bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crew Resource Management: A Proven Model for Leadership in the Oilfield
Authors: Tower Patrick , Motruk Lonny , Williams Austin , Allcorn Marc 
Published: January 2016

Abstract
Many industries have reflected on the complexity and inherent risks involved in their operations and have developed systems to maximize safety and increase efficiency. At the forefront of this revolution to perfect operational execution are those industries designated as High Reliability Organizations (HROs). HROs such as commercial aviation, health care and the fire service have "no fail missions" in which lives are at considerable risk during every operation and the cost of mistakes can be staggering. HROs typically recognize human error as the root cause of most significant incidents leading to the application of a human factors approach to operational execution, called Crew Resource Management (CRM).
Since April of 2013, one oilfield organization has joined these HROs in the pursuit of operational excellence through the application of CRM. Since integrating a CRM leadership model into all elements of their operations, empirical evidence collected pre and post implementation from Corporate HSE&Q data established an increase in safety and service quality at the tactical level of operations. Further evidence supplied through field case studies demonstrates that the employment of CRM in oilfield operations has a positive impact in optimizing efficiency in the execution of operations while mitigating risks and maximizing crew safety.
This paper provides a high level curriculum of a CRM program including strategies for implementation and integration of CRM tools and processes within frontline oilfield operations. Significant findings of this research are demonstrated methods used to overcome cultural challenges in embedding CRM in an organization. This includes approaches to break down barriers to acceptance by leaders and operators at all levels of the organization. Drawing from research, as well as a field case study, this paper will examine the positive operational effects of applying CRM as a leadership model for the oilfield. It will also suggest tactics and considerations for training and implementation of CRM.
Modeling Real-Time Sag in the Wellbore
Authors: Kulkarni Sandeep D. , Jamison Dale E. , Gollapalli Joshua S. 
Published: January 2016

Abstract
Weight material sag occurs during drilling operations when drilling fluids remain idle in the wellbore for time periods ranging from hours to several days at static or low-shear conditions. This paper presents a novel method of predicting real-time sag behavior in the wellbore. The method also accurately predicts the fluid mud weight collected at the surface as it is circulated out after a sag event, providing a significant advancement in drilling fluids engineering.
Weight material sag is broadly viewed as the settling of barite particles in drilling fluids (primarily oil-based) under various mechanisms. Fluid composition (barite size/concentration and oil/water ratio) and fluid properties (i.e., rheology) influence the barite settling rate. The well geometry (i.e., inclination and diameter) also affects sag behavior. In addition, well operating conditions (i.e., temperature, pressure, and time for which fluid is uncirculated) also influence sag severity. A comprehensive computational approach was developed to model the sag behavior in wellbores using fluids composition/properties and wellbore geometry/conditions information.
The wellbore sag model predicts information about the changing fluid composition along the wellbore depth as affected by sag, when the fluid in the well is under idle conditions (static or low shear). Specifically, for a wellbore section of a given inclination, the model provides quantitative density/rheology estimates of the barite-depleted zone at the top of the section and the barite-accumulated zone at the bottom. As the sag-affected fluid is circulated out after an idle period, the model also predicts the varied mud weight of the fluid collected at the surface and the corresponding transient bottomhole equivalent circulating density (ECD) as the circulation begins.
The wellbore sag model predictions, especially the variation in the mud weight of the fluid collected at the surface after the sag event, were tested on several wells and fluid systems. The model provided good correlations between measured and predicted fluid density, typically less than 0.1 lbm/gal. The model accurately demonstrates how certain fluids show good sag resistance in some wells yet fail in some complex wells. The model also shows excellent sag resistance of certain specialized fluids in complex wells, which is in agreement with the field observation.
A method to accurately determine real-time sag in the field has been a long-standing need. The successfully validated wellbore sag model, which captures the combined effect of fluids composition/properties and wellbore geometry/conditions, could serve as a useful tool for mud engineers to evaluate the sag behavior. It could also enable fast decision making at the rig site to optimize fluid formulations and operating conditions for sag management.
Selecting Optimum Drilling Parameters by Incorporating Vibration and Drilling Efficiency Models
Authors: Al Dushaishi M. F. , Nygaard R. , Andersen M. , Jeffery C. , Hellvik S. , Saasen A. , Hareland G. 
Published: January 2016

Abstract
To avoid severe vibrations, different drillstem (or drillstring) vibration models have been used to predict and avoid resonance regions by selecting bottom hole assembly (BHA) components and operating parameters such as weight on bit (WOB) and RPM. The overall efficiency of the drilling operations can be evaluated using either a mechanical specific energy model or an inverted rate of penetration (ROP) model. The key output from the analysis described herein is a method to improve drilling efficiency by incorporating a drillstem vibration model with an ROP model.
A data set including vibrational data was collected from a section of a well drilled in the North Sea to analyze the level of drilling efficiency for the drilled section. A drillstem vibration model was created using nonlinear finite strain theory, including coupled axial, torsional and lateral vibration modes. To optimize the drilling process, the vibration model was integrated with an ROP model. The vibration model calculates the critical speeds for a given BHA at a given depth, supplied with an operational window for WOB and RPM combinations that gives the optimal combination in therms of ROP.
By analyzing the drilling variables such as WOB, rotational speed, and ROP, the drilling operational effectiveness was evaluated. The operational window with low vibration level and with the potential maximum instantaneous ROP was chosen to be the optimum drilling scenario for the target hole section. The model was verified with the analysis of the collected field data where the level of drilling efficiency was obtained for the different sections drilled. This paper presents a new methodology to increase drilling performance by means of drillstem vibration and ROP modeling.
Method for Pore Pressure Estimation Using Mechanical Specific Energy and Drilling Efficiency
Authors: Majidi Reza , Albertin Martin , Last Nigel 
Published: January 2016

Abstract
Pre-drill prediction of formation pore pressure and pressure detection while drilling to recognize deviations from the expected pressure are important inputs for well planning and operational decision making.
A method is proposed to determine pore pressure from a combination of downhole drilling mechanics parameters and in-situ rock and stress data using the concept of mechanical specific energy (MSE) and drilling efficiency (DE). This pore pressure estimation method (termed "DEMSE") is based on the theory that energy spent at the bit to remove a volume of rock is a function of the differential pressure (wellbore pressure minus pore pressure) that the rock is subjected to during drilling.
A workflow is provided that illustrates the steps required to estimate pore pressure from drilling parameters and rock/stress data using DEMSE method. Pore pressure estimated from the DEMSE method is compared with a pore pressure estimate using a conventional sonic log based empirical technique for a deep water well in the Gulf of Mexico. Pore pressure estimates from the DEMSE method generally agree in magnitude and trend with the pressure estimates derived from sonic log data.
The results of the DEMSE method have also been compared with pore pressure estimates from the classical d-exponent (dXc) methodology. Unlike the d-exponent methodology, which is an empirical correlation that considers only weight on bit (WOB), DEMSE is an energy based approach that takes into account both torque and WOB. Moreover, the normal compaction trendline (NCT) used in the DEMSE method can be correlated to a normal compaction porosity trendline; the same NCT used as a basis for conventional log-based pore pressure estimates. This gives the DEMSE method a significant advantage over the dXc method, in terms of predictive capability, by reducing the subjectivity that is involved in dXc-based pore pressure estimates.
Finally, the importance of using downhole vs. surface data for pore pressure estimation purposes, specifically torque measurements at the bit, is illustrated through a field example. These findings suggest that downhole drilling mechanics data, when properly utilized, can provide reliable independent estimates of pore pressure in real-time at the bit, and for post well analysis to assist with constructing pore pressure forecasts.
Buckling of Tubular Strings in Open Sea
Authors: Kyllingstad Åge 
Published: January 2016

Abstract
An analytical model for lateral buckling of near vertical tubular strings is presented in the paper. It applies both for marine risers and for drill strings used during riser less drilling. The model represents a tool for predicting critical compression force at the lower end and for calculating critical shortening length of the buckled string in situations when the top site heave compensation or tensioner system fails.
The static lateral deflection of the string is described by a fourth order differential equation that can be linearized for small inclinations. Non-trivial analytic solutions include homogeneous and inhomogeneous Airy functions that can be combined to satisfy various boundary conditions and shortening lengths. The effect of an optional side force is also included in the solutions.
The paper discusses the validity of the underlying assumptions, such as linearity, simplified boundary conditions, and the neglecting of dynamic effects. Finally, the theory is successfully compared with experimental results from a small scale physical model.
Well Placement Optimization in a Gas Condensate Reservoir to Prevent Condensate Banking
Authors: Evans Edward , Ghalambor Ali , Orangi Abdollah 
Published: January 2016

Abstract
Horizontal wells with multistage hydraulic fractures have become the most common practice to obtain viable commercial production from shale and tight gas reservoirs. With a marked increase of gas production emerging from these tight reservoirs, it is necessary to further study the effects of formation damage due to condensate dropout and how best to prevent and mitigate this damage. There are two common ways to mitigate and treat condensate banking. The first method is to fracture the existing well. This allows bypassing the condensate and therefore increasing well productivity. The second method is to shut-in the well and allow pressure to build up so that the dropped out liquids are revaporized back into the gas. These options, respectively, involve large capital expenses and temporary decrease of production. Before deploying these solutions, the condensate dropout damage can be strongly reduced at no (field) cost by optimizing the well location.
This objective in this study was to determine the optimum well location to mitigate formation damage due to condensate dropout in a tight gas well. Compositional reservoir simulations were conducted with different condensate gas ratios and relative permeability curves to quantify the loss of productivity due to formation damage under different conditions. The target formation was 100 ft thick, and a tartan grid was used to represent the hydraulic fractures within the tight gas well.
This study determined that well placement plays a key role in preventing damage due to condensate banking. The optimized placement of the well can drastically enhance the viability of a project by allowing for a larger recovery.
A Comparative Study on Operational Performance of Advanced Low Friction Residue-Free Fracturing Fluid versus Conventional Fluid Systems
Authors: Schnoor Eli , Singh Dipti , Russell Aaron , Jespersen Matt , Lewis Chad 
Published: January 2016

Abstract
This paper compares the operational performance of a newly developed low friction, nearly residue-free (LF-RF) fluid system to a conventional derivatized guar-based fluid system and an existing nearly residue-free (RF) fluid system. The RF system has provided increased well production in numerous applications; however, the system requires lower treating rates due to increased friction. During recent field operations, the LF-RF system surpassed previous treating rates, which were previously unattainable, while maintaining maximum fluid cleanup.
The friction responses between the RF, LF-RF, and derivatized guar-based fluids were assessed through quantitative analysis of surface treating pressures. All comparisons between fluid systems were made between wells on the same pad with the same completion method. The wells used in this study were all located in the Denver/Julesburg (DJ) basin and pumped using the same hybrid treatment design. Along with field data, laboratory testing was conducted to compare the viscosity profiles of the LF-RF and derivatized guar-based fluid, which were used in the field.
Guar-based fracturing fluids have long been the industry standard. However, these fluids produce insoluble residue on breaking, which can reduce proppant pack conductivity and adversely affect well production. The RF fluid is an ultraclean, proven system, which has been successfully pumped in more than 16,000 stages. This fluid leaves virtually no insoluble residue, which has led to increased production from unconventional reservoirs. Yet, the RF fluid tends to exhibit increased treating pressures compared to guar-based fluids, which might require lower treating rates during operations. Additionally, a higher gel loading is necessary with the RF fluid to achieve comparable viscosities to the guar-based fluids. The new LF-RF fluid system retains all the beneficial cleanup properties of the RF system, while providing improved friction reduction. Intervals pumped with the LF-RF fluid provided lower treating pressures compared to those pumped with RF fluid, even at increased treating rates. With the improved friction reduction verified, the LF-RF fluid was pumped alongside a derivatized guar-based system at 80 bbl/min; a rate well beyond that which the RF fluid is generally pumped. The LF-RF fluid successfully placed all proppant and had similar treating pressures to the derivatized guar-based system toward the heel of the well. The LF-RF fluid was also able to accomplish this using a gel loading comparable to the derivatized guar-based system.
Through quantitative analysis of the surface treating pressures, the LF-RF system has demonstrated increased friction reduction compared to the existing RF system. The improved friction reduction allows the LF-RF fluid to be pumped at high rates, expanding the range of possible well and treatment designs which this fluid system can accommodate.
Field Results and Experimental Comparative Analysis of Sodium and Nonsodium Chelant-Based HF Acidizing Fluids for Sand Control Operations
Authors: Smith Alyssa LaBlanc , Woon Geok Cheen , Smits Ferry , Govinathan Kesavan , Yong Wei-Jin , Beuterbaugh Aaron , Garcia Enrique A. 
Published: January 2016

Abstract
Field results and laboratory data are presented for the purpose of identifying best practices for two different acidizing fluids based on chelating agents containing hydrofluoric (HF) acid employed in clean-up treatments in high-rate water pack completions (HRWP). The HF fluids are a newly introduced aminopolycarboxylic acid (APCA), pH 2.5 to 3 that contains sodium ions, and an established hydroxycarboxylic acid (HCA) fluid, pH 3, sodium-free.
Flow testing was conducted at the anticipated bottomhole static temperature (BHST) of 270°F in synthetic packed columns with formation sand. However, the field conditions at which the treatments were run corresponded to a BHST of 202 to 216°F and a bottomhole pressure (BHP) of 1,800 to 2,000 psi. The permeability of the sands was 89 to 162 md. Comparative data and results stemming from laboratory testing and field use of the HF/chelant fluids are analyzed for concentrations of 1 and 1.4% HF and APCA at 0.6 M, and 1% HF with HCA. Field data and production results are discussed for two set of wells treated with each type of HF fluid.
The chemical differences, reactivity and characteristics among the APCA/ and HCA/ -HF fluids on formation sand and on formation core are described. Fluid testing excluded acid preflush and NaCl or KCl was the sole brine employed. Laboratory results indicate that both HF fluids are compatible with the brines used within the scale of the experiment and provide full or increased relative permeability. The field application of the APCA/HF fluid in HRWP appears to perform less efficiently, requiring longer pumping times, than the HCA/HF fluid. A salient observation from laboratory testing indicates greater effectiveness at pH 2.5 vs. 3 for the APCA/HF fluid. A differentiating characteristic is that the APCA/HF fluid can be used to treat heterogeneous sandstone with moderate carbonate content and HCA/HF is mostly compatible with clean sandstone unless an acid preflush is incorporated. The operational outcomes observed during the field use of the APCA/HF fluid appear to indicate significant differences in laboratory vs. field performance requiring further assessment to identify appropriate practices in HRWP.
The APCA/HF fluid can stabilize problematic ions in the spent fluid without the need for acid preflushes and without maintaining highly acidic conditions. The effective field use of the newly developed APCA/HF fluid containing Na+ with and without an acid preflush indicates that future work with this type of stimulation fluid is viable in matrix acidizing.
Numerical Modeling of a Soil‐Borehole Thermal Energy Storage System
Authors: Catolico Nora , Ge Shemin , McCartney John S. 
Published: January 2016

Core IdeasBorehole thermal energy storage is studied with a 3D transient fluid flow and heat transfer model.BTES heat extraction efficiency increases with decreasing soil thermal conductivity.BTES efficiency decreases with convective heat losses associated with high soil permeability.Borehole thermal energy storage (BTES) in soils combined with solar thermal energy harvesting is a renewable energy system for the heating of buildings. The first community‐scale BTES system in North America was installed in 2007 at the Drake Landing Solar Community (DLSC) in Okotoks, AB, Canada, and has since supplied >90% of the thermal energy for heating 52 homes. A challenge facing BTES system technology is the relatively low efficiency of heat extraction. To better understand the fluid flow and heat transport processes in soils and to improve BTES efficiency of heat extraction for future applications, a three‐dimensional transient coupled fluid flow and heat transfer model was established using TOUGH2. Measured time‐dependent injection temperatures and fluid circulation rates at DLSC were used as model inputs. The simulations were calibrated using measured soil temperature time series. The simulated and measured temperatures agreed well with a subsurface having an intrinsic permeability of 1.5 × 10−14m2, thermal conductivity of 2.0 W m−1°C−1, and a volumetric heat capacity of 2.3 MJ m−3°C−1. The calibrated model served as the basis for a sensitivity analysis of soil thermal and hydrological parameters on BTES system heat extraction efficiency. Sensitivity analysis results suggest that: (i) BTES heat extraction efficiency increases with decreasing soil thermal conductivity; (ii) BTES efficiency decreases with background groundwater flow; (iii) BTES heat extraction efficiency decreases with convective heat losses associated with high soil permeability values; and (iv) unsaturated soils show higher overall heat extraction efficiency due to convection onset at higher intrinsic permeability values.
Splitting the structured paths in stratified graphs. Application in Natural Language Generation
Authors: Dănciulescu Dana , Colhon Mihaela 
Published: January 2016

Abstract
The concept of labeled stratified graph (LSG) introduces some method of knowledge representation. The inference process developed for this structures uses the paths of the stratified graphs, an order between the elementary arcs of a path and some results of universal algebras. The order is defined by considering a structured path instead of a regular path. The application described in this paper interprets the symbolic elements of a LSG with natural language constructions. In this manner we obtained a mechanism for generation coherent texts in a natural language (for this approach, Romanian). The generation method is based on labeled stratified graph representation and the inference mechanism is guided by the structured paths of these representations.
The Relationship Between Landing Sound, Vertical Ground Reaction Force, and Kinematics of the Lower Limb During Drop Landings in Healthy Men
Authors: Wernli Kevin , Ng Leo , Phan Xuan , Davey Paul , Grisbrook Tiffany 
Published: January 2016

Study Design Controlled laboratory study, cross-sectional. Background Soft-landing instruction, which is advocated in several injury prevention programs, is thought to have a qualitative relationship with decreased vertical ground reaction forces (vGRFs) and increased lower-limb joint excursions. Objective To quantify the relationships among landing sound, vGRFs, and lower-limb kinematics during a drop-landing task. Methods Twenty-six asymptomatic men aged 18 to 35 years were asked to perform 15 single-leg drop landings from a 30-cm height. Five trials were collected under 3 sound conditions: normal, quiet, and loud. The vGRF, lower-limb kinematics (sagittal plane), and impact sound were recorded during the deceleration phase. Results A simple linear regression revealed a significant relationship between landing sound and vGRF (R2 = 0.42, P<.001). A repeated-measures analysis of variance showed that ankle and knee excursion significantly increased by 7.0° and 11.7°, respectively, during quiet landing (compared to normal landing; P<.001). During the loud landing condition, ankle joint excursion significantly decreased by 9.4° compared to the normal landing condition (P<.001), and hip joint excursion significantly increased by 4.0° compared to normal landing condition (P<.045). Conclusion As landing sound decreases, so does vGRF during a drop-landing task. These reductions were achieved by increasing ankle and knee joint excursions. Conversely, as the landing sound increases, so does vGRF. This was the result of decreasing ankle joint excursion and increasing hip joint excursion. J Orthop Sports Phys Ther 2016;46(3):194–199. Epub 26 Jan 2016. doi:10.2519/jospt.2016.6041