bluuebunny/crossref_metadata_2025_split huggingface dataset:
Frictional Heating of Casing Due to Drill String Rotation – Finite Element and CFD Simulations
Authors: Assaad Wissam , Tarr Brian , See Kwee Choong 
Published: February 2019

Abstract
A drill string in a wellbore always contacts a casing. However, in a curved section of casing the contact force between the drill string and the casing can be significant. Friction between the casing and a rotating drill string tool joint in contact with the casing generates a heat source at the interface between the two objects. The generated heat energy is a function of rotational speed of the drill string, side force and friction coefficient between the hard-banding layer covering the tool joint and the casing. Heat partition between hard banding layer and casing depends on the thermal properties of both. When there is no mud circulation, e.g. due to a pack-off in the annulus or lost circulation, and the contact region stays in the same section, the resulting temperature increase can lead to degradation of the mechanical strength of both the drill string tool joint and the casing. In addition, the casing strength reduction can facilitate casing wear, which may lead to leak and tool joint heating can lead to heat checking cracks or mechanical strength weakening which may result in a parted drill string due to brittle or ductile fracture.
When there is no mud circulation, rotation of the drill string leads to mud angular rotation inside and outside the drill string. Convection heat transfer occurs due to mud rotation and convection heat transfer coefficient depends on mud flow regime. CFD simulations were performed to compute the convection heat transfer coefficient. Two and three-dimensional steady state and transient finite element simulations were performed to compute the temperature distribution in the casing and the drill string tool joint when there is no mud circulation.
Results show that, when there is no mud circulation, conduction through the drill string and casing has the highest impact on the maximum temperature generated due to frictional heating. Two graphs are plotted, one shows the steady state temperature versus side load at different rotational speeds while the other shows casing yield and ultimate stresses degradation versus increase in temperature. Both graphs can be used by drilling engineers at the well design phase to select the appropriate rotational speed of drill string to avoid failure when there is no mud circulation.
Novelty of this paper is in thermal analysis of a tool joint hard banding layer rubbing against casing. In the analysis the convection heat transfer through mud rotation is involved.
Managing Shallow Water Flow During Tophole Drilling Operations in the Southern North Sea – A Case Study
Authors: Solarin Adebowale 
Published: February 2019

Abstract
With a shallow water flow-back in excess of 200 bbl/hr from the Top Chalk formation during the 17½" section, the deviated exploration / development well "Well #4" was planned and drilled successfully with a jackup rig. The well was planned from a platform in the Southern North Sea.
The primary goal for the 17½" section was to safely drill to section TD, set casing and cement same with zero incident in a minimum amount of time while encountering shallow water flow.
The key challenges for this well were: Flowing Top Chalk Formation: The Top chalk formation flowed at all three previously drilled offset wells with 12.0 ppg EMW and approximately 200 bbl/hr. Several attempts to shut in the well and stop the flowing Top Chalk on the offset well "Well #1" failed.Obtaining regulatory approval from authorities, and commitment and acceptance by all involved parties to drill the well under flowing conditions.Hole cleaning and hole stability considerations when drilling with seawaterPermanently shutting off the shallow water flow with a two-stage cementation.Rig uncertainty and general service market (in 2017): A new drilling contractor and drilling services not familiar with the peculiarities of operations in this areaSafety, communication and human factor considerations for a potentially hazardous non-routine operation.
A collaborative well-planning and preparation process involving the operator drilling team, the drilling contractor and key service providers was critical to the success of the overall operation.
The team worked together to ensure all requirements, risk mitigating measures, lessons learned from previous operations and offset wells, and human factor considerations were incorporated in the execution program.
The well was successfully drilled to TD, evaluated, completed and flowed. The notable highlights from the top-hole drilling operation include: Fastest 17-1/2" phase compared to offset wells: drilling and casing operations completed in 94.25 hrs with the well flowing.Zero NPT in the 17-1/2" drilling phase: drilled 654 m in 37.5 hrs with an average ROP of 17.5 m/hr without any complications.Continuous monitoring and fingerprinting of the shallow water flow
This paper describes the key planning considerations, preparations and creative solutions deployed to deliver the well. The lessons learnt will serve as a resource for planning future wells with similar challenges.
Well Safety and Performance Gains from MPD in Unconventional High Overpressure Reservoirs in Argentina
Authors: Lage Antonio Carlos Vieira Martins , Arduino Edgard Gurgel do Amaral , Loureiro Sebastião de Andrade , Vanni Guilherme Siqueira , Filho Hercilio Pereira da Silva 
Published: February 2019

Abstract
The present paper describes performance improvements and well safety achieved with the use of Managed Pressure Drilling (MPD) in the exploratory block of Parva Negra Este, in Neuquén Basin. Petrobras Argentina S.A (PESA), with the technical support from the Petrobras’ headquarters, in Brazil, drilled two exploratory wells applying MPD and targeting Vaca Muerta shale oil & gas play.
High-pressure zones characterized the drilling scenario, reaching, usually, pore pressures higher than 18 lbm/gal in unconventional reservoirs, composed of tight sand and shale. The use of MPD in both well constructions was quite efficient, including well control and plug and abandonment (P&A) operational applications. Those operations proved that MPD can effectively replace the Under-Balanced Drilling (UBD) system, which is standard practice in that area.
In the first well, PESA reported significant gains in drilling performance when compared to other wells previously drilled. Drilling with MPD did not record non-productive time (NPT), differing substantially from the previous wells constructed in the surroundings of Parva Negra Este with an average NPT of 20 days. A considerably larger recovery of coring samples was achieved, being also possible to eliminate one well section, by drilling two zones of interest in a singlesection. Additionally, lessons learned were implemented, resulting on higher rate of penetration (ROP) with the support of MPD.
In the second well, a high overpressurized pore zone was reached, leading to a very complex well control event followed by a permanent P&A operation. The formation pore pressure was much higher than the expected for the area. Instead of using an 18 lbm/gal drilling fluid, it was necessary to weight the fluid up to 21.3 lbm/gal, adding hematite as weighting material. In that scenario, the use of MPD made the operations of circulation and well cementing safer than with the conventional drilling approach utilized in that vicinity.
The application of Dynamic Formation Integrity Tests (DFIT) and Dynamic Pore Pressure Tests (DPPT) ensured a more precise operational window, helping to formulate risk matrices for safely pulling the drilling string out of the hole. In addition, the precise definition of the operational window was a valuable information to plan the best approach for P&A. Besides performing those tests, the MPD system was very useful to evaluate operational parameters and verify how effective was the settlement of the abandonment cement plugs.
In summary, MPD supported safer drilling and P&A jobs, better drilling performance and greater information achievement through more efficient well logging and sample coring.
A Laboratory Study of the Effect of Casing Pipe Roughness to Cement Plug Integrity
Authors: Corina Anisa Noor , Opedal Nils van , Vrålstad Torbjørn , Sangesland Sigbjørn 
Published: February 2019

Abstract
Cement holds the most critical role for providing long-term zonal isolation for permanent abandonment phase. The loss of cement integrity is undesirable as it may threaten the surrounding environment and safety on the surface. The quality of cured cement is commonly associated with the properties of cement material and cement placement in the wellbore. However, there are still limited investigations that link these factors specifically to the sealing ability of cement plug, especially with the lack of proper equipment in the past.
In the present work, a small-scale laboratory setup has been constructed to test the sealing performance of a cement plug. The cement plug is contained inside a test cell, connected to a pressurizing system and placed inside a heating cabinet. Consequently, the test can be simulated at downhole conditions in a controlled manner. By using this setup, it is possible to monitor the minimum pressure required for the plug to fail and the gas leak rate.
Two different cement systems, neat- and silica-cement, were prepared as plugging materials. Both cement systems are placed inside pipes with three different levels of surface roughness and then tested. Results show that the inner surface roughness of the pipes affects cement plug sealing significantly, and the effect is independent of the type of cement systems. Plugs placed inside a very-rough pipe significantly reduce the gas leak rate. Our results also show that an immediate gas leak occurs in all samples from leak paths formed at the cement/steel interface.
A Novel Microbially Induced Self-Healing Cement/Concrete for Underwater Concrete Offshore Structures
Authors: Noshi C. I. , Schubert J. J. 
Published: February 2019

Abstract
Techniques for offshore structure concrete remediation have received minimal consideration in the oil and gas industry in spite of its potential. Emerging "bio-concrete" to plug micro-cracks have shown concrete results in various lab experimentations. Recently, MICP technology has garnered world-wide attention and popularity for various multi-disciplinary applications where smart synthesis of calcium carbonate minerals generate at ambient conditions contributing to bio-cemented self-healing agents by mixing bacteria into the cement slurry. Concrete fails to self-heal and repair cracks greater than 0.2 micron.
The technique comprises of mixing the preparatory material with operative quantities of urease producing spores and a calcium ions under standard conditions of hydrolyzed urea. Scientists found that microbes extensively multiply when nutrients comprising of cheap carbon sources like molasses/glycerol is added to the mixture. Live microbes propagate via cracks channels and micro-voids and smartly cement the cracks by calcifying the matrix structure.
Bacteria can then act as a autogenous self- healing agent. The precipitating bacterial strains generate urease enzyme which metabolically precipitate calcium minerals in the neighboring environment as calcium carbonate. The degradation of urea via bacterial metabolism locally rises the surrounding pH allowing the carbonate microbial calcification. These precipitates can autogenously plug the cracks and improve concrete robustness. The calcifying bacteria can be secluded from cement matrix or various natural sources. The purified spores can cultivate for limited time periods and then supplemented to the concrete matrix for application. The spores remained viable after prolonged periods. After short curing times, the healing capability of micro-cracks, durability, and tensile strength showed significant improvement.
This novel approach of crack plugging is highlighted to save substantial costs associated with crack restoration and repair of underwater concrete offshore structures and platforms.
Advanced Real-Time Monitoring Provides Early Detection and Prevention of Costly Well Problems
Authors: Mayani Maryam Gholami , Rommetveit Rolv , Helgeland Stig , Oedegaard Sven Inge , Kjørstad Kristian Olaf 
Published: February 2019

Abstract
The objective of this paper is to demonstrate how advancedrealtime monitoring (ARM) utilizing advanced hydraulic and mechanical modelling of the drilling process provided early detection of anomalies by giving diagnostic messages during drilling operations. These achievements can minimize non-productive time and invisible lost time and maximize the benefits and value of operations; if they are utilized to its full potential by operations. Some well cases are used to illustrate the methodology and its results. Among problems diagnosed are losses, stuck pipe during drilling and casing running, downhole equipment leakage and improper hole cleaning. In some cases, action was taken based on the diagnostics; and the operational conditions were modified to mitigate the situation. In other cases, the warnings were not taken seriously, the situation worsened until the problem was irreversible and a stuck situation occurred. In one well presented in the current study a stuck pipe situation happened during drilling 8½" section which led to a downtime of more than 20 days. By utilizing the ARM, it couldhave been possible to detect some early signs of the stuck conditions in the wellbore and avoid it. Another stuck situation in awell during 14-inch Casing running, led to downtime of more than 10 days which involved breaking out the casing above the stuck point and performing P&A. The ARM provided early signs of stuck casing that was about to occur, and these signs first started appearing about 15 hours before the pipe got completely stuck. This paper will present the Advanced realtime Monitoring ARM System and the modelling behind this. Also, the plans for further implementation and integration of this in the work processes will be discussed, before results from the first year of utilization will be presented with examples.
An Analytical Model for Double-Shouldered Connection Strengths
Authors: Pettit Grant 
Published: February 2019

Abstract
The drilling industry has become enamored with the extra torsional capacity and clearance that are available when double-shouldered connections are used in the place of the single-shouldered connections that are in the public domain. These proprietary connections allow us to drill farther, faster, and with less damage to our drill string.
To this point, however, no analytical model has been introduced that can accurately calculate the tensile and torsional capacities of these useful connections. Typically, the connection designer and/or manufacturer creates an empirical formula that is calibrated through laboratory and field testing. This approach is perfectly acceptable, but it hinders those tool designers that need something different from what is offered on the public market. It is rarely cost-efficient to perform laboratory and field testing for a one-off connection design.
Single-shouldered connections, such as API drill stem connections, have a straightforward analytical equation that can be used to determine the capacities of any connection. This equation may not be perfect—it relies on linear assumptions that are probably not descriptive of the connection loading—but several decades of use have allowed the industry to be confident in its strengths and aware of its shortcomings.
Thus, what is needed is to simply extend the approach of the original single-shouldered equation to account for a second shoulder. Though the mathematical complexity increases a bit, the assumptions are the same, lending the same confidence to the extended equation that the industry has for the original.
This paper presents the derivation of just such an equation. The implicit assumptions present in the original equations are discussed, and then the same ideas are applied to a double-shouldered connection. The full set of new equations are developed and described, including tips on their practical use gained from tool-design experience.
Advanced Drilling Simulators for Well Control Training: Bringing Together People, Procedures and New Technology
Authors: Howell Robert , McKenzie Brian , Leslie Craig , Poletzky Isabel 
Published: February 2019

Abstract
As more complex and challenging wells are being drilled along with the use of new technologies, well control remains a critical operation that requires personnel not only with the right skills set but also to be able to communicate and manage the operation during these stressful situations.
This paper will focus on describing the steps taken before, during and after drilling crews have participated in the well control training; it will also highlight the integration of people skills in the schedule and what results, advantages have been observed/obtained by operators and drilling contractors.
The use of advanced drilling simulators provides a new environment where drilling crews can not only be trained in how to react and implement the well control procedures, but also allows the implementation of new technologies such as Managed Pressure Drilling (MPD) in highly sensitive environments such as deep water; it provides a safe environment where the drilling team/crew can evaluate these new technologies, and it also facilitates the familiarization with the tools, operational procedures, and communication protocols.
While the Drill the Well on Paper exercises provide an opportunity to get the drilling team together and get more familiar with the drilling plan, high end drilling simulators offer a more realistic platform to illustrate the main challenges that crews could face when drilling wells, providing a hands-on learning environment where skills and procedures can be assessed for normal operations as well as during well control scenarios.
Effect of Polypropylene Fiber Reinforcement in Cement Sheaths Exposed to Cyclic Fatigue Loading at Wellbore Conditions
Authors: Giesler Steven , Schubert Jerome 
Published: February 2019

Abstract
Cement slurry is pumped downhole to create cement sheaths that induce zonal isolation and maintain well integrity throughout the well’s lifetime. This task is difficult to achieve due to adverse wellbore conditions and rig operations. In particular, hydraulic fracturing stimulation generates cyclic stresses detrimental to the cement sheath. The primary research objective was to conduct cyclic fatigue tests on cement sheaths reinforced with polypropylene fibers, then compare results with cement sheaths that were not fiber reinforced. The secondary research objective was to observe crack initiation and propagation in computed tomography (CT) scans of the cement sheath before, during, and after cyclic fatigue testing.
An experiment was built to mimic wellbore conditions during hydraulic fracturing. Cement sheath samples were cured at wellbore conditions of 6,000 psi and 250°F, then exposed to pressure and temperature cycles to evaluate fatigue performance. Internal casing pressure was applied to a restraining cement sheath, then cycled from the wellbore confining pressure to a positive pressure differential and back to the confining pressure. Intermittent temperature cycles were also applied from wellbore temperature to room temperature. Samples endured the applied stresses initially, but failed after reaching their respective fatigue limits due to cyclic fatigue.
Two baseline slurries without fibers were tested: one contained Class H cement plus 35% silica flour by weight of cement (bwoc) while the other contained Class H cement plus 35% silica flour bwoc plus 8% bentonite bwoc. Polypropylene fibers were added at a concentration of 0.75% by volume of batch (bvob) with the intention to improve performance of the baseline slurries. Results showed that fiber reinforcement increased the fatigue life of cement sheaths tested with 0 psi confining pressure, however it lowered the fatigue life of cement sheaths at 6,000 psi confining pressure. Three types of failure were observed including radial cracks, disk cracks, and cement-casing debonding. Cross-sectional CT scans displayed mature radial and disk cracks, but not the gaps formed from debonding. In conclusion, further testing is needed to assess fiber reinforcement’s ability to improve cement sheath durability in oil and gas wells.
Targeted Interventions to Prevent Chronic Low Back Pain in High Risk Patients: Development and Delivery of a Pragmatic Training Course of Psychologically Informed Physical Therapy for the TARGET Trial
Authors: Beneciuk Jason , George Steven Z. , Greco Carol , Schneider Michael , Wegener Stephen T. , Saper Robert , Delitto Anthony 
Published: February 2019

Abstract
Background

Low back pain (LBP) is a public health concern because it is highly prevalent and the leading cause of disability worldwide. Psychologically Informed Physical Therapy (PIPT) is secondary prevention approach that first aims to identify individuals at high risk for transitioning to chronicity and then provides tailored treatment to reduce that risk. Training models that are feasible to implement with acceptable training quality are needed to improve scalability for widespread implementation of PIPT. This manuscript describes the PIPT training program that was developed for training physical therapists providing PIPT in the TARGET Trial.

Methods

The PIPT training program was developed, tested, and modified using an iterative process. Content development consisted of stakeholder engagement, beta testing, modification of training and confirmation of final course objectives. Methods of delivery consisted of a website that included brief educational modules followed by a live 8 hour workshop that included video based mock case scenarios and case-based role playing. Attitudes, beliefs and confidence in implementing PIPT principles were assessed before and immediately after training to measure training quality and impact.

Results

Early stakeholder engagement and beta testing indicated the need for increased emphasis on experiential learning opportunities and patient-centered communication training. Booster training varied extensively across TARGET sites with involvement of ‘clinician champions’ brief follow-up sessions identified as best practice. Favorable post training changes in physical therapist attitudes and beliefs toward biopsychosocial treatment orientation and increased confidence in implementing PIPT principles were observed.

Conclusions

PIPT training for provider participation in the TARGET Trial was feasible to deliver. Course content was acceptable to physical therapists and resulted in improved beliefs and confidence in applying PIPT skills during clinical practice. Ongoing consultation and site-based continuing education were methods by which specific TARGET sites maintained or augmented PIPT skill training, however implementing ongoing training was challenging in general. Consistent with a pragmatic trial whether this training directly impacted treatment fidelity was not measured, which was a limitation to our training approach.

Trial registration

ClinicalTrials.gov Identifier: NCT02647658