bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
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

Abstract
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

Abstract
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

Abstract
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 (&lt; 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

Abstract
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.