bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding Lost Circulation While Cementing: Field Study and Laboratory Research
Authors: Therond E. , Taoutaou S. , James S. G. , Way P. W. , Gomes P. , Dondale A. 
Published: March 2017

Abstract
Lost circulation is a time consuming and expensive challenge, costing the oil and gas industry billions of dollars each year in materials and non-productive time. To mitigate lost circulation during cementing operations, a better understanding of how wellbore strengthening mechanisms apply to cement slurries is necessary. The ability to control cementing fluid properties to strengthen the wellbore and minimize losses during cementing operations is imperative for achieving adequate zonal isolation.
A comprehensive field analysis was performed to understand lost circulation initiation during different phases of drilling and primary cementing. Offshore wells from four different locations were studied: Gulf of Mexico, United Kingdom, Angola and Azerbaijan. In parallel, laboratory research was performed to understand the behavior of cement slurries in controlled lost circulation scenarios using a block tester. Measurement of formation breakdown pressure and formation propagation pressure were made with different cement slurry compositions and compared with pressures obtained with drilling muds.
In an analysis of 40 well sections that reported losses prior to, or during, primary cementing operations, the rate and severity of lost circulation varied for the wells studied, but it was concluded that losses were commonly induced while running casing or pre-cement job mud circulation, but rarely during cement placement.
The laboratory research confirmed the field observation: It would take much more pressure to open or re-open an existing fracture with cement slurry than with a synthetic oil-based mud.
This paper will present findings from the field analysis and laboratory research. It will also discuss strategies to prepare the wellbore for preventing losses before the cementing operation and to optimize cement formulations in case losses have been induced during drilling, casing running or pre-job mud circulation.
True Self-Healing Geopolymer Cements for Improved Zonal Isolation and Well Abandonment
Authors: Liu Xiangyu , Ramos Matthew J. , Nair Sriramya D. , Lee Hanna , Espinoza D. Nicolas , van Oort Eric 
Published: March 2017

Abstract
Targeting the incompatibility issue between traditional Portland cements and non-aqueous drilling muds, a mud solidification technique based on geopolymer cements was recently introduced to the industry. This technique was achieved by incorporating non-aqueous fluids (NAF) such as synthetic-based or oil-based drilling mud in a geopolymer cement that is formed by blending an aluminosilicate powder with an alkaline activating solution. In a previously completed study, the consolidated mud, or "geopolymer hybrid", was evaluated for its compressive strength, thickening time and stability for applications including primary cementing as well as lost circulation control. In an effort to further develop the geopolymer hybrid system as a new generation well cementing material, the present work comprehensively studies their mechanical properties, self-healing capabilities and cement-to-pipe bond strength.
One of the concerns currently preventing the use of geopolymers for well cementing is its low early compressive strength. This study shows that although the early age uniaxial compressive strength of geopolymer is lower than that of Portland cement, with an applied confining stress, geopolymers have more than sufficient strength for primary cementing applications.
Furthermore, the abilities of cement to properly bond with steel casing and rock formations, as well as to withstand subsurface stress changes over time are of paramount importance for long-term cement integrity. The triaxial tests performed in this study show that geopolymers are less brittle than Portland cement, and can therefore accommodate stress changes without localized failure. The geopolymer bond strength measurements showed that geopolymer could bond to steel even in presence of non-aqueous drilling muds. In addition, the triaxial tests revealed that geopolymers exhibit true self-healing capabilities, characterized by samples fully regaining their mechanical competence with 28 day post-failure strength exceeding the native 7-day strength. Portland cement, in comparison, retained lower ultimate strength than its 7-day strength. The self-healing capability of geopolymers is ideally suited to adapt to subsurface stress changes, making such materials ideally suited for use as permanent barriers in plug and abandonment operations.
MWD Surveying Enhancement Techniques and Survey Management Workflows Applied at a Barents Sea Field for Accurate Wellbore Positioning
Authors: Monterrosa Leida C. , Rego Marina Ferreira , Blackburn Jason D. 
Published: March 2017

Abstract
This paper aims to provide an understanding of the various measurement-while-drilling (MWD) surveying enhancement techniques applied in drilling operations at the Goliat Field located in the Barents Sea to assure accurate wellbore positioning.
In high-latitude locations such as the Barents Sea, the elevated, time-dependent variations in the magnetic field create a challenge to the azimuthal measurements provided by the MWD tool. This will induce large uncertainty levels in the MWD surveys compromising the azimuthal errors established within the standard industry error models. To compensate for this effect, crustal magnetic field and time-based magnetic field disturbances were acquired to understand their impact on the MWD surveys and any associated error. This permitted drilling without compromising rig time, and the resultant reduction in lateral uncertainty was approximately 65%.
With regards to true vertical depth (TVD) optimization, the nature of the reservoir targets required tight TVD tolerances. To reduce the TVD uncertainty and maximize these targets, dual inclination analysis was performed while drilling. Control checks of the continuous and static inclination data from the MWD and rotary steerable system (RSS) reduced the sensor error term of the TVD error model definition and hence produced an improvement of up to 67%.
Seven wells have been drilled in the Goliat Field based on the methodology described in this article. In the planning phase, it was noticed that extra surveying techniques would be required to achieve the objectives for lateral and TVD placement. Survey management workflows were implemented to ensure consistency with regards to surveying accuracy.
Drilling and environmental challenges encountered in the Barents Sea push the boundaries of every aspect of current surveying techniques. Adherence to survey management procedures and understanding of the impact in the measurements generated by the disturbance in the magnetic field improved efficiency in the drilling operation and helped to achieve the critical well positioning objectives for this field.
The Role of Phosphate Conversion Coatings in Make-Up of Casing Connections
Authors: Ernens D. , Riet E. J. , de Rooij M. B. , Pasaribu H. R. , van Haaften W M. , Schipper D. J. 
Published: March 2017

Abstract
Phosphate conversion coatings are widely used on (premium) casing connections for protection against corrosion. Next to that, in conjunction with the lubricant these coatings provide galling protection. The friction and wear that occurs during make-up and subsequent load cycling determines the sealing performance of the metal-to-metal seal. Therefore, phosphate conversion coatings play an important role in the sealing performance of metal-to-metal seals. An extensive test program was set-up to investigate the role of phosphate coatings during make-up. With pin-on-disc, anvil-on-strip and ring-on-ring tests the interactions between substrate, lubricant and phosphate coating was investigated. A comparison was made between uncoated and coated specimens using base greases, and formulated greases: API modified and two commercially available yellow dopes. The results indicate a strong influence of the phosphate coating leading to damage free make-up, low wear, and less dependence on the lubricant. This is attributed to the formation of a hard and smooth dissimilar surface, the ability to adsorb the lubricant and the generation of a transfer layer on the uncoated counter surface. It is concluded that taking the interaction with phosphates into account could enable lubricants to be tailored for sealing performance and thus can ease the transition to environmentally friendly rated lubricants.
Experimentally Validated First-Principles Multivariate Modeling for Rheological Study and Design of Complex Drilling Nanofluid Systems
Authors: Gerogiorgis Dimitrios I. , Reilly Simon , Vryzas Zisis , Kelessidis Vassilios C. 
Published: March 2017

Abstract
The demand for more efficient and reliable oil and gas drilling fluid systems drives their development with unprecedented sophistication: the key challenge is to achieve predictable rheological properties, but also to enable their judicious customization, particularly for High Temperature High Pressure) (HTHP) applications and tough environments. This study presents the development and validation of a first-principles multivariate rheological model, allowing yield stress and viscosity prediction for new drilling fluids with iron oxide nanoparticles (NP).
Previous studies show that water-bentonite suspensions of variable Fe3O4 NP concentration exhibit non-Newtonian shear-thinning behavior, accurately captured via a tri-parametric nonisothermal Herschel-Bulkley (HB) rheological model form; nonlinear least squares regression yields reliable parameter sets. The resulting fluid shear stress and viscosity are expressed as explicit functions of independent variables (shear rate, temperature, NP concentration) and the correlations are validated against experimental data. A new parameter set must be computed by nonlinear regression for each combination of conditions, a necessity compromising the predictive potential of this data-driven rheological modeling approach.
To obtain truly predictive, first-principles rheological models, a systematic strategy is presented: shear stress and viscosity have now been expressed as physics-based (not data-driven) multivariate correlations of the aforementioned independent variables, using microscopic arguments for colloidal particle behavior, as confirmed by Transmission/Scanning Electron Microscopy (TEM/SEM) images. Shear stress is thus studied by distinguishing key additive contributions, on the basis of explicit bounds on colloidal inter-particle distances: our novel functional forms consistently capture the non-Newtonian fluid behavior, but require only one parameter set computation for the entire dataset.
Real Time Engineering-Based Simulation Training Addresses Risk in Managed Pressure Drilling
Authors: Rommetveit Rolv , Davidson Ian , Svendsen Morten 
Published: March 2017

Abstract
Managed Pressure Drilling (MPD) enables safer operations and reduces non-productive time and thus provides the opportunity to reduce well costs. Many operators however, are not fully embracing the opportunity offered by the technology, due to strict regulatory requirements, and their perception that MPD is complicated and increases risk. A basis for this perception is that operator engineers in their designs, and contractor drilling crews in day-to-day operations, are insufficiently MPD experienced to fully and safely exploit the benefits of the technology.
Today, the advanced, and field proven, engineering (mathematical) models that are part and parcel of the software used in well design are also available in state of the art simulators. These engineering models and model based simulators are used by engineers during the design phase of MPD projects to replicate the conditions that will be encountered during actual well construction; picking optimal casing setting depths, using different equipment set-ups, selecting optimal drilling parameters and demonstrating the integrity of the design under a wide scenario of well conditions.
Once the well design is finalized, and before drilling operations commence, the same well design is programmed into a real-time drilling simulator. During subsequent simulator exercises,, rig personnel are exposed to the range of scenarios that can unfold during actual operations, taking into account uncertainties and unexpected events. Crews, at the hard end of operations, are able to hone their competence to deal with the unexpected in a team environment under the supervision and guidance of experienced coaches.
During actual MPD operations, the same advanced models can be used for automatic simulation and well monitoring purposes; they can also be integrated into the MPD control system to accurately maintain the required well pressures.
This paper describes the models used and both the classroom simulator-based engineering training and the real-time rig floor simulator training that will respectively provide operator engineers and contractor well site staff the in-depth understanding of MPD that will enable them to develop their respective skills to safely and cost effectively exploit the many benefits offered by MPD.
Real-Time Borehole Condition Monitoring using Novel 3D Cuttings Sensing Technology
Authors: Han Runqi , Ashok Pradeepkumar , Pryor Mitchell , Oort Eric van , Scott Paul , Reese Isaac , Hampton Kyle 
Published: March 2017

Abstract
Wellbore instability and stuck pipe incidents are large contributors to drilling-related non-productive time (NPT). Drilling cuttings/cavings monitoring is crucial for early detection and mitigation of such events. Currently, monitoring is done manually and lacks a streamlined approach. Automating this process would be very beneficial, and is possible due to recent advances in sensing technology. Real-time cuttings/cavings monitoring can be used to quantify cuttings volume, measure size distribution, and analyze shape. By correlating these measurements with ongoing drilling operations, the hole condition (in particular hole cleaning/cuttings transport efficiency, wellbore stability situation, etc.) can be automatically assessed in real-time. This makes pro-active prevention and mitigation of NPT related to hole cleaning and wellbore instability possible.
In this paper, we detail a system designed and prototyped to allow us to measure cuttings/cavings in real-time. A highly portable device employs a 2D high-resolution camera and a 3D laser sensor to determine the physical properties of cuttings. The 3D point cloud/depth data obtained by this device provides cuttings size distribution, volume and shape characteristics. Comparisons and discrepancies between expected and sensed quantities can then be used for alarming purposes and taking appropriate corrective action.
A prototype experimental setup was constructed to evaluate the ability to quantify relevant cuttings properties and profiles in the presence of drilling fluids. In a controlled environment, the cuttings slide down a shaker table's clearing chute while simulating various realistic external variable scenarios. The environmental impact on the accuracy, repeatability and robustness of the various sensors under investigation was determined to identify the sensors best suited for the task at hand. The optimum device configuration was then implemented and evaluated to verify that the system is viable for use in the field. The automated cuttings monitoring system can warn drillers to potential hazards associated with poor hole cleaning conditions, ongoing wellbore breakout, and the likelihood of stuck pipe events.
Saving a Hole Section by Using Real-Time Wellbore Stability Analysis
Authors: Odunlami Tosin , Amorocho Claudia 
Published: March 2017

Abstract
A real-time wellbore stability analysis capability was developed to help an operator reduce high costs of nonproductive time (NPT) in an area prone to stuck pipe, lost borehole assemblies (BHAs), and lost hole sections. A multidisciplinary team created integrated processes for predrill, dynamic real-time, and post-drill modeling to help identify wellbore instability and pore pressure events that cause kicks, tight holes, and stuck pipe incidents.
A Predrill wellbore stability model for the proposed well was built based on offset well data. The model enabled the identification of depth intervals and formations where there are potential wellbore stability issues. A multidisciplinary team consisting of geomechanics engineers, pore pressure specialists and drilling optimization engineers provided 24-hour monitoring of drilling parameter trends and analyzed quad-combo logging-while-drilling (LWD) data in real time to determine the health of the wellbore. This enabled calibration of the predrill model in real time, which consequently served as an ahead-of-bit prediction of undrilled sections of the well.
Four wells were drilled in this project. The first two wells had lost hole sections resulting from wellbore stability challenges that caused high NPT costs. The new process was instituted on the third well which resulted in no lost time due to troubled hole sections and subsequently resulting in 30% lower well cost due to reduction in expected NPT. The same results were achieved on the fourth well, which demonstrated repeatability of the new process. The predrill model indicated that a pore pressure ramp was expected and that the operator's planned mudweight and casing program posed potential risks of formation fluid influx and hole breakout with resultant cavings falling into the wellbore. During drilling operations the expected pressure ramp was confirmed by an observed increase in connection gas and cavings across the depth intervals identified in the predrill model. This was communicated to the operator and informed their timely decision to increase the mud weight range for the hole interval and to set the casing shallower than planned to avoid potential hole problems.
This multidisciplinary approach to address well challenges by integrating technology, tailored expert response, and collaboratively managed delivery helps to reduce uncertainty, improve safety, and increase efficiency of planned wells and depth intervals. The new process comprising predrill, dynamic real-time, and post-drill phases identifies drilling hazards for correct mitigation. Lessons learned during the drilling operations are documented and applied to subsequent wells for continued improvement of operational parameters and best practices.
Mitigating Drilling Dysfunctions and Enhancing Performance with Self-Adjusting Bit Technology: Analytical and Experimental Case Studies
Authors: Jain Jayesh R. , Ricks Gregory , Ledgerwood L. W. , Phillips Anthony 
Published: March 2017

Abstract
Mitigating drilling vibrations and pushing the upper limit of performance while drilling long sections in a single bit run remains a challenge for fixed polycrystalline-diamond-compact (PDC) bits. Recently, new self-adjusting depth-of-cut (DOC) control technology was introduced to help overcome these challenges. This paper presents further details of how the technology works in a wide range of drilling conditions and demonstrates performance benefits in research wells.
Building on the conceptual illustration presented in SPE-178815, time domain modeling is performed to study influence of the self-adjusting mechanism on the drilling system response. The results of simulations are corroborated with full-scale testing in the laboratory. Additionally, field testing is conducted in research wells to demonstrate the ability of the technology to reduce drilling vibrations and push the performance envelop. Scenarios such as torsional stick/slip vibrations, weight-on-bit (WOB) transfer issues, improper starting procedures, and heave excitation in offshore wells are considered on conventional rotary as well as motor bottom-hole assemblies.
The technology provides the bit with the ability to continuously adjust its DOC control characteristics to suit the drilling environment: it engages DOC control when encountering vibrations to mitigate them and disengages when drilling smoothly to deliver high rate of penetration (ROP). Significant benefits are observed when drilling with self-adjusting PDC bits in a variety of operating conditions. In addition to mitigation of stick/slip vibrations, reduction in cutter overload is observed when sudden loading is encountered, such as during weight stack-up events or re-starting after connections. When subjected to oscillating WOB, which mimics heave excitation, downhole measurements of vibrations show self-adjusting bits exhibiting reduced levels of torsional vibrations compared to fixed PDC bits. The testing also shows promise in reducing cutter wear and extending bit life.
The paper enhances the understanding of how the novel self-adjusting DOC control technology works in realistic drilling conditions. The simulation and testing results demonstrate applicability of the technology in a variety of drilling dysfunctions experienced in the field.
Innovative Drill Stem Rotary Shoulder Connection Designed for Cost Efficient Operations in the Most Challenging Drilling Environments
Authors: Lafuente Marta , Carrois Fabien 
Published: March 2017

Abstract
For the last century, the oil and gas industry has been pushing the limits of the existing drilling envelope to reach deeper more remote hydrocarbon reservoirs. The evolution of drilling programs has driven drill string manufacturers to engineer new drill pipe solutions able to safely develop the most challenging horizontal and extended reach drilling (ERD) well profiles.
In response to the development of newer drilling challenges, drill stem elements evolved to provide better mechanical and hydraulic performances. Based on industry requirements, drilling products steadily improved its tensile strength-to-weight ratio and its torque ability in order to help operators overcome frictional drag forces and achieve improved hydraulic performances, rates of penetration, control of well trajectories and hole cleaning.
But with the latest economic trends in the oil and gas industry, drilling economics has become an equally, if not more, important factor for operators when choosing their drill string.
Today, when operators plan their projects they seek for technologies that will allow them to drill these further reach wellbores successfully and more economically. Drilling equipment is required, not only to provide the required mechanical performances but also to be reliable and easy to handle on the rig floor.
A new ultra high-torque Rotary Shoulder Connection was designed and extensively tested to verify its ability to improve the operational and economic performances of drilling operations in the most challenging drilling environments.
The new connection's unique and innovative design provides the following advantages: The highest available torque in the market for a double shoulder connector without compromising on other performances such as tensile strength which allows for deeper, further drilling operationsEngineered single start thread design which allows for faster trip timesMake-up to break-out torque ratio between 0.7 and 1.1, which reduces the risk of the string backing out while drillingInnovative thread form that reduces the stress on the critical cross section and enhances fatigue resistanceOptimized taper and thread design that allows for a deeper stabbing and eliminates the need for stabbing guidesThe ability to design tool joints with a reduced OD and an enlarged ID which reduces the pressure and hydraulic horsepower requirements for circulating drilling fluids, viscous pills, and cement.
This paper describes the design of a new Drill Stem Rotary Shoulder Connection Design, the rigorous testing program used to qualify it, and the operational and economic benefits that this new technology brings to the drilling operation.