bluuebunny/crossref_metadata_2025_split huggingface dataset:
Overcoming the Operational Challenges of +13,000-ft Well Laterals With 2.375-in Coiled Tubing
Authors: Galvan Irma Irais , Mallanao Genesis , McClelland Garry , Perez Jessica , Skufca Jason , Suarez Mary 
Published: March 2020

Abstract
The latest growth of North American unconventional shale plays is supported by the shift towards improved well designs: extended well laterals, high-intensity proppant loadings, and adoption of slick water fluids for fracturing. To optimize well productivity and economics, producers continue to push the well lateral boundaries from 10,000-ft to over 15,000-ft, creating super lateral wells, which pose significant challenges and pushed the boundaries of extended reach Coiled Tubing (CT) operations. This document outlines field operational details, string design and downhole tool considerations that had a major effect on the success of extended reach CT interventions in super laterals with 2.375-in CT diameters.
Currently, several U.S. operators have succeeded with 7,500-ft to 10,000-ft range laterals using CT in post-fracture plug mill-out and clean-out operations. These well designs and successive service operations require larger CT diameters and higher pumping pressures to effectively complete job objectives. Generally, 2.375-in CT diameters of over +23,000-ft in length, that feature a robust wall design and materials are being used to withstand the combined pressure loadings and access target depths, –while minimizing bend cycle fatigue accumulation and deformation during operations. Operational plans comparing CT forces, lock-up behavior and hydraulics analysis, along with friction matching of post-job data evaluations, were used to compare the CT performance in the newest well lateral records. Other operational factors, such as equipment availability, logistical issues, and field deployment, are also considered in the analysis of using CT in these complex wells.
Field results demonstrated that CT well interventions in over 14,500-ft laterals are feasible by using highly engineered 2.375-in CT, friction reduction tools accompanied by fluids chemical additives, and tailored operating techniques that improve efficiencies. The application of high strength quench and tempered material with specific wall configurations that feature the use of the thickest gauge used in a working CT string, and the newest taper technology that transitions through four nominal wall thicknesses within couple hundred feet, –have been found to maximize lateral reach capabilities and service life in extended reach operations. The inclusion of the latest technologies on extended reach tools and fluid additives is a must to maximize friction reduction and wellbore cleaning at rates of over 4 BPM and working pressures of over 7,000 psi.
These industry records demonstrate that the potential for longer laterals is far from being exhausted. Technological innovations on surface equipment, downhole tools, CT materials and highly engineered strings configurations, along with refined operational practices and logistics, are required to perform safe extended lateral completions on a larger scale.
Best Practices on Live Well Coiled Tubing Interventions in High Temperature Geothermal Field
Authors: Singh Ishaan , Wijoseno Danny Aryo , Wolf Kellen , Sorman Ignatius , Dutta Shaktim 
Published: March 2020

Abstract
This paper shares the best practices for performing coiled tubing (CT) operations in high-temperature geothermal wells with major challenges such as live well challenges, scaling of pumping fluid, high surface temperatures causing damage to wellhead stack, and CT tag issues. Some geothermal wells have very high bottomhole temperature (BHT) of 550 to 600 °F and surface temperature of 350 to 400 °F, which possess many service quality and health, safety, and the environment risks.
With limited CT geothermal interventions as compared to conventional operations, performing live well CT interventions can be highly risky. Because commonly available pressure control equipment (PCE) seal material is rated to 250°F, the biggest risk is damage to the surface CT equipment, which may result in a well control situation. Generally, the lead time is high, and it is expensive to use temperature seal material rated more than 250°F. A generalized design methodology was developed to check the CT job feasibility in a high-temperature geothermal well. To gain further understanding on the same, three cooling loop designs are compared in this study. Then, the best solution was simulated, implemented, and verified on some wells of "X" field. This design proved to be effective operationally and has reduced the risks for steam inflow into the PCE.
For the case of scaling caused by pumping fluids at high temperatures, this was identified while performing CT operations in geothermal wells of X field. The scale deposited on the CT along with pumping fluid was sent for laboratory hardness and solubility analysis. The results were compared, and lessons learnt to prevent any scaling are discussed. Most of the geothermal wells are completed with a large-diameter completion (7-in., 9.625-in., and higher), which has a bigger flow area to accommodate high steam inflow. Using even a 2.875-in. CT in these wells presents issues of CT tagging at the completion-liner interface, lower annular velocities, and lifting capacity, among others. The best practices were developed on the job to identify the most efficient bottomhole assembly (BHA) design, reducing the probability of CT getting tagged at these depths.
Evolution and Improvement of Coiled Tubing Interventions Across an Unconventional Project in Saudi Arabia
Authors: Danish Syed Muhammad , Ambrosi Giuseppe , Vega Roberto 
Published: March 2020

Abstract
The procedural development implemented across an unconventional project in Middle East is explored, delving deeper into coiled-tubing (CT) design, from metallurgical properties and string specification to bottomhole assembly (BHA) and fluid selection, tailored to plug-and-perf operations involving the use of a specialized frac plug. Further discussed is the "learning curve" generated, highlighting improvements achieved across the "iron triangle" of operating time, cost, and quality, referring to case studies of interventions conducted across multiple horizontal wells.
Unconventional CT interventions have always been challenged by an operator's quest to drill the longest possible lateral to maximize per-well estimated ultimate recovery (EUR) by maximizing the number of fractured clusters/stages. CT job designs across these projects usually rely on running the biggest outer diameter (OD) CT with the largest hydraulic downhole motors available to enable the deepest reach, highest weight on bit (WOB), torque, and circulation rate. However, this conservative approach causes operations to be overdesigned, ultimately resulting in excessive operational cost and nonproductive time. As observed from this experience, an engineered process enables an operator to select the correct resources to meet the operational objectives.
A successful multiwell campaign of prefrac-drift, wellbore fluid displacement, cement sheath cleanout, followed by tubing-conveyed perforation (TCP) and post-frac 32–44 plug millout was performed across high-pressure/high-temperature (HP/HT), sour, unconventional wells in Middle East. After respective CT interventions, the wells were successfully fractured and flowed back. Based on lessons learned and various corrective action items implemented, service efficiency (single run) and job time (+50% reduction) were substantially improved. This enhancement was mainly attributed to the revised surface piping and instrumentation (P&I) rigup, CT material and dimension selection, BHA components, including custom-built mill/motor and extended-reach vibrating tool, gel and friction reducer fluid placement, reduced wiper trip frequency, etc.
These optimized CT interventions created a more balanced approach to unconventional operations, wherein bigger is not always better. The CT procedure evolved, initially referencing best practices from analogue unconventional plays, while slowly progressing into a tailored fit-for-purpose operation. This approach enabled the operator to achieve operational objectives more efficiently.
Deploying Coiled Tubing Using the Low Head Method of Well Control
Authors: Talbot Ben 
Published: March 2020

Abstract
The Nelson N-20 production restoration project was created to restore &gt;1,500bopd after the well was shut in in May 2018 due to excessive sand production from a failed open hole standalone sand screen completion. The aim was to perforate ~490ft of the horizontal reservoir section and install a 1900ft screen assembly inside the completion. To deploy the guns and screens a live well deployment system was considered however ruled out due to the high project costs. As the well is sub-hydrostatic, the low head method of well control was utilized, managing a column of fluid subsurface, rather than at surface. This enabled the guns and screens to be deployed safely and cost effectively. As this was the first time Shell UK would carry out this operation without a functioning drilling package, a sharp focus was put on the planning stage to ensure success. Technical assurance on the well control aspects of the operation from across the wider Shell company and across the industry gave the team confidence to proceed. The operation was executed in June 2019, unfortunately encountering a liner damage in the reservoir section during the well clean up stage and resultantly were only able to perforate 138ft and deploy a 1,571ft screen assembly. However, the operation was completed safely, with technical success and proves that the low head method can be used for intervention activities of this sort and can simplify and take cost out of complex operations.
Optimized Milling and Intervention Operations in Low Pressure Wells by Combining Real-Time Downhole Telemetry and Diverting Agents
Authors: Watson Brad , Layton Ben , Matiasz Kevin 
Published: March 2020

Abstract
During an underbalanced milling campaign in an area of the Montney formation in the Western Canadian Sedimentary Basin (WCSB) in 2017 to early 2018, a well servicing company experienced a series of three coiled tubing complete immobilization incidents. An initiative was created between the well servicing company and the well operator to address the growing challenges associated with underbalanced milling.
The approach was a yearlong process of introducing real time downhole telemetry and fluid loss agents to milling operations. Downhole telemetry was utilized to better understand motor performance, decrease motor damage and identify the key factors in lost circulation events. Far field diverting agents were then pumped through the cleanout or milling bottomhole assembly (BHA) to optimize fluid returns and reduce the required nitrogen volumes.
After tracking results, best practices were put in place to ensure a repeatable operation. Not only were immobilization events eliminated, but achievable depth, well complexity and operational efficiencies were all pushed further than predicted. By utilizing data from the downhole telemetry tools, fluid inflow in specific zones was identified as the reason for lost circulation. Best practices were then put in place to identify and rectify fluid inflow in less time than previous practices. Overall time savings were realized by the operator along with repeatable results that reduced financial risk.
This paper outlines the technical details that contributed to a new and unique approach to underbalanced coiled tubing interventions that has exceeded the limits previously considered possible in challenging well conditions.
Diagnose and Remediate Leak on Constrained Operating Conditions Brings Back to Production Important Gas Well in Egypt Delta Region
Authors: Vazquez Maria Leticia , Marie Mostafa , Salama Ehab , AbdelRahman Ahmed , Vago Bronislav , Ziada Khaled , Sharab Mahmoud , Sabanegh Nader , Ikhsanov Meirbek 
Published: March 2020

Abstract
Suez Oil Company in Egypt encountered well integrity issues due to a suspected leak in a 3 ½-in completion, in a gas well in Desouq, Nile Delta Region. This led to well closure and consequent loss of production. (figure 1) The memory multi-finger caliper was showing pitting but was not conclusive on identifying the leak point. Suez Oil Company required a rig-less solution to diagnose and pinpoint the leak and repair the well, so production could resume. (figure 2) However, conducting well intervention techniques on conventional slickline could not provide precise depth placement, much less real-time control and monitoring capabilities to confirm operations. Production logging services were deployed on E-line to detect the leak point in the tubing in real time by the variation of the quartz gauge's pressure and temperature measurements and spinner rotation associated with the flow. Once the Leak point was properly identified, Straddle system was deployed to remediate the leak, utilizing digital slickline, and the well was placed back into production.
Testing Electromagnetic Multi-Pipe Thickness Tools in Azimuthally Constrained Defects for Deepwater Applications
Authors: Pettitt-Schieber Lucy , Graham Tom 
Published: March 2020

Abstract
Tubular corrosion in high water-cut wells has long been an industry concern, typically accounted for during the initial completion design phase. Direct evaluation of metal loss in production tubing is an established practice, with a range of tools on the market to deliver accurate azimuthal measurements. Some of these same techniques can be employed to evaluate casing through tubing but have reduced resolution and are currently omnidirectional in their measurement. A yard test was performed with several electromagnetic wireline tools to understand the lower detection limits of the tools and their overall accuracy when logged through tubulars containing multiple azimuthally constrained engineered defects.
For the purposes of testing, it was supposed that spatial corrosion in tubulars can occur either homogenously or localized. Detecting pitting through pipe has historically been more difficult due to tool resolution. A tubular could theoretically contain severe localized corrosion, but the electromagnetic tools could measure little to no corrosion since bulk metal volume loss is low. Defects were machined into several joints of casing; some in the form of general defects (pipe OD reduction) and others in the form of localized defects (drilled features on pipe OD). Chrome tubing (25%) was inserted into the machined string of casing, with control (non-defect) casing on either end. Four logging tools were selected to participate in the test.
All four tools identified all machined defects in the casing. Generally, the quantitative analysis of the metal loss was conservative – the measured wall thickness was less than the actual machined defect wall thickness. Metal loss measurements were generally more accurate in measuring the general defects metal loss than the localized defects. Defects with less metal loss were generally better resolved than those with larger metal losses. The test ultimately illustrated that azimuthally constrained defects (not 360-deg circumferential defects) can still be identified with all four tools, even with only 5% bulk metal loss (over a 5-foot interval), but the tools were not always accurate in their measurements of absolute metal loss.
Overall, this controlled test reaffirmed that electromagnetic measurements are more appropriate for use as metal loss identification tools than wall thickness measurements to be relied upon quantitatively when dealing with real world scenarios. The size and shape of the potential corrosion or pipe defect was shown to be significant; different defect types can lead to the same interpreted wall loss.
Methodology for Breaking Up Nanoparticle-Stabilized Oil/Water Emulsion
Authors: Nunez Cristian , Dabirian Ramin , Gavrielatos Ilias , Mohan Ram , Shoham Ovadia 
Published: March 2020

Summary
A state-of-the-art portable dispersion characterization rig (P-DCR) is applied to study emulsions with Exxsol™ mineral oil (ExxonMobil Chemical Company, Houston, Texas, USA), commercial distilled water, and hydrophobic silica nanoparticles (NPs) as emulsifiers. The emulsion is prepared in the P-DCR batch-separator vessel, whereby the separation kinetics are observed and recorded. In this study, emulsion breakup by the integration of oil extraction/water addition and a stirring process is investigated, which is formed with 25% water cut (WC) and 0.01% w/w hydrophobic NPs (dispersed in the oil phase). The experimental data are divided into three data sets: oil extraction only, oil-extraction/pure-water addition, and oil-extraction/water with hydrophilic NP addition.
For oil extraction only (Data Set 1), the WC of the fluid mixture increases, and for a sufficient volume extraction, phase inversion occurs that results in a complete separation of the oil and water. The minimum final required NP concentration for a fast separation, defined as the minimum concentration of NP required to begin the phase separation of the emulsion, is approximately 0.0045%.
The acquired data for oil-extraction/pure-water-addition (Data Set 2) result in a faster breakup of the emulsion, as compared with oil extraction only. The oil-extraction/pure-water-addition process increases the system WC faster, reaching the phase-inversion point sooner. For the oil-extraction/pure-water-addition, the final lowest WC and NP concentrations are approximately 37% and 0.006% w/w, respectively, for fast separation. Thus, it can be concluded that the NP concentration and the WC are related. Repetitive oil-extraction/pure-water-addition cycles enable determination of the combined effects of the WC and NP on the separation process. A relatively stable emulsion is reached after approximately 2 minutes from the beginning of each cycle, which enables determining whether a quick separation occurs at the current cycle.
Data Set 3 (oil-extraction/water with hydrophilic NP addition) results reveal that dispersing hydrophilic NPs in water does not promote emulsion breakup. On the contrary, the NPs produce a slightly more stable emulsion. The separation process, however, does not differ significantly even for high hydrophilic NP concentrations, emphasizing the dominant role of the hydrophobic particles (dispersed in the base-case emulsion).
Phytoremediation effect of Medicago sativa colonized by Piriformospora indica in the phenanthrene and cadmium co-contaminated soil
Authors: Li Liang , Zhu Pengyue , Wang Xiaoyang , Zhang Zhenhua 
Published: March 2020

Abstract
Background: Coexistence of polycylic aromatic hydrocarbons (PAHs) and heavy metals deleteriously threatens the quality of environmental health . Few reports uncover the mechanism of inoculation plants with Piriformospora indica for remediating PAH- m etal co-contaminated soil by analyzing the chemical speciations of contaminants . This study investigated the influence of inoculation Medicago sativa with P. indica to remediate phenanthrene (kind of PAHs ) , and cadmium (one of heavy metals ) co-contaminated soil by analyzing the plant growth, physiological parameters and chemical speciation in rhizosphere and non-rhizosphere . Results: T he presence of P. indica significantly increased plants tolerance, Chlorophyll a , Chlorophyll b , maximum quantum efficiency of PSII photochemistry and electron transport rate values in phenanthrene an d /or cadmium contaminated soil. P. indica inoculation in M edicago sativa root increased f luorescein diacetate activities in phenanthrene, cadmium and both of that co-contaminated soil, especially in non-rhizosphere . The presence of phenanthrene hindered the inoculated plant from accumulating cadmium to some extent ; Whereas the presence of cadmium did not hinder the degradation of phenanthrene in both rhizosphere and non-rhizosphere after P. indica colonization. Although the poor bioavailability of cadmium in rhizosphere restricted the transportation into stem, P. indica colonization in plant efficiently increased cadmium accumulation in root in cadmium and phenanthrene co-contaminated soil. Conclusions: In conclusion, t he work provides the theoretical basis that Piriformospora indica combined with Medicago sativa contributed to the remediation of PAH-Metal co-contaminated soil.
Neurofeedback for tinnitus: Study protocol for a single-blind randomized controlled trial assessing the specificity of an alpha/delta neurofeedback training protocol in alleviating both the sound perception and the psychological distress, in a cohort of chronic tinnitus sufferers
Authors: Jensen Martin , Hüttenrauch Eva , Schmidt Jennifer , Andersson Gerhard , Chavanon Mira-Lynn , Weise Cornelia 
Published: March 2020

Abstract
Background Tinnitus is a very common condition, which for some can have debilitating psychological consequences. Although some interventions are helpful in learning how to cope better with the tinnitus, at present there is no cure. Neurofeedback is an emerging treatment modality in tinnitus. Previous studies, utilizing an alpha/delta training protocol have shown promise. However, they were characterized by small sample sizes and lack of neurofeedback control conditions. Therefore, the aim of this study is to investigate, if an alpha/delta neurofeedback training protocol, compared to beta/theta neurofeedback or a diary control group, is effective in reducing, not only the tinnitus sound perception, but also the psychological symptoms associated with the condition. Methods The study is designed as a three-armed, single-blinded randomized controlled trial. Participants are randomly assigned to either an established neurofeedback protocol for tinnitus (alpha/delta training), another neurofeedback protocol as active comparator (beta/theta training) or diary control group. In the four-week intervention period, participants in both neurofeedback groups undergo ten sessions, whereas participants in the diary control group complete a diary bi-weekly. The primary outcomes are between group differences in tinnitus sound percept change, as measured with the Tinnitus Magnitude Index (TMI) and changes in tinnitus distress, measured with the Tinnitus Handicap Inventory (THI), four weeks post baseline. Secondary outcome measures include changes in tinnitus distress, sleep quality, depressive symptoms and whether neurofeedback leads to specific power changes in the trained frequency bands. Discussion This is the first double-blind, randomized controlled trial examining the efficacy of an alpha/delta neurofeedback training protocol in reducing the tinnitus sound percept and the distress associated with the condition. Compared to former studies, the present study is designed to assess both the specificity of an alpha/delta neurofeedback training protocol by including an active comparator, beta/theta neurofeedback training, and in addition to control for placebo effects by inclusion of a diary control group. We hope this study contributes not only to our understanding of the neurological underpinnings of tinnitus, but also to the potentiality of neurofeedback as a therapeutic agent.