bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of a Full-Scale Horizontal Liquid-Liquid Separator under Conditions of Varying Flow Rate, Water Cut, and Viscosity with Experimental Validation
Authors: McCleney A. B. , Owston R. A. , Green S. T. , Viana F. , Nelson S. M. 
Published: April 2017

Abstract
Computational simulation of a full-scale, horizontal liquid-liquid gravity separator has been undertaken by Southwest Research Institute® (SwRI®) to model the batch separation of oil and water flow. Separator modeling using Computational Fluid Dynamics (CFD) represents a powerful and economical option for design, but caution must be used in the setup and interpretation of data. Many examples are available in literature of poor agreement between simulation results and experimental/field data. No clear consensus on valid modeling methodology currently exists. Results require interpretation before taking them at face value due to the complexity of the various submodels that can be utilized. This work offers an evaluation of multiphase flow modeling techniques, and provides a unique comparison with experimental data that covers a broad range of flow rates, water cuts, and viscosities.
The performance of a horizontal gravity separator with perforated baffles has been investigated using CFD. The simulations have been carried out using an Eulerian-Eulerian multiphase approach. These simulations were conducted using constant dispersed water droplet sizes in an oil-continuous phase. Separation efficiencies and water-cut percentages at several locations throughout the test separator were compared against experimental results for a wide range of inlet flow rates, water cuts, and oil viscosities. Computational results indicated that the horizontal liquid-liquid separator can be modeled within 10% accuracy of the local experimental separation efficiency values for the various test conditions. This effort demonstrates the capability of reliable modeling of multiphase flow fields inside of horizontal gravity separators, and offers an economical option for aiding in the design of separation equipment.
Comparison of Self Weight Penetration Prediction Methods for Large Diameter Monopiles in North Sea Soils
Authors: Shonberg A. , Anusic I. , Harte M. , Schupp J. , Meissl S. , Liingaard M. A. 
Published: April 2017

A significant number of large diameter monopiles (&gt;6 m diameter) have been installed as foundations for offshore wind turbine generators (WTG) across Northern European waters over the past decade, where the self-weight penetration (SWP) during the installation process was recorded. The prediction of the SWP for offshore foundations, such as piles and skirted foundations, is an important installation design task. The prediction of the SWP is subject to great uncertainty, resulting in a large range between lower and upper bound SWP predictions.
The methods available to predict the SWP range from simple empirical methods that derive the penetration resistance from cone penetration test (CPT) measurements using skirt and tip resistance coefficients to more advanced methods, based on bearing capacity theory requiring soil strength parameters as input. For the empirical methods, the prediction accuracy is directly dependent on the data used to establish suitable resistance coefficients. Investigating different soil conditions and foundation dimensions (scale effects), therefore, extends and improves the applicability of the empirical SWP prediction methods. This paper will use a portion of the recorded SWP data to benchmark existing SWP prediction methods and to establish improved resistance coefficients for the empirical method using a Monte Carlo type approach.
For the Westermost offshore wind farm assessed in this study, the findings show that the existing SWP prediction methods generally under predict the observed SWP. The results of the Monte Carlo type analysis show that the new resistance coefficients are generally lower than the generic resistance coefficients provided by DNV (1992). The results also show that the tip resistance in coarse grained materials and the shaft resistance in fine grained have the largest influence on the accurate prediction of the SWP.
HORA Hinge-Over Riser Assembly Riser System
Authors: Martins S. B. C. , Harris S. W. , Nakajima E. 
Published: April 2017

Abstract
HORA (Hinge-Over Riser Assembly) is a new riser system that improves the traditional Free Standing Riser (FSR). The system includes an articulated horizontal connection located at the base structure, eliminating the requirement for a subsea base jumper between the flowline and riser needed with the conventional FSR. HORA's key advantages compared to the traditional FSR system concept are: (1) shorter installation schedule; (2) increased reliability of the riser system; (3) increased operational flexibility and improved ability to respond to contingencies; (4) lower installation risk; and (5) reduced capital expenditure.
HORA incorporates two novel technologies. The first is a hinge-over system that enables seamless integration of flowline and riser pipelay tasks, also allowing the riser to be laid on the seafloor during installation. The second is a locking mechanism connecting the HORA in-line structure (ILS) with the foundation suction pile, effectively isolating the subsea horizontal connector from any loads that could potentially cause its failure.
This proprietary HORA Technology solution has progressed from the concept to maturity and is a viable option in offshore oil and gas field developments. During the design phase the major focus areas were to effectively isolate the horizontal connection from overstress and fatigue loads due to external loading, as it is the primary flow path component that enables the hinge-over function. In-place and installation analyses were developed to identify these loads and the ILS and locking mechanism were designed using finite-element models (FEM) to address them. FEM was also used to address the in-place riser and installation loads imposed on the hinge-over mechanism. In addition, an offshore installation method has been detailed and a failure modes, effects and critical analysis (FMECA) performed by an independent engineering organization.
HORA is an improvement from the traditional FSR concept and an alternative for offshore field developments and for specific scenarios and applications such as Marine Well Containment Systems (MWCS), Early Production Systems (EPS) or in areas prone to inclement weather, short installation windows or risky environment. This paper presents the engineering solutions to meet the performance targets defined for HORA Technology Development Project.
Fast-Track Development of Managed Pressure Drilling Flexible Mud Return Line
Authors: Szekely Gergely , Peixoto Eduardo , Czovek Zuzana , Mezo Tamas 
Published: April 2017

Abstract
In the oil and gas industry there is a common misconception that bonded flexible pipes designed according to the only approved standard for deepwater MPD applications, API 17K are overdesigned and heavy.
This paper is to clarify the misconception and present to the industry the flexibility that API 17K gives to tailor the hose construction reflecting the actual requirements and customer needs. Over the last few years a lot has been learned on the MPD operations, using inputs of the industry's major players, the hose requirements that in the past led to overdesigned, heavy and expensive flexibles have been revised, allowing a more efficient hose construction to be developed keeping the design premises of API 17K.
Brief overview on API specifications is given in terms of their applicability to MPD operations. Technical challenges and solutions are discussed in details for the flexible pipes carrying well effluents in kick situations with special emphasis on the importance of selecting the proper liner material. Gas diffusion phenomena in bonded flexible pipes is detailed. Technological advances are highlighted resulting meaningful weight and cost savings while not compromising on HSE and quality – meeting the stringent design and test criteria of API 17K. Results of the full scale tests demonstrating the hose performance are presented, such as bending stiffness test, blistering test and burst test.
This paper is providing an example of a quick turnaround research and development project of an equipment manufacturer with heavily integrating the feedbacks of the first years of MPD operations to result a fit for purpose and cost effective product.
Adding Thousands of Barrels for Little Cost in a Gulf of Mexico HPHT Deepwater Field, an Effective System Modelling & Optimization Case Study
Authors: Ogugbue Chinenye , Pietrobon Marney , Stewart Carlos , Duvivier Giles , Macnamara Robert , Bishop Simon 
Published: April 2017

The Thunder Horse offshore Field, located in the Gulf of Mexico, consists of multiple producing complex oil reservoirs. The producing zones have been developed with approximately 20 wells flowing, via 5 subsea flowline-and-riser systems, into a dual train production facility.
The combination of risers, trains, and separation stages allows a wide range of routing flexibility and optimization opportunities for this production system. However, the complexity of the different combinations requires innovative system optimisation strategies to identify optimal configurations. An Integrated Asset Model (IAM) was built which achieves excellent fidelity and reliably predicts production improvements. One particular application of the IAM in 2015 informed the safe, reliable routing of a well directly to a second stage separation vessel resulting in the delivery of over 5 mbopd extra production. These techniques are now being applied to other BP assets with continued success.
This paper describes some key elements of these models, the challenges in maintaining and calibrating these models, and a case study to showcase its value.
Offshore Trinidad AWAC Wave Data Assessment
Authors: Mendelsohn D. L. , Fratantonio R. , Hanson J. , Bangs A. S. , Withall T. , Crosby A. R. 
Published: April 2017

Abstract
To support and facilitate deep-water operations, accurate measurements of metocean conditions are needed to assess constraints and provide criteria for offshore design and installation. BHP Billiton installed three deep-water (1,770 – 2,120m), taut-line moorings for 12-months in 2014-2015, offshore Trinidad and Tobago measuring waves, currents, salinity, and temperature to accomplish this task.
An associated metocean analysis was performed on the Acoustic Wave And Current (AWAC) sensor data, with supporting Navy Global Environmental Model wind data. The objective of this study was to analyze the AWAC data to understand the wave climate in the region, and specifically, to perform a wave partitioning analysis to compute time-evolving wind-sea and swell wave system parameters. The data set was then used to check analyses and predictions made in the development of operational and extreme metocean design and operational criteria. Taut-line moorings can periodically respond to forcing, dependant on mooring length, mass, buoyancy and drag, which can negatively influence measured directional wave characteristics. Analysis found that the natural mooring response frequency to periodic forcing was in the range of 140 s, outside the range of wave or current variability in the region.
Wind roses verify the predominance of easterly wind flow with corresponding waves roughly aligned. Bulk significant wave heights appear normally distributed with a median wave height of approximately 1.4 m. Peak periods are predominately 8-9 s, with occasional wave events to approximately 18 s period. Wave directions are east-northeast to east most commonly, and most energetic during winter and spring. There is an absence of waves from the south and west due to the blocking effects of Trinidad and South America. Peak wave events were identified with a peaks-over-threshold algorithm, for Hs &gt; 1.5 sigma above the mean, showing a maximum event with Hs = 4.0 m and Tp = 10.6 s, and three events with Tp &gt; 13 s at all 3 moorings with directions mostly from the northeast.
Wave spectra directional distributions at higher frequencies appeared compromised as a result of instrument deployment depths, affecting the horizontal spacing of near surface velocity cells used in internal AWAC processing. Modified spectral partitioning with high-frequency masking was developed to eliminate suspect frequencies from the analysis. Partitioning used an inverse watershed algorithm to isolate peak domains in directional wave spectra. Wind sea peaks were identified using directional wave age criterion. Wave component clustering was used to form time-evolving systems from the partition results. Resulting wave systems can be traced to a specific generation region on the ocean surface. Wave vector history plots showed that the Trinidad wave field was typically a mixed sea and regional swell field with occasional long-period swell events from distant storms.
Plastic Limit Analysis of Laterally Loaded Piles and Wells Conductors in Soil Profiles with Crust
Authors: Grajales-Saavedra Francisco J. , Aubeny Charles P. , Jeanjean Philippe , Drew Dane 
Published: April 2017

Abstract
This paper presents a series of studies in which traditional upper bound plastic limit analysis (PLA) methods are modified to accommodate non-linear strength profiles which correspond to soils with crust. The collapse mechanism presented comprises a surface failure wedge, a flow-around region and a spherical base failure surface. Results are compared to predictions from 3-dimensional finite element analyses for case of a surficial stiff ‘crust’ overlying a thicker layer of soft soil. An introductory discussion on the origin of such ‘crusts’ is included. Comparisons are presented in terms of both horizontal bearing capacity and lateral unit bearing capacity profiles, which are depth-dependent. A series of parametric studies is presented in which the effect of pile diameter and soil strength is assessed. The paper presents a simplified practical approach to calculate lateral bearing capacity factors for soils with crust, by modifying an existing solution for linear soil profiles.
Stability and Performance Evaluation of Hybrid Foundation System for Subsea Applications
Authors: Jang Sehoon , Suroor Hadi 
Published: April 2017

Abstract
A hybrid foundation system defined as the combination of shallow and deep foundations has been developed as an alternative to large diameter suction piles, to tackle ever increasing flowline walking loads in deep water subsea field developments. In the current environment of cost effective measures and continued expansion of offshore developments, a hybrid subsea foundation, typically consisting of a mudmat and corner pin-piles, can offer significant fabrication and installation cost savings, compared to traditional large diameter suction piles, as flowline restraint anchors. Since a hybrid foundation combines shallow foundation (i.e. mudmat) with deep foundation (i.e. pin piles); the current industry standards / guidelines do not provide any specific recommendations as to the design requirements of this complex foundation system. This study is primarily aimed to elucidate the performance and stability evaluation of the hybrid foundation based on the full 3 dimensional (3D) finite element analysis (FEA) results.
Since the emergence of this relatively new hybrid foundation concept, a limited number of technical papers have been published based on analytical, experimental as well as numerical approaches with no clear consensus in design principles. This comprehensive numerical study aims to bridge the gaps in the previous studies by developing 3D failure envelops (yield surface) to provide better understanding of the effects of multi-directional loadings on the capacity and displacements of a complex hybrid foundation system. The study also investigates the pattern of the soil resistance mobilization under various loading conditions to understand the soil-structure failure mechanism as well as displacements of the hybrid subsea foundation.
Heading Control of a Turret-Moored FPSO with and Without Forward Thrusters
Authors: Kaasen Karl , Ludvigsen Halgeir , Aas Kristian 
Published: April 2017

Abstract
A valuable property of a turret moored FPSO is its ability to weathervane or self adjust its heading to the varying metocean environment. Still, heading control with thrusters is necessary when a different heading than the natural weathervaning heading is wanted for operational reasons. In particular, in non-colinear metocean conditions it may be desirable to keep the bow of the FPSO against the waves to reduce rolling. It may happen that the weathervaning becomes unstable. In this case, the vessel will go into fishtailing motion, which is a phenomenon that is governed mainly by interaction between sway and yaw. Fishtailing is weather-dependent. When it happens, heading control is needed to stabilize it.
One important objective of the study has been to investigate if satisfactory heading control can be obtained using thrusters aft only, or if thrusters forward are necessary.
For a given FPSO design, we study weathervaning stability by formulating a linear model in sway and yaw. Based on this model with damping neglected, we develop three simplified criteria for stability. Using heuristic argumentation, we accept the criteria as conditions for sufficiency. The system's eigenvalues give sufficient and necessary conditions for stability. Using metocean hindcast data covering a time span of 56 years, the simple criteria are tested against the eigenvalues of the sway-yaw model. We found good agreement.
The heading controller used is essentially a PID controller. It is found that with aft thrusters only, good heading control can be achieved for all the metocean states in the 56 years span, provided the controller gain is moderate. With high controller gain, the thrusters may excite resonance in the turret mooring. Using additional thrusters forward gives the freedom to reduce turret resonance. Time domain simulation with an accurate 6-degree-of-freedom model shows that thrusters aft and forward gives slightly better control than control using aft thrusters only. Still, using only aft thrusters appears to give satisfactory heading control.
Real-Time Monitoring and Diagnoses on Deepwater Cement Barrier Placement: Case Studies from the Gulf of Mexico and Atlantic Canada
Authors: Contreras Jose , Bogaerts Martijn , Griffin Dave , Rodriguez Faiber , Sianipar Sakti , Villar Vitor , Taoutaou Salim 
Published: April 2017

Abstract
The updates in the US code of federal regulations 30 CFR Part 250 Oil and Gas and Sulphur Operations in the Outer Continental Shelf, released in 2016, relate to, among other things, real-time well monitoring on critical well operations including cementing. The regulations do not assume that onshore-based staff would assume operational control, but rather that onshore expertise can assist the offshore location in determining anomalies before they become critical issues. Currently, cement job monitoring is often limited to the acquisition of pressure, rate, and density measurements. Based on those measurements, a basic evaluation is performed during the job. A new software tool has been developed to improve the ability to interpret and diagnose critical job parameters while the cement job is in progress.
The real-time cement monitoring (RTCM) simulator combines data from the cement job design with acquisition data from the cement unit and rig to provide a detailed picture of the operation by comparing acquired values with predictions computed in real time. Data acquired during the cement placement are processed by a hydraulics simulator incorporated into the software to provide key information about the fluids' position in the annulus, comparative trends of acquired versus simulated surface pressures, density quality assurance and quality control, and real-time visualization of dynamic well security. Based on the real-time estimation of the fluids' position in the annulus and other key parameters measured during the job execution, a contingency plan can be followed, thus avoiding the need to wait on a detailed post-job analysis of the raw acquisition data.
This paper describes the methodology of the software and how it helps to diagnose the cement barrier placement in deepwater wells. The real-time monitoring of the cement job starts with the evaluation of the pre-job circulation and ends with the final displacement. With the real-time capabilities, experts can remotely view operations and provide recommendations during the cementing operations and immediately advise on post-cementing rig activities. Through case studies from the Gulf of Mexico and Atlantic Canada, the process and benefits will be shown to improve barrier verification as early as possible in the well construction phase.
The novelty of the software is that it can be used to diagnose the quality of cement jobs during the execution stage. Synchronized visualization of wellbore schematics showing fluids position, equivalent circulating density (ECD) progression, and combined measured versus simulated surface pressures are critical to help determine the position of fluids in the annulus and provide early verification of a barrier.
Qualification and Development of the World's First High Pressure Subsea Boosting System for the Jack and St. Malo Field Development
Authors: Hjelmeland Mads , Reimers Oeyvind , Hey Chris , Broussard Dan 
Published: April 2017

Abstract
The Jack and St. Malo fields were developed in a deepwater Gulf of Mexico (GoM) setting by Chevron and co-owners and commenced production in 2014. The reservoirs are located roughly 25 miles apart, about 250 miles southwest of New Orleans, Louisiana. Water depths in both fields are around 7,000 feet, and the reservoirs lie approximately five miles below the water surface. The Jack and St. Malo fields were developed with subsea completions flowing back to the Walker Ridge Regional Platform, the largest, by displacement, semi-submersible floating production unit (FPU) in the GoM.
The Lower Tertiary trend (LTT) in the GoM poses a number of documented challenges for flowing reservoir fluid from the sand face to surface facility. The key challenges are related to low permeability, high pressures, high temperatures, as well as water and well depths.
The naturally high pressures driving Jack and St. Malo fields during the early stages of development will decrease over time as the fields are produced. To compensate and maintain production levels, it was decided to deploy three powerful subsea pumping systems on the seabed to boost fluids from the wells to the host platform. While a number of subsea boosting systems have been deployed over the years, the Jack and St. Malo fields required technology qualification in order to meet design requirements in terms of water depth, pressure rating and shaft power.
This paper will describe the technology qualification program of the world's first high pressure seabed boosting system, as well as the subsequent delivery project and deployment of three subsea boosting systems in the Jack and St. Malo fields. An overview of the drivers for selecting this technology will be provided, as well as insight into early operational experience from the field.