bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wellhead Fatigue Monitoring During Subsea Well Plug and Abandonment Activities
Authors: McNeill Scot , Agarwal Puneet , Bhalla Kenneth , Ge Michael , Leonard Jay 
Published: April 2017

Wellhead fatigue monitoring was performed during Plug and Abandonment (P&A) activities of a well in the Gulf of Mexico (GOM). Fatigue monitoring was deemed necessary for several reasons: an older vintage of wellhead system with uncertain fatigue life consumption from previous drilling activities, excessive wellhead stick-up, potentially large rig motions from a moored drilling rig for P&A. Fatigue monitoring was performed to ensure the integrity of the wellhead during P&A operations.
The wellhead fatigue monitoring methods previously developed by several of the coauthors was applied in the wave-dominated GOM environment. Motions of the Blow Out Preventer(BOP) stack were measured and combined with a model of the riser/BOP/wellhead/casing system to reconstruct fatigue damage in the wellhead, conductor and surface casing. To measure wellhead motions, Subsea Vibration Data Loggers (SVDLs) were run with the riser and retrieved via Remotely Operated Vehicle (ROV). Fatigue damage reconstruction in the wellhead, conductor and surface casing was performed directly using the measured motion data and an analytical transfer functions obtained from the calibrated Finite Element (FE) model. Results were provided with fast turnaround time to support operations.
Results demonstrated that fatigue damage rates compared well with pre-deployment predictions, though measured fatigue demand was slightly higher. It was also demonstrated that the primary cause of fatigue damage was due to wave activity at the site. Analysis of low frequency response at the riser natural frequencies indicated that the first few riser modes may have been excited by currents. It was also demonstrated that the low frequency response did not contribute significantly to fatigue life.
The wellhead monitoring methods discussed result in rapid turn-around of valuable fatigue life consumption information, enabling informed decisions to be made in challenging conditions. The monitoring instrumentation and fatigue analysis methods increase the safety and efficiency of drilling, workover and P&A activities. In a larger sense, measured data also serves as a benchmark for analytical model calibration activities, reducing the known conservatism in stress and fatigue in future deployments.
Design Verification and Validation Testing of the Stones Jumper Breakaway Joint
Authors: San Pedro Ramón I , Boubenider Rafik , Neelam Mohan K , Walden Nathan L , Epperson David R 
Published: April 2017

Abstract
The design verification analysis and validation testing of an 8 inch jumper and integrated breakaway joint for the Stones subsea development is described. To control the jumper's failure mode in the event of an accidental pipeline displacement, the assembly was designed such that the maximum bending moment occurred at the location of the breakaway joint. The design and analysis investigated a series of U and M shaped jumper configurations and notched failure point geometries to achieve the desired objective.
Linearly-elastic finite element analysis was performed for a series of code check cases to ensure stresses in the jumper and breakaway joint due to normal in-service loads were below allowable values. Nonlinear elastic-plastic finite element analysis was performed to determine the capacity of the jumper and breakaway joint due to pipeline snag loads. The material properties for the nonlinear elastic-plastic analysis were based on tensile tests on specimens taken from prolongations on the actual breakaway joint forgings. The results of the analysis indicate the breakaway joint notch is the weak point in the final jumper configuration, with a moment capacity well below the rated capacity of the manifold connectors. The fatigue analysis concludes the design life of the breakaway joint is greater than that of the jumper assembly welds.
Validation tests were conducted to confirm the design of the jumper and breakaway joint. A pure bending test was performed on the breakaway joint and a full-scale test was performed on a portion of the jumper (quarter jumper). A test fixture for the full size quarter-jumper pull test was modified to ensure enough stroke was available to fail the jumper sample in a single, continuous pull. Strain gauges, a data acquisition system, and video system were used to monitor and record the strains and displacements along the quarter-jumper test sample. Both tests demonstrated excellent agreement (96%) with the predicted analytical results obtained during the jumper assembly design phase.
Introducing Reactive Flex-Joint: 10–15 Times Prolonged Wellhead Life
Authors: Rørgård Ove , Sønåsen Knut Olav , Ellefsen Øystein 
Published: April 2017

Awareness of the challenge with lower available Wellhead fatigue life has increased as the Oil and gas industry has gained more knowledge through advanced analysis and tests. Loads on Wellhead are influenced by movements from drilling rig transferred through Marine Riser and BOP. These loads cause cyclical bending moments and Wellhead fatigue degradation. The intention of Reactive Flex-Joint (RFJ) is to lower the fatigue damage by reducing cyclical bending moment, which is a main contributor for Wellhead fatigue.
It's was built a technology demonstrator (scale 1:25) in 2006 and patent of the system was approved. Later a full-scale workshop test model was constructed including a Flex-Joint (FJ) for simulation of environmental conditions. In addition there were preformed thousands of transient dynamic simulations with irregular sea conditions. An independent company duplicated these analyses and all results are verified by 3rd party. The 3rd party company also approved product qualification and use before offshore deployment. An environmental test through a complete drilling campaign of a new well was preformed spring 2016, verified the technology and efficiency covering a wide variety of environmental conditions. The BOP was instrumented to monitor live bending moments and inclination with and without the RFJ. More than 50 subsea tests proved 55 - 65% reduction of cyclical bending moment meaning 10 - 15 times extension of the remaining Wellhead fatigue life. The conclusion is that a modified FJ can reduce dynamic bending moments transferred from Riser to Wellhead during drilling and Work-Over operations. Reduced fatigue exposure gives increased Well access, improved Well Integrity and significant extended Wellhead fatigue life. The reduction of cyclical bending moments on Wellhead give extension of available days for connection, enabling additional Workover and/or side track drilling resulting in Increased Oil Recovery.
Breakthrough Technology Overcomes Long Standing Challenges and Limitations in Cement Integrity Evaluation at Downhole Conditions
Authors: Kamgang Sebastien , Hanif Amer , Das Rajdeep 
Published: April 2017

Abstract
Typical industry standard for evaluation of cement integrity at downhole conditions is through the use of acoustic measurements. These systems generate compressional acoustic waves which travel through wellbore fluid to impact the casing. Attenuation of these waves is used to derive cement compressive strength or acoustic impedance bonded to the casing.
Some of the long lasting fundamental limitations faced by the current technology are: The wellbore must be filled with liquid for the compressional wave to be able to travel to the casing wall. Heavy muds and solids particles in the mud can cause further complications.The in-situ compressive strength may not fully characterize cement mechanical properties.Micro-annulus condition can be difficult to differentiate from poor bond condition without a separate pressure pass.
A new technology, which uses electro-magnetic acoustic transducers (EMAT), has set a new industry standard for cement evaluation. This new sensor technology is incorporated into an established and highly successful sectored pad-type tool design. This tool design provides multiple measurements azimuthally, making fully compensated measurements, allows good tool centralization in high wellbore deviations, and enables evaluation of multiples casing sizes in a single pass.
The primary mechanical forces responsible for the failure of the cement sheath are shear forces differences between the wellbore and surrounding formation. The new technology measures the horizontal shear wave which responds to the cement in-situ shear modulus coupled to the casing.
EMAT technology is wellbore fluid neutral and as such, eliminates the need of filling wellbore with fluid prior to logging. This presents a very important advantage as the cement condition can now be evaluated in downhole conditions similar to conditions when the well is on production. Additionally, fluid-filled micro-annulus can be better recognized without the need to pressurize the casing.
The wider dynamic range of the new measurement also yields a higher resolution evaluation, provides us with the ability to evaluate cement bond in a wide range of heavy cement slurry density down to ultra-light cements and in contaminated cements, as well as other slurries types such as resins.
This paper will discuss theoretical background, numerical modeling and actual recorded data demonstrating the above breakthrough advancements in cement sheath evaluation at in-situ conditions.
While preserving the advantages of current technology, the EMAT measurement now provides operators with much needed flexibility to analyze, with consistent high resolution, cement bond quality over a wide range of slurry densities. Operators are no longer required to isolate existing opened perforations and load wellbores with fluid in preparation for logging, resulting in significant time and cost savings.
Seamlessly Integrated Subsea All-Electric Systems: Laggan-Tormore as a Case Study
Authors: Pimentel Juliano , Mackenzie Rory , Thibaut Edouard , Garnaud Frederic 
Published: April 2017

TOTAL is strongly committed to the strategy to have, in the coming years, seamlessly integrated all-electric systems as part of the available technologies for future subsea and deepwater developments. It is part of the company's road map to accomplish flexible and configurable systems to meet the assets requirements in terms of functionality, safety and availability, but also that can reduce CAPEX and OPEX.
This paper will evaluate the impact of technology change from electro-hydraulic to all-electric system in the recently started Laggan-Tormore field in the UK shelf.
It will be shown that by proposing new all-electric technologies, currently or shortly available, it is possible to reach functional specifications and potentially reduce CAPEX and OPEX keeping system overall availability.
All-electric systems were investigated for Laggan-Tormore, an already delivered project, originally with electro-hydraulic technology, in order to evaluate the pros and cons of their implementation in future fields. Currently available all-electric building blocks were considered in the analysis, such as DC/FO distribution system, electric Xmas trees (or those driven by electric actuators) and electric downhole safety valve. Additionally, a future subsea compression expansion in the field was also considered and subsea power equipment maturity was assessed, as well as the interface with LV distribution and control systems.
This paper will present a proposed all-electric architecture to meet the project's functional specifications. This architecture will be assessed in terms of system optimization and facilities CAPEX.
New ways to safely design subsea power and communication will be presented, with the introduction of recently qualified technology. The benefits in terms of functionality, system availability, CAPEX and OPEX will be discussed.
Pragmatic Solution to Continued Failures of Critical Subsea Connector Bolts
Authors: Chaudhury Gautam 
Published: April 2017

Abstract
A pragmatic robust solution has been developed to combat recurring failures of tension loaded bolts used in subsea wellhead connectors. This is a paradigm shift in tension loaded bolt design that will be inherently reliable; "Maximum possible preload to Minimum allowable mean stress".
Failures of safety critical bolts are continuing for more than a decade in spite of replacing over 10,000 bolts and following QC recommendations from industry subject matter experts. The work has demonstrated that existing practice of extremely high preload has compounding adverse effects on integrity of high strength bolts leading to premature failures.
The proposed robust solution employs a fracture mechanics based fit for service design procedure using engineering critical assessment, fatigue life verification, selection of robust material, and attainable manufacture and installation Q/A and Q/C that can withstand minor unintended deviations to strict specifications.
Johan Sverdrup. Creating a Unique Environment for Successful Drilling Operations in an Accelerating Spotlight Project
Authors: Øregaard Jákup , Carlsen Jørn Andre , Rafoss Svein Inge , Tønnessen Tor , Jones Barry , Henriksen Knut , Gloppen Trond 
Published: April 2017

Abstract
Johan Sverdrup is one of the five largest oil fields on the Norwegian Continental Shelf (NCS), and will be one of the most prominent industrial projects in Norway during the next 50 years. The field will come on stream at the end of 2019 and create enormous value. The resource estimate is between 1.9-3.0 billion barrels of oil equivalents. Drilling operations started with predrilling of eight producers in March 2016. Due to challenging market conditions it was recognized early in the project planning phase that a step change in efficiency was needed.
This paper presents the aggressive goals that were set, the overall strategy brought to play to reach the ambitious goals and key new innovative work practices. The Eight Wells Drilling Campaign has been recognized as very successful in all aspects, and was completed eight months ahead of schedule. The paper describes how a trilateral partnership, consisting of the Operator, the Drilling Contractor and the Main Provider of Drilling & Well Services, together reached aggressive targets for tangible efficiency gains.
Important success-factors and new work practices are described, which include key elements such as long-term and comprehensive contracts, integrated operations, integrated services and a new incentive system. Equally important is the development and implementation of a shared vision and shared priorities. Furthermore, the paper describes how demands from a challenging customer were operationalized, and created engagement and motivation across companies. The development of a joint operating model clarified roles, responsibilities, expectations, understandings and ensured that the same message was given to all. An aligned leadership cooperation both offshore and onshore was identified as important. Technically well-equipped operation rooms offshore and onshore allowing real-time collaboration, video-conferencing and real-time sharing of information across geographical and company boundaries were seen as key enablers. Furthermore, important for the radical efficiency improvements was fast and efficient decision processes made possible by the delegation of operational decision making power to a joint operations team lead by the Operating Company.
Extrapolation of Subsurface Current Observations to the Sea Surface: Applicability and Limitations of Basic Algorithms
Authors: Magnell B. A. , Ivanov L. I. , Morrison A. T. , Ramos R. J. 
Published: April 2017

Abstract
Information about near-surface currents provided in near-real-time is required in a variety of applications. However, direct measurements of near-surface currents are scarce. In the Gulf of Mexico, the oil industry has been collecting current profiles from deepwater rigs, platforms, and moorings in accordance with BSEE Notices to Lessees (NTLs) since 2005. On the rigs and some platforms, these profiles are usually collected with long-range ADCPs positioned beneath the rig/platform keel, so the measured current profiles typically extend from 70-80m below the surface to as deep as 1000m. Unfortunately, only a few stations are equipped to provide good-quality near surface current data. This study assesses the validity and limitations of some simplistic current profile extrapolation algorithms, including approximation of the near surface current by "slab" flow and profile extrapolation algorithms derived from the shape of the measured subsurface profile or from a generic current profile shape.
The analysis is based on data collected by a long-term mooring anchored in approximately 1400m of water in the north central Gulf of Mexico (Green Canyon 782, NDBC ID 42369) and on a year-long data set from a mooring deployed in Keathly Canyon in approximately 1900m of water. The available data include periods of Loop Current Eddies (LCEs), weak cold-core eddies, relatively strong flows characterized by a subsurface current intensification, and high-amplitude inertial oscillations.
Velocity profiles were mapped onto fixed depth levels. The subsurface section of the profiles was used to extrapolate mappings from 80-100m to the near-surface. Our analysis shows that, in the winter and in the absence of an LCE, currents in the upper 80m of the water column were quasi-homogeneous. Although current speed near the surface is likely to be higher than current speed at 80m, there is a 90% probability that this difference does not exceed 10cm/s and a slab flow extrapolation is reasonable. When an LCE is present, the accuracy of extrapolation is better if the shape of the near-surface current profile is based on deeper observations. This is also true for the stratified summer water column. The uncertainties of profile extrapolation are quantified for each data set and for each flow regime.
Kinetics of Fluid Phase Behavior Changes: A Critical Uncertainty for Offshore Field Development
Authors: Lavenson David M. , Kelkar Aniruddha V. , Joshi Nikhil , Portman Lance 
Published: April 2017

Abstract
With increasing pressure on project costs, accepting uncertainty is increasingly less viable for offshore field developments. An urgent issue that affects conventional and novel technologies across the production landscape is that of the kinetics of fluid phase behavior changes. Be it pressure boosting using electrical submersible pumps (ESPs) or separation with novel compact separators, the rates of gas dissolution and evolution are a critical uncertainty. PVT laboratories today report fluid properties at equilibrium points, with a prevailing unwritten assumption that the system can achieve the new phase equilibrium either instantaneously or at a time scale that is negligible when compared with production system residence time scales. However, even anecdotally, many in the industry understand this assumption to be optimistic and recognize there is a kinetic process that must occur to achieve the new equilibrium state. Fluid property measurements – kinetics included – are highly valuable to a variety of disciplines: research engineers, process engineers, flow assurance engineers, and more. To effectively apply fluid property measurements to field development activities, each engineer must have a quantitative understanding of the data uncertainties. The kinetics of fluid phase behavior changes are, however, often overlooked; nearly all industrial process simulators apply equilibrium models, regardless of whether the system has achieved the equilibrium state. As the industry drives towards more challenging offshore fields and focuses on simplifying designs, reducing size, and reducing costs, the result is an increasing risk of consequences due to incomplete evolution or dissolution of gas. Engineers currently have no tools available to predict or estimate the rate at which the gas will evolve from or dissolve into solution. This unknown propagates to potential issues in a variety of applications, including design and optimization of artificial lift systems, design and operation of electrical submersible pumps, subsea or topsides pumping, compact separations, and more generally gas-liquid separations. In this paper the authors share insight and information about challenges in design, development, operation and troubleshooting with regards to the uncertainty in the kinetics of fluid phase behavior. Discussion also covers the value in developing an alternative fluid property measurement for quantifying and predicting the rates of gas evolution and dissolution.
Development of Sour Service Corrosion Resistant High Strength Steel Pipe Grades at TMK
Authors: Panda D. , Lolla T. , Mokirala R. , Metelsky D. 
Published: April 2017

Abstract
API Specification 5CT [1] and NACE MR0175 [2] and TM0177 [3] provide guidelines for the use of carbon steels with desired characteristics in oxygen-free environment containing H2S and CO2. TMK IPSCO has developed a range of suitable grades to meet such service requirements; this paper describes in detail the necessary processing tools that have been developed and implemented to achieve the desired pipe properties and consequently ensure their performance in the well.
It is well known that low alloy carbon steels of higher strengths are susceptible to SSC (Sulphide Stress Cracking) in such sour service conditions. As the strength (and hardness) of steel increases, controlling impurities within the steel matrix becomes critical in the development of pipes for such applications. Development of technologies to reduce the inclusion content and ensure "clean" steel for the production of these grades at our steel production facility in Koppel is presented. Additionally, the use of rigorous heat treatment practices aimed at controlling the micro-structure and mechanical properties of the steel, which are achieved by monitoring and controlling critical parameters such as the furnace temperatures, are discussed. To meet the stringent quality requirements for these grades, improve process efficiency and reduce operational error, the use of automatic hardness testing machines have been implemented to batch process the hardness tests on such grades. Furthermore, a novel use of automated microhardness machine to predict the disposition of test samples to failure during SSC testing is presented.
Investigations of steel specimens have shown that application of "clean" steel practices, like the implementation of TruStir® technology has resulted in a marked and consistent enhancement in the cleanliness of such sour service steel grades. Heat treatment studies point to enhancements in hardness control and distribution resulting from heat treatment practices involving double quench and tempering. Such heat treatment routes are believed to result in a better control of prior austenite grain size and prevent formation of localized "hard" spots in the material, which could become sites susceptible to SSC. Recent developments of the control of furnace operating parameters at our Baytown Heat Treating facility and resulting improvements in the performance of our sour service grades are discussed.
Production of these sour service grades require stringent quality checks as mandated by API specification 5CT and ISO specification 15156. Apart from extensive hardness testing, these grades require prolonged corrosion testing. Aside from standardized testing methods for these grade, our internal microhardness testing of these grades have revealed a relation between the frequency of microhardness distribution and the corrosion performance of these grades. Based on these results, a quick methodology of predicting the corrosion performance of a material is being explored.