bluuebunny/crossref_metadata_2025 huggingface dataset:
Power and Influence: Assessing the Conceptual Relationship
Authors: Zaaiman Johan
Published: February 2020

Power and influence are fundamental concepts used in the social sciences. As closely-related concepts it is not easy to distinguish them clearly. There are diverse definitions for power and influence in academic literature. Different views are also held on the relationship between these concepts. The present article revisits these debates. The researcher explains the difficulties to define concepts in general and those of power and influence in particular. This is done by referring to academic attempts to clarify the meaning of the mentioned concepts and thereby their conceptual relationship. It is demonstrated that the debate is complicated and a final answer cannot be found that easily. However, this article explores the differences in meaning between the concepts from the literature. Based on these distinctions, the researcher identifies the concepts’ primary meanings as well as the areas where these meanings overlap. This article contributes by providing users of these concepts with conceptual markers that could help them use and integrate the concepts meaningfully.
Wearable Robot Arm with Consideration of Weight Reduction and Practicality
Authors: Kojima Akimichi ,   Ritsumeikan University 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan, Yamazoe Hirotake , Lee Joo-Ho
Published: February 2020

In this paper, we propose a wearable robot arm with consideration of weight and usability. Based on the features of existing wearable robot arms, we focused on the issues of weight and usability. The behavior of human hands during physical work can be divided into two phases. In the first, the shoulder and the elbow joints move before commencing the task by using the hands. In the second, the wrist joints move during the actual work. We found that these features can be applied to wearable robot arms. Consequently, we proposed hybrid actuation system (HAS) with a combination of two types of joints. In this study, HAS is implemented into the prototype wearable robot arm, assist oriented arm (AOA). To verify the validity of the proposed system, we implemented three types of robot arms (PasAct, Act, 6DOF) using simulation to compare the weight, working efficiency, and usability. Furthermore, we compared these simulation models with AOA for evaluation.
Extensive Atraumatic Heterotopic Ossification of the Achilles Tendon in an Adolescent with Metabolic Syndrome
Authors: Su Lisa , Arshi Armin , Beck Jennifer J.
Published: February 2020

Case:

A 15-year-old boy with type 1 diabetes mellitus, hypertension, and obesity presented with atraumatic posterior ankle pain and stiffness due to extensive heterotopic ossification (HO) of the Achilles tendon. The ossification was successfully surgically resected and tendon primarily repaired. Wound dehiscence was noted at the first preoperative visit, managed conservatively by local wound care, and healed uneventfully by secondary intention. One-year follow-up showed no recurrence of HO, return to baseline activities, yet low Oxford scores.

Conclusion:

HO of the Achilles tendon is a rare clinical entity. We report an atraumatic case in an adolescent patient with metabolic syndrome, which may demonstrate systemic inflammation because of metabolic syndrome as a risk factor for HO.
Effects of Diabetes on The Output of Farmer and Its Policy Implications
Authors: Naqvi Syed Asif Ali , Hussain Bilal , Shah Syed Ale Raza , Makhdum Muhammad Sohail Amjad
Published: February 2020

This study investigated the impact of diabetes on work performance of different farming communities from Punjab, Pakistan. This study was based on cross-sectional data. A representative sample of 374 farmers was collected from five selected districts. Three types of respondents were analyzed in the study e.g.,laborer, small and large growers. Poisson and logistic regression techniques were used for the sake of analysis. According to the investigated results for thelabor category, respondents with more age, less qualification, low earning per month (Rupees), and having positive record of family diabetes, would havemore leave per month. In the same way, findings for small farmers revealed that education, family size, family with diabetic records, marital status and availability at farm (hour/day) were significant. In case of third category, study outcome highlighted that age, education, marital status, having positive record offamily diabetes and number of hours spent at farm would be positively correlated with the reduction in working efficiency at farm due to diabetes. It can beconcluded that diabetes have negative influence on the work performance of selected farming groups.
Fatigue Modeling in BHA Connections: Is BSR Helpful?
Authors: Pettit Grant , Lee Kang
Published: February 2020

Bending Strength Ratio (BSR) is a time-honored technique for choosing BHA connections, and is often the basis for the popularity of some connections over others. However, experience and some isolated research indicates that it might not be accurate in predicting the best connection. This paper attempts to use Finite Element Analysis (FEA) coupled with fatigue-life modeling to develop a systematic picture of the effectiveness of BSR as a design criteria.

The modeling process used has been developed previously (Ellis et al 2008, for example). Each connection and collar size studied is modeled in detail using Finite Element Analysis (FEA) techniques, and the resulting stresses and strains can be used to calculate the number of cycles to failure for a given set of parameters. These results are not accurate for predicting actual component failure, but they are helpful for comparison between options to choose the best designs. This work represents a fairly-complete cross section of the BHA connections in regular use, studied for their relative performance.

A challenge of directly modeling fatigue lives is finding a way to compare the results for global patterns. Since different collar sizes will have different applied stress levels at different curvatures, a method for normalizing the results is developed here. This allows an easy global comparison between the different connections.

The outcome of this in-depth study of connection fatigue-modeling results is a surprise: BSR is not helpful for design, and there seems to be no clear pattern for ID and OD sizing. Instead, the drill string designer should choose the right connections at the time of manufacturing, and use a normalized comparison method to determine the relative risk in each operation.
Automated Procedural Compliance Drives Real Time Drilling Optimization
Authors: Kamyab Mohammadreza , Yalamarty Sai Sharan , Rogers Philip , Cheatham Curtis
Published: February 2020

Operators have established procedural requirements as part of their HSE, risk and cost control policies. Automating procedural compliance enables real-time operations oversight while reducing risks associated with manual processes. A novel technique was developed and implemented to automatically check rigs’ procedural compliance with an operator's guidelines and alert users in real time.

Textual procedures are initially converted into structuralized JSON (JavaScript Object Notation) format making it easier for the user to form the logics and generate a format usable for the computer. Each procedure consists of starting and ending triggers and compliance rules. As WITS data is fed to the engine, they are automatically compared against the given guidelines. Triggers are detected in WITS data using automated rig activity detection (e.g. wash up, or rotary drilling). Subsequently, compliance rules are checked and, if all criteria are met, it is detected as complied; otherwise, an alert is triggered.

The following procedures have been developed and deployed: zeroing of weight on bit and mud motor differential pressure for more accurate ROP (rate of penetration) optimization, lowering BHA (bottom hole assembly) back to bottom with reduced RPM, connection practice procedure, and capturing steady-state hook-load values for improved torque and drag monitoring. Each procedure was identified to influence future optimization efforts to a varying degree. Consider if the weight on bit is not zeroed properly it can cause incorrect driller's road-map recommendations for new wells.

The framework has been extensively tested and refined with the assistance of a Permian operator until it reached an acceptable accuracy: 95% for back-to-bottom procedure, 99% for zeroing WOB (weight on bit), and 90% for zeroing DIFF (differential pressure). Reports have been generated to display the statistics of the compliance for each rig and crew. A Permian operator, who has field tested the procedural compliance application, estimates that it will save millions of dollars per year by avoiding costly equipment damage as well as from significant time savings by standardizing a back-to-bottom procedure.

Real-time procedural compliance is a novel technique to check whether the rig personnel follow the operator's procedures. It has a flexible back-end interpreter, and each procedure is provided separately. This ensures the procedure is not attached to the original code and can be easily modified. Through the use of a real-time compliance engine, every operator can load their respective procedures and check for compliance in real-time.
Wellhead Movement Analysis with a Finite-Element Model for Well Integrity Assessment of Complex Configurations
Authors: McSpadden Albert R. , Cooper Richard G. , Trevisan Ruggero
Published: February 2020

Analysis of mechanical and thermal-induced wellhead growth and resultant loads is critical for tubular stress design and failure analysis of offshore platform wells. A particular need to address is the growing trend of field life extension projects for platform installations in which outer structural casings are retained. In most cases this involves installation of a new completion and often entails well conversion to new purposes different from the original design basis. Another key feature is the use of mudline suspension (MLS) systems for wells drilled in various water depths. For well integrity assessment of these and other complex configurations, wellhead movement analysis with a 1-D finite-element model (FEM) is described by which diverse configuration and analysis scenarios are accommodated in a comprehensive analysis.

The wellhead movement analysis presented uses standard FEM techniques for structural analysis with 1-dimensional linear or non-linear bar members. This is based on the familiar structural stiffness matrix. Because the wellbore system may be discretized as needed, it is straight-forward to accommodate a wide variety of well configuration options and well integrity factors. Likewise the wellhead movement model need not be limited to a single degree of freedom (DOF) at the wellhead itself but rather can and should accommodate the full complexity of the real-world configuration. Hence multiple degrees of freedom involving multiple MLS hangers or failed components are included for explicit analysis.

Due to the aging infrastructure of many mature offshore assets, the ability to economically and safely exploit remaining reserves may depend on the suitability of retained casings. Thus it is necessary to accommodate a variety of infrastructure integrity issues such as wall loss from corrosion, weakened connections, and damage to cement or grout. Another frequent design issue arises from the prevalence of MLS systems. These introduce an extra degree of freedom which makes wellhead movement analysis more complex, especially if problems arise during installation. Problems with tiebacks in a well featuring an MLS system do arise and a case study is given to demonstrate the level of flexibility required to correctly and safely assess operational parameters.

Aside from the analysis model itself, the interaction of wellhead movement and well integrity degradation on ageing and re-purposed offshore platform wells is given detailed attention. Also potential complications involved in MLS configurations are demonstrated. Building on previous work, the analysis methodology and case studies discussed in this work provide an explicit and intuitive approach to wellhead movement and loads. Certain types of wellhead load events which are not accommodated using available commercial software are modeled and analyzed.
An Evaluation of the Cement Sheath Quality of Casing Sections Recovered During a Well Abandonment Operation
Authors: Obando Palacio Guillermo , Gardner Dave , Delabroy Laurent , Govil Amit
Published: February 2020

Cemented casing sections were recovered from the upper part of a Norwegian North Sea production well during a permanent abandonment operation. The barrier quality of the cement sheath, which has been sandwiched between two casing strings for more than 30 years since the well was constructed, has been investigated. Measurements recorded using acoustic logs, fluid leakage testing, and core plug analysis are evaluated, and the results are presented.

Two sections were selected from those recovered during well abandonment, the deepest from approximately 260 m depth and a second from the interval covering the top of cement (TOC). The leakage properties of these sections were measured using water and nitrogen. Core plugs were recovered from the top and bottom of each section and petrophysical, chemical, and mechanical properties were measured. The casing ends were sealed with pressure-tight bulkheads enabling acoustic logging to be performed under pressure. The sections were logged at their initial condition: "dry", as delivered onshore and thereafter "wet" after attempting to saturate them with water.

Initial leakage testing with nitrogen enabled the distribution of the fluid leakage paths through the ends of each section to be visualized. The leakage path properties were observed to vary axially along each section and also for different positions around the azimuth of the outer casing. The acoustic logs were analyzed and provided a detailed map of the axial and azimuthal variations of the cement bonded to the inner casing of each well section. The variation of the log response recorded under dry and wet conditions was correlated with the leakage property variations measured along and around the casing sections. The log response was found to be consistent with the physical observations and leakage test results. The presence of microdebonding between the casing and cement and the transition to mud solids and fluid pockets above the top of the cement were readily observed.

A unique and comprehensive data set has been acquired comprising acoustic logs and laboratory measurements of water and gas leakage rates and cement properties, recorded on casing sections retrieved after more than 30 years of operational exposure downhole. The measurements enabled the cement log analysis to be compared directly to physical measurements of the well barrier quality.
An Automated Workflow for Real-Time Monitoring and Benchmarking of Connection Time in Drilling Operations
Authors: Karimi Vajargah Ali , Banirazi Reza , Pablo Mejia Juan , Haffner Phillippe
Published: February 2020

Invisible lost time (ILT) during drilling can add up to be extremely costly. Since a significant portion of ILT occurs during drilling and tripping operations (including running casing), the aim is to develop a workflow based on analytics algorithms that accurately identify and record how long it takes to make both drilling and tripping connections in real time using 1-second surface data. By capturing these KPIs, performance differences across the rig fleet were identified, and best practices were shared.

The developed workflow and algorithms for the drilling and tripping connection times can be applied to both active and historical wells in a fully automated fashion. The algorithm consumes 1-second surface drilling data to identify each connection. For more in-depth analysis, the drilling connection is divided into three stages: pre-connection, slip-to-slip, and post-connection. The algorithm relies on an advanced "rig state" (e.g., drilling, tripping in, tripping out, running casing) to determine the current state of the drilling process.

The algorithm was applied to more than 500 historical wells, drilled in three major business units in northwest Texas and southeast New Mexico. These wells had different levels of complexity, from shallow vertical wells to complex horizontal wells, and thus provided a very valuable data set for benchmarking and lookback studies. Through this process, more than 750,000 connections were identified. Analysis was done to determine a correlation between the connection performance and various factors such as rig type and contractor, crew, well design, hole depth, and drilling region. Best performers were identified for each unit to help determine the operational goals. The analysis showed that the drilling connection time varied significantly among different rigs, with a gap of more than 3 minutes for one of the business units, suggesting a huge improvement opportunity. In addition, the algorithm is currently being deployed at the rig site using the Internet of Things (IoT) Edge technology to run the application locally in real time and provide the drill site manager and driller with connection time, which had immediate impact on performance improvement.

The developed workflow in association with the algorithm, online visualization platform, and real-time monitoring, provides a powerful tool to improve efficiency, set realistic goals, make intelligent business decisions, and reduce the well delivery time without compromising safety. In addition, this study reveals that a reduction of up to 3% in drilling time of future wells can be achieved by lowering the current average connection time to the P10 value (best performers).
Drilling Performance Evaluation Using Advanced BHA Modeling and Field Validation
Authors: Greenwood Jeremy , Marck Julien , Nair Vakkeyil Naveen , Munguia Joseph
Published: February 2020

A methodology to optimize bottomhole assembly (BHA) designs to deliver improvements in wellbore quality has been developed. BHA modeling accurately simulates the drilling process and is combined with measurements of the wellbore to establish selected drilling key performance indicators (KPIs) leading to the successful optimization of BHA designs. The benefit of improved hole quality is to drill further, faster, and increase downhole tool life.

The methodology evaluates the drilling performance of mud motor runs using KPIs that evaluate the borehole quality and drilling performance. A BHA model evaluates the bending moment at critical housing locations at incremental measured depths. Changes in bending moment throughout the wellbore indicate variations in borehole tortuosity. Variation in borehole diameter during the slide and rotate modes identifies overall borehole rugosity. Multiple mud motor field runs in different basins in North America were analyzed to establish the KPIs. The tortuosity KPI results demonstrated the differences in borehole quality as a function of bending moment, where a tortuous borehole is attributable to increased bend ing moment. The fatigue life of the motor stator connections and the rate of life consumption with a larger accumulation of bending stress cycles was established. The borehole rugosity KPI demonstrated the increase in number of slide/rotate transitions, particularly in curve sections. In horizontal sections, the percentage of slide accounted for loss in rate of penetration (ROP) and consequently increased drilling time and borehole tortuosity. The combination of these factors was used to rank the different BHA designs in terms of their effectiveness to deliver a good quality borehole delivered in the least drilling time. Once the ranking was established, the effectiveness of each of the BHA design elements was established and this information used to improve the subsequent BHAs.

The approach creates a new performance evaluation methodology by combining both BHA modeling and field data to optimize designs. This methodology can be implemented before drilling to select the proper BHA design and post-job to evaluate a BHA designs performance.
Self Sealing Cement System Enables Prevention of Water Intrusion and Long Term Zonal Isolation in Um Gudair Field: A Case Study in West Kuwait
Authors: Jaffar Ali Hussain , Mohammed Jassem Ali , Khaja Mohammed , Haddad Hassan , Raturi Sushil , Albohamad Dalal , Abdel Lateef Emad , Aldakheel Rashed
Published: February 2020

Cementing the 7″ liner in UG field has always posed a great challenge due to the poor cement bonding across the target production zone, Minagesh Oolite. This is due to the high water influx, from the proximity of the aquifier drives to the production zone, hence leading to contamination of the cement slurry during the cementation. This has resulted in the loss of zonal isolation in addition to the unwanted water production. Water cut production has been observed to rise from 30% upto 70% and 90% within the course of less than 10 years. This has burdened a major Middle East operator with increased cost associated with remedial cementing jobs & disposal of water. Furthermore, conventional water shut off techniques, including cement plug back techniques, were proven to be largely ineffectual, hence an efficient control method was sought out as an alternative.

This paper discusses the implementation of an optimized, fit for purpose cement slurry, with enhanced mechanical and self-repairing properties along with the operational optimization in West Kuwait UG field which has improved the overall cement quality around the liner along with the reduction of water content (WC%) with production throughout a six month observation period.

An optimized, fit-for-purpose cement slurry system, with expansive and enhanced mechanical properties was developed and tested to simulate the conditions downhole during and after the 7″ liner cementation. Self-repairing, also known as self-sealing, and expansion properties in the presence of water and hydrocarbons were also tested by inducing fractures in the cement and observing the expansion and swelling capability in the presence of up to 90% water and only 10% hydrocarbon.

The self-sealing slurry was implemented in a step by step in a planned manner in UG field, with preset KPI's so as to evaluate the effect of slurry on water intrusion. Furthermore, operational execution and optimization was also considered to ensure a flawless cementing job execution.

Implementation of the first 3 self-sealing cementations of 7″ liner in UG field, showed great improvement in the cement bond log after 48hrs of cement placement. Further, the water cut in one case was reduced from 52% after initial testing to 24% and 22%, in subsequent 3 month and 6 month evaluation, respectively. This technology has also been used in other fields across Kuwait where water intrusion is apparent and different downhole conditions were observed. There is a large scope to use this technology as high water cut and poor cementation is a very common problem across different fields.
Fully Automated Managed Pressure Drilling Delivers Precise Control Through High Pressures in a Narrow Drilling Window
Authors: Muhammad Jamal uddin , Sugiarto Chajar , Hadj Moussa Ayoub , Kadadha Abdallah , Iturrios Carlos
Published: February 2020

Managed pressure drilling (MPD) helps operators efficiently navigate through narrow pore pressure-fracture pressure windows. The challenges encountered during one onshore drilling campaign included pore pressure uncertainty, high pressure influxes, total losses and high incidences of differential sticking, which at times led to abandoning wells when drilled conventionally. The case study highlights how these challenges were counteracted with the implementation of a fully automated MPD system.

MPD is a safer and more effective drilling technique, as compared to conventional drilling, especially in wells with narrow drilling windows and downhole hazards. A fully automated, early kick detection and control system that enables nearly instantaneous, precise adjustments to the bottomhole pressure adds great value to the client's operations.

It has been observed that in wells with a narrow window, precise determination of downhole pressure margins (i.e. pore pressure, wellbore stability and fracture pressure) and precise control of bottomhole pressure are imperative to complete the well without well-control incidents. A fully automated MPD system helps to achieve these goals.

Prior to the start of drilling with MPD, the exact formation pressure is determined by conducting pore pressure tests, and then during drilling the target bottomhole pressure can be precisely adjusted almost instantly by adjusting the surface pressure at the MPD choke. The MPD system greatly reduces the time to stabilize well conditions when encountering well control problems or downhole losses.

This paper summarizes the implementation of the fully automated MPD system as a sophisticated tool to precisely control such situations instantly, saving time, associated mud costs and hence optimize the overall drilling process. This paper describes a few MPD milestones in drilling the 8 3/8-in. and 12-in. hole sections in the field despite of difficulties including total losses and high-pressure influxes leading to well control events. The primary objective of MPD application in this field was to drill to the liner landing point by adjusting the bottomhole pressure (BHP) in real-time to eliminate the problems caused by uncertainty in the over pressured target formation and minimizing or eliminating the downhole fluid losses in the lower formations.

The paper describes results from two case studies. In the first case, the well was drilled with a 1 pound per cubic foot (pcf) (0.13 ppg) narrow window, with accurate detection and control of influxes while mitigating losses. In the second case, initially the bottomhole mud-losses were minimized instantly and later the well was precisely displaced under partial losses to a lighter mud to save mud costs while maintaining well control.
Hole Opening Challenges and Efficiencies – Interpretation and Implications of Bit and Reamer Dull Conditions
Authors: Mensa-Wilmot Graham , Woldtvedt Gust , Cardoso Marcos , Diwaku Wantuadi
Published: February 2020

Simultaneous hole opening with bit and reamer, based on acknowledged benefits, has become an drilling industry mainstay. Considering Bottom Hole Assembly (BHA) design and compliance requirements, bit and reamer in BHA, and issues with drilling parameters management, the operation presents severe drilling dynamics challenges. Additionally, several other factors initiate, sustain, and/or amplify dynamic dysfunctions. In their totality, these factors and conditions compromise hole opening efficiency, leading to increased cycle times and higher operational costs.

Current hole opening solutions and strategies have yielded inconsistent performances. Consequently, appropriate and effective solutions are needed to address above listed challenges. Data analysis must help identify factors and/or conditions that influence performance. These revelations must drive holistic solution approach for hole opening, that will be more effective at cycle time reduction, leading to project costs reductions. These expectations are only achievable, when appropriate implications are derived from effective interpretations of bit and reamer dulls. This paper will highlight and support these considerations with relevant field data, that focuses on hole opening efficiency factors, particularly dynamic dysfunctions. Cycle time effects and project costs considerations, as they relate to hole opening performance in challenging drilling environments will also be discussed.
Automating Anti-Collision Calculations for Autonomous Drilling Systems
Authors: Willerth Marc , McGregor Andrew , Bhaduri Sashmit , Eaton Joshua
Published: February 2020

The complexity of calculation along with the high stakes of error has traditionally meant that efficient implementation of anti-collision procedures required an experienced operator at the drill site. This is not ideal, as the expertise is only truly needed in isolated high-leverage situations. With the advent of automated drilling systems, more expertise is being moved from the drill site into the office. A system is proposed capable of balancing the efficiency of automated systems while retaining the safety afforded by expert supervision. Changing the way collision avoidance is conducted enables the full realization of the benefits of autonomous drilling systems.

The varied nature of collision avoidance operations makes it unlikely that the entire process will be completely automated in the foreseeable future. Sawaryn, et. al. (2018) outline eight elements required for a successful collision avoidance system. These elements are analyzed for the extent to which they can be automated. Historically, wellbore collisions are caused by operational shortcomings rather than a failure of calculations. The ideal system design would minimize any delay to the drilling process by focusing human efforts on validating the operational processes prior to drilling while automation handles the routine collection of data and application of calculations during drilling.

An autonomous drilling system can safely and efficiently execute in a collision avoidance scenario with the supervision of a remote monitoring center and appropriate risk-based escalation rules. Remote experts ensure that operational setups are valid prior to the start of drilling and that escalation conditions are clearly outlined. Separation-based cost functions are used to enable the autonomous drilling system to proactively steer away from escalation events. Mechanisms are defined that automate updates to provisional wellbore trajectories based on the automatic validation of survey data, projection of future possible well paths, and execution of separation calculations against separation rules. At necessary intervals human review confirms definitive wellbore trajectories, survey programs, and convergence plans. This moves tasks that require heavy human involvement outside of the critical drilling workflow. At appropriate risk levels, escalation occurs to increase the immediacy of the supervision, up to and including a stop-drilling condition requiring full management of change.

As more autonomous drilling systems are introduced in dense drilling environments, there is an increasing need to harmonize the requirements of these systems with collision avoidance workflows. By leveraging the ability of automation to identify critical points in the process, it is possible to move expertise to remote centers without sacrificing efficiency. Effective use of computer-assisted well planning can enable quick approval an optimal way forward leaving the execution to the automated drilling system.
Investigation of Frictional Heat Check Casing Failures in Offshore Deepwater Wells Leads to New Mitigation Strategy
Authors: Fitzsimmons Michael , Reyes Rollyn , Maskos Krystian , Thomas Tim , Sutin Sam
Published: February 2020

Chevron experienced four casing leaks in subsea deepwater environments with an estimated cost of $80 million to remediate the wells. A similar incident at BHP resulted in parted casing and cost the company an estimated $21 million. This paper describes the investigative techniques which led to the conclusion of heat checking as the likely root cause of the casing leaks and the development of a 3D static FEA model which predicts downhole casing temperature. The model was validated by historical data analysis of more than 20 deepwater wells and found strong correlations between predicted downhole casing temperature and casing leak incidents. The results provided confidence for the implementation of a drilling parameter window and real-time temperature prediction algorithm to monitor and mitigate the potential for heat checking. The intent of this paper is to share with industry the recent realization and understanding of heat checking as a casing failure mode and mitigation measures put in place to manage a known but not necessarily widely monitored risk.
Automated Trajectory Drilling for Rotary Steerable Systems
Authors: Hansen Christian , Stokes Matthew , Mieting Ralf , Quattrone Francesco , Klemme Vanja , Nageshwara Rao Karthik , Wassermann Ingolf , Zaeper Ralf
Published: February 2020

Directional drilling today is a manual process characterized by monitoring drilling parameters and trends, predicting the future wellbore trajectory and adjusting steering parameters as required. When drilling with a rotary steerable system (RSS) in the bottom-hole assembly (BHA), the trajectory control system is distributed between surface and downhole. The surface control makes use of downhole measurements and capabilities of the rotary steerable BHA, and in turn is used to control the downhole components, forming a ‘directional drilling control loop’ and allowing the efficient drilling of a quality wellbore. Traditionally, the directional driller assumes the surface control, whereas downhole control was executed by the RSS-BHA allowing to drill certain parts of a section automatically. With the advent of automation, the surface control can be executed by a control system.

This paper introduces a new automated trajectory drilling service for a rotary steerable system. The system is capable of predicting the wellbore trajectory, deriving steering proposals to follow the planned trajectory closely or steer back to plan, and submitting those steering downlinks automatically to the downhole RSS with the directional driller observing the system. The paper explains the underlying control methodology and the automation system architecture. Furthermore, operational considerations such as handling of formation disturbances are discussed. The concept of embedding the driller and directional driller in the decision-making workflow is outlined. Finally, the performance of the automated trajectory drilling system is assessed and field test results from two case studies are presented, where up to 98 % of a single wellbore has been drilled automatically. To date, a total of 3,926 m have been drilled automatically with the automated drilling system.
Cloud-Based Coherent Wellbore Stability, Improving Trajectory Design for Unconventional Well Construction Planning
Authors: Reyes Allan , Huang Jing Jing , Yuan Zhaoguang , Temple Phillip , Liang Qingjian , Morana Jorge , Hashemian Yahya
Published: February 2020

Wellbore instability is one of the most consequential drilling operation risks. Planning a trajectory without knowing the wellbore instability risk can be costly during operations. It is critically important for engineers to be able to validate wellbore stability coherently when trajectories are planned and be able to adjust and optimize a trajectory to minimize the risk during the planning phase. The risks of wellbore collapse in the buildup sections, if the trajectory azimuth is not optimized with formation stress orientation, could be catastrophic. Due to shale heterogeneity, the horizontal section of the wellbore also has a high risk of wellbore instability. All the wellbore instability issues can lead to non-productive time and increase the cost of well construction. The solution presented in this paper is a cloud-based, coherent trajectory planning solution with wellbore stability validation using a Mechanical Earth Model (MEM).

Detailed well planning is required to mitigate all the wellbore instability issues. This cloud-based, coherent wellbore stability validation provides an efficient way to improve trajectories by advising the best azimuth and hole inclinations to avoid wellbore instability risks. The MEM is automatically used to compute the wellbore stability (WBS) on the trajectory design. Mud weight can also be validated in the wellbore stability model based on the mud weight window provided by the MEM. In the cloud collaborative environment, all other well planning workflows, such as BHA, casing design, etc. will be validated with the designed trajectory. A case study of unconventional well planning will be presented to show how to avoid wellbore instability by choosing a different trajectory than original proposal.

In the case study, WBS was computed from a MEM whose data are acquired from wireline logging. This study mitigated the risk of wellbore instability in the curve section by changing the dogleg of the trajectory. Simultaneously, mud design, BHA design, and casing design were concurrently validated to ensure safer and better well planning. Non-productive time was avoided because of a better trajectory design and wellbore stability.

This new workflow can help operators optimize well trajectory with reduced effort and deliver high quality well planning.
Automated Geosteering with Fault Detection and Multi-Solution Tracking
Authors: Maus Stefan , Gee Timothy , Mitkus Alexander M. , McCarthy Kenneth , Charney Eric , Ferro Aida , Liu Qianlong , Lightfoot Jackson , Reynerson Paul , Velozzi David M. , Mottahedeh Rocky
Published: February 2020

Development of autonomous drilling technologies requires the automated analysis and interpretation of Logging While Drilling (LWD) data to optimally land the well in the target formation and keep it in the pay zone. This paper presents a fully automated geosteering algorithm, which includes advanced LWD filtering, fault detection, correlation, tracking of multiple interpretations with associated probabilities and visualization using novel stratigraphic misfit heatmaps.

Traditional geosteering uses manual stretch, compress and match techniques to correlate measurements along the subject wellbore against corresponding reference type logs. This results in a crude representation of strata by linear sections with offsets at fault locations. Instead of automating this manual process, we instead determine the possible interpretations as solutions of a geophysical inverse problem in which the total misfit between the subject and reference data is minimized. Interpretations are parameterized as discontinuous splines to accurately follow curved strata interjected by fault offsets. To account for ambiguities, multiple possible interpretations are continuously tracked in real time and assigned probabilities based on the misfit between the latest measurements and the reference data. Unrealistic solutions are suppressed by penalizing strong curvature and large fault offsets. Viable interpretations are simultaneously visualized in real time as paths on a novel stratigraphic misfit heat map, where they may be corroborated against valleys of minimal misfit between the subject and reference data. The user can guide the interpretation by setting control points on the heat map which the automated solutions must respect.

The algorithm has been validated using wells from different regions across North America for which previous manual geosteering interpretations are available. The automated spline interpretations represent the actual curved strata more accurately than manual interpretations. Operationally, the automated interpretations can be provided within minutes compared to typical manual turn-around times of hours. Automation leads to more consistent and repeatable results, removing the subjectivity of manual interpretations.
Gas Powered Engines with Energy Storage - A Game Changer in Land Drilling
Authors: Hopkins Diana , Fox Isaac , Molen Don
Published: February 2020

This paper describes the recent real-world demonstration of a gas-fueled power generation system for drill rigs which utilizes automation, energy storage, and integrated electronic controls to achieve excellent performance and efficiency. Land drilling rigs are typically powered by a set of diesel-fueled generator sets, but natural gas has been an attractive alternative fuel due to lower fuel cost and lower emissions. Lean-burn natural gas generator sets have traditionally not had the transient response required to accept the large load changes imposed by the drawworks motors on a drill rig while maintaining a steady bus frequency, unless combined with energy storage or resistive load banks, while rich-burn generator sets for drilling have been large and inefficient. In this demonstration, a set of high-performance lean-burn natural gas generator sets with superb transient response were combined with an energy storage system to mitigate the effects of transient load demand and showed excellent performance in real-world drilling situations over a period of more than 6 months. Furthermore, an automated supervisory control system was implemented which automated the starting and stopping of generator sets to achieve efficient operation and simultaneously provide a long life of the batteries in the energy storage system. Fuel savings have been calculated based on observed performance of the subject rig compared to simulated performance with a diesel power generation system under the same conditions, and by comparison of the subject rig to neighboring rigs. The integrated automatic control system reduced fuel usage by 13% and engine operating hours by 30% compared to running the same natural gas generator sets and energy storage without automation nor frequent manual interventions. Fuel savings compared to a conventional diesel-powered drill rig were estimated to be 612,500 gallons of diesel per year based on the observed operating loads.
Measuring Microinvisible Loss MILT Time in Drilling Operations
Authors: Mittal Manish , Lakhanpal Vikrant , Samuel Robello
Published: February 2020

Within both productive and nonproductive time (NPT), a drilling operation can include invisible lost time (ILT), which is the time lost because a portion of the drilling operations is not performed at maximum efficiency. Within this ILT, another dimension of lost time can exist because of the inherent nature of the process, use of unoptimized equipment, or because the process might not have been performed at the optimum efficiency.

Both NPT and ILT concepts have been discussed in the literature. Some concepts are based on the maximum theoretical performance (MTP), and others are based on threshold time calculation. Regardless of the estimation method used, NPT and ILT are generally quantified in the literature as products of downhole conditions. Another dimension of NPT: microinvisible lost time (MILT) is introduced in this work. MILT is identified as being affected by two major factors: surface equipment design and efficiency and process optimization. MILT also includes ergonomic human inefficiencies attributable to these factors.

A case study is presented to identify the MILT using an online statistical analysis method. It can be integrated with future management and well design plans to improve the efficiency of drilling operations. The objective is to help identify the commonly ignored hidden factors that contribute to NPT; consequently, it can help promote faster, more efficient, and more cost-effective drilling.
SOLAG: An Intelligent Gas Lift Optimization System for Continuous and Intermittent Gas Lift Wells
Authors: Cadeño M. , Ortiz J. L.
Published: February 2020

Offshore production operations in Lake Maracaibo field are characterized by having an average of 4,500 gas lifted wells, producing from more than 400 different reservoirs. These complex processes require constant surveillance to allocate the proper gas injection rate for each well, based on available gas from each one of the seven existing gas compression and distribution systems.

To determine the required gas injection rate for each well in a distribution system, we developed in 1980 a computerised system celled SOLAG which stands for Gas Lift Optimization System. This system has been upgraded during the past 12 years and it capable of analyzing and selecting the appropriate production data from field measurements, determining individually the optimum gas injection rate based on the actual gas lift method, and finally allocating the required gas injection rate based on two situations that could be present in a distribution system: (1) available gas is greater than required, and (2) available gas is less than required.

In-house mathematical correlations are used to estimate optimum gas injection ratea for continuous and intermittent gas lift wells. Another feature is the application of artificial intelligence to represent the knowledge needed to interpret and select proper data from field measurements.

In this paper we describe the system, the mathematical correlations used to estimate optimum gas injection rates for each well, and our approach for allocating a total volume of available gas in a group of wells. Examples are used to illustrate the application of the system.
The protective effects of MSC-EXO against pulmonary arterial hypertension through inhibition of Wnt/BMP signaling pathway
Authors: Zhang Zhaohua , Liu Xiaoli , Ge LiLi , Zhang Shanshan , Wang Jue , Jiang Wen , Xin Qian , luan yun
Published: February 2020

Background The aim of the study was to explore the mechanism of mesenchymal human umbilical cord msenchymal stem cells derived exosomes (MSC-EXO) against experimental pulmonary artery hypertension (PAH) pulmonary vascular remodeling . Methods and results After PAH model was successful established, the animals received tail vein injections of MSC-EXO. Post-operation, the pulmonary artery pressure was measured, and the lung tissues were stained to evaluate the pulmonary vascular remodeling. Our results showed that MSC-EXO could significantly inhibit the pulmonary arterial hypertension, attenuate pulmonary vascular remodeling and lung fibrosis in vivo . Furthermore, the hypoxia-induced pulmonary artery endothelial cell (PAEC) model was used in vitro . Our results showed the expression of CD31, V-Ecadherin, Wnt5a, Wnt11, BMPR2 and Smad1/5/8 were significantly higher, but the expression of alpha smooth muscle actin (a-SMA), β-catenin, cyclin D1 and Smad2/3 were significantly lower in in MSC-EXO administration group then that in MCT or hypoxia group. Moreover, the present study found that BMP signaling suppressed obviously when the cells were transfection with Wnt5a siRNA. Conclusion In conclusion, these results suggested that MSC-EXO could protect PAH vascular remodeling through regulation of Wnt/BMP signaling pathway.
Utility of serial procalcitonin measurement in management of febrile neutropenia in a resource constrained setting.
Authors: Halder Rohan , Seth Tulika , Chaturvedi Pradeep , Mahapatra Manoranjan , Pati Hara Prasad , Tyagi Seema , Saxena Renu
Published: February 2020

Background: Febrile neutropenia is a common cause in morbidity and mortality during treatment of hematological neoplasms.Methods: Subjects included all cases admitted under hematology department with febrile neutropenia from February to June 2018. Diagnostic work up for each febrile episode was done including Procalcitonin (PCT) was sent at fever onset 0,24,48hour, day 7 and day 14.Results: Data was analyzed for 52 febrile episodes in 50 patients.PCT cut off value at 24 hours of ≤1.2ng/ml had a sensitivity and specificity of 62.5% and 87.5% for discriminating IFI and MDI (p=0.033). PCT had a negative predictive value of 70% for the diagnosis of IFI as compared to MDI. PCT cut-off of 0.4ng/ml on day 7 had a sensitivity and specificity of 60.98% and 100% respectively for discriminating IFI and PUO (p= 0.0001). There was a significant fall in the level of PCT by day 14(median fall in PCT of 10.8) in the group of patients who had both IFI+ MDI when compared to other groups (p=0.047). PCT level at 24 and 48hours can be a predictor of severity of infection.Conclusion: Procalcitonin at 24 hours could discriminate between bacterial and fungal infection and between fever due to fungal infection and disease fever.