bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automation Improves Shaker Performance
Authors: El Dorry Khaled , Dufilho Bill 
Published: March 2012

Abstract
One of the limitations of current shale shakers is that their performance can be negatively impacted by changes in the feed rate. Standard shakers operate with vibratory motors running at a constant speed, yielding a constant output force. This results in a shaker having its peak g-force during non-loaded conditions. As soon as drilling fluid is added to the system (more mass), the acceleration (g-force) decreases and in turn, the shaker performance decreases as well.
A significant improvement for shale shakers has been achieved with the introduction of the second generation of the controlled acceleration technique. The improved technology allows the shaker to continuously adjust the shaker basket’s g-force to the proper pre programmed set point. This improvement offers significant advantages over the first generation of controlled accerletion in terms of performance, cost, safety and downtime.
Field tests have shown that a shaker equipped with the second generation of controlled acceleartion is still capable of screening 2 API classes finer or better as is the case with the first generation. Use of this technology allows for improved solids removal efficiency and the potential to reduce rig non-productive time (NPT) and improve rate of penetration (ROP) by helping to yield a cleaner wellbore.
Presented will be the differences between the first and second generations of controlled acceleration along with field and theoretical data showing performance curves.
Analytical Model to Predict the Effect of Pipe Friction on Downhole Temperatures for Extended-Reach Drilling (ERD)
Authors: Kumar Aniket , Singh Ajay Pratap , Samuel Robello 
Published: March 2012

Abstract
The advent of extended-reach drilling (ERD) has led to increased effects of friction on the drillstring and the drilling fluid. Wellbore mechanical friction attributable to pipe rotation or to torque and drag plays a significant role in drilling operations and is considered to influence the temperatures downhole. An analytical mathematical model will help to provide physical insight to understand the borehole conditions.
This study aims to develop a simple mathematical model to analyze the heat generated from borehole friction and to predict the temperature of the drilling fluid during a drilling operation at any depth in the well. The model presents a steady-state solution for heat transfer between the drillstring and the fluids in the drillpipe and annulus, as well as heat transfer between the annular fluid and the formation. Heat generated from friction has been modeled using the torque acting on the drillstring as a result of contact forces. A linear temperature gradient for the formation and a constant borehole wall temperature has been assumed to simplify the model. Frictional pressure losses in the drill pipe, in the annulus, and across the bit have been incorporated in the model because they contribute to the heat generated in the borehole.
This paper will present the derivations of the generalized heat transfer model and the application of the model in a field case. The temperature of the drilling fluid has been calculated both in the annulus as well as inside the drillpipe at various depths for the considered well profile. The drillstring temperature profile has been estimated using the calculated drilling fluid temperatures. Wellbore mechanical friction and downhole temperatures were thoroughly studied by varying the underlying drilling parameters in the model.
Automation in Drilling: Future Evolution and Lessons from Aviation
Authors: Thorogood J. L. 
Published: March 2012

Abstract
Automation of the drilling process has been gathering pace over the last 10 years, with progress being made on many fronts, from choke control in managed pressure drilling (MPD) operations, through a new generation of auto drillers to intelligent systems that prevent the driller from exceeding parameters that might cause downhole problems.
Observing the current state of automation in drilling, it is clear that in the case of MPD, automation has resulted in closer and more stable control of a process that can be achieved by a manual system. Auto-drillers combined with downhole rotary steerable systems have resulted in improved progress rates compared to manual systems. By contrast, modern rigs with highly mechanised pipe handling systems are still controlled manually with a crewing arrangement that has changed little while the technology has evolved dramatically. These developments pose a number of questions, for example:
In what direction is automation likely to evolve in the future, and why? Can the drilling community avoid the mistakes of other industries and how might this be prevented?
The paper reviews developments of automation in aviation and describes some of the problems that have arisen. It then outlines the analogous efforts in drilling and identifies lessons that could be learned. The paper presents a rationale on which further automation initiatives might be based and some of the related changes that might be necessary as a result.
Development of a New Advanced Multiple Activation System for Concentric Underreamers
Authors: Torvestad Bjørn Tore , Ray Tom , Hu Jianbing , Gjertsen Ole Jacob , Muir Michael 
Published: March 2012

Abstract
Hole Enlargement While Drilling (HEWD) using a concentric underreamer is a widely used technique for efficient wellbore construction. Most underreamers are fitted with lock-out systems to provide a means of drilling out the shoe-track with the cutters close before enlarging the borehole below casing. Several vendors also provide a system to lock the tool closed after reaching total depth (TD) to enable full flow while pulling out of the hole for best possible wellbore cleaning.
However, most available underreamers cannot be reactivated after deactivation. Another limiting factor is that the tools must be placed on top of the Bottom Hole Assembly (BHA) due to the ball drop activation method.
To solve the problem, a new system has been developed that makes it possible to perform multiple activation/deactivation of the underreamer. The most obvious advantages are infinite open/close cycles for selective underreaming and the more flexible placement opportunities within the BHA due to the activation method. Other advantages are time saving through the elimination of several runs, shorter activation time and higher flow rate capabilities.
Several successful tests in realistic drilling environments were performed prior to starting the field testing program. Through the field testing stage the system has performed as planned under normal drilling conditions and has a significant cost saving potential for the operator. The authors will discuss the application challenges, benefits, features and engineering efforts including field testing, that led to a commercial Ream on Demand (ROD) system.
Multilateral History - Deepest Level 4 Cemented Junction Installation
Authors: Hua An Wen , Qing Teng Xue , Tong Yang Xiang , Xiang Bai Deng , Ponton Calvin , Roberts Justin , Durst Doug 
Published: March 2012

Abstract
An operator was challenged with increasing production efficiencies from new single wellbores in the deep Tarim basin reservoirs of China. To increase and optimize single well production performance, multilateral drilling and completion technology were implemented on this initial pilot test well.
The remote location of the multilateral well in the Tarim Desert of the Xinjiang Province in northwestern China proved to be an operational and logistical challenge in terms of time (4 to 5 days travel by vehicle) and distance (3600 kilometers) to the nearest repair and maintenance facilities in Tanggu, Tianjin Province in eastern China. Critical planning, aggressive project management oversight, and strong collaboration between the operator and service supplier resulted in the world’s deepest TAML Level 4 cemented multilateral installation at 5082 m TVD junction depth and 5889 m MD at the lateral toe.
The well design was based on a vertical pilot well, or motherbore, drilled and cased into the reservoir. The multilateral system was then installed to add an additional wellbore, thereby increasing reservoir exposure. The goals of this system were to accelerate production, increase ultimate recovery and, for this particular operator, to qualify multilateral technology for this particular field application. Because of the unprecedented depth of the proposed junction, thorough project management and planning were required throughout, from the feasibility phase through the execution phase, to amplify risk mitigation and to effect a successful project installation.
This project is the first multilateral installation for this client; it was the first cemented Level 4 multilateral in China, and is the deepest Level 4 multilateral installed worldwide. This paper describes the objectives, challenges, best practices, contingencies, logistics issues, results, and lessons learned from the implementation of this deep-set multilateral technology.
Dynamic Modelling of Gas Distribution in the Wellbore During Kick Situations
Authors: Spoerker H. F. , Gruber C. , Brandstaetter W. 
Published: March 2012

Abstract
The paper presents a Computational Fluid Dynamics (CFD) simulation of the distribution of influx gas in the drilling fluid during kick situations. Special focus is put on the bottom-hole inlet region of a vertical well, with the aim of obtaining a highly resolved phase distribution. An interfacial tracking method (VOF) is used to simulate the unsteady motion of incompressible drilling fluid and compressible gas, taking into account turbulence as well as non-Newtonian rheology. This method describes both phases with a single set of equations and additionally solves an equation to calculate the local volume fraction of the phases. Hence no a priori assumptions need to be made regarding flow patterns. The result of these simulations will subsequently be used to model the chemical reaction kinetics of the buffering process between H2S influxes and high-pH drilling fluid environments.
From Field Test to Successful Integration of Broadband Drillstring System for Offshore Extended Reach Wells
Authors: Veeningen Daan , Palmer Jason , Steinicke Greg , Saenz Jesus , Hansen Troy 
Published: March 2012

Abstract
High-angle offshore wells in Trinidad and Tobago are characterized by hole cleaning challenges, wellbore instability, and downhole vibrations damaging both tools and drill bits. To reduce operational risks and improve project economics, the operator selected a multi-well campaign to implement a wired pipe or broadband networked drillstring system. The broadband network system provided high resolution data from downhole tools and along string annular pressure evaluation in real time for approximately 97% of the 75,000ft drilled during the trial period.
The project achieved a significant decrease in wellbore instability related to non-productive time, as well as higher tool reliability through downhole diagnostics, improved hole cleaning, and stick-slip vibration mitigation.
This paper describes the successful implementation of high-definition downhole operations through project management, collaboration with third party tool partners and resourceful scalable solutions to solve operational and logistical challenges. Lessons learned include the implementation on two rigs, data swivel installations, the commissioning of a shorebase and the pioneering of local repair and maintenance for specialized networked drilling tools, all leading to the complete integration into the customer’s workflow and process.
Effective Force and True Force: What are They?
Authors: Samuel Robello , Kumar Aniket 
Published: March 2012

Abstract
The predictions of hookload, tension, and stresses are important for the successful completion of any well operation, as well as for the selection of optimum operating parameters. The terms effective axial force and true force or effective tension and true tension are used for various tubular designs, including riser designs. To further complicate matters, they are also defined as buoyancy and pressure area methods of calculating forces. Discussions of these two forces occasionally raise doubts regarding how to treat the internal and/or external pressures. The main problem stems from the perception that effective force as a fictitious force, and the inclusion of the internal and external pressures as counter intuitive source of misunderstandings and wrong designs. Although several authors have used the calculation and concepts correctly, other previously published papers failed to address the issue clearly and in a simple way; as a result, confusion still exists. These two forces further result in two neutral points, which raises the questions of “when you apply pressure, does the neutral point change?” and “which neutral point should be used for stuck pipe calculations?” The working envelop using yield limit with combined loading of uniaxial force and pressure forces are important. Using the wrong force/tension will result in an incorrect interpretation of the burst and collapse limits. This paper provides the mathematical treatise and discusses the theoretical basis of these two forces, including how they are used in torque, drag, buckling, stress, and limit calculations. This paper describes the details, apparent definition, pitfalls, and context in which these forces can be used. Simple guidelines are presented, as well as several example calculations to help explain various tubular modeling aspects for future generations of drilling engineers.
Drilling Automation: Potential for Human Error
Authors: Iversen Fionn , Gressgård Leif Jarle , Thorogood John , Balov Mohsen Karimi , Hepsø Vidar 
Published: March 2012

Abstract
Mode confusion is when an automated system behaves differently than expected; in such a way that the operator is not aware of or does not properly understand what the system is doing. Mode confusion is well recognized in the aviation community and has been indicated in a number of high profile aviation accidents. As an example, a Jas Gripen fighter jet crashed during a test flight in the 1980s due to the pilot trying to manually correct instability while the plane's computer was automatically trying to do the same. The potential for the same type of problems, and associated safety hazards, arises in drilling rig operations as a result of the increasing trend for automation and advisory systems. A simple example could be formation fracturing with an automated ECD control system when displacing to higher mudweight caused by the driller relying on the automated system to maintain sufficiently low flowrate without having reconfigured the system with the new mud properties. Through the reported study the authors wish to analyse how use of a drilling support system in different modes and levels of automation may influence the system operator's performance and risk of human error. Development of a systematic method for detecting mode confusion problems by model checking is central in this respect. The test cases have been simulated in a synthetic test environment created at IRIS specifically for such purposes. The test environment and test cases are described, and results are reported and discussed.
Continuing Efficiency and Assurance Advances for Deepwater BOP Testing
Authors: Franklin C. Mark , Cully Rick 
Published: March 2012

Abstract
Recently, a significant advancement in deepwater BOP leak detection was introduced through an industry sponsored software development project. This application combined innovative algorithms for validating pressure tests with an intuitive user interface for test plan management, testing and reporting. The results have validated the application’s ability to achieve accurate and objective test results with a significant increase in testing clarity and leak detection efficiency. While widespread implementation presented some obstacles, such as dealing with rig motion and complex new pumping systems, these challenges were overcome. With the experiences and suggestions gathered over the past two years, the application has advanced to new levels of assurance and functionality. This paper provides a functional review of the application and significant advancements achieved over the last year.
In addition to utilizing the application to plan, conduct and report BOP pressure tests accurately, objectively and efficiently, rigs can now utilize a customized interactive schematic feature, modeling the rig’s BOP and manifold within the application. Working interactively with this model, users have the ability to optimally design tests by simply clicking on valves, rams and annulars ("components") to open or close them and visualize the resulting pressure test path. The same methodology is used to define the objectives of a test plan ("component coverage") by selecting required valve sides and BOP rams, annulars and pipe sizes.
Throughout planning phase a visual representation of each test step is provided, including clear identification of pressure paths and component coverage. During tests, real-time updates automatically and continuously inform users of test coverage progress. Comprehensive reports ensure clear and concise communication of test plans, valve alignments and test results.
Revolutionizing Drilling Performance through Advanced Real Time Performance Advisory System
Authors: Dow B. , Harmer R. , Belaskie J. 
Published: March 2012

Abstract
The industry continues to apply scientific methods searching for drilling performance improvement. Advanced applications aimed at rate of penetration (ROP) improvement, bottom hole assembly (BHA) longevity through performance management and lost time avoidance through early event detection have evolved as downhole and surface data continue to become more robust. Applying this science to actually improve well construction requires a workflow that enables the operations team to respond to the data in a timely manner. The driller is the most influential person in the performance improvement workflow, yet drilling performance ranks down the list of priorities, rightfully so, behind well control, crew safety and rig equipment operations. Successful well construction improvement requires a tool that delivers timely advice to the driller, enabling performance improvement without distracting from other priorities.
This paper will discuss the development and field application of a new technology that allows data to be turned into actions at the well site, improving overall well construction performance. The development team applied a rich understanding of existing wellsite workflows, technology and workplace ergonomics and key attributes from gaming and telecommunications industries. The end result is a piece of technology that brings together several performance improvement analytical tools developed over years of research and development into one console, turning data into clear directions for the driller, and delivering performance improvement feedback immediately.
Results, Observations, Conclusions: Field data from 10 wells throughout the world show how the system has been used to reduce well construction time by more than 20%. The radical new way of presenting data to the driller was a significant key to success. The software development platform allowed for quick feedback throughout field testing, integrating user input to continuously evolve the best fit-for-purpose application.
Assessment of Intrastromal Corneal Ring Segment Position With Anterior Segment Optical Coherence Tomography
Authors: Gorgun Ebru , Kucumen Raciha Beril , Yenerel Nursal Melda , Ciftci Ferda 
Published: March 2012

BACKGROUND AND OBJECTIVE:
To examine the exact position of implanted Keraring (Mediphacos, Belo Horizonte, Brazil) segments by high-resolution anterior segment optical coherence tomography (AS-OCT).

PATIENTS AND METHODS:
This study included 17 eyes of 13 patients with keratoconus who underwent uneventful intracorneal ring segment implantation with the aid of femtosecond laser. Eyes were evaluated by AS-OCT at the third postoperative month. Distance from the apex of the triangular cross-section of the ring segment to the anterior corneal surface and distances from two basal corners to the posterior corneal surface were measured.

RESULTS:

Distance from apex to anterior corneal surface (263.1 ± 42.9 μm) was significantly smaller than target depth calculated intraoperatively (356.9 ± 35.7 μm,
P
< .001). Distance between outer basal corner and posterior corneal surface was significantly greater than distance between inner basal corner and posterior corneal surface.

CONCLUSION:
High-resolution AS-OCT is a rapid, convenient, and valuable technique in the follow-up of patients with implanted Keraring segments that may be helpful in predicting ring-related complications.
Distinct APCs Explain the Cytokine Bias of α-Galactosylceramide Variants In Vivo
Authors: Bai Li , Constantinides Michael G. , Thomas Seddon Y. , Reboulet Rachel , Meng Fanyong , Koentgen Frank , Teyton Luc , Savage Paul B. , Bendelac Albert 
Published: March 2012

Abstract
α-Galactosylceramide represents a new class of vaccine adjuvants and immunomodulators that stimulate NKT cells to secrete Th1 and Th2 cytokines. Synthetic variants with short or unsaturated acyl chains exhibit a striking Th2 bias in vivo but no evidence of defect in TCR signaling or stimulation of NKT cells in vitro. Using cd1d1fl/fl mice, we demonstrated that distinct APC types explained the cytokine bias in vivo. Whereas NKT stimulation by α-Galactosylceramide required CD1d expression by dendritic cells (DCs), presentation of the Th2 variants was promiscuous and unaffected by DC-specific ablation of CD1d. This DC-independent stimulation failed to activate the feedback loop between DC IL-12 and NK cell IFN-γ, explaining the Th2 bias. Conversely, forced presentation of the Th2 variants by DC induced high IL-12. Thus, lipid structural variations that do not alter TCR recognition can activate distinct Th1 or Th2 cellular networks by changing APC targeting in vivo.
Soluble CD23 Controls IgE Synthesis and Homeostasis in Human B Cells
Authors: Cooper Alison M. , Hobson Philip S. , Jutton Mark R. , Kao Michael W. , Drung Binia , Schmidt Boris , Fear David J. , Beavil Andrew J. , McDonnell James M. , Sutton Brian J. , Gould Hannah J. 
Published: March 2012

Abstract
CD23, the low-affinity receptor for IgE, exists in membrane and soluble forms. Soluble CD23 (sCD23) fragments are released from membrane (m)CD23 by the endogenous metalloprotease a disintegrin and metalloprotease 10. When purified tonsil B cells are incubated with IL-4 and anti-CD40 to induce class switching to IgE in vitro, mCD23 is upregulated, and sCD23 accumulates in the medium prior to IgE synthesis. We have uncoupled the effects of mCD23 cleavage and accumulation of sCD23 on IgE synthesis in this system. We show that small interfering RNA inhibition of CD23 synthesis or inhibition of mCD23 cleavage by an a disintegrin and metalloprotease 10 inhibitor, GI254023X, suppresses IL-4 and anti-CD40–stimulated IgE synthesis. Addition of a recombinant trimeric sCD23 enhances IgE synthesis in this system. This occurs even when endogenous mCD23 is protected from cleavage by GI254023X, indicating that IgE synthesis is positively controlled by sCD23. We show that recombinant trimeric sCD23 binds to cells coexpressing mIgE and mCD21 and caps these proteins on the B cell membrane. Upregulation of IgE by sCD23 occurs after class-switch recombination, and its effects are isotype-specific. These results suggest that mIgE and mCD21 cooperate in the sCD23-mediated positive regulation of IgE synthesis on cells committed to IgE synthesis. Feedback regulation may occur when the concentration of secreted IgE becomes great enough to allow binding to mCD23, thus preventing further release of sCD23. We interpret these results with the aid of a model for the upregulation of IgE by sCD23.