bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Lateral Soil Strength and Stiffness on Jacket Foundation Integrity and Design for South China Sea Sites
Authors: Nichols Nigel Wayne , M.J. Rohani , Mukherjee Kaushik , B Ayob M Sapihie , Clausen Carl J.F. , Lunne Tom 
Published: February 2015

Petronas Carigali Sdn Bhd (PCSB) manages about 150 existing platforms at various sites across South China Sea. Integrity reassessment on these existing structures using non-linear pushover analyses has frequently indicated lateral foundation failure at collapse. However to date there has been no physical observations of foundation failures.
Foundation design and integrity assessment takes into consideration lateral soil properties to determine the adequacy of structure-foundation combined system. Observation on Gulf of Mexico foundation performance during hurricane events provided PCSB with the insight and motivation to recalibrate both static and cyclic lateral p-y characteristics of soil currently seen to be conservative.
PCSB together with Norwegian Geotechnical Institute (NGI) undertook a study incorporating literature reviews, review of field lateral load data and numerical modeling to recalibrate API RP2A static and cyclic p-y data and derive new modified p-y relationships to suit Malaysian conditions. Further three(3) platforms were reanalyzed using current API RP2A p-y equations and newly modified p-y equations to study the impact of the recalibration made.
Result indicates that the modified static p-y resistances provide positive global improvement to pushover analyses. This improvement provides a better justification for the life extension of the existing structures as required in an enhanced loading scenario. Minor to negative improvements are seen when the modified cyclic p-y resistances were used for the purpose of in-place analyses. This paper will focus on the methodology adopted, assumptions and philosophy that form the basis of the recalibration and development of the modified p-y method. Discussion on results of in-place and pushover analyses will be made to provide recommendations on the further use of modified static and cyclic p-y calculation method.
Volumetric Hardening in Axial Pipe Soil Interaction
Authors: Smith V.B. , White D.J. 
Published: February 2015

The Norwegian Geotechnical Institute (NGI) and The University of Western Australia (UWA) has been working on understanding pipe soil interaction for a long time. NGI has performed a series of large-scale model tests investigating the axial pipe soil interaction in soft clays. Variables investigated are the weight of the pipe, velocity of movement, roughness and diameter.
One aspect of axial pipe soil interaction that needs further investigation is the increased axial resistance that is observed with cycling. This is attributed to volumetric hardening. However, there are also observations that this effect is erased by cycles at a higher velocity. In order to use the effect of volumetric hardening in design of pipelines, further investigation of the phenomenon is needed.
The paper will describe the test equipment used in the NGI laboratory. It will investigate the increased axial friction with axial cycling of the pipe for a variation of the pipe weight at an undrained velocity. It will attempt to show, through measurements of water content of the clay around the pipe, that the clay is contracting during undrained cycling. The paper will also look into the mechanisms contributing to erasing this effect and the influence of pipe weight and velocity.
Deep water fields are often developed using pipelines, both infield and for transportation. Through its life, pipelines go through a series of cycles of production and closedown that changes the pressure and temperature and thus changes the length of the pipe. The axial resistance of the soil on the pipe is one of the parameters governing the buckling and walking behavior resulting from the repeated lengthening and contraction of the pipe.
Riser VIV Suppression Device Test
Authors: Ng D.J.T. , Teng Y.J. , Magee A.R. , Ahmad Zukni N.B. , Aramanadka S. Bhat , Abdul Malik A.M. , Abd Kader A.S. , Haji Ismail N. , Abdul Ghani M.P. 
Published: February 2015

Vortex induced vibration (VIV) occurs when a body is exposed to a fluid flow that causes an unsteady flow pattern due to vortex shedding at or near the structure's natural frequency leading to resonant vibrations. This phenomenon frequently happens in slender elements such as risers used in deepwater oil and gas developments. Such vibrations may reduce the fatigue life of the riser, potentially causing catastrophic damage to the integrity of the system and the environment. Installation of VIV suppression devices onto risers will affect the vortex shedding patterns and is thus able to mitigate VIV. A model test was carried out to study the effectiveness of a newly developed U-shaped fairing in reducing drag and VIV of risers.
The U-shaped fairing is an alternative to conventional spiral strakes and tear-drop-shaped fairings for riser VIV suppression. The model test findings offer useful information for its industrial application in suppressing riser VIV.
The model test was performed in a towing tank facility in Malaysia located at Universiti Teknologi Malaysia (UTM). Current flow was simulated by towing a vertically submerged scaled-down riser section underwater with a moving carriage. The riser model was attached to a custom-designed test rig to replicate a section of the actual riser and to simulate its 2D motions. The model riser was tested in three different conditions, i.e. (a) bare riser without fairing; (b) riser with weathervaning fairing (normal condition) and (c) riser with fairing stuck at different orientations (abnormal condition). The test results show significant reduction of VIV on the model riser with fairing under normal condition. In addition, it is found that the drag load for the riser with fairing is significantly lower compared to that of a bare riser or a typical straked riser.
This test marks a significant collaboration between a local research institute and the offshore oil and gas industry, aligned with the initiative of increasing local capabilities. Effective mitigation of VIV of risers using suppression devices could lead to improved riser fatigue life and overall a more economical platform design.
Investigating the Dynamic 3D Loading Effects on Perforating Guns Imposed by Shaped Charges-Downhole Evaluation
Authors: Glenn Timothy S. , Serra Marco , Rodgers John P. , Wight Jim , Zhang Wei , Craddock G.G. , Harive Kevin 
Published: February 2015

Modern development of shaped charges has resulted in greater and greater explosive loads on the perforating guns and has stretched the capacity of perforating guns into uncharted territory. Traditional gun design approaches and standards use collapse pressure calculation and swell measurement with overloaded charges as design verification methods. The extremely complicated interactions between explosives, fragmented casings, and the gun wall are evaluated on an empirical basis, and the nature of these interactions is not well understood. In this paper, we present a new design model that augments traditional design approaches and provides gun designers with better data on gun system structural performance including the effects of phasing, shot density, and charge type.
The loads imposed on the gun body by the explosives are multi-dimensional due to the spiral arrangement of most shaped charges. The resulting dynamic response of the gun body is therefore quite complex and requires three-dimensional analysis. High-frequency bending, torsion, and tensile loads are expected. The casings are typically fragmented, and some of the larger fragments can impose large impact loads on the gun wall. A fully-coupled computer model has been developed that incorporates the rapid explosion, casing fragmentation, and multi-dimensional structural responses.
Multiple instrumented surface tests were carried out to validate the dynamic three-dimensional model. Proprietary testing techniques were used to extract gun internal pressure history and gun stress history at multiple locations immediately following detonation. Redundant strain gages were used and shots were repeated to ensure the integrity of the data.
This paper first presents the newly developed three-dimensional simulation model in full details. The second section describes the instrumented gun test set up and results. The final section of this paper presents validation of the model through comparison with test data.
Well and Reservoir Surveillance in Mature Gas Field Peciko and Its Application in Well and Reservoir Management
Authors: Nathanael Christian , Masitah Siti 
Published: February 2015

Peciko is a giant gas field operated by Total E&P Indonésie which has been in production since late 1999. The field is situated in Mahakam PSC about 25 km offshore. After more than six years of production, the field entered its decline phase after reaching peak production at 1.3 Bscfd in 2005. With the total number of wells exceeding 130, sustaining the field production has become very challenging in this maturation phase. Problems like liquid loading, scale, tubing breach and sand production require immediate remedial action to prevent wells from suffering any further. Gas water contact movements must also be monitored prior to define targets for infill drilling.
Data acquisition is of key importance to spot on problems which may impair the producing wells, and to understand the well and field behavior for any next development phase. From 2010 to 2012, around 120 Production Logging Test (PLT) were done as well as over 20 jobs of caliper log. PLT is widely used to evaluate reservoir performance and to identify source of water, while caliper log is commonly used for quantifying wellbore access restriction or enlargement.
Many wells with high water production are associated with wellbore restriction due to scale build-up. Production logging combined with caliper log has also helped tubing breach identification in a zone completed with sleeve only. Further, more than 70 jobs of pulse neutron logging were run to monitor the movement of gas water contacts. Sand production is also an issue in Peciko field, and to these end 10 jobs of sand detection logging were acquired. Results are conclusive for a couple of wells, whilst ambiguous for the other, and for these wells the challenge for a solution to remedy sand production remains.
This paper explains how reservoir management team of the Peciko field has extensively used surveillance technologies in fighting the decline by solving liquid unloading problem, maintaining wellbore integrity, and horizontal well placement for hydrocarbon recovery optimization.
Stinger Stiffness and Its Effect on Deepwater Lay Analyses
Authors: Suwarno Gunawan , Lim Gerry , Hua Lee Choon 
Published: February 2015

The most economic way to install a subsea pipeline in deepwater is using Slay method because of the lay speed, due to number of workstations. But on Slay method, the lay vessel requires a massive structure which we called "Stinger" to guide the pipe down to seabed. A Stinger is an extension structure at the stern of the vessel which used to support pipeline on its way to seabed. This stinger is also used to control the strain level by controlling the stinger radius. The length and the radius of the stinger will govern the pipe departure angles which in the end, it will govern the length of pipe span on catenary as well as the tension require for pipe laying.
Typically modern stinger consists of one, two or three space frame and hold by stinger holding frame and stinger hitch. On each of the space frame, the pipeline will be supported on few number of roller supports. These supports are called "Roller Box". The Stinger radius are adjusted by setting the "Roller Box" at certain heights and also set the angles between Stinger Sections.
Typically during Pipelay analyses, Stinger was assumed to be fixed, at certain extent, this rigid assumption is valid. Many Pipelay operations have been analyzed based on this assumption. The pipeline is becoming deeper and deeper and the deeper pipeline required longer stinger and typically the un-supported part of the stinger also become longer which make the stinger does not stiff enough or it will deflect much more compare to shorter stinger.
This study is about using Pipelay Analyses Software and Structural Analyses Program to calculate the displacement of the Stinger based on Reaction Load on the Roller Box taken from Pipelay Analyses. And the interaction between the two softwares was used to predict appropriate stiffness of the stinger. In the end of the study, comparison using Rigid Assumptions and Non Rigid Assumption on Pipelay Analyses was drawn to understand the effect of the stain level, tension required and the gap on stinger last roller.
Early Stage Geohazard Assessments in Tectonically Active Areas: Application to Potential Developments in South-East Asia
Authors: Clare M. , Smith C.A. , Dan-Unterseh G. , Spinewine B. 
Published: February 2015

A methodology is outlined for performing desktop studies in geohazard-prone areas to estimate feasibility for subsea cables and pipelines. Various global cases studies are referenced with relevance to development areas in South-East Asia. This involves a review of available geological, geophysical and geotechnical data, to provide guidance for routing, planning of surveys, and geohazard mitigation. Seismic hazard is not discussed in detail as it is comprehensively dealt with elsewhere.
Enhanced subsea construction activity results from increased demand for energy supply and communication networks. The need for transportation of these products often necessitates the crossing of tectonically active areas that may be prone to geohazards which may result in pipeline rupture or cable breakage. Implications of tectonic activity may be direct (e.g. earthquakes), as well as shaping the terrain through imposition of structural controls, and providing potential trigger mechanisms for slope instability and density flows.
Seafloor morphology is characterized on a regional-scale to understand structural controls, and local-scale to identify characters indicative of seafloor rupture, past slope instability, or future flow conduits. Interpretation of geophysical data provides information to feed an evolutionary geological model. This rationalizes periods of tectonic activity with geohazard scenarios, e.g. regional-scale catastrophic slope failures during intense rifting, compared with smaller, discrete landslides during periods of relative quiescence. Integration with available geotechnical data provides information to understand sedimentary processes and inform forward-looking analyses, such as debris-flow modeling. Thus, an estimation can made of magnitude and duration of forces impacting on structures. Examples are provided of how slope failures and sediment density flows may vary on slopes that have been modified by different tectonic processes. Conduits laterally offset by faults, or uplifted by toe-thrusts may limit the downslope run-out of flows; however, linear, fault controlled canyons may permit longer travel distances.
A phased and integrated framework is outlined for early stage geohazard assessment in tectonically active areas to inform feasibility and concept routing studies. The intention of this approach is to ensure early stage decisions can be made with respect to route selection and to maximize the efficiency and effectiveness of future data acquisition.
Regulatory and Safety Challenges of FLNG
Authors: Fagan Conn 
Published: February 2015

Liquefaction of natural gas is moving offshore as an economic means of developing natural gas fields. This trend is currently in the start phase with a number of projects currently under construction and many more at concept and engineering phases. In addition FLNG projects are being proposed for location in an increasingly larger number of geographical locations, coming under a number of different regulatory jurisdictions.
There is currently little engineering experience associated with such applications and in addition standards and regulation specific to this new technology may lag behind the industry developments. Different jurisdictions may also have varying approaches when it comes to means of ensuring safety on their own continental shelf.
This paper will address the approach adopted by DNV in specifying requirements for design and construction of offshore LNG production units and our view on how this approach relates to the bigger picture of regulatory compliance.
In addition some key technological areas which DNV see as a safety challenge with regard to such units will be discussed.
The paper will therefore bring together experience gained from a number of projects and present some generic lessons related to the issues of safety and regulatory compliance which may be of use in future FLNG designs.
Effective Slug Handling and Sand Separation Using Innovative Separator System
Authors: Zainal Abidin S.A. , Harun Z. , Jothy A. 
Published: February 2015

In many oil and gas developments with multiphase flow lines, production instability due to slugging is a major flow assurance concern. Slugging initiates oscillations, puts excessive demands upon the separation and operation, and increases the wear and tear of equipment. Large liquid surges can cause poor performance, separator shut down, high pressure trips, or flaring. An integrated separation system has been developed to provide high separation efficiency through effective handling of sand and slug, energy efficient inlet heating, stable 3-phase separation (gas, oil and water) with efficient liquid droplet removal and with minimal pressure drop.
The compact integrated system is applicable for all facilities performing three phase separation both onshore and offshore, facilities with space limitations, waxy fluid services, facilities with slugging issues, facilities with sand issues and motion sensitive issues such as FPSO.
Several units were successfully installed in various countries such as TGT FPSO for HLJOC, Vietnam, D1 FPSO ONGC, India and PETRONAS Carigali facility in Anjung Kecil & Kayu Manis, Malaysia. The installations have demonstrated CAPEX, weight and footprint savings of up to 50 percent compared to conventional separator system.
Middle East to India Deepwater Pipeline (MEIDP) Crossing of the Owen Fracture Zone
Authors: Nash Ian , Burnett Christopher , Parry Simon 
Published: February 2015

The Middle East to India Pipeline (MEIDP) will provide an economic and secure source of gas for India, where the demand for energy will continue to increase over the coming decades. The proposed pipeline will be the deepest major infrastructure pipeline laid with water depths exceeding 3000m for significant sections of the 1200km route.
This paper will give details of the 2013 geophysical reconnaissance survey along the pipeline route. Five areas were highlighted during desktop studies as significant for potential geohazards, namely the Indian and Omani continental slopes, the Indus Fan, the Owen Fracture zone and the Qalhat Seamount. The findings in these areas will be presented with particular focus on the Owen Fracture zone crossing, where the continental plate boundary between the Arabian and Indian tectonic plates meet forming a right lateral strike slip fault movement zone. The movement on the plate boundary will be investigated and examples of survey data will demonstrate the challenges that need to be overcome in crossing this major geohazard feature. The results of the survey will be discussed together with details of the geohazard design process required to identify a feasible route and necessary intervention works at this feature to bring this project closer to reality.
Lessons Learned from Pig Rescue Operations During Precommissioning of a 290 km Offshore Pipeline in Persian Gulf
Authors: Tabatabaei A. , Tabassomi H. , Mahmoudi M. 
Published: February 2015

Pigs are devices utilized when carrying out various pipeline operations during its lifetime. The most serious threat for each pigging operation is stoppage in the pig movement. "Pig Rescue" operations refer to the activities for making the pig continue its path and move along the pipeline. Normally when the pig gets stuck, the first task is to estimate the location of pig in the pipeline. Situation is even more disastrous for the case of offshore pipelines since locating the position of the pig would be a hard and costly task.
Most reputable pipeline service contractors and operators have gradually built their own knowledge base when dealing with different scenarios of pig rescue operations. However, choosing a cost-effective engineering solution in a reasonable time period is always a major challenge.
This article describes the lessons learned from pig rescue activities done during precommissioning operations of a 290 km offshore pipeline from Siri Island to Asaluyeh Port in the Persian Gulf. The 32-inch natural gas pipeline is considered the longest offshore pipeline in the region. As a series of valuable experiences achieved from the project, this paper presents different procedures for moving the stuck pig based on the pipeline conditions and the type of pig itself. Some of the procedures include pressurizing the pipeline with gas or liquid, performing sudden fluid discharge, inserting other pigs inside the pipelines, etc. Furthermore, necessary engineering and safety considerations when following up the pig rescue procedures are discussed that would be absolutely useful for practitioners in the oil and gas industry.
Unconventional Approaches for the Unconventional Resources in Central China
Authors: D'Amore A. , Hii K.K. , Moh T. , Chen Z.Y. , Phan V.C. , Lim J.M. , Tellez F. , Kok J. , Poor A. , Huang B. 
Published: February 2015

Operator started evaluating the shale gas block in Central China since Dec 2010. During exploration and appraisal phases, 3 horizontal wells were drilled. The challenges were hard, abrasive, kicks, losses, stuck pipe, over pressure, high formation dip, faults, and high stratigraphy uncertainty. As a result, it was unable to achieve performance drilling with conventional motor BHA, difficult to run casing, and multiple geological side-tracks were required. Wells were exceeding the AFE curves. Average well duration was 220 days.
This paper will feature the challenges and lessons learned and the unconventional approaches that were employed. Four key categories of the process were identified:
Emerging technologies were hybrid and more robust rotary steerable system, real time ROP optimization, high resolution real time LWD image data and high telemetry rate MWD. Drilling and best practices adopted were MPD Drilling, hole cleaning, high dog-leg-severity curve with smoother borehole, and low cost rotating BOP with higher RPM. In the absence of 3-D seismic data, 2-D seismic data combined with LWD data were used. Integrated Operations & Innovative Commercial Contract with local drilling service contractors had made a big impact in terms of faster well delivery and overall cost saving. Another step change was the performance based commercial contract which helped to attain the ultimate goal that meets both HSE and time requirements.
During first half of 2013, 5 horizontal wells were completed, 2 were Top Quartile and 3 were Best-In-Class. Some highlights were zero geological side-track; double footage drilled per day and significantly reduced drilling cost. Average well duration was 120 days.
The accomplishment has a big impact on drilling schedule sequence. Longer horizontal wells will be planned with greater confidence as results of predictability and repeatability.
The paper will conclude with learning curves summary and compare them to the peer. The team believes that this is a big step towards delivering Best-In-Class wells in complex geological structure. The next step is to realize the ambition of factory drilling at further reduced cost to un-tap the unconventional in Sichuan and to bring cleaner fuel to Central China as a replacement of coal.