells show that Pragoscutulidae are Caenogastropoda and document that early Caenogastropoda displayed considerable disparity.
An unusual new gastropod from an Eocene hydrocarbon seep in Washington State
Authors: Kiel Steffen
Published: December 2007

Subduction-Related Hydrocarbon-Seep carbonates in Cenozoic deepwater sediments in western Washington State, USA, yield fossil invertebrate communities that are largely endemic to these localized microhabitats (Goedert and Squires, 1990; Peckmann et al., 2002; Goedert et al., 2003; Kiel, 2006). An unusually large species of the deep-sea gastropod Abyssochrysos Tomlin, 1927 has been described from the oldest of these seep carbonates, which occurs in the Humptulips Formation on the southern slopes of the Olympic Mountains (Goedert and Kaler, 1996). New material of this species was recently collected at this site and shows that this species has a deep notch and a selenizone at the base of the outer lip, a feature that is very unusual among living gastropods, and unknown from Abyssochrysos. This feature is also present on two gastropod specimens, found in the collection of the Burke Museum (UWBM) that are, according to the label, from the Humptulips area but without detailed locality information. Stable isotope analysis of the micritic matrix adhering to the specimens showed δ13C values as low as −37 to − 41‰ relative to PDB standard. Such negative values clearly indicate that the carbonate formed under the influence of anaerobic oxidation of biogenic methane (cf. Whiticar, 1999; Peckmann et al., 2002). The isotope analysis was carried out in the same lab using the same methods as described in Kiel (2006). The Humptulips area is currently covered with dense vegetation and attempts to locate the carbonate outcrop where these two specimens could have come from have been unsuccessful. The purpose of this note is to introduce a new genus for this unusual species, to discuss its possible place among the gastropods, and to speculate about the function of the two deep sinuses in the outer lip of the aperture.
Some disparid crinoids from the Upper Ordovician (Shermanian) Walcott-Rust quarry of New York
Authors: Brower James C.
Published: December 2007

locrinus trentonensisWalcott, 1883 is characterized by the widest food grooves and the largest covering plates of any of the Walcott-Rust Quarry crinoids, which indicates that the animal captured relatively large food particles with large and widely separated tubefeet. Although iocrinids are generally considered as primitive disparids, their anal sac is unique. the holdfasts ofI. trentonensisconsist of distal stem coils that are tightly wrapped around the columns of other crinoids. the relatively long column ofEctenocrinus simplex(Hall, 1847) was attached to a wide range of shelly substrates by a small irregular and somewhat lobate holdfast. Ectenocrinids ate much smaller food items that were collected by smaller and more tightly packed tubefeet. the ontogeny ofE. simplexillustrates the differences between the food gathering systems of conspecific crinoids from shallow and deep water habitats. the calceocrinidCalceocrinus barrandiiWalcott, 1883 lived with its long stem forming a runner along the seafloor. the crown was movably hinged to the basal circlet and the stem. Moderately wide food grooves were probably present.
Conulariids of the Upper Talak Formation (Mississippian, Visean) of northern Niger (West Africa)
Authors: Iten Heyo Van , Konate Moussa , Moussa Yahaya
Published: December 2007

Conulariids of West Africa have received relatively little detailed attention in the literature on this widespread extinct group of marine cnidarians. Recently, however, Babcock et al. (1995) described two new species, Paraconularia feldmanni and P. sahara, from the upper part of the Mississippian (Visean) Talak Shale Formation in the Tim Mersoi Basin of northern Niger. This was the first report of the genus Paraconularia Sinclair, 1940 from Africa as well as the first assignment of Carboniferous conulariids from that continent to the species level. Since then two of the present authors have collected 24 additional conulariid specimens from the Talak Formation in the same area that yielded the two specimens described by Babcock et al. (1995). Like the previously described material, most of the new specimens, described below, have been worn or weathered to such an extent that it is difficult to identify them to the species level. In some cases, moreover, identification to the genus level is problematical, but this may ultimately be due to the fact that currently recognized conulariid genera (e.g., Moore and Harrington, 1956b) have been defined phenetically, rather than on the basis of prior analysis of the phylogenetic relationships among conulariid species. This means that at least some currently recognized conulariid genera may have been defined by similarities that are primitive or analogous.
ANTECEDENT EFFECTS OF OBSERVING PEER PLAY
Authors: Bruzek Jennifer L. , Thompson Rachel H.
Published: December 2007

The relative reinforcing value of toys was assessed in the absence of, and immediately following, participant observation of a peer manipulating one of the toys. Preference assessments were used to identify preference hierarchies. Reinforcer assessments were conducted with a high‐preference item, a low‐preference item, and a control. Each participant allocated responding toward the high‐preference item during baseline. When reinforcer assessment sessions were preceded by a peer observation period, 3 of the 4 participants shifted allocation to the toy manipulated by the peer. The 4th participant shifted allocation only when the high‐preference stimulus was replaced with a medium‐preference stimulus. These data suggest that, among preschoolers, response allocation is influenced by observations of peers playing.
IMPROVING READING OUTCOMES FOR CHILDREN WITH LEARNING DISABILITIES: USING BRIEF EXPERIMENTAL ANALYSIS TO DEVELOP PARENT‐TUTORING INTERVENTIONS
Authors: Gortmaker Valerie J. , Daly Edward J. , McCurdy Merilee , Persampieri Michael J. , Hergenrader Melanie
Published: December 2007

The present study assessed the effects of summer parent tutoring on 3 children with learning disabilities using empirically derived reading interventions. Brief experimental analyses were used to identify customized reading fluency interventions. Parents were trained to use the intervention strategies with their children. Parents implemented the procedures during parent‐tutoring sessions at home and results were measured continuously in high‐word‐overlap and low‐word‐overlap passages to determine whether generalization occurred. Parent and child satisfaction with the procedures was assessed. Results demonstrated generalized increases in reading fluency in both high‐word‐overlap and low‐word‐overlap passages as a function of parent tutoring. Also, acceptability ratings by children and their parents indicated that they viewed the interventions as acceptable and effective. Results are discussed in terms of structuring reading fluency interventions that promote generalization and maintenance of treatment effects.
THE EFFECTS OF SCRIPTED PEER TUTORING AND PROGRAMMING COMMON STIMULI ON SOCIAL INTERACTIONS OF A STUDENT WITH AUTISM SPECTRUM DISORDER
Authors: Petursdottir Anna‐Lind , McComas Jennifer , McMaster Kristen , Horner Kathy
Published: December 2007

This study examined the effects of scripted peer‐tutoring reading activities, with and without programmed common play‐related stimuli, on social interactions between a kindergartner with autism spectrum disorder and his typically developing peer‐tutoring partners during free play. A withdrawal design with multiple baselines across peers showed no effects of peer tutoring on social interactions. A withdrawal design with 1 peer and continuing baselines across the other 2 peers showed that adding play‐related common stimuli to the peer‐tutoring activity increased social interactions during free play.
IMPROVING WRITTEN LANGUAGE PERFORMANCE OF ADOLESCENTS WITH ASPERGER SYNDROME
Authors: Delano Monica E.
Published: December 2007

The effects of a multicomponent intervention involving self‐regulated strategy development delivered via video self‐modeling on the written language performance of 3 students with Asperger syndrome were examined. During intervention sessions, each student watched a video of himself performing strategies for increasing the number of words written and the number of functional essay elements. He then wrote a persuasive essay. The number of words written and number of functional essay elements included in each essay were measured. Each student demonstrated gains in the number of words written and number of functional essay elements. Maintenance of treatment effects at follow‐up varied across targets and participants. Implications for future research are suggested.
Application of Coiled-Tubing Fracturing Method Improves Field Production
Authors: Fussell L. D. , Redfearn J. R. , Marshall E. J.
Published: December 2007

Application of a new coiled tubing assisted fracturing method (CTFM) has been implemented in the Elm Grove Field in Bossier Parish, Louisiana. The new method has allowed all potential pay intervals to be efficiently stimulated. As compared with traditional methods of stimulation, the new method has resulted in better sustained production.
On the Development of a Three-Dimensional Model for a Coiled-Tubing/Riser System
Authors: Adnan S. , Zheng A. S. , Chen Y.
Published: December 2007

This paper establishes a three-dimensional mathematical model for a tubing/riser system subjected to external loadings. Effects such as mud weights, internal pressure in the tubing and annulus, and cable forces are all included in the model. The derivations of the mathematical model are based on principals of beam-column stability theory, which lead to a set of ordinary differential equations with the loading and displacements as functions of the axial location of the riser. With the system equations established, the rest of the paper is devoted to the devise of a numerical algorithm to solve the equations with boundary conditions imposed. The problem is re-casted as two points boundary value problem (TPVBP). Modified Quasilinearization Algorithms (MQA) together with Method of Particular Solution (MPS) are employed in the search of numerical solution for the TPBVP. Results from these algorithms are compared to those obtained from commercial finite element program to verify the validity of the mathematical model and accuracy of the numerical algorithm.
Operability Challenges During Coiled-Tubing (CT) Well Intervention: Panna Field Case Histories From Western India Offshore
Authors: Kale S. V. , Proctor R. J. , Paliwal S. K. , Nayak S. K.
Published: December 2007

Coiled Tubing (CT) applications are performed to intervene in completions installed in the lateral section of Panna wells in Western India Offshore.

The paper discusses the analysis process and the challenges during CT well interventions. Work done to improve CT entry in the lateral section is also discussed in the paper. The paper compares simulated CT entry against the actual reach in each well. Illustrative examples of the actual field data are presented as case histories.

The process is elaborated in this paper. The paper also discusses specific examples where application of tools to excite the BHA was attempted with success, along with the resources needed to accomplish the analysis process effectively.

To describe the challenges this paper groups Panna completions in three categories; open hole, open hole with tail pipe and cased hole with swell packers. Sliding sleeves to operate selective sections of the well are installed in the completion and CT entry to operate the sliding sleeve is imperative.

The operational challenges are grouped as either logistical or environmental.

The paper focuses on technical design challenges and analysis processes to determine the feasibility of future well intervention.

To improve operational success the authors recommend that each intervention campaign be engineered utilizing the results from the previous operations. This increases the likelihood of successful interventions.
CT-Deployed Multipurpose Nozzle for Effective Sand-Cleanout and Acidizing Operations in a Single Trip: Injector Wells Case Histories
Authors: Uchendu C. V. , Awoleke O. O. , Rowland S. P. , Ndinemenu F. O.
Published: December 2007

Wells requiring combined sand clean out and acidizing operations have been routinely treated using BHA's containing different nozzles in multiple trip operations. This is especially true for sanded-up completions. The normal scenario would be to use a standard wash nozzle for both acidizing/sand cleanout operations or to use a switchable nozzle for the sand clean-out, POOH and then run a rotating jetting nozzle (for acidizing). Ho wever, the former scenario would not be optimal because standard washing nozzles are not effective against filter cakes / scale and the latter alternative might be in some situations an over-kill leading to really expensive operations.

This paper describes the use of a specialized nozzle that generates a ‘vortex’ or a fast swirling mass of fluid in the completion tubulars/open hole. Jet velocities and rotational speeds commonly exceed 460 ft/sec and 8000 rpm, respectively. Because of a specially designed internal flow guide, this nozzle entrains debris and also provides improved jet coherence and projection compared to standard jetting nozzles. This dual feature of the nozzle made it particularly attractive for use in combined sand clean out/acidizing operations of sanded up injectors. This nozzle also has no moving parts or rubber seals; therefore, the commingling fluid phases would not affects the efficiency of the tool.

These injectors are vertical completions with architecture ranging from perforated intervals to standalone screens. The sediments consist of a mixture of organic deposition, fine siliceous material and carbonate scales. This paper analyzes the improved post injectivity and compares results using this nozzle to those using a wash nozzle/rotating nozzle combination on the basis of cost, operational efficiency/simplicity and technical effectiveness. These results suggest that some non-aggressive scales can also be treated using this nozzle as an alternative to a rotating jetting system leading to reduction in well intervention cost through a single trip approach.
Vortex-Induced Vibration of Tubings and Pipings with Nonlinear Geometry
Authors: Adnan S. , Chen Y. , Chen C. L. P.
Published: December 2007

Vortex-induced vibration (VIV) of tubings and pipings is of practical interest to oil industry. When VIV occurs to pipes, it induces alternative stress that results in the reduction of pipe fatigue life. The objective of the paper is to investigate VIVs in tubings or pipings with non-linear geometry.

This paper categorizes the occurrence of cross-flow and in-line VIVs of pipes based on flow directions and pipe orientations. The complexity of VIV for pipes with non-linear geometry, as compared to straight pipes, is demonstrated. We devised a scheme to incorporate power balance principal into finite element method (FEM) to analyze the cross-flow VIV for tubings and pipings with non-linear geometry. A main feature in our approach is the modeling of lifting forces (excitations) and hydrodynamic damping in FEM. At present stage, most commercial VIV packages mainly deal with risers or pipelines that are either straight or with large radii, and they only considered curvature component associated with the cross-flow direction of the flow (d.o.f.), that is the direction perpendicular to the flow velocity. Stress calculation near the bends and elbows of the pipes, is not accurate. Our approaches, on the other hand, consider the responses in all 6 d.o.f of each element along the pipes and it is a truly three dimensional vibration analysis. Our approach provides an alternative to complement the existing method for solving the VIV problem for tubings and pipings with highly non-linear geometry.
Dynamic Upscaling From a Complex Triple-Porosity System to a Single-Porosity Model: A Successful Application for a Miscible-Gas-Injection Project
Authors: Tealdi L. , Giordano D. , Nembrini E. , Cappanera F. , Francia L.
Published: December 2007

Dual porosity numerical models are widely adopted in the oil business to model the performance of complex systems characterised by two different porous media. However, for numerical models of a certain complexity due to the large number of active grid-blocks, the dual porosity approach is often computationally unaffordable especially when a compositional formulation must be used.

This paper describes the methodology that was developed to mimic the dynamic performance of a complex triple porosity system by means of a single porosity model. The three porous systems were the matrix blocks, the fracture network and the dissolution karst bodies. The methodology was derived for a complex massive carbonate field not yet producing which is currently envisaged to be developed via miscible gas injection.

The matrix and karst bodies were statically modelled independently from the fracture network system. The characterisation of the fracture network has been driven using a DFN approach by integrating seismic, continuity cube interpretations and well data, such as FMI and mud losses. Due to the lack of dynamic data, the fractures' petrophysical properties were calculated from correlations. The matrix, karst bodies and DFN derived fractures were then up-scaled to a dual porosity model. The dual porosity model dynamic performance was considered as the reference to be matched by an equivalent up-scaled single porosity model.

An innovative procedure to up-scale matrix, fracture and karst properties into the equivalent single porosity model was tested for both a natural depletion and a miscible gas injection scenario. The methodology was firstly evaluated in representative sector models and then extended to the full field model. This methodology resulted to be very efficient being able to reduce the simulation time and model complexity drastically while capturing all the dynamic key performance indicators of the more complex and computationally expensive dual porosity model.
Influence of Prior Cycling on Fatigue Damage Caused by Defects in Coiled Tubing
Authors: Tipton S. M. , Neuharth L. G. , Sorem J. R.
Published: December 2007

Fatigue is known to be a major factor limiting the useful life of coiled tubing in the field and the presence of a defect is known to accelerate the onset of fatigue. Research efforts are underway to study the influence of defects such as scratches, dents, gouges, and other geometric discontinuities. The majority of this research has been conducted by placing defects in new tubing samples and cycling to failure. However, tubing in the field often incurs mechanical defects later in life, after fatigue damage has already accumulated due to prior cycling of the tubing in a defect-free state. This paper presents results from a quantitative investigation of the influence of varying amounts of cumulative damage from prior cycling on the detrimental effect of a defect. Coiled tubing with yield strengths of 90 and 110 ksi are used in the experiments and defects consist of transverse cuts made with a hack saw blade. The data indicate that prior cycling can influence the rate of damage accumulation caused by a defect, but this dependence appears to be dependent on the internal pressure level, which was held constant during these tests. The application of a simple Miner’s rule makes conservative estimates of fatigue lives for tubing cycled with low internal pressure, but estimates can be nonconservative for higher pressure levels.
Overview of the Kuparuk CTD Program and Recent Record-Setting Operations
Authors: Venhaus D. E. , Blount C. G. , Dowell K. E. , Gantt L. L. , Sarber J. G. , Worthington A. J. , Rixse M. G.
Published: December 2007

The Kuparuk Coiled Tubing Drilling (CTD) program began with the development of dynamically overbalanced CTD techniques1 in 1998. Although many of the first wells were technical successes, the economic and productive results were less than expected.

Starting with a step change in 2002, improvements in the economic results of the CTD program have materialized over the past 3 years fueling excitement about CTD in the Kuparuk River Unit (KRU). Results from the 11 well 2005 CTD program suggests that the successful application of CTD technology will continue in the Greater Kuparuk Area (Fig. 1).

Technological advances, changes in target focus, improved well designs, improved CT drilling techniques, and persistence all paid off. The 2004 & 2005 CTD programs delivered wells yielding rates beyond expectations and, in the case of 2005, were achieved "at or below" the authorized expenditure budget. In addition to the overall CTD program success story, what the authors believe as 3 new world records were set on one particular well: Deepest 3" CTD sidetrack – 18,350’ MD; deepest CTD openhole sidetrack – 17,935’ MD; and deepest CTD liner run – 18,320’ MD. All drilling objectives were achieved and the well completed under the AFE (Authorization for Expenditure).
Integration of a Risk-Management Tool and an Analytical Simulator for Assisted Decision-Making in IOR
Authors: Alvarado V. , Reich E. -M. , Yi Y. , Postsch K.
Published: December 2007

Risk management has become an integral part of the decision-making workflow in the oil and gas upstream business. As many oil fields reach a mature state, the need for rejuvenation and decline mitigation of assets set ground for Improved-Oil Recovery (IOR) opportunities. However, the associated decision-making process requires incorporating screening, reservoir simulation and financial evaluation, demanding complex multidisciplinary team efforts. It is important that any stage of the analysis, technical, strategic and economically sound decisions should be made.

On one hand, IOR screening, whether based on technical grounds or ‘gut feeling’ experience, or better yet on both criteria, leaves a number of possible IOR processes available for evaluation through simulation. Analytical simulation and applicability screening tools are often favored on early stages. However, their crude application could mislead the decision process if results are not carefully interpreted and combined with reservoir engineering expertise and additional evaluation criteria.

We propose to combine IOR screening strategies with spatial reservoir information to help to create appropriate sector models as starting point for more detailed evaluations. For this purpose, we couple an analytical simulator/IOR screening tool with a software tool that aids framing the IOR decision-making problem effectively, in the form of influence diagrams. From these diagrams, it is possible to create Tornado Diagrams, Decision Trees and Monte Carlo profiles that assist Reservoir Engineers with the task of properly and rationally framing the decision process, for example with regard to economic risk assessment and NPV analysis associated with IOR.

The coupling between both software solutions is proposed in a way that avoids the inflexible monolithic constructions. We illustrate advantages of the proposed approach through a speedy analysis of a publicly available case.
Risk Analysis With History Matching Using Experimental Design or Artificial Neural Networks
Authors: Reis L. C.
Published: December 2007

Oil companies have increasingly adopted Risk Analysis in decision-making processes. Most risks are related to reservoir uncertainties. Risk Analysis, even combining possible values of the input parameters (uncertainty variables) in the flow simulations, can create unrealistic models and compute wrong results (decision variable). Some reservoirs have dynamic data that can reasonably constrain the model increasing the Risk Analysis confidence.

Three methodologies based on Experimental Design and Response Surface Modeling (RSM) to model flow simulations are proposed. In the first method, one RSM is built to model the decision variable and another RSM is built to represent an Objective Function that takes into account dynamic data. Then, a relationship among the uncertainty variables obtained from the RSM of the Objective Function is applied to the RSM of the decision variable to constrain the model, enabling the Risk Analysis with History Match. In the second methodology, a maximum tolerance of the Objective Function is used as a filter to select the models taken on Risk Analysis. The third method is similar to the second one, but Artificial Neural Network replaces RSM to model the flow simulation. Even though requiring more simulation runs, such approach seems to be skillful to deal with non-linearities.

The methodologies were applied to two different reservoirs in Campos Basin, Brazil: a semi-synthetic case where dynamic data were simulated to represent the behavior of an appraisal phase field and a real case where the reservoir produces for more than five years. Significant reduction on the decision variable uncertainty is observed showing the importance of constraining the models when dynamic data are available.

The methods show that it is possible to improve the quality of the Risk Analysis, constraining the possible range of the uncertainty variables by taking into account dynamic data.
A Practical Approach in Building Upscaled Simulation Model for a Large Middle East Carbonate Reservoir Having Long Production History
Authors: Nair C. V. G. , Al-Maraghi E.
Published: December 2007

A comprehensive reservoir model that provides excellent turnaround time for historymatch and evaluation of different development scenarios had been developed through careful application of upscaling methods for the large carbonate reservoir of Umm Gudair field located inKuwait and partitionedneutral zone. The model was built maintaining integrity of the geological model.

The detailed geologic model, built using the latest techniques, was very large (157 layers, 10 million cells) and itwas necessary to upscale the model into a reasonably sized simulation model thatruns smoothly witha good turnaround timetomakemultiple runs tomatch 42 years oil/water productionand pressure history ofabout 200 wells. The vertical upscaling were to bedone maintaining the integrity of the fine-scale geological model, preserving physics of the displacement process and providing provisions for water shut off jobs implemented through squeezing off bottom perforations.

Although the flux-basedupscaling techniques provided guidance, it alone was not sufficient to optimize the layering scheme for the simulation model. A hybrid approach combining the elements of the methods of minimizing variation and flux, manual judgment and streamline simulation was applied to generate a vertically upscaled model with 42 layers that effectively replicated the fine-scale fluid flow behavior. Two simulation modelswere generatedwith different arealdimensions - a coarse modelwith 200×200 mt (to accelerate the history match process) and a fine-scale model with 100×100 mt (983,000 active cells) for infill drilling studies. Excellent history match has been achievedand the model has been demonstrated as an effective reservoir management tool for further field development.

This paper discusses the steps applied towards effectively converting the geologic model to simulation model through upscaling, the systematic approach towards buildingthe history match model highlighting the critical steps and an overview of the quality ofhistory match.
Suplacu de Barcau Field—A Case History of a Successfull In-Situ Combustion Exploitation
Authors: Panait-Patica A. , Serban D. , Ilie N.
Published: December 2007

This paper describes the thermal recovery implementation used on the Suplacu de Barcău field, from the beginning of the production life until 2005. The field is a heavy oil, near surface Pliocene clastic reservoir, situated in the north-western part of Romania, in the Pannonian Depression.

Drilling operations, beginning in 1956, revealed a heavy and viscous oil reservoir. In 1961 a few wells were put into production, as part of an in-situ combustion (ISC) test. Between 1960 and 1970, an important number of wells established the structure and reservoir parameters, from which an original oil in place volume was calculated.

In order to confirm the theoretical model of high efficiency, related to thermal recovery methods, steam drive (SD) and in-situ combustion (ISC) were concurrently tested during the period 1963-1970. The better performance of ISC during this semi-commercial stage led to the decision in 1970 to design the entire reservoir exploitation using this method. The ISC exploitation has been successfully developed and improved in time, becoming the largest of this type in the world and is one of the most important fields exploited by Petrom.

There are now nearly 800 wells with a total production of about 1200 tones/day of crude oil (2005). The cumulative extracted crude in 35 years is about 17,8 million tones, which corresponds to a current recovery factor of 44,6%.

This paper presents the most significant highlights of this field exploitation, including the challenges encountered, the surveillance methods, as well as the important lessons which have been drawn from the exploitation of this field.
The Development of a Revolutionary Scale-Control Product for the Control of Near-Well Bore Sulfate Scale within Production Wells by the Treatment of Injection Seawater
Authors: Collins I. R. , Duncum S. D. , Jordan M. M. , Feasey N. D
Published: December 2007

The formation of sulfate scales arising from the injection of seawater into hydrocarbon-bearing formations for pressure maintenance and secondary oil recovery has been a significant problem in many onshore/offshore operations. To address this, batch scale inhibitor squeeze treatments, scale removal, and modification of the injection brine (sulfate removal, produced water injection, aquifer water injection) have been applied with varying degrees of success. The development of deepwater projects, where conventional scale control technology may be uneconomic for the control of mineral scale, has required a re-evaluation of the methods of scale inhibitor deployment.

For the past five years, BP Exploration has been developing a novel approach to the application of scale inhibitors with the objective of eliminating the requirement for both active scale inhibitor squeezing and scale removal operations. This has been achieved by the development of nano-sized, controlled release, solid scale inhibitor particles that can be added to the injection water such that the particles pass through the formation and release the scale inhibitor into the fluids near the production wells.

The principle of solid particle transport in porous media is demonstrated using core flooding tests and reservoir modelling. This confirms that solid particle transport is possible and that minimum retardation relative to the injected brine can be achieved. Static and dynamic release characteristics of the scale inhibitor formulations evaluated to date will be presented. The factors to be considered in the commercial manufacture and initial field trial results will also be presented together with the economic justification for this type of scale control process.

This technology offers a revolutionary scale control process that could eliminate the need for sulfate-reduction plants whilst still providing effective scale control within the reservoir and near-wellbore region for deep water developments.
PDOB's Proactive Approach to Solving a Zonal Isolation Challenge in Harweel HP Wells Using Swell Packers
Authors: Laws M. S. , Fraser J. E. , Soek H. F. , Carter N.
Published: December 2007

The Harweel Cluster in Southern Oman is PDO’s first EOR Project. It is being developed in a phased manner using miscible gas injection. Reservoir simulations have been carried out to show that a significant increase in ultimate recovery can be achieved by successfully isolating gas (and water) if it breaks through prematurely to producing wells. In order for the additional reserves to be obtained, zonal isolation is required over the reservoir section. To date, isolation has proved to be inadequate using conventional cementing technology and techniques.

A trial was therefore carried out to determine the effectiveness of using oil swellable elastomers ("Swell Packers") to achieve zonal isolation. Three swell packers were run in a well and tests were devised to determine the success of the elastomers following expansion.

Based on the results, zonal isolation was achieved as indicated by a combination of selective perforating, wireline logging and production testing. This is the first time that zonal isolation has been observed in these challenging, HP, sour wells.
Application of Engineered Cementing Solution to Solve Long-Term Cement Integrity Issues in Tunisia
Authors: Krusche K. , Johnson C. R. , Braud N. Y. , Ghazi H. B.
Published: December 2007

An operator faced a recurring problem of early cement-casing/cement-formation microannulus development followed by interzonal communication. In some cases, this unwanted communication led to the complete loss of production, resulting in a drastic loss of revenue. The loss of production was attributed to water-cut levels up to 78%. At this point, the operator was no longer willing to risk another massive loss, so a step-change decision was made to cure the problem at the source; hence, it was necessary to devise a solution to eliminate this detrimental effect in future well production.

Due to well events, which induced downhole pressure and temperature changes, additional stress was imposed on the cement sheath. An example of a temperature decrease was swapping drilling mud with colder brine prior to running the completion. This systematically caused contraction across the production interval, resulting in development of a microannulus on both sides of the cement sheath.

Computerized stress simulations indicated the presence of a microannulus, which compromised hydraulic isolation across the pay zone. This was also evident in previous wells in this field. The operator felt that requiring an engineered solution would maintain long-term zonal isolation.

This paper describes a case history covering the challenge faced by a North African operator, the development of an engineered solution, and the field execution of the job. The success of applying cementing technology will also be shown through cement bond log response. In addition to the successful step-by-step approach adopted by the operator, the results have allowed further work to be performed with other operators in Tunisia who face similar challenges.