bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coiled Tubing Velocity String Hang-Off Solves and Prevents Liquid-Loading Problems in Gas Well: Case Study in the Gulf of Guayaquil, Ecuador
Authors: Quintana Juan , Duque Eusebio , Diaz Jose D. , Eras Jose , Rodas Jose , Vergara Enrique , Prieto Washington 
Published: November 2015

Abstract
The Amistad field in the Ecuadorian Gulf of Guayaquil has been producing dry gas since 2002 from the productive formation Subibaja. This field covers an area of 2,250 km2 and is located offshore about 100 km southwest of the city of Guayaquil. Six wells in the field produce 60 MMSCFD and 940 BWPD. Gas production from this field is affected by water production and reservoir pressure declination. In particular, liquid-loading is considered a critical problem in the gas wells productivity, with water intrusion occurring in the wellbores during temporary shut-in for workover operations.
A coiled tubing (CT) velocity string is a known method to unload liquids in gas wells; the correct choice of CT size may optimize gas well productivity. The smaller-diameter CT is installed inside the production tubing to improve gas velocity, thereby avoiding water column accumulation at the bottom of the well.
The reservoir inflow performance relationship (IPR) and tubing performance relationship (TPR) are considerations in velocity string design. Both curves are independent and their intersection, compared with the minimum gas flow rate on a J-curve, indicates whether liquid loading will occur in a gas well.
This paper discusses the technical concepts of velocity string design, as well as simulations and analysis for a case history of deploying velocity string technology in a gas well with optimal results.
Techniques and Benefits of Drilling into 2 Sections in the Ecuadorian Basin
Authors: Loaiza M. , Ramirez F. , Morales . , Colmenares E. , Tapia E. 
Published: November 2015

Abstract
The design of wells into two sections (16″ × 13 3/8″ and 12 ¼″ × 9 5/8″) in the Ecuadorian basin is a challenging effort of engineering. The success of the well depends on various techniques that will be analyzed in the following paper, which include precise casing seating depth, accurate fluid density for each section, appropriate formation bridging and sealing in the production zone (Napo), correct chemical selection as part of the fluid system to reduce formation damage on the producing reservoirs, plan a suitable directional trajectory if vertical section aloud (less than 2000') use "S" type design and appropriate BHAs for each section taking into account formation tendencies in terms to reduce slides in the case of PDM BHA is used. Other techniques applied that are going to be reviewed are include cementing production casing can be used slurries with higher densities to achieve better cement quality having less ECD during jobs; the two section design allows to run larger diameter guns and higher penetration bullets into productive sands, artificial lift systems can be set close to the producing reservoir. Using these techniques in the two sections design can provide several advantages compared with conventional three or four sections design in the Ecuadorian basin. This advantages are less cost for Drilling Event by time, by materials and equipment used, avoid adding risk when setting expandable 7″ Liner Hangers, reduce risk of drilling tools and Wireline logs to get stuck related to higher clearance between them also Casings can run smoothly, improving production from reservoirs drilled through.
The result of first well drilled using these techniques will be presented in the following paper taking into account design facts, programs and procedures during the operation, and the results that will demonstrate the value of the design.
Model-Based Adaptive-Predictive Control and Optimization of SAGD under Uncertainty
Authors: Guevara J. L. , Ortega A. , Canelón J. I. , Nava E. , Queipo N. V. 
Published: November 2015

Abstract
When it comes to SAGD optimization, two of the biggest challenges are controlling subcool to achieve conformance (a uniform growth of the steam chamber along the complete length of the well pair), and maximizing an economic performance measure, such as net present value (NPV); both desirable outcomes are not necessarily associated with the same values of the operational parameters (e.g., injection rates). Overcoming these challenges is necessary for achieving optimum SAGD performance, but this may be difficult through common operating policies, e.g. injecting steam at a empirically specified constant rate, considering well-known features of SAGD processes, e.g., complex dynamics (nonlinear, slow, high order, time varying, potentially highly heterogeneous reservoirs), operational constraints, model uncertainty and measurement noise. In the context of this work, the aforementioned challenges are both formulated as optimization problems of adjusting injection rates in order to optimize a particular objective function (e.g. minimizing subcool error or maximizing NPV). To address these challenges, this paper presents a nonlinear model-based adaptive-predictive control approach, alternative to the classical Proportional-Integral-Derivative (PID), for subcool control and NPV optimization of SAGD processes under uncertainty. Using case studies with an idealized heterogeneity pattern (subcool control) and multiple geological realizations based on logs from the Orinoco Belt region (NPV optimization), the proposed approach was compared with a decentralized PID for subcool control, in terms of response speed (mean square error and reaching time), steady state behavior (settling time, measured subcool mean and standard deviation) and control energy spending. While the proposed approach offered a slower response (not a critical issue in terms of oil recovery), it significantly outperformed the PID control during steady state and in control energy spending. On the other hand, the effectiveness for NPV optimization under uncertainty was demonstrated against constant steam injection strategies considering mean NPV, steam injection, water produced, and SOR, and when modeling alternative risk aversion scenarios.
Replacement of ESP with Long Stroke Pumping Units in Heavy and High Viscous Oil in Maranta Block Wells
Authors: Sarmiento D. B. , Prada J. W. , Quiros H. M. , Mora J. , Sun D. 
Published: November 2015

Abstract
Contribution of heavy oil in total oil production in Colombia has shown an increase year after year, currently representing around 50% of the market. The challenge for Artificial Lift is to offer an efficient design to obtaining an economical solution for wells of heavy oil with high pumping costs and failure rate.
Use of Long Stroke Pumping Units extends the operating range for reciprocation rod lift and represents a cost-efficient alternative instead of electrical submersible pumps (ESP) to produce oil wells with low to medium productions (up to a production rate of 1,500 STB/D) where operational and energetic optimization is needed. In wells with a high frequency of failures, long stroke pumping units can reduce rod failure, prevents pump problems, increases run lifes, and reduce workover costs.
Since March 2014, four artificial lift conversions to Beam Pumping were implemented in Maranta Block achieving significant reductions in operation and intervention costs compared to artificial lift system previously installed in each well (Electric Submersible Pumps - ESP). These savings are mainly represented by reducing of electric consumption around 79% and increasing run life 2.8 times that result in less production losses and workover costs considering fewer corrective interventions.
Nanoporous Copper Doped Aluminium Pillared Montmorillonite for Dye‐containing Wastewater Treatment
Authors: Tepmatee Pratyaporn , Siriphannon Punnama 
Published: November 2015

ABSTRACT: Copper doped aluminium pillared montmorillonite (Cu‐Alpill‐MMT) was prepared by adding Cu2+ into the suspension of aluminium pillared montmorillonite (Alpill‐MMT) using high power ultrasonic treatment and calcining to CuO at 500 °C. The XRD and XRF data revealed that the doped CuO partially occupied both internal and external surfaces of the Alpill‐MMT. The N2 adsorption/desorption analysis showed that the Cu‐Alpill‐MMT consisted of slit‐like mesopores with two ranges of pore diameter, i.e. ~3.8 nm and ~6‐30 nm. The Cu‐Alpill‐MMT exhibited the superior adsorption capacity for Basic Yellow 1 (BY1), however, it hardly adsorbed Reactive Orange 16 (RO16). The decolorization of RO16 was achieved when the H2O2 or H2O2/UV was introduced into the treatment system together with the Cu‐Alpill‐MMT, acting as heterogeneous catalyst for Fenton or photo‐Fenton oxidation processes, respectively. The Cu‐Alpill‐MMT could exhibit the antibacterial activity after intimate contact with Escherichia coli ATCC®25922 under JIS L 1902: 1998 (Qualitative) test method.
Uricosuric activity of <i>Tinospora cordifolia</i>
Authors: Shah Palak A. , Shah Gaurang B. 
Published: November 2015

<p class="Abstract">Uricosuric activity of different extracts of <em>Tinospora cordifolia</em> was studied in hyperuricemia induced in albino Wistar rat using potassium oxonate. The uric acid level in serum and urine were measured. Uricosuric activity was also evaluated using phenol red dye excretion model. Phenol red levels were measured in blood. In potassium oxonate induced hyperuricemia, probenecid, aqueous, hydro-alcoholic, dichloromethane extract and galo satwa (starch of <em>T. cordifolia</em>) significantly lowered the serum uric acid levels. All the extracts increased uric acid excretion and decreased the elevated serum uric acid levels induced due to potassium oxonate. Probenecid, aqueous extract and galo satwa significantly increased fractional excretion of uric acid and phenol red levels in blood indicating uricosuria. Polysaccharides in aqueous extract and galo satwa may be responsible for uricosuric action.</p><p class="Abstract"> </p><p class="Abstract"><strong>Video Clips</strong></p><p><a href="https://www.youtube.com/v/t7ok0iHx8pM">Preparation of extracts</a> 4 min 22 sec</p><p><a href="https://www.youtube.com/v/jUyQMEa8rBg">Prepared extracts</a> 26 sec </p><p><a href="https://www.youtube.com/v/cnxmo69V550">Potassium oxonate induced hyperurecimia</a> 1 min 46 sec</p><p><a href="https://www.youtube.com/v/A4s8bdqVrls">Injection of red phenol into tail vein</a> 52 sec</p><p><a href="https://www.youtube.com/v/aZf3jyKDMUM">Collection of blood</a> 16 sec</p><p><a href="https://www.youtube.com/v/TVbBi-B7xPk">Estimation of uric acid</a> 1 min 44 sec</p><p> </p>
Validation of the OMERACT Psoriatic Arthritis Magnetic Resonance Imaging Score (PsAMRIS) for the Hand and Foot in a Randomized Placebo-controlled Trial
Authors: Glinatsi Daniel , Bird Paul , Gandjbakhch Frederique , Mease Philip J. , Bøyesen Pernille , Peterfy Charles G. , Conaghan Philip G. , Østergaard Mikkel 
Published: November 2015

Objective.To assess changes following treatment and the reliability and responsiveness to change of the Outcome Measures in Rheumatology (OMERACT) Psoriatic Arthritis Magnetic Resonance Imaging Score (PsAMRIS) in a randomized controlled trial.Methods.Forty patients with PsA randomized to either placebo or abatacept (ABA) had MRI of either 1 hand (n = 20) or 1 foot (n = 20) at baseline and after 6 months. Images were scored blindly twice by 3 independent readers according to the PsAMRIS (for synovitis, tenosynovitis, periarticular inflammation, bone edema, bone erosion, and bone proliferation).Results.Inflammatory features improved numerically but statistically nonsignificantly in the ABA group but not the placebo group. Baseline intrareader intraclass correlation coefficients (ICC) were good (≥ 0.50) to very good (≥ 0.80) for all features in both hand and foot. Baseline interreader ICC were good (ICC 0.72–0.96) for all features, except periarticular inflammation and bone proliferation in the hand and tenosynovitis in the foot (ICC 0.25–0.44). Intrareader and interreader ICC for change scores varied. Guyatt’s responsiveness index (GRI) was high for inflammatory features in the hand and metatarsophalangeal joints (GRI −0.67 to −3.13; bone edema not calculable). Minimal change and low prevalence resulted in low ICC and GRI for bone damage.Conclusion.PsAMRIS showed overall good intrareader agreement in the hand and foot, and inflammatory feature scores were responsive to change, suggesting that PsAMRIS may be a valid tool for MRI assessment of hands and feet in PsA clinical trials.
Rheumatoid Arthritis: Trends in Antirheumatic Drug Use, C-reactive Protein Levels, and Surgical Burden
Authors: Pedersen Alma B. , Mor Anil , Mehnert Frank , Thomsen Reimar W. , Johnsen Søren P. , Nørgaard Mette 
Published: November 2015

Objective.Over the past decade, the therapeutic approach used to treat patients with rheumatoid arthritis (RA) has considerably changed. It remains unclear whether these changes have been accompanied by decreased disease severity and surgical treatment burden at the population level. Therefore, we investigated time trends in antirheumatic drug consumption, C-reactive protein (CRP) levels, and use of orthopedic surgery among Danish patients with RA.Methods.Using medical databases, we identified all patients with RA living in Northern Denmark during 1996–2012. For each calendar year, we computed the annual rate of antirheumatic drug use (1996–2010), the median CRP value in mg/l (1996–2011), and the proportions of patients who underwent hip replacement and other orthopedic procedures (1996–2012).Results.Antirheumatic drug consumption per patient increased 5-fold, from 145.0 defined daily doses (DDD) in 1996 to 695.4 DDD in 2010. Median CRP declined from 20.5 mg/l [interquartile range (IQR), 10.0 to 43.5 mg/l] in 1996 to 10.0 mg/l (IQR, 4.2–17.8 mg/l) in 2011. From 1996 to 2012, declining proportions of patients with RA underwent hip replacement (14.9% to 10.1%) and other joint operations (29.1% to 23.4%), while the annual proportion of patients who underwent soft tissue procedures increased from 20.7% to 23.4%.Conclusion.Antirheumatic drug consumption has substantially increased among patients with RA since 1996, in association with reduced disease activity (i.e., lower CRP levels), fewer joint procedures (including hip replacements), and more soft tissue procedures.
Incidence and Predictors of Biological Antirheumatic Drug Discontinuation Attempts among Patients with Rheumatoid Arthritis in Remission: A CORRONA and NinJa Collaborative Cohort Study
Authors: Yoshida Kazuki , Radner Helga , Mjaavatten Maria D. , Greenberg Jeffrey D. , Kavanaugh Arthur , Kishimoto Mitsumasa , Matsui Kazuo , Okada Masato , Reed George , Saeki Yukihiko , Tohma Shigeto , Kremer Joel , Solomon Daniel H. 
Published: November 2015

Objective.We conducted a longitudinal observational study of biological disease-modifying antirheumatic drugs (bDMARD) to describe the proportions of patients with rheumatoid arthritis in remission who discontinued these agents, and to assess the potential predictors of the decision to discontinue.Methods.We used data from the US COnsortium of Rheumatology Researchers Of North America (CORRONA) and the Japanese National Database of Rheumatic Diseases by iR-net in Japan (NinJa) registries, and ran parallel analyses. Patients treated with bDMARD who experienced remission (defined by the Clinical Disease Activity Index ≤ 2.8) were included. The outcome of interest was the occurrence of bDMARD discontinuation while in remission. The predictors of discontinuation were assessed in the Cox regression models. Frailty models were also used to examine the effects of individual physicians in the discontinuation decision.Results.The numbers of eligible patients who were initially in remission were 6263 in the CORRONA and 744 in the NinJa. Among these patients, 10.0% of patients in CORRONA and 11.8% of patients in NinJa discontinued bDMARD while in remission over 5 years, whereas many of the remaining patients lost remission before discontinuing bDMARD. Shorter disease duration was associated with higher rates of discontinuation in both cohorts. In CORRONA, methotrexate use and lower disease activity were also associated with discontinuation. In frailty models, physician random effects were significant in both cohorts.Conclusion.Among patients who initially experienced remission while receiving bDMARD, around 10% remained in remission and then discontinued bDMARD in both registries. Several factors were associated with more frequent discontinuation while in remission. Physician preference likely is also an important correlate of bDMARD discontinuation, indicating the need for standardization of practice.
Patient’s Global Assessment as an Outcome Measure for Psoriatic Arthritis in Clinical Practice: A Surrogate for Measuring Low Disease Activity?
Authors: Lubrano Ennio , Perrotta Fabio Massimo , Parsons Wendy J. , Marchesoni Antonio 
Published: November 2015

Objective.To assess the low disease activity (LDA) in a group of patients with psoriatic arthritis (PsA) receiving antitumor necrosis factor-α (TNF-α) by using the patient’s global assessment (PtGA) in clinical practice, and to compare PtGA with minimal disease activity (MDA) and other outcome measures.Methods.Patients with PsA classified by the ClASsification for Psoriatic ARthritis (CASPAR) criteria and consecutively admitted to an outpatient clinic dedicated to biologic therapy were assessed during their routine followup. The primary outcome measure was the proportion of patients achieving a PtGA ≤ 20 at 4-, 8-, and 12-month followups. Secondary outcome measures included the proportion of patients achieving MDA and other outcome measures. Correlation of PtGA with MDA and other process and outcome measures were also performed.Results.During the period of observation, 124 patients were evaluated. PtGA ≤ 20 was achieved in 25.7% at 4 months, 48.9% at 8 months, and 65.3% at 12 months of followup. The percentage of PtGA ≤ 20 statistically improved throughout the 3 timepoint assessments and it was statistically correlated to MDA. A significant correlation with the Disease Activity index for PSoriatic Arthritis (DAPSA), Bath Ankylosing Spondylitis Disease Activity Index, and Health Assessment Questionnaire was also observed. MDA, DAPSA, and Disease Activity Score at 28 joints with C-reactive protein remission were achieved at 12 months in 64%, 36%, and 71% of patients, respectively.Conclusion.PtGA can estimate the LDA status and could be considered as a surrogate of outcome measures for the assessment of global disease activity in patients with PsA receiving anti-TNF therapy during routine clinical practice. These data suggest that PtGA might be used in outpatient settings, being a simple, reliable, and not time-consuming instrument.
Consolidation Drainage and Climate Change May Reduce Piping Plover Habitat in the Great Plains
Authors: McCauley Lisa A. , Anteau Michael J. , van der Burg Max Post 
Published: November 2015

AbstractMany waterbird species utilize a diversity of aquatic habitats; however, with increasing anthropogenic needs to manage water regimes there is global concern over impacts to waterbird populations. The federally threatened piping plover (Charadrius melodus; hereafter plovers) is a shorebird that breeds in three habitat types in the Prairie Pothole Region of North Dakota, South Dakota, and Canada: riverine sandbars; reservoir shorelines; and prairie wetlands. Water surface areas of these habitats fluctuate in response to wet–dry periods; decreasing water surface areas expose shorelines that plovers utilize for nesting. Climate varies across the region so when other habitats are unavailable for plover nesting because of flooding, prairie wetlands may periodically provide habitat. Over the last century, many of the wetlands used by plovers in the Prairie Pothole Region have been modified to receive water from consolidation drainage (drainage of smaller wetlands into another wetland), which could eliminate shoreline nesting habitat. We evaluated whether consolidation drainage and fuller wetlands have decreased plover presence in 32 wetlands historically used by plovers. We found that wetlands with more consolidation drainage in their catchment and wetlands that were fuller had a lower probability of plover presence. These results suggest that plovers could have historically used prairie wetlands during the breeding season but consolidation drainage, climate change, or both have reduced available shoreline habitat for plovers through increased water levels. Prairie wetlands, outside of some alkali wetlands in the western portion of the region, are less studied as habitat for plovers when compared with river and reservoir shorelines. Our study suggests that these wetlands may have played a larger role in plover ecology than previously thought. Wetland restoration and conservation, through the restoration of natural hydrology, may be required to ensure that adequate habitat exists among the three habitat types in the face of existing or changing climate and to ensure long-term plover conservation.
Effects of the US Stock Market Return and Volatility on the VKOSPI
Authors: Han Heejoon , Kutan Ali M. , Ryu Doojin 
Published: November 2015

Abstract
The KOSPI (Korea Composite Stock Price Index) 200 options are one of the most actively traded derivatives in the world. This paper empirically examines (a) the statistical properties of the Korea’s representative implied volatility index (VKOSPI) derived from the KOSPI 200 options and (b) the macroeconomic and financial variables that can predict the implied volatility process of the index, using augmented heterogeneous autoregressive (HAR) models with exogenous covariates. The results suggest that the elaborate HAR framework is proficient at describing the dynamics of the VKOSPI and that some domestic macroeconomic variables explain the VKOSPI. More importantly, we find that the stock market return and implied volatility index of the US market (i.e., the S&P 500 spot return and the VIX from the S&P 500 options) play a key role in predicting the level of the VKOSPI and explaining its dynamics, and their explanatory power dominates that of domestic macro-finance variables. Further, while the domestic stock market return does not predict the VKOSPI, the US stock market return does so rather well. When two global factors, both the US stock market return and the US implied volatility index, are incorporated into the HAR framework, the model exhibits the best performance in terms of both in-sample fitting and out-of-sample forecasting ability.
Una ciudad, un santo, una Orden: Bolonia, Domingo de Caleruega y la Orden de los Frailes Predicadores. Entre la vocación al estudio y la custodia de las sagradas prendas
Authors: Borghi Beatrice 
Published: November 2015

<p>En el presente ensayo se ilustrarán los acontecimientos y los símbolos de la devoción a un santo, a una ciudad, a un monumento: Domingo de Caleruega, Bolonia y la basílica y monasterio de los frailes predicadores. No es raro, en Italia, asistir a una integración tan fuerte entre tres diferentes y, al mismo tiempo, complementarias dimensiones de una dinámica histórica. No obstante, en el caso de Bolonia hay algo más: un “cuarto elemento”, que alude a la historia y a la función de la Ordo praedicatorum aun precediéndolas más o menos en un siglo. Se trata de la Universidad: el célebre Estudio, valiéndose desde mediados del siglo XII de la previsora legitimación de Barbarroja, y aquellos (en origen y en teoría cualquier convento, porque en cada uno de ellos se estudiaba teología) de los “studentes in sacra pagina”.</p>