bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radial Velocity Measurements of HR 8799 b and c with Medium Resolution Spectroscopy
Authors: Ruffio Jean-Baptiste , Macintosh Bruce , Konopacky Quinn M. , Barman Travis , De Rosa Robert J. , Wang Jason J. , Hoch Kielan K. W. , Czekala Ian , Marois Christian 
Published: October 2019

Abstract
High-contrast medium resolution spectroscopy has been used to detect molecules such as water and carbon monoxide in the atmospheres of gas giant exoplanets. In this work, we show how it can be used to derive radial velocity (RV) measurements of directly imaged exoplanets. Improving upon the traditional cross-correlation technique, we develop a new likelihood based on joint forward modeling of the planetary signal and the starlight background (i.e., speckles). After marginalizing over the starlight model, we infer the barycentric RV of HR 8799 b and c in 2010 yielding −9.2 ± 0.5 km s−1 and −11.6 ± 0.5 km s−1, respectively. These RV measurements help to constrain the 3D orientation of the orbit of the planet by resolving the degeneracy in the longitude of an ascending node. Assuming coplanar orbits for HR 8799 b and c, but not including d and e, we estimate

and

.
The 2L1S/1L2S Degeneracy for Two Microlensing Planet Candidates Discovered by the KMTNet Survey in 2017
Authors: Shin I.-G. , Yee J. C. , Gould A. , Penny M. T. , Bond I. A. , Albrow M. D. , Chung S.-J. , Han C. , Hwang K.-H. , Jung Y. K. , Ryu Y.-H. , Shvartzvald Y. , Cha S.-M. , Kim D.-J. , Kim H.-W. , Kim S.-L. , Lee C.-U. , Lee D.-J. , Lee Y. , Park B.-G. , Pogge R. W. ,   (KMTNet Collaboration), Abe F. , Barry R. , Bennett D. P. , Bhattacharya A. , Donachie M. , Fujii H. , Fukui A. , Hirao Y. , Itow Y. , Kamei Y. , Kondo Iona , Koshimoto N. , Li M. C. A. , Matsubara Y. , Miyazaki S. , Muraki Y. , Nagakane M. , Ranc C. , Rattenbury N. J. , Suematsu Harmon , Sullivan D. J. , Sumi T. , Suzuki Daisuke , Tristram P. J. , Yamakawa T. , Yonehara A. ,   (MOA Collaboration), Fouqué P. , Zang W. ,   (CFHT-K2C9 Microlensing Collaboration)
Published: October 2019

Abstract
We report two microlensing planet candidates discovered by the Korea Microlensing Telescope Network (KMTNet) survey in 2017. However, both events have the 2L1S/1L2S degeneracy, which is an obstacle to claiming the discovery of the planets with certainty unless the degeneracy can be resolved. For KMT-2017-BLG-0962, the degeneracy cannot be resolved. If the 2L1S solution is correct, KMT-2017-BLG-0962 might be produced by a super Jupiter-mass planet orbiting a mid-M-dwarf host star. For KMT-2017-BLG-1119, the light-curve modeling favors the 2L1S solution but higher-resolution observations of the baseline object tend to support the 1L2S interpretation rather than the planetary interpretation. This degeneracy might be resolved by a future measurement of the lens-source relative proper motion. This study shows that the problem of resolving 2L1S/1L2S degeneracy exists over a much wider range of conditions than those considered by the theoretical study of Gaudi (1998).
Discovery of an Accretion-rate Independent Absolute RMS Amplitude of Millihertz Quasi-periodic Oscillations in 4U 1636-53
Authors: Lyu Ming , Méndez Mariano , Altamirano D. , Zhang Guobao , Mancuso G. C. 
Published: October 2019

Abstract
We investigate the frequency and amplitude of the millihertz quasi-periodic oscillations (mHz QPOs) in the neutron-star low-mass X-ray binary 4U 1636–53 using Rossi X-ray Timing Explorer observations. We find that no mHz QPOs appear when the source is in the hard spectral state. We also find that there is no significant correlation between the frequency and the fractional RMS amplitude of the mHz QPOs. Notwithstanding, for the first time, we find that the absolute rms amplitude of the mHz QPOs is insensitive to the parameter S

a
, which measures the position of the source in the color–color diagram and is usually assumed to be an increasing function of mass accretion rate. This finding indicates that the transition from marginally stable burning to stable burning or unstable burning could happen very rapidly since, before the transition, the mHz QPOs do not gradually decay as the rate further changes.
Granting Operating Permit Based Upon a Preemptive Risk Assessment
Authors: Manhaes Alexandre Campos , Neto Aloysio Garcia , Zanetti Alessandro Aparecido , Muller Daniel Tiago , Radespiel Eduardo dos Santos , Garcia Leonardo Marazzo 
Published: October 2019

Abstract
Dealing with well integrity non-compliances with respect to the principle of two well barrier envelopes is a problem of paramount importance in well integrity governance during the life cycle of wells. Besides, during production phase, operators might experience several difficulties related to the feasibility and conclusiveness of well integrity assessments, this is especially true for subsea wells. On the other hand, those assessments are quite conclusive and easy to perform by the rig when a workover is in progress. Namely, because there is usually only one fluid phase (brine) during pressure test and the feasibility of performing those tests in the actual flow direction, the well barrier elements evaluations performed by the workover rig are, in general, conclusive when compared to the verifications done by the production platform during production phase.
Thus, it is common to find out some unforeseen well integrity non-compliances with respect to the principle of two well barrier envelopes during a workover. Therefore the operator must establish a process for making up a decision concerning whether the handover process after the intervention back to the production team or downhole plugging the well whenever it is necessary, depending upon the well integrity status. This decision is based upon a preemptive (preventive and anticipative) risk assessment.
The use of a preemptive risk assessment leads to very interesting results, namely: a) standardization of decision making process avoiding subjectivities about well integrity statuses evaluation; b) savings on applying highly skilled technical human resources; c) mitigating environmental and compliance problems; and d) guidance on workover designers with better intervention planning practices concerning well integrity uncertainties.
This paper describes how it can be done as well as the regulations aspects related to it. Furthermore, it is shown case studies to illustrate the whole process of making up the right decision of handing the well over or downhole plugging whenever it is needed.
Flow Assurance Issues on Mexilhão Field Operation
Authors: Lorenzeti Canato Jorge Fernando , Da Silva Alves Christiano , Barbosa Marques Thales 
Published: October 2019

Abstract
This paper shows the main concerns related to Flow Assurance during Mexilhão gas field operation. Mexilhão is located in Santos Basin, Brazil and flows from seven gas wells to a fixed platform through a subsea manifold. Well’s water depth average is about 470 meters and platform’s water depth is 172 meters. The tieback between the manifold and platform is 22 kilometers and there are two production pipelines of 12-inch diameter connecting them.
The thermo-hydraulic profile of the production fluid enters in hydrate formation region and hydrate thermodynamic inhibitor (MEG) is injected to prevent hydrate formation. This MEG is recovered at the platform and it is reinjected in the wells. Dosing valves located at subsea manifold distributes the desirable quantity of MEG for each well. During eight years of operation, no production loss caused by hydrate blockage has been reported. This paper also shows the method of wax deposit management in Mexilhão subsea system. Although certain amount of wax had been anticipated to accumulate along pipeline, very little wax was found after pig runs. It has been observed that wax appears in platform process plant, however it does not seem to accumulate in the pipeline. Pig runs occur only for the purpose of corrosion monitoring.
Another item discussed here is scale prevention, which could be performed with downhole inhibitor injection and it has not been required until today. Finally, transient simulation results which guided the operational procedure to increase gas flow rate are shown. There is no slug catcher at the platform, then, in order to avoid shut downs due to large liquid slug arrival at process plant, the procedure to increase gas flow rate must be performed carefully.
Novel Solution for Cementing Operations in Scenarios of Losses and Improving Cement Bonding Results in the Brazilian Deepwater Pre-Salt
Authors: Freitas Rodrigo , Rossi Lucas , Pagani Leonardo , Gregatti Ana Carolina 
Published: October 2019

Abstract
Brazilian pre-salt reservoir is mainly composed of carbonate rocks which are naturally fractured and where severe loss of circulation has often occurred.
Loss of circulation during drilling or cementing is a serious issue that usually leads to nonproductive time, increase of well construction costs, and impairment of cement sheath quality, which may lead to deficient zonal isolation in the future and compromise well integrity in long term.
Data analysis from studies developed by operators around the world show that approximately 12% of all nonproductive time accumulated in a certain period is due to loss of circulation occurrence. In Brazil, an analysis performed by an operator in 2014, pointed that more than 100 days were lost in pre-salt wells in operations to cure or minimize loss of circulation. This same analysis concluded that more than 170 000 barrels of drilling fluid were consumed due to this scenario of losses. It is also important to emphasize the cases where a remedial cementing job was necessary due to failure of zonal isolation achievement through primary cementing, resulting in additional costs and nonproductive time.
Said that, it was important to develop and implement a new technology capable of mitigate losses during cementing operations and minimize the risk of a remedial cementing need. Since January 2017, Fibrous Loss Circulation Material has been used in the cementing jobs for production casings in the pre-salt wells successfully. Up to now, six wells were cemented using this technology; no remedial job necessary and the cementing logging evaluation showed excellent results.
A Detailed Examination of the Mechanics of Slip Crush When Landing Heavy Casing Strings
Authors: Thibodeaux Robert 
Published: October 2019

Abstract
Over the last 50 years, the oil & gas industry has continually pushed the limits of exploration, riding the wave of recent technological advances to pioneer ultra-deepwater areas of the globe. Not until the early 80s, though, did operators start delving below the salt canopy, into reserves like the Wilcox in the Gulf of Mexico. This sub-salt (or pre-salt) trend expanded well program depths in excess of 30,000 ft MD, in water depths exceeding 10,000 ft, necessitating longer, heavier casing/landing strings.
Meanwhile, new government regulations have begun mandating well designs capable of sustaining Worst Case Discharge (WCD). Deeper casing strings, in turn, must now be constructed to withstand higher collapse loads, shallow casing strings to handle more robust burst loads. Certain well designs must even feature an intermediate tieback able to endure WCD, where previously a nested liner was sufficient.
This confluence of increasingly deep wells and stringent regulations presents challenges. Longer, heavier casing/landing strings push the limits of existing tubular tensile capacity, but as important, they also raise concerns about handling equipment possibly crushing landing strings due to excessive radial load (slip crush).
In response, since the mid-80s, a research and testing program has been analyzing and quantifying specific factors involved when crushing loads affect tubular goods failure. Some of the identified causatives behind these increased tubular stresses are handling equipment design, vessel heave-induced dynamic loading, dynamic loading during tripping, and handling equipment-related slip crush loading. A detailed analysis of the mechanics of slip crush revealed modifying certain parameters has a material effect on the radial load imparted onto the pipe by the slips. The research shows that modifying and optimizing the combination of these parameters can not only lead to the design of handling equipment with higher slip crush capacities, but it also leads to the development of a comprehensive model that can more accurately predict the failure of tubular goods due to slip crush.
Mechanically Lined Pipe MLP with Improved Fatigue Resistance
Authors: Popescu Silviu , Montague Paul Anthony 
Published: October 2019

Abstract
Mechanically lined pipe (MLP) has been successfully used in many applications where the fatigue load is low. The use of mechanically lined pipe in higher fatigue load applications require proof of fatigue strength and therefore, additional testing, including full scale fatigue testing, are typically performed. Petrobras has been a pioneer in this work and has developed an MLP specification designating in detail the qualification conditions for using MLP pipe in dynamic applications (see [1]).
This paper describes the qualification of Cladtek MLP for dynamic applications including the results of full-scale fatigue testing and a concept, designed by Cladtek, intended to further improve fatigue performance of MLP. Cladtek has filed a patent application for this concept named: Upset-end MLP with improved fatigue resistance [3].
This document presents full-scale fatigue testing results higher than experimental data previously available but in line with the results presented by Subsea 7 in the document IBP1137_15 (see [4]). These results demonstrate that improved fabrication techniques could lead to the use of MLP in the applications with high fatigue demand where, up to now, only clad pipes were considered suitable for use. The use of MLP in high fatigue load applications results in substantial cost savings.
Low Impact Drilling Fluid for Deepwater Drilling Frontier
Authors: Kakadjian Erna , Shi April , Porter Justin , Yadav Prahlad , Clapper Dennis , Pessanha Wallan 
Published: October 2019

Abstract
One of the biggest challenges when drilling in deep water is the excessive dependence of drilling fluid rheological properties on temperature. Conventional drilling fluids often have high viscosity at the seabed temperature, which increases the Equivalent Circulating Density (ECD) and surge pressures when running pipe or initiating circulation, elevating the risk of fracturing the wellbore. This paper describes the development of a drilling fluid for deep-water applications, with minimum viscosity variation with temperature.
Multiple laboratory formulations were evaluated during the development of the new, non-aqueous based drilling fluid that meets deep-water's challenging rheological and barite suspension requirements. CaCl2 brine was used as the internal emulsion phase, and synthetic isomerized olefin as the base oil. The testing followed the API Recommended Practice for Field Testing Oil-based Drilling Fluids. Samples were aged at dynamic conditions for 16 hours at several temperatures. Then, rheological properties and high-pressure high-temperature (HPHT) fluid loss, emulsion stability, and dynamic sagging were tested. Static sag experiments were also carried out for up to seven days together with improved step down rheology tests.
A low-impact, non-aqueous drilling fluid (LIDF) was designed to minimize ECD increases by reducing the effect of cold temperature on the fluid viscosity. The fluid offers a superior low viscosity profile and rapid-set, easy-break gel strengths, while maintaining low shear rate viscosity at high temperatures with optimal weight material suspension. The fluid is also compatible with all contaminants usually found during the drilling operation and meets all the regulatory requirements for the Gulf of Mexico and other deep-water operational areas. Field application demonstrated that LIDF reduced the effect of temperature on the fluid rheological properties and minimized the risk of induced formation losses. These same rheological features reduced non-productive time associated with cement displacement and barite sagging.
Supporting laboratory and field data are presented to demonstrate the superior performance of the fluid in maintaining rheological and barite suspension properties over a wide range of temperatures. The properties of the LIDF are achieved by matching the effects of emulsifier, organophilic clay, and rheological modifiers to maintain correct rheological properties at low and high temperatures.
Flexible Riser Repair and Dissection Following Exceedance of API Fatigue Limit
Authors: Tapias Renan , Mansour-Tehrani Mehrdad , K. Langhelle Nina 
Published: October 2019

Abstract
This paper presents detailed learnings into the dissection of a flexible riser section, which had been operating for seven (7) years and subjected to high rates of fatigue damage, after operational field changes.
Detailed global and local fatigue analyses were performed to assess the response of the riser system taking into account significant changes between the design and the operational history. These environmental and operational changes were shown to have a negative impact on the fatigue performance of the risers, in particular the top section located inside the bend stiffner.
Fatigue analyses are performed using field measured data such as vessel headings, internal pressures and environmental conditions, aiming to replicate the riser response history and calculate fatigue usage to date. Actual field data are shown to be more onerous than design data and therefore a detrimental fatigue response is expected. Results from detailed fatigue analysis shows that flexible risers fatigue usage were above the maximum allowable of 0.1, as outlined in API [1,2]. The most critical location was the pressure armour wires of the top section, located inside the bend stiffener. A mitigation plan was proposed, including an immediate reduction of internal pressure to reduce the risk of riser failure, and the removal of the fatigued riser top section. After removal of the fatigue critical section, the riser was re-terminated and its fatigue performance reinstated.
The pipe section removed from operation was carefully dissected. Following the dissection, each riser layer was investigated to determine possible signs of degradation. Additionally, fatigue testing of both pressure and tensile armour wires were performed to determine potential fatigue degradation and confirm analyses findings. Dissection and fatigue tests have demonstrated that the pipe condition was better than expected, highlighting conservatisms in design and analyses methodologies.
In-service inspection of flexible riser internal layers is highly complex, with no detailed insight of all the respective layers. Dissection of a flexible riser, in service for seven (7) years and exposed to high rates of fatigue damage, provides valuable information about the state of the different layers comprising the cross section. This is particularly useful since analytical work have shown the riser to have exceeded the fatigue limit of 0.1 as defined per API. The good state of the flexible riser, on the contrary to the prediction, highlights a good level of conservatism in flexible riser design and methodology.
Structural Analysis of Thermal Behavior On Cooling Trapped Annular Pressure In Water and Gas Injection Wells
Authors: Junior Nelson Moreira , Agostini Cristiano Eduardo , Dos Santos Cleidilson Moura , Roman Roger Savoldi , Schnitzler Eduardo , Magalhães Mateus Dias , Ferreira Marcus Vinicius Duarte , De Souza Charlton Okama 
Published: October 2019

Abstract
This paper presents the findings of a comprehensive structural analysis in which the influence of thermal transient pressure behavior on the trapped annuli in an injection well in a Brazilian pre-salt field was assessed, mainly motivated by physical evidence of a well failure. The study focus on a transient heat flow in radial direction during a well failure investigation, and its impact in tubular design safety factor under a given casing design methodology.
During the investigation of this well integrity failure, a thermal analysis was performed considering the well construction history, but standard simulations using a world-class commercial software was not enough to explain the failure. Thus, a modified thermal analysis for casing and tubing was made in order to evaluate the design safety factor during each operation. This modified thermal analysis consists in splitting each operation in short time steps, in order to capture the short transient behavior. It was found that, during short transient time, the collapse stresses reached higher values than predicted in the previous standard steady-state modeling. Such result is basically related to the transient effect caused by radial heat flow.
Based on theoretical studies and comparing them to downhole P&T sensors in confined annuli, a correlation was stablished and showed the importance of this type of analysis. In certain scenarios, where the confined annuli are subjected to progressive and non-proportional cooling down effect between the casing layers, a sudden pressure drop may occur in the internal side of the casing, without reaching the same pressure drop on the external side, which can lead to a dramatic external differential pressure for a given string.
In wells with multiple confined annuli, such as in ultra-deepwater projects, this type of analysis represents a greater challenge. The results obtained so far have shown that the permanent and transient radial heat flow cannot be neglected in some scenarios and, therefore, open a new frontier for well design, especially when the tubing and multiple casing trapped annuli are subjected to rapid transient cool down.
Setting a New Benchmark in ROP and Bit Durability in the Pre-Salt Section Carbonate Rocks of the Deepwater Mero Field in Brazil
Authors: Silva Nalon , Boulton Arturo Jose 
Published: October 2019

Abstract
This work explains the process of how a bit was designed specifically to address drilling challenges of the reservoir section of the Mero Field offshore Brazil. The performance of this new bit is compared to previous bits used in the field.
A systematic process to design and evaluate the performance of a new bit involves interaction with the operator to understand the challenges and gather information, evaluate previous bit performances, use software to simulate the new bit design based on drilling conditions in the field, manufacture the bit according to design specifications, run the bit according to planned parameters, capture and report results, and evaluate results to identify possible improvements.
The reservoir section has a high hardness and is primarily composed of calcareous rock and silica intercalations. Since the discovery of the Mero Field, more than 17 wells have been drilled by different companies. In the majority of the wells, the reservoir section was drilled using impregnated bits and turbines. As a result, the application of a systematic process was used to solve operator challenges where a new bit was designed and run in the field to drill the reservoir section of two wells. A comparison was performed between the previous bits used in the field and the new bit concept, certifying that the new bit reduced the reservoir section drilling time by 59%.
This work discusses improved drilling efficiency in the reservoir section by drilling with a new bit design in a field where only impregnated bits and turbines were used. This created a new benchmark for drilling performance in the Mero Field.