bluuebunny/crossref_metadata_2025 huggingface dataset:
Lucius and Hadrian South Projects: Development Overview
Authors: Lamey M. , Gayneaux J. , Hart D.D. , Arthur T.
Published: April 2015

This paper provides an overview of the development of Anadarko's Lucius oil field and ExxonMobil's Hadrian South natural gas field tie back to the Lucius facility. These projects were successfully completed in 1Q 2015 in the southeast corner of the Keathley Canyon area of the deep water Gulf of Mexico. The Lucius project team responded to the opportunity created by the Hadrian South resource and other challenges resulting from the use of new build vessels, a strained labor market, and new regulations affecting the Gulf of Mexico since 2011. The ability of the project to execute in roughly three years from sanction and only five years from discovery can be credited in large part to the operator's development strategy of utilizing a core group of proven, trusted suppliers. To mitigate site terrain challenges, simplify riser design, and minimize cost/schedule risk, the operator chose a truss spar as the hull for this wet tree only development. It is the operator's largest spar to date.

The Hadrian South project is ExxonMobil's deepest sub-sea tie-back. It was contracted on a competitively bid basis and executed in parallel with the Lucius development. Close cooperation with the Lucius project team, disciplined management of change, and rigorous opportunity and vulnerability tracking resulted in a capital efficient project with a number of scope optimizations and minimal EPC changes.

The Lucius field is located in Keathley Canyon blocks 874, 875, 918, and 919. It holds an estimated 300-plus million recoverable barrels of oil equivalent. This project was sanctioned in December 2011, and achieved first production in January 2015, with the first production from the nearby South Hadrian field in March 2015. The truss spar's topsides process systems can process more than 80,000 BOPD and 450 MMSCFD. The reserves will be produced through six initial wet-tree wells. The Hadrian South field, located in Keathley Canyon block 964, was discovered in 2009, and was sanctioned in December 2011. Hadrian South was developed as a two wet-tree well 300 MMSCFD tieback to the Lucius spar located eight miles to the north/northwest.
Repair and Intervention of HPHT Flowlines
Authors: R. Ayers Ray , A. Wilson Ian , N. Gage Eric , Rebello Armando
Published: April 2015

The objective of this paper is to report progress and recent findings related to the remediation of damaged high-pressure, high-temperature (HPHT) flowlines in deep water. The flowline repair technology currently being developed utilizes an R&D process of systematically identifying technical gaps, and then developing methods to close those gaps.

While defects or damage to deep-water export pipelines and flowlines is a relatively rare, low-occurrence/high-consequence event, recently compiled information shows that flowline problems involving paraffin or hydrate plugs are more frequent than previously believed. In addition, removing these plugs is complex and difficult.

In 2014, thirteen paraffin plugs and four hydrate plugs occurred in the GOM and are keeping the affected lines out of service. In contrast, only a few flowline repairs are called for each year.

This paper builds in part on prior work by the authors described in OTC 23143 [2], which revealed that the traditional elastomer packer seals used for non HPHT pipeline repair tools will extrude out of the packer cavity and leak when exposed to HPHT conditions that are common to thermally insulated flowlines, rather than uninsulated export pipelines. As a result, sealing system designs must utilize significantly improved sealing methods replacing elastomer packers with diecast graphite packers used for traditional offshore pipeline seal systems.

This paper describes the critical technical gaps identified and closed while conducting a joint industry program for a group of major international operators: (1) removal of wet insulation, (2) development of HPHT sealing systems and (3) development of a subsea coiled tubing insertion hot tap system. The unique approach to developing the technical solutions to these technical gaps involved physical testing of the proposed solutions with test jigs to demonstrate their functionality.
SS-Space Technologies for the Offshore Deepwater Industry: Robotic Solutions for Exploration, Earth and Space
Authors: Ambrose Robert O.
Published: April 2015

Objectives/Scope

This paper describes the challenges NASA sees in space exploration, highlighting several of the robotics solutions now being developed and tested. Overlaps with terrestrial exploration challenges will be noted as potential areas of collaboration. Results from a specific and ongoing collaboration will be described, showing a robot built for exploring tanks on the sea floor with access through existing pipes.

Methods, Procedures, Process

NASA has developed a roadmap for robotics and autonomous systems, as a part of a larger road mapping process for all space technologies. Roadmaps study future missions to identify where new technologies could reduce costs, shorten schedules or enable completely new approaches. These roadmaps are periodically updated by NASA, and the most recently released version will be presented for robotics and autonomous systems.

Results, Observations, Conclusions

Once technologies are identified as needed to support missions, NASA uses technology projects to develop and then test prototypes in labs, test facilities and/or in space. The design and development cycle will be presented for a mix of such efforts, including delivery of robots to space for testing.

Novel/Additive Information

NASA's challenges include operating in extreme pressures, temperatures and radiation. Our missions also take humans and their machines far from Earth, where the speed of light induces time delays for control. NASA has pioneered new techniques for controlling robots in these harsh environments and across time delay with limited bandwidth. These techniques will be described with relevance for the offshore oil and gas industry.
Development and Execution of a Wax Remediation Pigging Program for a Subsea Oil Export Pipeline
Authors: Stevenson Colin J , Davies Simon R , Gasanov Ilgar , Hawkins Paul , Demiroglu Muge , Marwood Andy P
Published: April 2015

We show how state-of-the-art wax deposition modelling can provide an accurate estimate of the location, shape and volume of wax deposits which is key information for the development of a pigging program and the design of the pigs. We show how pigs can be designed to controllably and progressively remove targeted volumes of wax starting from 50% of pipeline diameter while maintaining drive through another 130 kilometers of relatively clean pipeline. Finally, we demonstrate how instrument packages in pigs can be useful in locating and quantifying pipeline restrictions and in providing important data for validating flow assurance models.
Comparative Study on Calculation Methods of Mud-Weight Window for Subsalt Wells: 1-D, 3-D, and Integrated 3-D Methods
Authors: Shen Guoyang , Shen Xinpu , Standifird William
Published: April 2015

Owing to the complex distribution of stress directions around a salt body, accurate prediction of mud-weight window (MWW) for subsalt wells has presented a challenge to the industry for a long time. This paper presents a comparative study on methods practically used in calculating the mud-weight window of subsalt wells. Selected methods, which include the 1-D analytical method, 3-D numerical method, and the integrated 3-D method, are compared. A subsalt well section in deepwater GoM was chosen as a validation example. Both workflows of each calculation method and resultant MWWs obtained with each method are analyzed and compared. The TVD depth of the investigated subsalt well section is from 22,000 to 30,000 ft. The salt body's thickness along the wellbore trajectory is 20,000 ft, and its width is 18,000 ft. With seismic sectional data, an anti-cline structure is constructed accordingly at its bottom surface. Mohr-Coulomb criterion is adopted in the calculation of MWW. A 1-D solution of MWW is calculated with the geostress field derived from overburden stress along the trajectory. A 3-D solution of MWW is calculated with the stress values obtained with finite-element submodeling techniques. An integrated 3-D solution of MWW is calculated with the 3-D stress field obtained from the finite-element method and an analytical tool for MWW calculation along the trajectory without using the submodeling technique. Comparisons have been made between the results obtained with the conventional 1-D method, 3-D finite-element submodeling method, and the integrated 3-D method. Solutions obtained with the conventional 1-D method have missed the abnormality of stress distribution at the salt base and have smaller values of MWW compared to the other solutions. The solution of MWW obtained with the integrated 3-D method is very close to the one obtained with the finite-element submodeling method, but at only one-tenth of the time cost. With the validation example of the subsalt well section, a comparison of workflows and the resultant MWW's accuracy has illustrated the advantages and disadvantages of typical 1-D, 3-D, and integrated 3-D method for MWW calculation. The results presented in this paper can be used as a reference deciding on the best practice for calculating the MWW of subsalt wells. This work also presents an example of best practice.
SS Delta House - Topsides Fabrication & Integration
Authors: Chapa J. , Zoss K.
Published: April 2015

This paper describes the Delta House FPS Project topsides fabrication and integration contracted to Kiewit Offshore Services, Ltd. (KOS) by LLOG Exploration Offshore, L.L.C. (LLOG). KOS' work scope included the fabrication, loadout, heavy lift and integration of a 9,500 s. ton topsides structure using KOS' Heavy Lifting Device (HLD). Other notable work included the offload and marshaling of a 12,500 s. ton semisubmersible hull.

Structural materials used in the construction of the topsides were higher API grade DNV approved plates and tubulars. KOS used European and domestic steel mills to supply topsides materials.

The topsides structure was divided into several major sub-assemblies weighing between 100 and 5,000 tons each. All sub-assemblies were fabricated in-house in KOS' yard in Ingleside, Texas.

Early Contractor Involvement (ECI) for the Delta House FPS project between KOS, Exmar Offshore Company (EOC), Audubon Engineering Company (AEC) and LLOG set the team up for success from the beginning. Prior to the start of fabrication, KOS was interfacing with engineering and LLOG operations teams. This involvement allowed KOS to provide input for a safer and more productive design, setting construction up for success with early contributions by all parties involved.

The single level Exmar OPTI-EX topsides design made for simpler construction and equipment integration and allowed KOS to compress the schedule and deliver on-time. A single level deck design for a facility of this size necessitates careful planning of larger components and (sub) assemblies, which in turn allows for more efficient construction.

The complete topsides structure was loaded onto a cargo deck barge and maneuvered under KOS' Heavy Lift Device where the structure was lifted and set onto the semisubmersible hull at the KOS bulkhead. Integration scopes were complete while the FPS was moored to the quayside allowing for productive and safe commissioning operations.
Predicting Internal Solitary Wave Loads on Spar Platforms
Authors: Huang Wenhao , You Yunxiang , Li Wei
Published: April 2015

Internal solitary waves (ISWs) can impose significant loads on offshore structures. During the past several decades, ISWs have led to a series of incidents. With large draughts, spar platforms can be affected by ISWs; therefore, the ISW effect should not be neglected during the design, installation and operation in areas where ISWs can occur. However, there is a gap in research into this area with only a few preliminary studies published so far.

In this paper, a series of experiments are carried out with a spar platform model in a large-scale stratified tank at Shanghai Jiao Tong University to investigate interaction characteristics of ISWs. Based on a two-layer ISW theory, a simplified theoretical model is established for predicting the ISW loads on a spar platform. It is shown that the horizontal ISW loads consist of drag and inertia components, which can be calculated using the Morison's equation, while the vertical loads are mainly the vertical Froude-Krylov force, which can be obtained by integrating the ISW-induced dynamic pressure over the spar bottom.

By fitting theoretical results with experiments, specific formulas are established to determine two empirical coefficients in Morison's equation under ISW conditions, which are different from traditional methods. The numerical results from this method show good consistency with experimental results on both the amplitude of the loads and the time varying characteristics. This research provides a practical theoretical model for predicting ISW loads on spar platforms.
Hydrate Formation in Gas Dominant systems
Authors: Sinquin Anne , Cassar Cyril , Teixeira Adriana , Leininger Jean Philippe , Glénat Philippe
Published: April 2015

Deepwater gas field development and/or gas fields’ production in remote locations requires long tiebacks with low temperature and high pressure flow paths and complex seabed topographies.

Hydrate formation and plugging is one of the most probable Flow Assurance risks under those conditions, and there is an urgent need for a better knowledge of these gas dominant systems behaviour regarding hydrate plug formation as well as effects of additives (Thermodynamic, Kinetic Hydrate Inhibition (KHI) and Anti-Agglomerant (AA)). Indeed, during the design phase of new field development, oil companies have to choose a hydrate mitigation strategy. To do that, important questions rapidly arise:

What about the gas layer protection?

How can non-volatile additives act/protect the non-wetted top of the line from condensed water hydrate formation in stratified flow?

Is there a need to take/run some specific procedures (such as slug of additives) to avoid hydrate problems?

The Additive and Hydrate at the Top of Line (AHToL) JIP phase 1 project's objective was to acquire knowledge and data in multiphase Lyre pilot loop in such gas dominant conditions.

The paper presents Lyre loop pilot tests performed with gas dominant systems without additive. The hydrate formation was performed in multiphase flow. The pilot and tests results in stratified flow are shown. Two types of fluids compositions were tested: Gas/Water and Gas/Condensate/Water.

The water to hydrate conversion rates are calculated. Photos of hydrate deposits inside the flow loop are shown. The plugging mechanisms identified show a direct correlation with the fluids compositions circulating
Approach for Assessing Dormant Reliability in Dual Electrical Submersible Pump (ESP) Systems in High-pressure, High-temperature (HPHT) Environments
Authors: Ye Zheng , Semple Ryan , Rafie Saeed
Published: April 2015

Dual electric submersible pump (ESP) systems are an attractive option for costly high-intervention wells because they provide greater assurance for uninterrupted operations. In dual ESP systems, a second ESP serves as a backup in the event that the active ESP fails. The backup ESP, however, can spend a significant amount of its lifetime in a dormant state, making the assessment of its reliability more difficult. Newer ESP systems used in deepwater, high-pressure, high-temperature (HPHT) environments are more sophisticated and must have longer service lives. However, these systems do not receive preventive maintenance and are not inspected for component deterioration after deployment, further complicating dormant reliability estimates. Even though its operating failure rate may be substantially greater than its non-operating failure rate under the same well conditions, the amount of time that the backup ESP remains dormant could be longer than five years, making dormancy a major factor to consider when estimating a mature dual ESP system's reliability and service life.

Because of their complexity and potential for prolonged dormancy throughout operations, dual ESP systems have an inherent need for higher dormant reliability. Developing an approach for assessing dormant reliability as part of the testing and evaluation process would help to meet this requirement. This approach should accurately estimate the effects of dormancy on operational effectiveness. Operational testing analyses must identify the failures that directly affect operational capability.

In this paper we present the framework for developing a methodology to estimate dormancy effects on the reliability of deepwater dual ESP systems, and models to predict dormancy effects. Actual measurement of dormant reliability is a long-term process that includes expensive real-life operational testing.

Methodologies for projecting system operational reliability at the component level are applied to dormant reliability analyses, and experiences from the field are iteratively applied toward improving the process.
Ultra-Deepwater Steel Riser Systems Hosted on FPSOs Offshore Brazil
Authors: Moreu M. , Taboada M. , Taboada A. , García C. , Moreu J. , Mansour A.M.
Published: April 2015

This paper investigates the potential feasibility of SCRs hosted on FPSOs in offshore Brazilian ultra-deepwater regarding to fatigue life at the Touch-Down Zone (TDZ) when the riser system is hanged off from a centered moonpool instead of from the unit's side. A case study is presented here in order to provide a suitable starting point for the study a 2 MMbbl FPSO has been preliminary dimensioned and the focus has been set on wave induced motions fatigue loading. Wave induced motions at two porch locations, one connected to the hull outer shell and another connected at the moonpool of the FPSO, are calculated and used as forced-displacement boundary conditions in a detailed riser FEM analysis whose stress cycle time series are eventually calculated to provide an estimation of the fatigue damage at the TDZ between the two locations. Despite the conservatism that this approach might introduce regarding the estimation of the fatigue life of the SCR due to the fact that the damage is concentrated in quite a few elements, the results from the calculations show a significant decrease in the wave fatigue damage at the TDZ when the risers are installed inside the moonpool.
Floater Concept Selection for Ultradeep Waters in Brazil
Authors: Toro Luis Felipe Batalla , Saraiva Thatiana Carvalho , Meroño Caridad García , Vizcayno Pedro López , Munáiz Manuel Moreu , Costa Ronaldo D'Antonio
Published: April 2015

Uncertainties on design basis during early design stages of offshore fields are a known challenge to deal with when selecting feasible development options. Ultradeep water discoveries have hampered these choices.

The scope of this paper is to describe the methodology applied for the identification of most suitable floater(s) to operate in an ultradeep waters block located in the Campos Basin south-east of Rio de Janeiro in Brazil. The block of study is located in a remote area far from shore within water depths nearly to 3000 m.

FPSO and semisubmersible floaters are identified as the most preferable floaters. The paper will show the combination of most important design players and decision trees for reaching flexible solutions feasible for several production scenarios at an early project stage.

Technical players such as Brazilian environmental conditions, variable risers and topsides loads, variable storage capacities, and floater motion restrictions have been combined with commercial and risk players, such as ultradeep waters technology maturity, local content, market requirements, shipyards capacities and previous experience in the country with solutions adopted in similar fields, locations or depths.

As a result, the study will show a number of floater options integrating one or two hulls feasible to develop on further design stages.
Airborne Ocean Surface Current Measurements for Offshore Applications
Authors: Anderson Steven P. , Zuckerman Seth , Smirren Jan Van , Smith Rob
Published: April 2015

Previous research programs have developed and demonstrated the capability to extract near-shore surface currents from airborne sequences of visual images of surface waves. This same technique can be used for remote sensing of the open ocean to retrieve surface currents over extensive areas in a relatively short period of time. Here, we demonstrate airborne current measurements over deepwater areas of the Gulf of Mexico. The system comprises a pair of digital cameras to image the surface waves, and inertial navigation system and software processing to retrieve the Doppler shift due to the ocean currents. The system measures currents in real-time along the flight path with an accuracy of 5 cm/s on 250 m × 250 m scales. A typical flight can cover 1000 km of linear flight lines in a 4 hour period. The survey data provide a synoptic scale view of Loop Current eddies and detailed measurements along oceanic fronts. This new technology can fulfill a need for rapidly acquiring real-time measurements of currents over a broad region in support of oil spill response; offshore surface current monitoring; and search and rescue operations.
The Challenges For Production Installations Offshore Brazil In A Complex Seafloor: How The Data From Marine Survey & Metocean Campaign Can Be Developed To Provide Better Information
Authors: Escalona L.G. , De Oliveira R. , Martin F.D. , Superchi G. , Batalla L.F. , Torres G.S. , El Mistikawi S.
Published: April 2015

This paper describe a methodology being used to characterize shallow soil strata and geological features in an area of complex stratigraphy with occurrence of shallow faults, boulders, grooves, sea surface currents, sediment transport and sedimentary succesion, slope failure and stability, etc; necessary for planning and prevent adverse locations within a selected area for sub-surface facilities development. The analysis is performed integrating the results of specialized seismic attributes and geotechnical campaign in order to detect and further characterize geomorphic domains, classifying then them in terms of potential hazards for production installations.
Development of a Water and Gas Blocked Medium and Low Voltage Cable Suitable For Deepwater Operation
Authors: Quintero Andrés , Lozano Carlos , Alvarez Wilson
Published: April 2015

This paper presents the results of design, manufacturing, testing and validation of a medium and low voltage cable which has been blocked against the ingress of water and gas potentially occurring at water depths up to 3500 meters. Offshore umbilical and deepwater applications are considered.

The power cable consists of a longitudinally blocked, stranded conductor which is surrounded by an insulating core of semi-conducting and insulating layers thereof. The conductor has an effective blocking system that includes strand seal compound or a combination with water swellable elements. For a given stranded conductor configuration, various blocking components were systematically studied using a specially modified manufacturing process developed to enforce a copper conductor that is able to provide satisfactory performance in the field and during the next manufacturing process stages.

The result was a cable core capable of passing a longitudinal water penetration test at 400 Bar according to the conditions expected on the seabed at 3500 meters. This characteristic, provides a safety power cable for use in harsh, demanding applications, and is designed to allow a repair even during the unlikely event of external damage of the cable jacket that can be caused by fishing, extreme environmental conditions or heavy objects dropped from the surface. In addition, the electrical performance of the cable was verified following industry accepted cable standards, in tests such as partial discharge, step voltage and conductor resistance.

Finally, the development of the new blocking system ensures that a power cable for water depths up to 3500 meters is able to support up to 400 bar of longitudinal pressure. The cable was successfully tested according to an umbilical cable validation protocol.
Experimental Investigation of Extreme Waves - Comparison With Analytical Models and CFD
Authors: Bahuguni Anand , Yanling Wu , Chen Yu , Stewart Graham , Krishhnan Nandakumar , O'Donoghue Tom , van der A Dominic
Published: April 2015

The study of extreme sea states and predictions of associated wave kinematics form the basis for the design and re-assessment of offshore structures. This paper compares analytical and numerical models with scaled wave flume experiments that were carried out at the University of Aberdeen, UK, to measure surface elevation profiles and the velocity beneath extreme crests. Focused wave groups representing the extreme events were generated at a given point in space and time. The input amplitude spectra for the flap-type wave maker were derived using Tromans’ NewWave theory which corresponds to the autocorrelation of the surface spectrum. The sea states in the experiments were chosen to represent extreme waves in the North Sea and Australian waters.

The effects of nonlinear wave-wave interactions, which shift the actual focus point and focus time from the linear position, are analyzed and discussed. The results from second order NewWave theory and higher order stream function waves are compared with the experimental results to evaluate the validity range of these analytical models. CFD simulations are also conducted and the results are compared with the experimental values.
Crosscutting Airborne Remote Sensing Technologies for Oil and Gas and Earth Science Applications
Authors: Aubrey A. D. , Frankenberg C. , Green R. O. , Eastwood M. L. , Thompson D. R. , Thorpe A. K.
Published: April 2015

Airborne imaging spectroscopy has evolved dramatically since the 1980s as a robust remote sensing technique used to generate 2-dimensional maps of surface properties over large spatial areas. Traditional applications for passive airborne imaging spectroscopy include interrogation of surface composition, such as mapping of vegetation diversity and surface geological composition. Two recent applications are particularly relevant to the needs of both the oil and gas as well as government sectors: quantification of surficial hydrocarbon thickness in aquatic environments and mapping atmospheric greenhouse gas components. These techniques provide valuable capabilities for petroleum seepage in addition to detection and quantification of fugitive emissions.

New empirical data that provides insight into the source strength of anthropogenic methane will be reviewed, with particular emphasis on the evolving constraints enabled by new methane remote sensing techniques. Contemporary studies attribute high-strength point sources as significantly contributing to the national methane inventory and underscore the need for high performance remote sensing technologies that provide quantitative leak detection. Imaging sensors that map spatial distributions of methane anomalies provide effective techniques to detect, localize, and quantify fugitive leaks. Airborne remote sensing instruments provide the unique combination of high spatial resolution (< 1 m) and large coverage required to directly attribute methane emissions to individual emission sources. This capability cannot currently be achieved using spaceborne sensors.

In this study, results from recent NASA remote sensing field experiments focused on point-source leak detection, will be highlighted. This includes existing quantitative capabilities for oil and methane using state-of-the-art airborne remote sensing instruments. While these capabilities are of interest to NASA for assessment of environmental impact and global climate change, industry similarly seeks to detect and localize leaks of both oil and methane across operating fields. In some cases, higher sensitivities desired for upstream and downstream applications can only be provided by new airborne remote sensing instruments tailored specifically for a given application. There exists a unique opportunity for alignment of efforts between commercial and government sectors to advance the next generation of instruments to provide more sensitive leak detection capabilities, including those for quantitative source strength determination.
Performance Evaluation of a Large Bore Expandable Liner Hanger for Field Operations in the Gulf of Mexico
Authors: Zhong Allan , Johnson Michael (Rick) , Kohn Gary , Koons Brian , Saleh Muhammad
Published: April 2015

Liner hangers are expected to maintain anchor capability and pressure integrity throughout the life of the well. For deepwater applications where operational expense is considerably higher, liner-hanger performance is essential. Recently, large-bore expandable liner hangers have been scrutinized for sustainability of their bi-directional anchor capability during worst-case discharge scenarios; the importance of this capability also has been reinforced by the Bureau of Safety and Environmental Enforcement (BSEE) requirements. Therefore, since testing of the many possible scenarios is economically prohibitive, it is necessary to use engineering analysis and methods to predict bidirectional anchor capability of large-bore expandable liner hangers (LBELH) under varying conditions. With accurate information, these analytical methods can be used to determine appropriate equipment selection while planning well-construction. The focus of this paper addresses the challenges of evaluating large-bore expandable liner-hanger installations offshore, where daily costs can reach $1.7MM.

Predicting performance is challenging, considering the varied physics existing from well to well and the fact that anchor loads at the liner hanger will vary due to downhole conditions that cannot be simulated accurately in laboratory test wells. Varying temperature, effects of earth horizontal stress, hydrostatic pressure, varying parent casing internal/external diameter and wall thickness all affect the anchor capability of the large-bore expandable liner hanger. Given the many varying parameters, finite element analysis (FEA) is required.

This paper discusses how FEA was used to estimate LBELH performance for several deepwater well completions in the Gulf of Mexico that required setting in 16-in. medium and heavy-wall target casing. It will also discuss how FEA analysis was used to facilitate liner-hanger development and to secure reliable results.

Due to the high cost of nonproductive time during the well construction phase, deepwater operators rely on service providers for reliable solutions that will reduce operational costs. The LBELH was chosen over conventional methods due to high deployment reliability, which can reduce high remediation costs.

The case studies presented in this paper will discuss successful job results for an operator that highlight the value offered by numerical simulations in deepwater GOM installations. One of these case studies will review loads applied during setting and post-cementing testing at an operator's well.
Testing In-Well Dual Canned ESP Completion System to Validate Safe Deployment in Deep Water: A Collaborative Effort to Understand Surface and Downhole Requirements
Authors: Tijerina Kim , Pardo Carlos , Hope Andy
Published: April 2015

Deepwater and ultradeepwater completions employ numerous hydraulic control lines for operating downhole equipment as the primary method of actuation or as back-up systems for control and actuation. Incorporating a completion system with an in-well lift, i.e., electric submersible pumps (ESPs), increases the number of electrical lines that are needed for operation. The total number of control and electrical lines maximizes the number of hydraulic and electrical lines that can be terminated back to the tubing hanger and wellhead. On surface, managing and running the numerous control lines can be daunting. Weight and size limitation and available rig floor, deck, and sub-deck space must be considered when planning placement of reeled lines, back-up systems, and preparation of supporting systems for spooler and reels.

In this paper we discuss the planning and execution of an installation test conducted in close collaboration with an operator. This stack-up test was conducted to determine whether a completion system incorporating a dual canned ESP system with multiple control lines can be efficiently and safely deployed in a deepwater, high-pressure/high-temperature (HPHT) environment.

The completion system uses numerous hydraulic control lines, tubing encapsulated conductor (TEC) lines, and ESP electrical cables to support the various downhole completion equipment systems. The control lines and cables are various sizes and shapes, further complicating their manageability. Testing was successfully performed in a 500-ft test well on a land rigand the equipment and processes used were deemed scalable to a drillship operating in deep water. Results of the test suggest that safely deploying a dual canned ESP system in a deepwater well is possible. Doing so would bring increased revenue from the additional years of production enabled by the dual canned ESPs.
Gulfstar - Structural Design of the Classic Spar Hull for Improved Constructability
Authors: Poll Philip , Park Y.C. , Converse Robin , Godfrey Dan , Gian Michael
Published: April 2015

Historically, Spar hulls have been compartmented using both flats and radial bulkheads. These hulls were fabricated into quarter or half sections and joined into full cylinder sections then into the full hull length while in a horizontal orientation. This approach left considerable fabrication work to be performed after assembly, disadvantageously, due to the horizontal position.

The configuration of the Gulfstar FPS reduces the number of radial bulkheads by locating the flats closer together, thus opening up the option to fabricate full cylindrical sections upright with open tops for ventilation and access during fabrication. Rotating each cylindrical section for final assembly was not required until all possible work, inside and out, on each section had been completed. This fabrication plan leaves only structural and systems tie-ins between sections once blocks are rotated and set in place.

Vertical fabrication of sections starts an overall structural arrangement philosophy to develop a configuration that is not only repetitive and efficient but also "fabrication friendly." The idea for improving constructability permeated other aspects of structural design. The purpose of this paper is to summarize some of the ways in which the Spar structure was arranged to improve fabrication and to evaluate the expected improvement with actual fabrication experience. This paper presents the genesis of the basic framing then culls out and discusses some notable lessons learned.

The information and results presented in this paper are applicable to engineers, designers and fabricators when evaluating structural arrangements and fabrication options for stiffened plate hulls, particularly Spar hulls. Cost and schedule benefits can potentially be achieved by incorporating some of the lessons learned presented in this paper.
Loads and Motions for Utility-Scale Floating Offshore Wind Turbines Supported by Semi-Submersible Platforms
Authors: Sahasakkul Watsamon , Manuel Lance , Nguyen Hieu , Sari Ali
Published: April 2015

This study is focused on the long-term reliability analysis of loads and motions for a utility-scale floating offshore wind turbine supported by a semi-submersible platform situated in the North Sea. The floating wind turbine, which consists of a 5-MW 3-bladed rotor, is assumed to be mounted on the OC4 semi-submersible floating platform. The platform consists of a main column, three offset columns, a cross frame, and pontoons, deployed at a site with a water depth of approximately 200 meters. A mooring system consists of three catenary lines together with the turbine and platform completes the integrated system. Based on the metocean conditions characterizing the selected turbine site, a number of sea states are identified for which coupled-dynamics simulations are carried out using the aeroelastic computer-aided engineering (CAE) tool for horizontal-axis wind turbines, FAST. Short-term turbine load and platform motion statistics are established for individual sea states that are analyzed. The long-term global performance analysis yields estimates of 50-year loads and platform motions that takes into consideration response statistics from the simulations as well as the metocean (wind-wave) data and distributions. This study seeks to assess long-term loads and motions associated with large utility-scale offshore wind turbines that might be deployed on floating platforms for planned offshore wind power development in the U.S.
Lucius Subsea Design and Installation
Authors: Dean Timothy , Haines Paul , Carlstrom Marsha
Published: April 2015

This paper describes the architecture of the Lucius Subsea Production System and the drivers behind it. Novel technologies are detailed including suction pile mounted Pipeline End Manifolds (PLEMs) and chemical injection backpressure regulator valves. Innovative installation techniques and highlights are described, including the use of laser metrology and a "strong back" system for rigid jumpers. Difficulties and lessons learned are also shared.
SCORCH JIP - Findings from Investigations Into Mooring Chain and Wire Rope Corrosion in Warm Waters
Authors: Rosen Jeremy , Jayasinghe Kanishka , Potts Andrew , Melchers Robert , Chaplin Richard
Published: April 2015

For years operators have reported accelerated rates of corrosion in wire rope and chain in warmer waters. Mooring design codes specify corrosion endurance of these components predominantly based on experience from the colder waters of the North Sea. The scope of the SCORCH JIP was to investigate and characterize corrosion of steel chain and wire rope moorings for a wide range of operating Floating Production Units (FPUs) and Floating Production Storage and Offtake vessels (FPSOs) in warm waters. A database was compiled of detailed corrosion measurements of in-service and retired mooring chains and wire ropes from about 30 FPUs operating in warm waters off Asia, Africa and the Americas. A set of standardized procedures were developed for forensic examinations of retrieved chain and wire rope, including photogrammetry and laboratory measurements that allowed 3D reconstruction and statistical analysis of corroded surfaces. The database was complemented by destructive tensile tests of a number of samples in order to correlate the observed degradation with residual breaking load. The SCORCH JIP also investigated the impact of sea temperature, water velocity, depth and oxygenation, steel grade and chain and wire rope construction through over 750 sample and full-scale tests spanning 3.5 years at sites around Australia. Additional laboratory tests were conducted into Microbiologically Influenced Corrosion (MIC) and the combined effect of corrosion and wear of mooring chains. The SCORCH JIP has produced a series of findings with long-lasting implications for the industry, including detailed investigations of factors in corrosion such MIC, chain pitting, chain wear, wire rope blocking compound efficacy, and the effect of environmental and operating conditions. The SCORCH JIP has produced tabulated predictions for corrosion in varying temperatures, at positions in the mooring line and for nutrient levels that could encourage MIC. The predictions are underpinned by a large number of field experiments and results from operating FPUs, and are supplemented by detailed operational guidance and recommendations for maximizing mooring corrosion endurance.
Best Practice Geotechnical Characterization and Pipe-soil Interaction Analysis for HPHT Pipeline Design
Authors: White D. J. , Westgate Z. J. , Ballard J-C. , de Brier C. , Bransby M. F.
Published: April 2015

This paper summarizes best practice cost-effective geotechnical design of high pressure high temperature (HPHT) pipelines, with an emphasis on HPHT lines in deep water, that are susceptible to lateral buckling and axial walking. It presents guidance on (i) tools for optimal geotechnical characterization of shallow seabed conditions along flowline routes and (ii) techniques to assess pipe-soil interaction parameters for input to pipeline structural modeling. Recent research into pipe-soil interaction measurement tools and analysis techniques has resulted in rapid advancements that are being quickly utilized in practice.

Advanced pipe-soil interaction techniques, firmly rooted in soil mechanics theory and linked to the operational sequence of the pipeline through cycles of start-up and shut-down, are presented. They are used to demonstrate benefits that can be realized on typical projects to reduce pipeline walking predictions and the associated mitigation measures such as hold-back anchors. Recommendations cover the appropriate selection of characterization tools and analysis techniques based on project-specific requirements such as seabed geotechnical complexity, pipeline operating conditions, project timing, mitigation strategies for global stability and the desired approach to risk management and use of the observational method.

The results, observations and conclusions presented in this paper represent the culmination of several years of research and development in pipe-soil interaction, as well as our experience on recent projects around the world where these techniques have been employed. The paper offers recommendations to guide both geotechnical studies and pipeline engineering work, and unlock benefits from maintaining close integration of these two disciplines through the design and operation of a pipeline.
Gulfstar - Porches and Pull Tubes - Comparing Two Riser Interface Options
Authors: Giles III George R. , Poll Philip , Converse Robin , Park Y. C. , Mao Charlie
Published: April 2015

Historically, Spar platforms have utilized both riser porches and riser pull tubes for interfacing steel catenary risers (SCRs) to the floating system. The riser porch requires a stress joint at the hang-off end of the SCR to withstand tension and bending loads at the fixed connection. The pull tube requires special hardware (e.g., a double-tapered stress joint) near the keel of the Spar where platform motions are first transferred to the riser system. Each of these options for the riser interface has advantages and disadvantages. The Gulfstar FPS utilized both pull tubes and a riser porch for riser interfaces.

This paper evaluates the experience designing and building the two different types of riser interfaces for the Gulfstar FPS and the experience offshore during installation of the risers. The paper quantifies the structural appurtenances required for each interface in addition to the equipment required for riser installation, which is significantly different for each interface type. The evaluation results in important lessons learned and recommendations for both types of riser interface strategies.

The paper also summarizes the keel interface utilized on the Gulfstar FPS. The Gulfstar FPS incorporates a different approach for the keel interface with the pull tube support compared to other recent Spar projects in the Gulf of Mexico. The results demonstrate the compatibility of the riser keel interface with the platform motions.

The information and results presented in this paper are applicable to engineers, designers and fabricators when evaluating riser interface options for floating systems, particularly Spar platforms.
Mooring of MRE Structures - Comparison of Codes, Including IEC
Authors: Stewart William P. , Achanta Vamsee
Published: April 2015

Objectives/Scope

This paper presents guidance on the design and selection of mooring systems, including anchors, specifically for Marine Renewable Energy (MRE) systems. It is based in part on the work of the ASCE COPRI MRE Committee over the last five years. The document gives guidance to MRE designers and analysts and gives confidence as to mooring systems reliability.

Methods, Procedures, Process

There are a few MRE systems, especially for Wave Energy Converters (WECs) that have evolved, which may be regarded as having a basically similar mooring system. However, selection of design criteria, including environmental conditions return period (and other parameters) as well as safety factors for WEC moorings has not yet evolved into a standard procedure. This paper contrasts the mooring system characteristics that are found for some typical WEC moorings when their design is selected to meet various mooring codes and standards. Codes considered include those published by: ISOAPIABSDNVLloydsIEC (International Electrotechnical Commission)US Navy

Results, Observations, Conclusions

Differences in the mooring codes are contrasted. Differences in the resulting mooring systems characteristics are contrasted resulting from using different codes. Differences in the systems are also contrasted with selection of different return periods and other environmental parameters. The results are also presented in the framework of the MRE Committee's approach to risk and reliability that has been developed by the oil and gas (O&G) industry over the last 40 years.

Novel/Additive Information

This paper presents an insight as to what is in the ASCE COPRI MRE guide for moorings
Lucius Offshore Installation of Flowlines, Risers and Topsides
Authors: Biggerstaff G. , Keith E. , Taylor B. , Taylor M. , Malarchick A.
Published: April 2015

This paper provides an overview of the design, fabrication and installation of Anadarko's Lucius Development flowlines, risers and topsides including all ancillary lifts required to fully complete the installation of the Lucius Spar.

The production flowlines, risers and associated structures were fabricated and installed by Heerema Marine Contractors US, Inc. utilizing the new build vessel DCV Aegir. At the time of contract execution the vessel was still under development and new vessel procedures as well as project installation procedures were required to perform the installation safely and within schedule. The export risers and flowlines were designed and fabricated by Technip USA, Inc. and installed using the Deep Blue reel installation vessel. The export risers were pulled in utilizing a custom built 1,000-ton capacity chain jack system designed, fabricated and installed by Versabar, Inc., The topsides installation was performed by Heerema Marine Contractors US Inc. utilizing the heavy lift vessel DCV Thialf for the 10,000-ton topsides lift and the heavy lift vessel DCV Balder for the ancillary lifts.

Some of the unique challenges addressed in this paper include some "firsts" which include the design and qualification of titanium stress joints on the export risers, the design and qualification of a diverless close in spool system as well as the design and qualification of a diverless pull head required to hang off the export risers. This paper also addresses the design and offshore installation of a 1,000-ton chain jack system which was designed late in the project life to install the export risers after the main topsides was installed. Additional firsts included the use of pile based riser base pipeline end manifolds which were designed to allow for a tight subsea architecture and sustain extensive bottom tension loads.