bluuebunny/crossref_metadata_2025_split huggingface dataset:
A challenge to categories: “What, if anything, is a mosasaur?”
Authors: Caldwell Michael W. 
Published: March 2012

AbstractThe concept of “mosasaur” is explored from the perspective of its historical origins, and tested empirically and phylogenetically in order to examine the concept in its modern application. Historical analysis of the origins of the concept of “mosasaur” makes it clear that the term bears significant historical burden (comparative anatomic, empirical, phylogenetic, paleontological, etc.). In order to address the flaws in the concept of mosasaur properly, this treatise critically assesses Camp’s [1923] diagnostic characters for Anguimorpha, Platynota, Varanoidea, and Mosasauroidea, concluding that Camp’s data permit mosasaurs to be viewed only as anguimorphans, not platynotans nor varanoids. A similar critical assessment is given for the characters used to diagnose anguimorphans and varanoids in Estes et al. [1988], concluding here that not a single character out of twenty-two is shared between varanoids and mosasaurs. The character concept developed by Romer [1956] for the “posteriorly retracted nares” of varanoids, and then later mosasaurs, is critically examined and found to be insufficient as a test of similarity of the intended primary homologs. The recent work of Rieppel et al. [2007], Conrad [2008] and Conrad et al. [2010] is critically reviewed as these authors revive the use, and subdivision, of the “posteriorly retracted nares” as a character in anguimorph phylogenetic analysis. Based on these criticisms, it is concluded here that there is no character-based evidence to support phylogenetic hypotheses that mosasaurs are derived aquatic varanoid lizards. A key recommendation of this treatise is that the hypothesis conceiving of mosasaurs as derived aquatic varanoids be abandoned. The final critical review presented in this treatise examines the taxonomic implications, relating to the concept of “mosasaur”, arising from the hypothesis of convergent paddle-like limb evolution in mosasaurs as presented by Bell and Polcyn [2005]. In conclusion, it is recognized that the concept and term “mosasaur” has ceased to exist in any biologically meaningful way, and that the future requires the construction of a new suite of terms and concepts to convey what we now think we know about these animals.
Rotary Steerable Tool Damage Prevention by Utilization of an Asymmetric Vibration Damping Tool
Authors: Burnett Timm , Feauto Benjamin , Forster Ian , Kabbara Alan 
Published: March 2012

Abstract
Slick-slip (SS) and lateral shocks are harmful to many expensive downhole tools such as rotary steerable systems, and downhole measurement and logging tools. Due to this concern, an asymmetric vibration damping device has been engineered to reduce these specified vibrational modes. This tool is uniquely specialized that, when placed and ran with the recommended drilling parameters, reduces stick-slip tendencies as well as dampen lateral shocks by placing the drill string near the tool in Forward Synchronous Whirl (FSW). As a result of placing the BHA (bottom hole assembly) into FSW, other harmful vibrational modes such as chaotic whirl and backward whirl are prevented from occurring. Stemming from the exclusive geometry of the tool, the tool will interrupt harmonic modes during rotation that can lead to harmful shocks and SS. Extensive research has been performed in laboratory and field testing using the vibration damping tool, and its success has been proven in multiple deep water applications (primarily with hole opening BHA’s), but also on land with bi-center bits. Recently, a new approach was undertaken, utilizing two vibration damping tools in a single BHA. This was intended to control vibrations and reduce shocks that were causing extensive damage to Rotary Steerable System (RSS) horizontal applications in North America. The initial trial wells used the dual placement within the vertical and horizontal sections, drilling into the Cotton Valley formation in North Louisiana. These applications have historically seen very high vibration levels due to both the trajectory and challenging formations.
Successful Application of Geomagnetic Referencing for Accurate Wellbore Positioning in a Deepwater Project Offshore Brazil
Authors: Poedjono Benny , Montenegro Diana , Clark Pete , Okewunmi Shola , Maus Stefan , Li Xiong 
Published: March 2012

Abstract
Accurate wellbore positioning is a major challenge in the Frade field, a deepwater heavy oil project offshore Brazil that has been historically technically and economically challenging. The inherent subsurface and surface complexities alone might have prevented the development of this asset, as the structure is a low-relief anticline with two main fault blocks, consisting of three stacked reservoirs, and spanning an area of 20 km2.
The key challenge in magnetic surveying in Brazil is the large discrepancy between downhole tool readings and the British Geological Survey (BGS) Global Geomagnetic Model (BGGM), which provides the magnetic field at a 400-km resolution. A better understanding of natural variations in the local magnetic field is essential for a successful development of the field. As such, a new method of mapping the natural variations was developed.
With its recent refinements, geomagnetic referencing can now produce significant savings in overall project cost by providing accurate, real-time data on wellbore position while corrections to trajectory are still possible, preventing the costly sidetracks often required when errors are discovered in a post-drilled survey. It can also eliminate the need for costly troubleshooting of downhole magnetic tools in real time, caused by inaccuracy of the geomagnetic model used.
This paper outlines collaboration among operator, contractors and academic experts, and the development of the High-Definition Geomagnetic Model (HDGM) by the United States National Geophysical Data Center, which improves the spatial resolution to 30 km. The large-scale magnetic field study was integrated with the Bacia de Campos aeromagnetic survey to account for the entire spatial spectrum of the geomagnetic field, down to the kilometer scale. Using ellipsoidal harmonic functions and an equivalent source technique, two 3D geomagnetic references were produced for comparison purposes, and the results were validated by observations from the downhole measurement-while-drilling (MWD) tool reading.
Pushing the Extended Reach Envelope at Sakhalin: An Operator’s Experience Drilling a Record Reach Well
Authors: Walker Michael W. 
Published: March 2012

Abstract
ExxonMobil, as operator for the Sakhalin 1 project, recently completed drilling operations at the Odoptu Field, located offshore Sakhalin Island, Russia. The Odoptu development drilled nine extended reach wells from shore, culminating with the world record reach OP-11 well. This record setting extended reach well reached a total depth of 12,345 m MD (40,502 ft) / 1,784 m TVD with 11,479 m of vertical section in 60 days with &lt;1% non-productive time. This paper provides a case history of the drilling and completion of the OP-11 well. The major well design parameters that led to the final design will be discussed. Additionally, operational summaries for each hole section will be provided to give an insight on the well construction process.
Use of extended reach drilling (ERD) practices has become a common means to economically access reserves from existing infrastructure, provide access to reserves that were previously out of reach, and reduce the environmental footprint of drilling / production facilities. Hence, operators are being challenged to stretch the limits of the ERD envelope, not only from a drilling perspective, but also from a completions perspective. The design for such wells typically employs detailed modeling work; however, a thorough understanding of ERD operational complexities is also required.
Over the course of drilling operations at Odoptu, well designs and operational practices evolved to maximize drilling performance while minimizing risks. This paper describes the challenges that were successfully overcome, including wellbore instability, shocks and vibrations, and high torque. Significant OP-11 results include the successful placement of the 9-5/8-in. floated liner at 10,758 m without rotation and the successful placement of completion equipment at world record depth. The operator's use of its performance management workflow successfully reduced downhole shocks and vibrations, optimized hole quality, and resulted in the drilling of each hole section with a single bottomhole assembly (BHA).
The design considerations and techniques described in this case history can be used to provide valuable insight for the drilling and completion of future extreme ERD wells. The lessons learned on extreme ERD wells should be thoughtfully considered when designing future wells that stretch the ERD envelope.
Mud Cap Application Solves Chronic Drilling Problem in a Highly Fractured, Low Pressure Reservoir
Authors: Ladron De Guevara J. Ernesto , Lozada Miguel Ángel , Torres Marcos Fuentes , Silva Gilberto García , Zalvidar Juan Antonio , González Ricardo Andres , Sizer James 
Published: March 2012

Abstract
The Cantarell field is located offshore in the Bay of Campeche, in approximately 50 m of water depth (Fig. 1). The two main productive intervals are the Upper Cretaceous and Jurassic Kimmeridgian. The Cretaceous is highly fractured with well developed, vugular secondary porosity. The Jurassic is also fractured with oomoldic porosity. Both contain sour hydrocarbons. Production from Cantarell began in the early 1980s and today the pore pressure gradient is down to a +/− 0.37 gr/cc equivalent. The productive interval is typically drilled using a 0.90 gr/cc emulsion mud and shortly after penetrating the fractured reservoir, total and uncontrollable loss circulation is experienced. As a result, the cost of drilling in the field has increased considerably due to the high cost of the oil-in-water mud losses and time spent either transporting, generating or waiting on weather to offload more mud to continue drilling.
Petróleos Mexicanos (PEMEX) in cooperation with Quantum Reservoir Impact (QRI) reevaluated the current drilling philosophy and recommended the application of a series of steps aimed at solving the current problems. The results obtained have been positive resulting in PEMEX now implementing such steps as part of its drilling philosophy where applicable on a regular basis.
This paper will describe the current drilling environment and the techniques implemented in the first successful mud cap application in the Cantarell field. It will also discuss some of the lessons learned as well as the new improved designs being implemented and will conclude with a summary of the benefits obtained and the plans for the future.
Optimized Steerable Motor Design Overcomes Drilling Challenges in Marcellus Shale Unconventional Play
Authors: Jones Anthony , Azizov Azar A. , Janwadkar Sandeep , Davila Wilfredo , Fabian John , Nguyen Minh 
Published: March 2012

Abstract
Although drilling horizontal wells in US-land unconventional shale plays has increased exponentially in the last few years, maximizing well productivity and improving drilling efficiency remains a major challenge. Well placement in the sweet spot and extended laterals help maximize productivity. Drilling a curve with higher dogleg severity (DLS) reduces its verticalsection and maximizes the length of subsequent lateral section in the productive zone. Wells in US shale plays demand a DLS of 10 to 14 deg/100 ft, but achieving high DLS presents numerous drilling challenges: rotating a steerable motor with a high adjustable kick-off sub (AKO) angle could result in bottomhole assembly (BHA) fatigue failure and premature damage to the bit; drilling in oriented mode limits the transfer of weight to the bit, reducing the rate-of-penetration.
These challenges led to the development and successful testing of a new steerable optimized design motor (ODM) with a short bit-to-bend (BTB) distance. In some cases, the ODM drilled all sections, including high-DLS curves, tangents and laterals with precise directional control and well placement with one BHA. Using the ODM helped the operator achieve higher build rates at lower AKO angle settings; rotate the BHA in well profiles where previously used motors could be operated only in slide mode, and maximize the length of curve interval drilled in rotary mode at higher RPMs. The new system significantly improved drilling performance with excellent directional control. Drilling high-DLS curves increased the length of laterals, enabling additional recovery of gas.
This paper will discuss the design, modeling and results of horizontal type wells drilled using the steerable ODM in the Marcellus unconventional shale play.
PDC Bit Steerability Modeling and Testing for Push-the-Bit and Point-the-Bit RSS
Authors: Menand S. , Simon C. , Gaombalet J. , Macresy L. , Gerbaud L. , Ben Hamida M. , Amghar Y. , Denoix H. , Cuiller B. , Sinardet H. 
Published: March 2012

Abstract
The footage drilled with rotary steerable systems (RSS) has increased significantly these last few years, due notably to the highly complex wells drilled today. Moreover, high requirements about borehole quality are needed to optimize drilling performances, running completion tools or increase the quality of formation evaluation.
Rotary steerable systems can be classified in two types according to the steering mechanism: point-the-bit and push-the-bit. Whatever the type of steering mechanism, both tilt and side force are applied on the bit. Although bit tilt is predominant in point-the-bit system, bit side force is the main factor that affects hole deviation in push-the-bit system. There have been many controversies in the scientific and industrial community regarding the deviation mechanisms involved in these two systems. To react to this controversy, a full-scale drilling bench has been developed to test drill bits in push-the-bit, point-the-bit or hybrid push-point mode. This new facility enables to apply any coupled tilt-side force on the bit to reproduce the RSS mechanisms.
This paper is intended to show results of this experimental campaign. First, the role of the side force and of the bit tilt in the deviation process have been fully differentiated and measured. Then, these results demonstrate that the bit steerability for a same given side force is strongly affected by the tilt applied on it. At last, one shows that borehole quality is not only affected by the bit design itself but also by the tilt-side force combination These experimental results presented in this paper have been validated with a software that enables to reproduce the hole deviation every inch drilled. The results of this paper should also contribute to improve bits selection for RSS in order to drill a smooth and uniform borehole.
Using Advanced Drilling Technology to Enable Well Factory Concept in the Marcellus Shale
Authors: Hummes Olof , Bond Paul , Jones Anthony , Symons Wayne , Bishop Manitou , Serdy Andrew , Pokrovsky Sergei , Polito Nicholas 
Published: March 2012

Abstract
In the Marcellus Shale, Northeast USA operators are moving from a phase of exploration and appraisal of gas wells to the development phase using "factory" drilling techniques: bringing down overall cost per well, increasing the number of wells that can be drilled using the resources available and maximizing the production from the wells that are brought online. This paper describes how one operator teamed up with a drilling service provider to adopt new technology that led to a substantial reduction in the operational time required to drill complex 3D profile Marcellus area wells.
Most horizontal wells in the Marcellus are currently being drilled with conventional motors and basic measurement while drilling (MWD) systems that are reaching the technical limit of their capabilities. Additionally, the area pad drilling requirement of the Marcellus further challenges the ability of conventional tools to drill the required complex 3D profiles. Traditional rotary steerable systems have not been able to offer operational enhancement in the curve section of the well because they lack the ability to deliver the build rates required to land the wells and then drill the lateral. The authors will use detailed case histories to show how a new rotary steerable system, which has been developed specifically to address the challenges seen in unconventional reservoirs, was utilized to provide a true step change in drilling performance and deliver the benefits expected from rotary steerable systems. The design of bit and bottomhole assembly (BHA) is crucial to ensure that the objectives are met (directional control, ROP, run duration, and hole quality). It will be shown that the new drilling technique will enable the development of reservoir blocks in the Marcellus shale from single pads using complex well profiles, including real-time reservoir navigation, while minimizing the time to drill the wells.
The Best Driller in the Gulf of Mexico
Authors: Griffon Romain , Gauthier Jacob 
Published: March 2012

Abstract
An analysis of more than 100 Gulf of Mexico (GOM) deepwater wells reveals that one operator is experiencing more drilling success than its peers in terms of consistent and repeatable top quartile drilling performance. These results are driven by the operator’s commitment to its drilling philosophy, its strong and well-established partnership with key service contractors, and its core drilling team of experienced and technically sound professionals.
One service company has developed an enduring relationship with the operator and contributes to the performance that the operator demands. Such performance requires a well-aligned focus between the service company and the operator. Four key areas have been identified that have allowed this partnership to thrive: people and culture, performance, structure and processes, and technology.
These key areas have played in major role in delivering multiple GOM drilling records, including the top 13 fastest wells (days per 1000 ft) from spud to total depth (TD)—with some wells drilled through extended salt intervals at IADC rate of penetration (ROP) records.
Real results show how best-in-class performance can be achieved when the four identified keys to the successful partnership are combined to complement and enhance each other’s strengths.
Subordinates as the First Line of Defense against Biased Financial Reporting
Authors: Jollineau S. Jane , Vance Thomas W. , Webb Alan 
Published: March 2012

ABSTRACT
Managers who generate financial reports often rely on subordinates who possess private information to provide inputs. When managers have incentives to manipulate reports, they may request biased inputs from subordinates. However, subordinates can act as informal controls and constrain managers' opportunism. We experimentally examine two potential determinants of subordinates' willingness to serve as informal controls: their perception of the subordinate-manager relationship quality and their beliefs about the ethical nature of the task. Subordinates who perceive a high-quality relationship with their manager provide more bias, despite a compensation scheme that makes compliance costly. This result suggests that managers who cultivate close working relationships with subordinates may undermine the control system. Subordinates' beliefs about the ethical nature of the task also reduce compliance, but more so when the manager requests income-increasing estimates. Our findings contribute to the management accounting literature by providing insights into the role of subordinate employees as informal controls.
Is aggressive treatment of traumatic brain injury cost-effective?
Authors: Whitmore Robert G. , Thawani Jayesh P. , Grady M. Sean , Levine Joshua M. , Sanborn Matthew R. , Stein Sherman C. 
Published: March 2012

Object
The object of this study was to determine whether aggressive treatment of severe traumatic brain injury (TBI), including invasive intracranial monitoring and decompressive craniectomy, is cost-effective.

Methods
A decision-analytical model was created to compare costs, outcomes, and cost-effectiveness of 3 strategies for treating a patient with severe TBI. The aggressive-care approach is compared with “routine care,” in which Brain Trauma Foundation guidelines are not followed. A “comfort care” category, in which a single day in the ICU is followed by routine floor care, is included for comparison only. Probabilities of each treatment resulting in various Glasgow Outcome Scale (GOS) scores were obtained from the literature. The GOS scores were converted to quality-adjusted life years (QALYs), based on expected longevity and calculated quality of life associated with each GOS category. Estimated direct (acute and long-term medical care) and indirect (loss of productivity) costs were calculated from the perspective of society. Sensitivity analyses employed a 2D Monte Carlo simulation of 1000 trials, each with 1000 patients. The model was also used to estimate these values for patients 40, 60, and 80 years of age.

Results
For the average 20-year-old, aggressive care yields 11.7 (± 1.6 [SD]) QALYs, compared with routine care (10.0 ± 1.5 QALYs). This difference is highly significant (p < 0.0001). Although the differences in effectiveness between the 2 strategies diminish with advancing age, aggressive care remains significantly better at all ages. When all costs are considered, aggressive care is also significantly less costly than routine care ($1,264,000 ± $118,000 vs $1,361,000 ± $107,000) for the average 20-year-old. Aggressive care remains significantly less costly until age 80, at which age it costs more than routine care. However, even in the 80-year-old, aggressive care is likely the more cost-effective approach. Comfort care is associated with poorer outcomes at all ages and with higher costs for all groups except 80-year-olds.

Conclusions
When all the costs of severe TBI are considered, aggressive treatment is a cost-effective option, even for older patients. Comfort care for severe TBI is associated with poor outcomes and high costs, and should be reserved for situations in which aggressive approaches have failed or testing suggests such treatment is futile.