bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pilot-scale Study of Buoyant Settling of Immiscible Heavy Fluid in Mud – A Promising Technique to Stop Annular Gas Migration above Leaking Cement
Authors: Demirci Efecan , Wojtanowicz Andrew K. 
Published: April 2016

Abstract
Irreducable casing pressure, also known as Sustained Casing Pressure (SCP), cannot be bled off permanently as it is caused by annular gas migration from the leaking cement. SCP poses environmental risk, and regulations demand its removal - particularly prior to well's plugging and abandonment operation. Bleed-and-Lube method, which is cheaper than the conventional mechanical removal methods, involves injecting heavy fluid into the affected annulus that would displace the annular fluid, balance the pressure at the top of cement and stop the gas leakage. Previous studies stated that the use of immiscible combinations of two fluids is more effective for the purpose; however, inattentive applications may result in excessive use of heavy fluid. In this study, a 20-foot carbon-steel pilot well annulus was manufactured and used for displacement experiments with various drilling muds and heavy fluids with different characters. Pressure change data was collected from four different levels of the annulus and volumes of fluids going in and out of the annulus were measured. Experiments indicated the formation of a mixture zone that would build bottoms up and expand during ongoing displacement. Proposed pressure build-up model suggests an exponential distribution of density of this zone, and shows its high depencency on fluids' properties and injection rate. The models were also converted into dimensionless process measures and proposed for the use in real well applications. The study clearly demonstrates the viability and recommends the correct application of the method.
Innovative Approach of Coiled Tubing Pipe Integrity Control in Chrome Completion and Harsh Environment
Authors: Zhaxybekov Anuar , Kusherbayev Gabit , Burov Anton , Jumagaliyev Yerlan , Gaidanov Robert 
Published: April 2016

Abstract
In recent years, well intervention operations have become more challenging due to the complex well completions and harsh formation conditions. This is particularly true for coiled tubing (CT) operations for one of the most complex development projects in the northern Caspian basin. Excessive abrasion acting on CT pipe has been encountered during CT operations in chrome completions in an H2S environment and this has resulted in a shortened CT service life.
The inability to predict the end of CT pipe service life could result in unexpected failures, which can cause the operator and service company down time, loss of well control, overall potential injury for personnel, and environmental harm.
This paper describes the shortfalls of the conventional CT pipe management techniques, which are largely based on assumed mathematical models and local practices, and how to reverse this trend by implementing the use of the non-contact technology of a magnetic flux leakage (MFL) measurement device with real-time inspection and monitoring of the CT pipe integrity.
In- Situ Heavy Oil Upgrading through Ultra-Dispersed Nano-Catalyst Injection in Naturally Fractured Reservoirs: Experimental Section
Authors: Orozco-Castillo Carlos R. , Pereira-Almao Pedro 
Published: April 2016

Abstract
Conventional reserves in Mexico are nowadays in depletion, unconventional or not straight forward reservoirs are the next challenge for maintaining the oil production plateau of the Mexican industry. Several EOR processes are under study in order to deal with this situation, one promising process for naturally fracture reservoirs is the "In Situ Upgrading" which produces EOR and Upgrading by injection of a hot fluid, proposedly vacuum residue from the heavy oil produced, with suspended nano-catalytic particles flowing down-hole along with dissolved hydrogen as precursor of partial Hydroprocessing of the residue. The combination of thermal and chemical reactions with a catalyst leads to In-Situ Upgrading (ISU) of the residue injected and the in situ oil at the conditions created in the reservoir near the surroundings of the injection well bore, while the heat carried to the reservoir, the diluents produced by upgrading processes, the steam and hot water generated warm up progressively the rock and the heavy oil in the porous media, enhancing oil extraction. Testing the reactivity of the oil from a particular field has to be assessed at temperatures, pressures and residence time characteristics for the targeted reservoir in order to determine the suitability of this EOR process in that environment.
Resilient Field Developments That Can Accommodate Uncertainty Are the Best Solution for a Sustained Low Oil Price Environment
Authors: Hopper C. T. 
Published: April 2016

Abstract
The upstream industry has been unable to deliver projects successfully over the last ten years, with up to 70% of projects failing to meet schedule or cost targets. This failure rate did not matter when the oil price was high as the projects remained profitable. However, after the oil price dropped in 2015, this level of project failure has become untenable.
The linear gated project management systems adopted by the industry over the last fifteen years are suitable for straightforward projects that can be well defined. However, they are not suitable for many of today's projects that are more complex and have significant uncertainty, which require a different approach.
This paper describes a project management process developed in the UKCS in the 1990's that was used to bring three projects stuck for 15 years to project sanction. In addition, a recent project is described where the development was designed to accommodate a range of outcomes and by doing so allowed the project to be sanctioned with significant uncertainty still remaining.
In the current environment of a sustained low oil price, across the board cuts are often implemented in an attempt to make projects economic. Arbitrary cuts on their own are unlikely to make projects viable and instead the industry needs to take a step back and question the processes that have been used and why they have failed. A different approach is suggested; one that embraces uncertainty to produce resilient projects that can accommodate change. Implementing this will require a change in mindset as much as a change in process.
Applied Methodology to Optimize the Intervention Sequence in a Mature Water-Flood Oil Field in the North Sea
Authors: Aponte Jesus , Trujillo Maria , Primera Alejandro 
Published: April 2016

Abstract
In mature water-flood oil field, interventions are key for reservoir management, by controlling water cut through water shut-off or maximizing oil production through additional perforations; however, intervention success is tied to the understanding the reservoir dynamic and hence the associated uncertainties; therefore an uncertainty analysis approach has been developed to select an optimal interventions sequence and work-overs. The corner stone of this methodology is the integration of multiple geological reservoir realizations, well timing, operational risk and different scenarios for capital and operating costs.
This methodology is applied through the following steps: Identification of remaining opportunities of bypassed oil and thief zones through well reviews and surveillance data. Twelve wells were identifiedIncorporate multiple reservoir models where history match per well, and field is achieved. Interventions were tested and NPV’s were calculated.A multivariate linear regression was performed to generate proxy models for each intervention.Using Proxy models, Monte Carlo simulation was set up, according to each variable range and distributions.A set of Monte Carlo loops were simulated across hundreds randomly generated sequences. A group of sequences with a greater NPV were selected.
The top twenty sequences based on NPV from a pool of five hundred potential sequences were identify as a results of this methodology. A common well order was generally observed across the best twenty sequences, for example: the top three wells and the bottom three wells were consistent across the cases; these results were cross-checked against the bottom worst NPV sequences with similar conclusions. The workflow showed that optimizing the intervention sequence of twelve wells could represent a gain of $17.3MM in NPV (estimations were done considering a low oil price environment).
As a secondary result the subsurface uncertainty and well timing were the primary factors affecting the KPI’s; costs and operational risk were ranked as variables with reduced impact in the case study.
This is a value added workflow that can be applied in any asset where intervention and work-overs are key to sustain production, because it is repeatable process, it is flexible enough to incorporate new wells, and new subsurface realization and operation views that may arise through continuous surveillance and production.
A Multidisciplinary Approach to Improve Reservoir Management of a Tidal-Fluvial Channel Reservoir in Tasbulat Field, Kazakhstan
Authors: Lechner Michael , Iltukov Renat , Mukushev Meirzhan 
Published: April 2016

Abstract
Tasbulat field was one of the fields discovered during Soviet times in the 1960’s by the regional exploration drilling campaign in the South Mangyshlak basin. It consists of multiple stacked oil and gas reservoirs of lower to mid Jurassic and mid Triassic age. The main reservoir in terms of oil production, initial oil in place, reserves and development progress is the Jurassic 10b which is an anticline shaped tidal-fluvial channel which is filled with under saturated oil. The lateral extension of the productive Jurassic 10b reservoir has been defined by a number of wells. Moreover, towards both flanks of the field the oil-water contact has been penetrated. Production from the Jurassic 10b reservoir commenced in the 1970’s under natural depletion. Water injection was started in 2003 and gradually increased in terms of volume and number of injection wells.
Breakthrough of injection and/or aquifer water has been observed in parts of the field. At present, the Jurassic 10b is being developed with 13 oil producers and 7 water injectors. A large portion of the producers have been hydraulically fractured which adds another layer of complexity. A recent multidisciplinary approach has significantly improved understanding of the Jurassic 10b by integrating static and dynamic data sets. The approach entailed a systematic review and interpretation of production, injection and well history based on which the lateral extension of the water flood front was estimated and drawn. The position of the flood front was subsequently confirmed and refined using dynamic reservoir simulation.
At the same time, sedimentological core description identified a number of lithofacies which identified the Jurassic 10b as a fluvial-tidal dominated system. Based on this knowledge a conceptual sedimentological model for the Jurassic 10b was obtained. In addition, seismic attribute analysis was performed and several channel features were identified and picked. The features were then projected on maps of different reservoir properties (e.g. net sand thickness, pressure, productivity index, water flood front etc.) and it was checked whether correlations existed between features and properties. Using the integrated approach it was shown that the Jurassic 10b channels exhibit hydraulic communication over a significant area, possibly in both, vertical and horizontal direction. And furthermore, that seismic attributes such as similarity and spectrum decomposition could potentially be used for predicting channel extensions.
This paper describes a real example how different methods and techniques such as seismic attribute modelling, lithofacies modelling, production surveillance/engineering, reservoir simulation can be practically used to define a field development strategy.
Effects of Nitrogen Application on Root Length and Grain Yield of Rain‐Fed Maize under Different Soil Types
Authors: Feng Guozhong , Zhang Yongjie , Chen Yanling , Li Qian , Chen Fanjun , Gao Qiang , Mi Guohua 
Published: April 2016

The effect of fertilizer N on maize (Zea mays L.) root size has been reported with inconsistency. It remains unclear whether a quantitative relationship exists between soil NO3–N and root growth under field conditions. A 3‐yr field experiment was conducted in three soils (loamy clay, clay loam, and sandy loam) with five N treatments (from 0–312 kg N ha−1). Soil NO3–N concentration and total root length were determined to a depth of 60 cm at the silking stage. It was found that plants grown in clay loam soil had larger root size compared with the other two soil. A weak parabolic relationship between N supply and root length was found in loamy clay and clay loam soil, but not in sandy loam soil. There was a parabolic relationship between soil NO3–N concentration in the 0‐ to 60‐cm depth and total root length per plant. This relationship was mostly found in clay loam soil. Across soils and years, there was a parabolic relationship between root length density (RLD) and shoot dry matter (DM) at silking and between RLD at silking and grain yield with fertilizer N rate £240 kg N ha−1. It is suggested that it may be not practical to regulate total root length by simply adjusting N fertilizer amount. Total root length is not relevant to maize yield under excess N input conditions.Core Ideas

Plants grown in clay loam soil had larger root than in loamy clay and sandy loam soils.
A parabolic relationship between soil nitrate‐N concentration and total root length.
A weak parabola relationship between N supply and root length was found in loamy clay soil and clay loam soil, but not in sandy loam soil. Root length and the maximum yield reached synchronously at optimum N rates (168–240 kg N ha−1 in the present study).
Assessing the Influence of Calcium Fluoride on Pyrite Electrochemical Dissolution and Mine Drainage pH
Authors: Wang Luying , Liu Qingyou , Zheng Kai , Li Heping 
Published: April 2016

We investigated the influence of dissolved calcium fluoride, CaF2(aq), on the electrochemical dissolution of pyrite and the corresponding environmental effects on acid mine drainage (AMD). The experimental results showed that CaF2(aq) promotes pyrite electrochemical dissolution. When the CaF2(aq) concentration increased from 0 to 10 mg L–1 up to saturation, the promoting efficiency was 15.80 and 57.25%, respectively. The reason for this phenomenon is that F‐ and Fe2+ form FeF2, and at a higher scan potential, F− and Fe3+ form the ion complex FeF63−. The mechanisms include: (i) the decreasing charge transfer resistance at the double layer due to the iron fluorine complex formation; and (ii) the decreasing passivation resistance at the cover layer due to the strong penetration of F− ions through it into the double layer. Although the hydrolysis reaction of F− in solution could increase the pH value of mine drainage, the AMD was significantly aggravated because CaF2(aq) promoted the pyrite electrochemical dissolution.Core Ideas
Results showed CaF2 could effectively promote pyrite electrochemical dissolution.
F– and Fe2+ form FeF2, and at a higher scan potential, F– and Fe3+ form the complex FeF63–.
Iron fluorine complex formation decreases charge transfer resistance at the double layer.
Strong penetration of F–into the double layer decreases the resistance at the cover layer.
AMD was significantly aggravated because CaF2 promoted the pyrite dissolution.
Heat Shock Protein 70 and Anti-heat Shock Protein 70 Antibodies in Nasal Secretions of Patients with Chronic Rhinosinusitis
Authors: Tsybikov Namjil N. , Egorova Elena V. , Kuznik Boris I. , Fefelova Elena V. , Magen Eli 
Published: April 2016

Background The issue of heat shock protein (HSP) 70 and anti-HSP70 antibodies in chronic rhinosinusitis (CRS) has never been explored. Objective To determine the nasal secretion (NS) levels of HSP70 and anti-HSP70 antibodies in patients with CRS with nasal polyps (CRSwNP) and patients with CRS without nasal polyps (CRSsNP), and to evaluate their associations with CRS clinical severity and correlation with NS interleukin (IL), IL-5 and interferon λ. Methods CRS severity was determined by Lund-Mackay scores. Levels of immunoglobulin E (IgE), IL-4, IL-5, interferon A, HSP70, and anti-HSP70 antibody levels in NS were measured by enzyme-linked immunosorbent assay. Results Forty-six patients with CRSsNP (25 women [543%] and 21 men [45.7%], mean [standard deviation {SD}]) age, 34.1 ± 123 years; 54 patients with CRSwNP (24 women [44.4%] and 30 men [55.6%], mean [SD] age, 37.9 ± 17.5 years). A group of 40 healthy subjects served as controls. Compared with the controls (with a mean [SD] NS HSP70 level of 0.05 ± 0.03 μg/mL), mean [SD]NS HSP70 levels in both the CRSsNP group (0.16 ± 0.07 ixg/mL) and CRSwNP group (0.21 ± 0.10 μg/mL) were increased (p < 0.001). Similarly, the mean (SD) NS anti-HSP70 antibody levels were significantly higher in patients with CRSwNP (0.25 ± 0.09 optical density value [ODV]) compared with CRSsNP (0.13 ± 0.04 ODV) (p < 0.001) and healthy controls (0.14 ± 0.02 ODV) (p < 0.001). NS HSP70 in subjects with CRSwNP showed a significant positive correlation with the Lund-Mackay score (r = 0.31; p < 0.05). NS levels of either HSP70 or anti-HSP70 antibodies were strongly correlated with NS IL-4 in the CRSwNP group (r = 0.62, p < 0.001; and r = 0.69, p < 0.001, respectively). Conclusion NS concentrations of HSP70 and secretory IgA anti HSP70 antibodies are increased in CRSwNP (but not in CRSsNP) and correlate positively with the Lund-Mackay score, NS IL-4, and NS IL-5.
A Rare Presentation of Sarcoidosis with Nasal Bone Involvement
Authors: Korkmaz Mukadder , Uslu Selen , Korkmaz Hakan , Çetinkol Yeliz 
Published: April 2016

Background Sarcoidosis is a multisystem granulomatous inflammatory disease that is induced by infectious or noninfectious environmental antigens in a genetically susceptible host. Tuberculosis and sarcoidosis are two diseases with similar clinical and pathologic findings. The link between these two diseases has been extensively studied. Objective Herein we describe a case of sarcoidosis associated with tuberculosis, treated for tuberculosis, and, 1 year, later presented with a nasal dorsal lump and skin lesions on the extremities. Methods Case report with clinical description. Results Our patient had a history of skin and cervical lymphadenopathy symptoms 1 year earlier and was treated with antituberculosis drugs in an outer medical center. Therapy had cured cervical lymphadenopathies, with no improvement in skin lesions. On appearance of the nasal dorsal lump, she presented to our outpatient clinic. We retrieved the previous specimens of the patient, which revealed coexistence of necrotizing granulomas with non-necrotizing granulomas, which was strongly indicative of the coexistence of tuberculosis and sarcoidosis. Radiologic, histopathologic, and microbiologic investigation revealed the diagnosis of sarcoidosis with nasal, cutaneous, and pulmonary involvement. Treatment with prednisolone and hydroxychloroquine resulted in dramatic improvement of nasal bone, pulmonary, and skin lesions within 2 weeks. Conclusion The clinical presentation of sarcoidosis can be complex, and the differential diagnosis from tuberculosis can be challenging. Atypical clinical pictures also can cause delays in diagnosis and proper management. In patients with granulomatous lesions that are unresponsive to antituberculosis therapy, physicians must be alerted to the possibility of coexistent sarcoidosis.
Clinical utility of a screening protocol for blunt cerebrovascular injury using computed tomography angiography
Authors: Tso Michael K. , Lee Myunghyun M. , Ball Chad G. , Morrish William F. , Mitha Alim P. , Kirkpatrick Andrew W. , Wong John H. 
Published: April 2016

OBJECTIVE
Blunt cerebrovascular injury (BCVI) occurs in approximately 1% of the blunt trauma population and may lead to stroke and death. Early vascular imaging in asymptomatic patients at high risk of having BCVI may lead to earlier diagnosis and possible stroke prevention. The objective of this study was to determine if the implementation of a formalized asymptomatic BCVI screening protocol with CT angiography (CTA) would lead to improved BCVI detection and stroke prevention.

METHODS
Patients with vascular imaging studies were identified from a prospective trauma registry at a single Level 1 trauma center between 2002 and 2008. Detection of BCVI and stroke rates were compared during the 3-year periods before and after implementation of a consensus-based asymptomatic BCVI screening protocol using CTA in 2005.

RESULTS
A total of 5480 patients with trauma were identified. The overall BCVI detection rate remained unchanged postprotocol compared with preprotocol (0.8% [24 of 3049 patients] vs 0.9% [23 of 2431 patients]; p = 0.53). However, postprotocol there was a trend toward a decreased risk of stroke secondary to BCVI on a trauma population basis (0.23% [7 of 3049 patients] vs 0.53% [13 of 2431 patients]; p = 0.06). Overall, 75% (35 of 47) of patients with BCVI were treated with antiplatelet agents, but no patient developed new or progressive intracranial hemorrhage despite 70% of these patients having concomitant traumatic brain injury.

CONCLUSIONS
The results of this study suggest that a CTA screening protocol for BCVI may be of clinical benefit with possible reduction in ischemic complications. The treatment of BCVI with antiplatelet agents appears to be safe.
Use of 3D CT-based navigation in minimally invasive lateral lumbar interbody fusion
Authors: Joseph Jacob R. , Smith Brandon W. , Patel Rakesh D. , Park Paul 
Published: April 2016

OBJECTIVE
Lateral lumbar interbody fusion (LLIF) is an increasingly popular technique used to treat degenerative lumbar disease. The technique of using an intraoperative cone-beam CT (iCBCT) and an image-guided navigation system (IGNS) for LLIF cage placement has been previously described. However, other than a small feasibility study, there has been no clinical study evaluating its accuracy or safety. Therefore, the purpose of this study was to evaluate the accuracy and safety of image-guided spinal navigation in LLIF.

METHODS
An analysis of a prospectively acquired database was performed. Thirty-one consecutive patients were identified. Accuracy was initially determined by comparison of the planned trajectory of the IGNS with post–cage placement intraoperative fluoroscopy. Accuracy was subsequently confirmed by postprocedural CT and/or radiography. Cage placement was graded based on a previously described system separating the disc space into quarters.

RESULTS
The mean patient age was 63.9 years. A total of 66 spinal levels were treated, with a mean of 2.1 levels (range 1–4) treated per patient. Cage placement was noted to be accurate using IGNS in each case, as confirmed with intraoperative fluoroscopy and postoperative imaging. Sixty-four (97%) cages were placed within Quarters 1 to 2 or 2 to 3, indicating placement of the cage in the anterior or middle portions of the disc space. There were no instances of misguidance by IGNS. There was 1 significant approach-related complication (psoas muscle abscess) that required intervention, and 8 patients with transient, mild thigh paresthesias or weakness.

CONCLUSIONS
LLIF can be safely and accurately performed utilizing iCBCT and IGNS. Accuracy is acceptable for multilevel procedures.