bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plug and Abandonment Using Reverse Cement Placement Technique in Deepwater Gulf of Mexico
Authors: Gubanov E. , Nana D. , Bogaerts M. , Moretti F. , Flamant N.C. , Kanahuati A. 
Published: June 2014

Abstract
Four deepwater wells in the Gulf of Mexico were identified for permanent abandonment in accordance with local regulations. The abandonment plan called for multiple cement plugs to isolate the production zones from seabed in each well. The most challenging cement plugs in each well were the ones directly above the production packer isolating the casing-tubing annulus and the production tubing. To avoid cement left in the Christmas tree at seabed and potential plugging off any valves in the manifold, cement plugs could not be placed the direct way, pumping down the production tubing.
An unconventional approach was proposed to address the challenge. It involved reverse placement of cement plugs, which is not common in deepwater even in these days. Using this technique, cement was pumped down the casing-production tubing annulus and, through perforations, back up the production tubing. Risk analysis indicated very low likelihood of plugging off any valves in the tree. However, this configuration did not allow use of mechanical separators between fluids to prevent intermixing. Additional challenges in placing the plug were the high deviation of the section and the completion brine in the wellbore.
Simulation of reverse placement is not possible with existing software. Therefore, the jobs were designed using experimental software, which enabled the design engineer to accurately reconstruct field conditions. Additional attention was given to the job procedure to minimize contamination with the brine and optimize cement placement. Viscous spacer was pumped ahead and behind the slurry to displace the brine. The slurry was designed with low fluid loss to be squeezed through perforations in the production tubing without plugging them off.
A total of seven plugs were placed using the reverse placement technique. Specific requirements with regards to the top of cement and plug integrity had to be met before any of the cement plugs could be accepted by the operator. All plugs were tagged and pressure tested successfully in the annulus as well as inside the production tubing on the first attempt. As a result of the campaign, the four wells were abandoned as per schedule and within budget.
Operation of Subsea Electrical Power Systems
Authors: Askeland Audun Magne , Sølvik Nils Arne 
Published: June 2014

Abstract
Reliable, dependable and cost effective subsea electrical power supply systems have been one of the most important factors in the successful development of the subsea boosting and processing applications and technologies over the last 15 years. This paper will provide an overview of how the system and component parameters and ratings have developed over this period. In the early days of subsea hydrocarbon production, there was a lot of skepticism using high voltage equipment under water - today we know that when the design and qualification is done thoroughly, high availability is achieved on subsea electrical power systems. Further, a focus on what have been the decisive factors for system design, correlation to the end-load and consequently component selection will be offered. An overview of key component qualification methodologies and programs will be described, and finally an overview of operational experience of the existing subsea power systems will be given. The end loads have increased in power rating from some hundred kilowatts to multi-megawatts. This have obviously had a significant impact on the design and utilization of the power components, such as subsea wet mateable connectors, subsea transformers, frequency converters, electrical motors, etc. In parallel to the increase in power rating, and consequently voltage and current, the water depths and environments for installation have changed in this time period and have led to increased requirements to pressure withstanding capabilities, cooling and physical robustness.
Gryphon Alpha FPSO - Experience Gained During Moorings Replacement and Hook-Up
Authors: Toal Fred J. , Martin John G. , Brown Martin G. , Lindsay Ian M. , Sinclair Robert 
Published: June 2014

Abstract
In a North Sea storm during February 2011 the Gryphon Alpha FPSO broke four of her 10 mooring lines and moved partially off station, causing damage to subsea assets. Heading control was re-established using the FPSO's thrusters and in due course the moorings which had parted were re-connected back to the Tentech turret. Following the incident, the FPSO was taken to dry dock for life extension work and to allow replacement of the damaged subsea infrastructure and moorings. The original mooring system was recovered for forensic inspection.
This paper describes the measures which were put in place so that the Gryphon mooring system could be replaced and the FPSO re-connected in accordance with a schedule which would not delay the installation of the subsea infrastructure or first oil. The intention is that this paper should be a useful reference for others engaged in similar work. It was decided to replace the original moorings, apart from the recovered Stevpris anchors that were refurbished. Since the size of the chain into the gypsy wheel fairleads at the turret was fixed, the mooring designers had to optimise their design to meet latest code requirements. This resulted in a 100 m long tri-parallel chain configuration to reduce FPSO mooring loads and excursions, but which also caused some handling issues. High specification Anchor Handling Vessels (AHVs) were needed for the prelay operation, which had after deck chain handling gantries to manipulate safely the heavy chain, delta plates and associated shackles.
A challenging design and procurement exercise was needed to make sure that all the mooring components were delivered on time. The initial mooring sections were pre-laid in February/March of 2012, including anchor proof tensioning, so as to suit the subsea schedule. The mooring lengths had to be adjusted offshore by chain cutting, depending on the final resting place of the chain ends after tensioning. This was to ensure each tri-chain end was correctly located so that the system stiffness would be uniform and the moorings properly balanced. The pre-deployed mooring lines were each buoyed off subsea for later ROV recovery.
The FPSO moorings hook-up took place in September 2012 using the AHVs previously used for the pre-lay. Due to the presence of three Mid Water Arches (MWAs) within the FPSO swing circle, four AHVs were used to hold Gryphon in position during the reconnection operation. The AHVs were positioned two forward and two aft about the FPSO. Adjustment of AHV tow lines enabled the FPSO to be held within just 5 m of the Field Turret Centre (FTC) during the entire reconnection operation. The FPSO also had access to a 3D computation and visualization package which provided real time in-situ position monitoring. This ensured that no mooring chain to subsea assets contact occurred despite the unusually tight installation tolerances.
Deep-Water Shipwreck Site Distribution: The Equation of Site Formation
Authors: Church Robert 
Published: June 2014

In 2007, marine archaeologists with C & C Technologies published a debris distribution model from data collected during a Deep Shipwreck Project with the former U.S. Minerals Management Service and NOAA's Office of Ocean exploration and Research. The researchers have continued to refine the formula with additional shipwreck information. Studying the Gulfoil site at a depth of 534 meters Below sea Level (BSL), as part of the Reefs, Rigs and Wrecks Program illustrated that a large portion of associated wreck debris fell outside the predictive distribution model and more information was needed to account for all the debris associated with catastrophic sinking events.
Using additional standard equations in combination with the distribution model provided a greater understanding of the initial site formation. The information learned was then applied to other deep-water sites such as the passenger freighter Robert E. Lee and German U-boat, U-166 (both 1,400 meters BSL) to help draw a clearer picture of the site formation process for other deep-water sites.
Deep-water shipwrecks and associated debris often sit on the bottom with relatively little disturbance except for the natural bio-chemical deterioration. The distribution of shipwreck material can often be calculated mathematically as a function of heading, speed, time, and water depth. The Equation of Site Formation is a method to better understand deep-water site formation and the wrecking events themselves.
Dynamic Plastic Deformation of Deepwater Steel Catenary Risers under Extreme Cyclic Compressive Loading
Authors: Hu Guanyu , Campbell Mike , Huang Chaojun 
Published: June 2014

Abstract
Steel catenary risers (SCR) on a large heave motion vessel are susceptible to compression in the riser touch down zone (TDZ). Dynamic compression can lead to over stress under extreme or abnormal weather conditions. The response of an SCR under compression is highly nonlinear and sensitive to various factors. However, the current available industry design codes and practices do not provide a clear guidance to address the acceptability of compression, over stress and the resulting plastic strains. In addition, the current analysis method used in industry common practice cannot accurately capture the nonlinear behavior of SCR involving accumulated plastic deformation, hysteresis effects and local buckling.
In this paper, a finite element analysis (FEA) modeling method using combined beam and solid elements is presented that enables simulation of large plastic deformation, pipe ovality and local pipe buckling in the TDZ of a deepwater SCR. The model is developed using ABAQUS. The SCR nonlinear response is examined through dynamic analysis of a deepwater SCR hung-off a semi-submersible. The key analysis results are compared with a nonlinear beam element model. Moreover, dynamic ratcheting analysis under multiple plastic strain cycles using the proposed solid riser model is conducted to understand the plastic strain accumulation and to check the acceptability of survival response of deepwater SCR under a series of severe Hurricanes in its service life.
This paper presents the methodology of evaluating the compression and plastic deformation that could be experienced by deepwater SCRs, including modeling approach, analysis results, possible failure modes, and conclusions. The impact of the study findings on the robustness and suitability of SCRs for deepwater application are discussed.
Development of an LNG Tandem Offloading System Using Floating Cryogenic Hoses - Breaking the Boundaries of LNG Transfer in Open Seas
Authors: Mauriès Benjamin , Lirola François 
Published: June 2014

This paper presents the extensive work performed to propose to the LNG industry an offloading solution fully compliant with EN1474 standard requirements using floating hoses. Between 2009 and 2013, a tandem offloading system using floating cryogenic flexible hoses developed and qualified to be able to transfer LNG in open seas. This arrangement was selected in order to combine the safety and the availability brought by the tandem configuration with the wide operational envelope provided by the use of floating hoses.
This system is composed of an innovative and compact hose storage system on the LNG Terminal allowing to store the hoses between two offloading operations, of a connection head (hose end termination piece) to ease the deployment/retrieval of the hoses and of a storage and maintenance platform for the connection head at the aft of the LNG Terminal, also allowing to replace a hose section in offshore conditions. On the LNG Carrier side, a bow loading platform is installed to ensure hoses connection even in exposed environmental conditions. The 20" ID cryogenic floating hoses to be used with this system has been developed and qualified in parallel with the development of the tandem system.
A red line for this development was to keep a similar level of safety, integrity and performance to onshore offloading operations. To fulfill this requirement, simple, robust and proven technologies have been considered for the main items of the system. The system incorporates a comprehensive panel of safety layers through monitoring, hardware, procedures and control philosophy providing protection for people and material during all steps of the offloading sequence. Regarding the performance, the system can transfer LNG at a flowrate of 10, 000 to 12, 000 m3/h using three hoses, which gives redundancy to transfer LNG even with one hose unavailable. To offer a high availability, dedicated solutions have been implemented in the system to withstand sea states with Hs up to 3.5 m for hoses connection and 4 m for cargo transfer and hoses disconnection.
This solution will help unlocking offshore stranded gas resources in many areas around the world through FLNG development.
Analytical Development of Seastate Limits Associated to the Abandonment Operations of a Structurally Compromised Subsea Well
Authors: Turner T. N. , Murdoch N. 
Published: June 2014

Abstract
When drilling a subsea well, a loss of structural integrity of the conductor can lead to a substantial reduction in the well's ability to resist the axial and lateral loads imposed by the drilling riser and BOP. This can then lead to hazardous conditions and increased risks to the asset performing the drilling as well as the personnel onboard. This may leave the operator with no choice but to abandon the well. In this situation, the hazards associated with the loss of integrity must also be considered when planning the abandonment operation itself. This paper presents a case study that details the analysis methods used to develop seastate limits for the abandonment of a subsea well with compromised structural integrity.
The well's high pressure and low pressure housings were observed by ROV inspection to have become un-latched during drilling. The inspection also revealed substantial conductor subsidence which suggested a failure of the 30" conductor and 20" surface casing cement jobs. Initial investigations indicated the well lacked the required levels of structural integrity to resist the loads involved with drilling to total depth. As a result, the decision was taken by the operator to suspend and then permanently abandon the well.
This paper discusses the technical approach used to develop the seastate limits imposed during the abandonment operation. The methodology utilized advanced non-linear finite element analysis techniques in conjunction with a novel statistical treatment of previously recorded in-situ BOP motion data.
Qualification Of A Cryogenic Floating Flexible Hose Enabling Safe And Reliable Offshore LNG Transfer For Tandem FLNG Offloading Systems
Authors: LAGARRIGUE Vincent , Hermary James , MAURIES Benjamin 
Published: June 2014

Abstract
Moving LNG production to an offshore setting certainly presents a serious set of challenges for the offshore oil and gas industry, particularly when it comes to the design and construction of FLNG facilities which need to maintain the utmost levels of safety and give increased flexibility to LNG production while withstanding the effects of winds, waves and currents in the open seas. With the first FLNG plants now in production and twenty other planned FLNG projects worldwide, it is safe to say that over the past few years these challenges have been overcome and these facilities have well and truly demonstrated their economic and technical viability to the industry. But while some challenges have certainly been met, others remain.
The environmental conditions of the current FLNG locations are at present quite mild and only require the use of the most straightforward technology for the unloading of the LNG, e.g. marine loading arms. But, with prospective new FLNG locations moving away from these ‘mild’ areas, to sites where sea states, wind and currents can be much more severe, only tandem LNG offloading systems appear to meet the challenges of the application as they improve safety, operability and availability.
Since 2009, Trelleborg has been developing floating cryogenic hoses which ensure LNG offshore transfer with minimum BOG generation, combine high flexibility, reliability and long service life, and also meet LNG operator and contractor's offloading requirements related to safety, flowrate capacity and operation availability. Through latest acquisition, this technology has been even further enhanced, with new parameters being put forward for the development of these hoses in order to become a key component in offloading systems for future offshore FLNG projects.
This white paper will discuss Trelleborg's 20" ID cryogenic hose development and qualification program and outline why tandem offloading solutions are a viable alternative for the industry – not only limiting downtime, but also improving safety. The paper will present in this case the innovative offshore LNG offloading system using cryogenic floating hoses which has been jointly developed with Saipem since 2009 and about to be qualified according to EN1474 standard requirements.
Using Technology Classification and Qualification Status as a Tool for Strategic Technology Screening and Selection
Authors: Huyse Luc 
Published: June 2014

Abstract
Technology Qualification (TQP) is the process of providing the evidence that a technology will function within specific operational limits with a specified level of confidence. A complete Technology Qualification is often initiated only once a Major Capital Project (MCP) has made a commitment to using the technology. At that stage of development, the TQ tools are used to manage the progression of the technology through the technology development stages (or technology readiness levels) and track the progress against the technology risk register and project schedule.
The focus of this paper is how the TQ tools set can be adapted and applied much earlier during the technology planning stage to determine possible opportunities for deployment. Early high-level risk assessment of new technology or new technology use can be very beneficial to non-technical communication of the technology risk to project decision executives. Using modified TQ tools to map out a clear technology road map for a MCP with both critical path as well as some of the possible fallback options provides a concise summary of the technology risks and landscape to the decision maker. Consistent application of these formats enables better business decision making.
Although the focus of the paper is on the conceptual and process level, some limited examples demonstrating the value of the approach will be provided.
Mars B- Olympus TLP Tow-Out Marks First Use of Synthetic Rigging; Finds Operational and HSSE Benefits
Authors: Shell Paul Dixon , Martinez Diego , Samson Justin Gilmore , Poroo Mike 
Published: June 2014

This paper will demonstrate the benefits realized from a towing and positioning system made of synthetic ropes, rather than traditional steel wire rope, to deliver the MarsB-Olympus TLP for the critical inland tow, open water tow and positioning spread during the TLP Installation campaign. This is the first time Shell has used synthetic ropes for an installation of this magnitude.
Documented throughout the paper is the methodology used to evaluate the operational efficiencies of synthetic lines, Concept Proof Testing, the unique challenges of the inland tow, and the risk management plan required to make the offshore tow and positioning during hurricane season. Additionally, early engineering and design determined that using synthetic ropes would allow standardization of the towing lugs and the ability to replace unique and complex one-off components required for steel wire rope with a much simpler, proven design. In all three phases of the installation, the lines were rigged quickly and efficiently by a minimum of crew and without additional handling equipment. Most importantly, none of the synthetic ropes failed during the transportation and positioning phases.
Olympus TLP Operations Team – Enabling a community of excellence
Authors: Trussell Jay , Chevis Marc 
Published: June 2014

How do you measure the success of a major deep water project? It is measured across the full range of its development phases—define, design, execute, and operate. Each of these phases requires effective integration of technical professionals ranging from geoscientists to surveillance engineers. Equally important is the integration of operations staff as early as the define phase. Building an operating organization which is effective in the early phases and grows to excel in the operate phase presents unique challenges. This paper focuses on building and enabling an operations organization during the execution and operation phases of the Mars B Development project. It will highlight a range of key enablers identified by the Olympus TLP operations team to create a community of excellence. These enablers ranged from organizational development to technology.
Organizational development is standard practice required for the creation of a new organization. The team put special emphasis on defining the right culture needed to be top quartile. That culture centers on caring, accountability, efficiency, and sustainability. Success in this area requires identifying and practicing individual behaviors supportive of the culture, and developing leadership attributes which enable the culture to grow.
Training and competency development are critical given the wide range of experience levels of the operating staff. The team identified unique competency requirements for the Olympus TLP which were beyond the core business unit requirements. Training was developed and delivered by senior operating personnel. Detailed computer-based training modules are used for more extensive training requirements, including the onboarding of new employees.
An integrated operations center in New Orleans merges asset support and operations personnel in a space designed around common work processes in support of the Olympus TLP. These groups are connected collectively: the TLP, subject matter experts, vendors and external support centers through collaborative work environment technology ranging from high-end video conferencing to real-time data sharing. The hub of this center is a remote control room which is an extension of the central control room on the TLP.