bluuebunny/crossref_metadata_2025_split huggingface dataset:
Out-of-transit Refracted Light in the Atmospheres of Transiting and Non-transiting Exoplanets
Authors: Dalba Paul A. 
Published: October 2017

Abstract
Before an exoplanet transit, atmospheric refraction bends light into the line of sight of an observer. The refracted light forms a stellar mirage—a distorted secondary image of the host star. I model this phenomenon and the resultant out-of-transit flux increase across a comprehensive exoplanetary parameter space. At visible wavelengths, Rayleigh scattering limits the detectability of stellar mirages in most exoplanetary systems with semimajor axes

≲
6

au

. A notable exception is almost any planet orbiting a late M or ultra-cool dwarf star at

≳
0.5

au

, where the maximum relative flux increase is >50 parts per million. Based partly on previous work, I propose that the importance of refraction in an exoplanet system is governed by two angles: the orbital distance divided by the stellar radius and the total deflection achieved by a ray in the optically thin portion of the atmosphere. Atmospheric lensing events caused by non-transiting exoplanets, which allow for exoplanet detection and atmospheric characterization, are also investigated. I derive the basic formalism to determine the total signal-to-noise ratio of an atmospheric lensing event, with application to Kepler data. It is unlikely that out-of-transit refracted light signals are clearly present in Kepler data due to Rayleigh scattering and the bias toward short-period exoplanets. However, observations at long wavelengths (e.g., the near-infrared) are significantly more likely to detect stellar mirages. Lastly, I discuss the potential for the Transiting Exoplanet Survey Satellite to detect refracted light and consider novel science cases enabled by refracted light spectra from the James Webb Space Telescope.
Completion of Successful Multistage Sliding Sleeve Fracpack in the Campos Basin
Authors: Correa Rubens , Cova Carolina Latini 
Published: October 2017

Abstract
The Campos basin is offshore Brazil in deep water and has unconsolidated formation characteristics. As such, wells located in this area are usually completed using sand control techniques. In the Roncador field, a vertical well with multiple pay intervals required a sand control solution for each zone. The primary challenge was to complete the total gross interval using a cost-effective sand control method that allowed selectively stimulating five zones and producing without solids.
The largest multipurpose oilfield stimulation vessel in the world was assigned to perform its first deepwater offshore multistage fracpack treatment, which is a combination of fracturing stimulation and gravel packing. The five individual treatment stages were successfully performed as designed using multitrip sliding sleeves, which would later allow selective production of the zones. This allowed the operator to selectively isolate the intervals during completion of each one. In addition, this was the first time using a new sand-storage system and blender without a tube, which provided better reliability and a shorter response time.
The operator and service providers collaborated to design the multistage well completion, providing both sand control and stimulation. The treatment plan was performed by this large modern service vessel without any reports of incidents or lost time. Additionally, all operational data were transmitted in real time to onshore operator and service company facilities. The five-stage treatment plan was performed in only 28 days, representing an estimated savings of 15 rig days for the operator compared to completions using a conventional treatment method.
This paper reviews a deepwater Campos basin well that has multiple pays and potential sand production. The operator and service provider applied new completion technology for stimulation/sand control, which provided several advantages, including a significant reduction in required rig days. This was the first opportunity for the large stimulation vessel to conduct such an operation, and the performance of both the equipment and service crew was excellent.
How to Improve the Use of PDG Data on Injector Wells: A Temperature Build-Up Approach
Authors: da Silva Victor Costa , Glitz Karime Louise Zenedin 
Published: October 2017

Abstract
One of the main activities of a reservoir engineer is to manage the production and injection of fluids in a reservoir. By managing the production and injection it is possible to react to the breakthrough of the injected fluids and control the rate at which BSW and GOR increase in the production wells. In wells completed in more than one target zone the reservoir management can be done by restraining or just closing the interval through which the injected fluids are inflowing. However to identify the interval through which the water or gas is produced in this kind of well is not an easy task, being the track of the paths through which the injected fluids flow in the reservoir (as well as in the neighborhood of the well) the main challenge of the reservoir management.
In this paper a set of data of different wells of a Santos Basin Pre-salt reservoir is presented. Intelligent completions with more than one target zone are installed in these wells and the temperature data of each zone are analyzed. Simplified analytical models are employed to describe the various regime flows observed in these wells, thus providing some insights in order to characterize the flow.
Temperature data of production and injection wells are analyzed in different scenarios were the gas and/or water saturation modifies near the wells. The main hypothesis adopted in this work is that the change in temperature behavior is associated to the modification of the saturation of the different fluids in the reservoir.
This paper aims at estimating the length of the modified saturation region near the injection well by assuming that the thermal diffusion is predominant. By doing so the problem is described by the energy balance equation and the boundary and initial conditions depends on the condition of the well (if it is operating or closed).
This methodology is further extended to analyze the change of fluids saturation near production wells in order to provide some insight about the breakthrough of injected fluids.
By comparing the theoretical response of the methodology presented in this paper to that observed in the wells it is possible to make some conclusions about (i) the injection profile in wells where the isolation between the zones in the well's neighborhood was lost during the stimulation of the formation and (ii) about the distribution of the injected fluid in the reservoir near the wells, whose isolation between zones was not lost during the stimulation.
A Physical Model for Scale Growth during the Dynamic Tube Blocking Test
Authors: Santos H. F. L , Castro B. B. , Bloch M. , Martins A. L. , Schlüter H. E. P. , Júnior M. F. S. , Jacinto C. M. C. , Rosário F. F. 
Published: October 2017

Abstract
A physical model for scale growth in the Dynamic Tube Blocking Test (TBT) is presented aiming at the determination of the first layer formation time and the scale growing rate. The proposed model has been applied to 38 experimental results, each one with a different water composition. The fluid compositions were selected to represent the majority of the fluids found in typical Brazilian oil wells. For the application of this model, no differential pressure was considered before pumping. Additionally, the pressure rising time was not taken into account in the calculation of the first layer formation time. The model showed excellent fitting to the experimental data, with correlation coefficients superior to 0.98 for most data. Furthermore, the results of the scale growing rate were compatible to the results from other experiments, utilizing: rotating cage; static reactors; and full scale Inflow Control Valves (ICVs). Furthermore, on a scientific perspective, the model can also be used for the development of scale growing models as a function of pressure, temperature, composition.
Ultra Deepwater Salt Zone Cementing in Gulf of Mexico Wells
Authors: Vallejo V. , Olivares A. , Salinas D. , Rojas R. Giron 
Published: October 2017

Abstract
One of the last exploratory frontiers offshore, where some of the biggest reservoirs have been found in late days, are the ultra deepwater areas of the Gulf of Mexico, in the Mexican side. Several methods and lessons learnt have been produced during the Exploratory Campaign of these waters, becoming the massive salt formations, one of the major challenges faced, not only for drilling methods and techniques, but for zonal isolation in general terms, related to cementing operations.
Cementing jobs executed in salt environments require cement slurries with specific concentrations of salt in order to avoid the acceleration/retarder effect of thickening time on the cement slurry due to formation salt incorporated during fluids placement in the annular space, and to avoid the dissolution of natural salt formation. Likewise compressive strength development must be capable of mitigating the effects of salt cuttings on the casing that isolates the zone to ensure the integrity of the section.
Salt is commonly classified as: Magnesium salts – regular movementHalite – low movementCarbonates – without movement
This paper includes lab tests to determine the physical and chemical properties of cement slurries with different concentrations of sodium chloride (NaCl) and potassium chloride (KCl). A deep analysis was performed with these slurries when in contact with salt formations, determining the dissolution effect of salt in cement slurries. Lab tests were performed with Halite samples from ultradeepwater wells in the Northern Region of the Gulf of Mexico.
Study of the Mechanical Properties and Fracture Morphology of Niobium Microalloyed 80 ksi Class Thick Plates Produced by Controlled Rolling Followed by Accelerated Cooling
Authors: Viana R. T. , Gorni A. A. , da Silveira J.H.D. , Camey K. , de Faria R. J. 
Published: October 2017

Abstract
This paper describes the first production trials of 80 ksi class thermomechanically controlled processing (TMCP) thick plates at the new Gerdau Ouro Branco plate mill. These trials were very successful, as the product fully satisfied the mechanical properties requirements for such grade, enabling the start of commercial delivery of this material. In addition, experience gained in this process will promote further technological improvement of this class of products, as well more sophisticated plates. The occurrence of separations in the fractured surface of Charpy specimens was considered with detail.
Deployment of Electro-Mechanical Cutting Tool on Intelligent Coiled Tubing for Horizontal Wells
Authors: Carvalho Ricardo de Paula , Barros Robledo Wakin , Gastaldo Felipe Toloi , Amorim Alexandre , Moreira Jean Narlon , Gomes Deylla Silva 
Published: October 2017

Abstract
This paper will describe the merits of deploying the Electro-mechanical cutting tool with the Intelligent Coiled Tubing, the advantage of this cutting method compared to ballistic, chemicals and other mechanical devices in terms of precision, time saving, safety and real time cutting assurance, as well as the added advantages generated by the Intelligent Coiled Tubing by itself on the overall operation.
The recent introduction of Intelligent Coiled Tubing services, equipped with real time downhole tools communication and power down capabilities within the market, has made possible the deployment of the electro-mechanical multiple cutting tool on Coiled Tubing. The emergence of this technology, allows the cutting tool to perform operations in previously unreachable environments, taking advantage of the Intelligent Coiled Tubing high level of efficiency and reliability, which historically was a concern when running wire line in horizontal wells.
With an increase in Plug and Abandonment projects expected, especially in deep water environments, new challenges will arise when it comes to cutting and retrieving completions. The electro-mechanical cutters have proven in recent years to be an extremely reliable, efficient, and a safe method to perform cutting operations in tubulars, sand screens, as well as releasing packers. The paper will present a case history detailing the methodology, and the involved pre-job planning, deployment, risk management& modeling, demonstrating the completeness of this solution and highlighting its reliability.
The paper will show how the combination of the Intelligent Coiled Tubing combined with the Electro-Mechanical Cutting device can render the usage of ballistic, chemical and other mechanical devices as unnecessary in challenging environments that rely on conventional Coiled Tubing
Technical-Economic Evaluation of Microfiltration Polymeric Membranes as Pretreatment of Offshore Sulfate Removal Units
Authors: Santos Tais Neno dos , Yokoyama Lidia , Lage Gustavo Garios 
Published: October 2017

Abstract
A technical-economic research was done evaluating microfiltration polymeric membranes and cartridge filters as pretreatment of Sulfate Removal Units (SRU). These units were installed in a Stationary Production Unit (SPU) to reduce the concentration of sulfate from seawater (injection water in Enhanced Oil Recovery). The use of seawater with low sulfate in enhanced oil recovery reduces the risk of sulfate deposits during the oil production. Ten companies from different nationalities involved in the industrial water treatment and manufacturing of polymeric membranes sector, have contributed to this comparative research (only a preliminary stage of the future study with qualitative and quantitative analyses). This paper shows that polymeric microfiltration is more advantageous because reduce operational costs and microbiological contamination resulting in a lower risk of biofouling. It also improves the quality of treated water, increases the operational stability and availability of the injection water, extending the lifetime of the nanofiltration polymeric membranes.
Production Experience of ICD/AICD for Heavy Oil at Peregrino Field
Authors: Araujo Susana Vasconcelos , Bolliger Alexandre , Pettan Cássio , Erlandsen Sigurd Myge , Leitão Ivan 
Published: October 2017

Abstract
The Peregrino Field is an accumulation of 13-16° API oil in the Carapebus Formation in the Campos Basin and is thereby one of the heaviest oil offshore developments in Brazil. The field was discovered in 1994 and in 2007 Statoil became a Peregrino partner followed by Peregrino operatorship in 2008. The field has been in production since 2011 by using two well head drilling platforms and one FPSO in water depth ranging between 95 to 135 m. There are 45 production and injection wells drilled so far and 15 remaining slots on the platforms. The Peregrino recovery mechanism is mainly based on reservoir depletion and rock compaction combined with aquifer pressure support and produced water reinjection in the water and oil zones.
The viscosity difference between oil and water at Peregrino gives an unfavorable mobility ratio, and water flows with a higher velocity than the oil. Any means to limit the water flow from the wells may enable an optimization of oil production. In 2013, a technology qualification program was conducted to qualify both Inflow Control Devices (ICD) and Autonomous Inflow Control Devices (AICD) technologies for use at Peregrino. Since then 2 wells have been equipped with ICDs and 7 with AICDs. The production experience from those ICD/AICD wells shows that the device is best suited in areas with good pressure support, high productivity index (PI) and heterogeneous reservoir.
The paper will cover a comprehensive evaluation done for the ICD/AICD wells in Peregrino focusing on subsurface data challenges and performance predictions.
Field Decommissioning Obligations in Brazil: The Differences and Impacts of Current Methodologies for Concessions and Sharing Regimes in Light of Investment Attraction
Authors: Gaspar Fabio , Bilda Katiana 
Published: October 2017

AbstractThis paper aims at exploring the different fiscal effects of field decommissioning in the Brazilian regulatory archetype and unveils the comparative law angle and resulting effect in country competitiveness and attractiveness.Concessions and Sharing regimes (PSC) come with the inherent obligation of infrastructure decommissioning at the end of the contract. To meet such obligations, concessionaires and contractors plan the ways and costs to do so and the Regulator (ANP) approves such plan. The mechanics of how those plans are undertaken are, however, different in each of the mentioned regimes and will result in different tax impacts. These methodologies and its inherent effects will play an important role with regards to how attractive the country is for Upstream investment.On Concessions, due to accounting rules, a provision is to be made in relation to these estimated costs. Because there are no legal grounds for deducting such a provision for corporate income tax (CIT) purposes, the deduction can only be taken at the effective cash disbursement moment, usually at the end of the field life.The PSC law and contract provide for a decommissioning fund to be formed by the Contractor in installments. Once cash is put into the fund, the Contractor cannot take it back; even if the actual expenditure later proves to be lower, case in which the remaining funds will be reverted to the Federal Union. In the PSC, rather than a provision a definitive expense (cash into the fund) is made by the Contractor. Therefore, the definitive cash put into the fund is more inclined to generate a tax deduction.The IMF (International Monetary Fund) has published a paper in 2012, Fiscal Regimes for Extractive Industries: Design and Implementation, where it suggests special fiscal rules for decomissioning tax deductions. Not only special rules will cause projects and countries to be more competitive and attractive, but also society may gain from its positive effects, which range from more jobs and higher income to responsible environment practices. Brazil could benefit from more competitive rules, especially after many other jurisdictions have prepared more welcoming regimes for the current low oil price world.
Short Term Production Optimization Using a Model of the Peregrino Field, Brazil
Authors: Kristoffersen Øystein , Stanko Milan , Hoffmann Arnaud 
Published: October 2017

Abstract
Peregrino is a field offshore Brazil with a FPSO and 2 fixed platforms currently producing close to 100 000 stb/d of oil. Production wells are equipped with electric submersible pumps (ESP) and all produced water is reinjected back into the reservoir using 6 injectors for pressure support. The viscosity of the crude is high (163 cp at reservoir conditions). The present work explores the merits and provides the development details of a model-based production optimization scheme to advice on the best frequency settings of the ESPs in each well. This to ensure the maximum amount possible of oil is produced when water injection capacity is a bottleneck. Furthermore, it studies how the optimal operating conditions change with time.
The optimization formulation considers maximization of total oil production, the maximum allowable water produced given by the available injection capacity and the operational constraints of the ESPs. The optimization was formulated as a Mixed-Integer Linear Problem (MILP). The performance of the wells is represented with piecewise linear tables generated from a commercial simulator.
For the cases tested, the proposed optimization scheme works successfully: It has low running times suitable for real time production optimization, handles successfully multiple operational constraints, and guarantees global optimality. Optimization results are presented for future times.
By using piecewise linear tables to represent the well performances the fidelity of the original model is maintained, while ensuring a robust and fast optimization of the problem. Moreover, it is suitable for frequent model updates without requiring changing the optimization formulation. In summary, this work proposes a method to handle part of the operational complexities of the Peregrino field using a digital twin.
Multi-Scale Ensemble-Based Data Assimilation for Reservoir Characterization and Production Forecast: Application to a Real Field
Authors: de Lima Alexandre , Gentilhomme Theophile , Riffault David , Allo Fabien , Anyzewski Alessandra S. , Emerick Alexandre A. , dos Santos Marcos S. 
Published: October 2017

Abstract
The paper presents the application of multi-scale Levenberg-Marquardt ensemblerandomized maximum likelihood(MS-LM-EnRML) method to an offshore field in Campos Basis. The objective of this method is to update an ensemble of spatial properties and flow parameters using observed productiondata while preserving the prior information already carried by the prior models. The final ensemble provides an estimate of the uncertainties and can then be used for productionforecast andinfill drilling projects. Instead of working directly with the gridblock values of the reservoir, the MS-LM-EnRML method performs a wavelet transform of the spatial properties. Based on this parameterization, a multi-scale approach is followed: different subsets of wavelet coefficients are successively updated with the data using the Levenberg-Marquardt ensemble-based data assimilationmethod. Thanks to the compression property of the wavelets, the field properties are well characterized with a small number of wavelet coefficients. The algorithm starts by optimizing an initial sub-set of large-scale coefficients. The parameterization is then progressively refined, and a new optimization is run on the new subset of coefficients. Because the data mismatch is highly reduced by the initial optimizations at large scales, the perturbation of the fine scale coefficients is minimized resulting in a better preservation of the prior models and a reduced level of noise in the final models.
For comparisons, a second history matching was conducted using the ensemble smoother with multiple data assimilation (ES-MDA) method without the multi-scale parameterization. The quality of the data match, the preservation of the prior models and the ensemble variance are used to compare the two methods. The results showed that although a better data matcheswereobtained with ES-MDA, MS-LM-EnRML preserved better the prior models, the geological consistency and the variability of the ensemble. These results indicate that the multi-scale approach is an attractive option especially when a large number of data has to be assimilated (e.g., long production history and 4D seismic data) or when geological features and seismic information of the initial models need to be preserved.